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Xerox University Microfilms 300 N orth Zeeb Road Ann Arbor, Michigan 48100 I i I t 75-14,797 NEARY, Dantel George, 1946EFFECTS OF MUNICIPAL WASTEWATER IRRIGATION ON FOREST SITES IN SOUTHERN MICHIGAN. Michigan State University, Ph.D., 1974 Agriculture, forestry & wildlife Xerox University Microfilms, Ann Arbor, Michigan 48106 EFFECTS OF MUNICIPAL W A S T E W A T E R IRRIGATION ON FOREST SITES IN SOUTHERN MICHIGAN By Daniel George Neary A DISSERTATION Submitted to Michigan State University in partial fulfillment of the requirements for the degree of D OCTOR OF PHILOSOPHY Department of Forestry 1974 ABSTRACT EFFECTS OF MUNICIPAL WASTEWATER IRRIGATION ON FOREST SITES IN SOUTHERN MICHIGAN By Daniel George Neary This study examined the impact of municipal wastewater irrigation on soil water quality, vegetation growth and nutrient status, soil chemistry, decomposition in a 20-year-old red pine Ait.) plantation and a maple-beech and Fagus grandifolia Ehrh.) and humus (Pinus resinosa (Acer saccharum Marsh hardwood forest. The pine plantation was spray irrigated with sewage stabilization pond effluent during the summer and early fall of 1972 and 197 3. Irrigation treatments consisted of weekly applications of 0, 25, 50, and 88 mm/week. The hardwood forest site received secondary sewage treatment effluent through a trickle irrigation system during the same period. The effects of five irrigation rates (0 mm/week 50 mm/week of well water, and 25, 50, and 75 mm/week of wastewater) were evaluated in the maple-beech stand. Soil water samples were collected by means of porous cup suction lysimeters at weekly and bi-weekly Daniel George N e a r y intervals. The lysimeters w e r e placed at depths of 60 and 120 c m in the red pine p l a n tation and 30 and 60 c m in the hardwood stand. w i t h 40 m g / 1 W a t e r samples w e r e preserved H g C l 2 and analyzed for ammonia nitrogen, nitrate nitrogen, total Kjeldahl nitrogen, and total phosphorus. Renovation of total phosphorus exceeded 99% in the red pine stand and 96% in the hardwood forest throughout both years of the study. In 19 72, total n itrogen renovation at the pine site was generally above 90% for all levels of w a s t e w a t e r irrigation. During 1973 total nitrogen renovation remained above 90% for the 25 mm/week treatment but dropped to 81 and 76% for the 50 and 8 8 mm/ w e e k treatments. Reductions in nitrogen renovation resulted from flushing of nitrate nitrogen. In the hardwood forest, total nitrogen ren o ­ vation fluctuated between 0 and 71% during the two-year period. Ammonia nitrogen renovation was usually above 96%, but no nitrate renovation occurred. Nitrate levels in soil w a t e r samples removed from lysimeters in plots irrigated with well wa t e r were as high as averaged between 1 and 4 mg/1. 10 mg / 1 and The nitrate nitrogen leaching was associated w i t h hourly irrigation rates in excess of 50 m m / h o u r . W a s t ewater irrigation prod u c e d significant increases in boron, nitrogen, and p o t a ssium contents of Daniel George Neary the red pine foliage. Boron levels in the range of 55-75 ppm were associated with toxicity symptoms (necrosis of needle t i p s ) . Nitrogen contents increased from 0.11 to 0.37% and potassium levels increased between 0.05 - 0.07% over the range of irrigation rates. Sig­ nificant decreases in foliage aluminum contents with increased irrigation were noted. There were no sig­ nificant changes noted in the nutrient content of the hardwood forest ground cover. Growth response to wastewater irrigation was most evident in the red pine stand. Needles from the upper one-third of the crown exhibited increases in length of 12 - 36% and increases in dry weight/fascicle of 6 - 55% over the range of irrigation rates. The most striking soil chemistry change was in pH levels. pH rose from 5.2 to 7.4 at the 15 cm depth in the red pine plantation and increased from 5.7 to 6.8 at the same depth in the hardwood stand with increases in irrigation rates. Increases in the rate of litter decomposition in the red pine stand were reflected by a 2 0 % decrease in needle litter and fine humus weight and a 1.5 cm decrease in total depth. Considerable numbers of fungal reproductive structures appeared after the second season of irrigation in the red pine stand. Slight decreases in leaf litter weights were also noted in the maplebeech woodlot. ACKNOWLEDGMENTS The author would like to express his gratitude to Dr. Gary Schneider and Dr. Donald White for their excellent guidance and assistance throughout the course of this study. A p p r e c i a t i o n is also extended to Dr. Earl Erickson and Dr. Dean Urie, the other members of the guidance committee. Considerable acknowledgments are due to Karl Krueger, A r l e n Johnson, Wortley, Ron Heninger, Roy Brown, Zati Eron, Juan Liesegang, Esmail Owtad, Louis Halloin, Mike Scott-Burke, Mike Phillips, Simpson, Galen Dale Brockway, Russ LaFayette, Richard John Cooley, and Bill Dunn for their valuable assistance throughout the field and laboratory phases of this study. This project was funded through the Michi g a n State University Institute of W a t e r Research Project No. A-055-MICH) (OWRR and the U.S. Forest Service North Central Forest Experi m e n t Station. The author is grateful to both of these agencies for their financial s u p p o r t . A very special thank you is extended to Dean Urie for his assistance, inspiration, understanding, and friendship during all phases of this project. Finally, the author would like to express his gratefulness to his wife, Vicki, for her invaluable help and inspiration as research assistant, and companion. typist, TABLE OF CONTENTS Page LIST OF TABLES ......................................... LIST O F F I G U R E S ......................................... V I T A .................................................... Chapter I. INTRODUCTION .................................. 1 Background .................................. Water Treatment. . . . . . . . . . Study O b j e c t i v e s ................... 6 II. LITERATURE R E V I E W ....................... 8 Historical Perspective ..................... Forests and Wastewater Recycling . . . . Hydrological Considerations. . . . . . Important Nutrients ........................ Soils and Vegetation Considerations . . . III. 1 3 STUDY S I T E S .............................. 24 A. M i d d l e v i l l e ....................... 24 G e o g r a p h y .......................... 24 G e o l o g y .............................. 27 S o i l s .............................. 27 28 C l i m a t e .............................. Study D e s i g n ....................... 31 Irrigation System ........................ B. Lott W o o d l o t ....................... 40 G e o g r a p h y .......................... Geol o g y .............................. S o i l s .............................. 40 43 43 8 11 13 14 21 34 Chapter IV. Page C l i m a t e ....................................... Study D e s i g n ............................ Irrigation S y s t e m ............................ 45 48 48 METHODS A N D M E A S U R E M E N T S ......................... 57 M i d d l e v i l l e ............................... 57 W ater Qual i t y Anal y s i s ..................... Red Pine Gr o w t h and N u t r i e n t Status. . Soils. ........................ H u m u s .......................................... Fungi C o u n t ................................... 57 6 3 64 65 69 M S U Lott W o o d l o t ........................... 69 Water Qua l i t y Anal y s i s ..................... Herbaceous V e g e t a t i o n ..................... S o i l .......................................... H u m u s .......................................... 69 69 70 71 RESULTS A N D D I S C U S S I O N ......................... 73 A. B. V. A. M i d d l e v i l l e ............................... 73 Water Q u a l i t y ................................ 73 Wastew a t e r Inputs . . . . . . . . Nutr i e n t L o a d i n g ......................... Ground W a t e r R e c h a r g e ..................... C a l c u lations of N u t r i e n t Renovation . N itr o g e n .............. . . . . . . 74 75 77 80 86 60 cm: 25 m m / W e e k .................... 86 60 c m : 50 m m / W e e k .................... 86 60 cm: 8 8 m m / W e e k ................. 91 120 cm: 25 mm/Week. .............. 95 120 cm: 50 m m / W e e k ..................... 98 120 cm: 8 8 m m / W e e k ......................... 101 Nitrogen S u m m a r y .............................104 Total P h o s p h o r u s 10 5 Red Pine Foliar N u t r i e n t s ......................105 B o r o n ........................................... 115 P o t a s s i u m ....................................... 120 v Page Chapter A l u m i n u m .................................. 121 N i t r o g e n .................................. 122 Red Pine Growth R e s p o n s e s ................. 122 ............................ 122 Needle Length Branch B u d s ............................... 124 Dry Weight per F a s c i c l e ................. 124 Diameter I n c r e m e n t ........................ 125 Needle Biomass ............................ 128 Stem B i o m a s s ............................... 132 Soil C h e m i s t r y ............................... 135 P h o s p h o r u s ............................... 14 0 P o t a s s i u m .................................. 142 C a l c i u m .................................. 14 2 Magnes i u m .................................. 142 Total Kjeldahl Nitrogen ................. 148 Loss on I g n i t i o n ........................ 14 8 B o r o n ...................................... 14 8 Humus S u r v e y ............................... 152 Soil O r g a n i s m s ............................152 Humus D e p t h ................................... 155 Total Humus W e i g h t ............................ 156 Fine H u m u s ............................... 159 N u t r i e n t s ...................................... 162 Fungal Fruiting Survey ..................... Nutrient Budget ........................... 169 179 B. Lott W o o d l o t ................................... 184 Water Q u a l i t y ................................... 184 Wastewater Inputs ........................ 184 Nutrient Loading ........................ 185 Ground Water R e c h a r g e .....................187 N i t r o g e n .................................. 191 30 30 30 30 cm: cm: cm: cm: 50 25 50 75 mm/week mm/week mm/week mm/week of of of of Well Water Wastewater Wastewater Wastewater 191 194 19 4 19 7 Chapter Page 60 60 60 60 cm: cm: cm: cm: 50 25 50 75 mm/week mm/week mm/week mm/week of of of of Well Water Wastewater Wastewater Wastew a t e r . . . . Nitrogen Summary ......................... Total P h o s p h o r u s ......................... V e g e t a t i o n ................................... Summer Flora Spring F l o r a 202 202 207 207 212 213 218 ............................ ............................ 218 223 Soil C h e m i s t r y ............................ 227 pH. .................. P h o s p h o r u s ................................ Potassium .................. C a l c i u m ................................... .................. Magnesium Nitrogen. ......................... Loss on I g n i t i o n ......................... 229 229 232 232 2 35 235 238 Soil M o i s t u r e ................................ Ox y g e n D i f f u s i o n ............................ H u m u s ....................................... Nutrient Budget ............................ 238 241 245 247 VI. SUMMARY A N D RECOMMENDATIONS .................... A. M i d d l e v i l l e ................................ B. Lott W o o d l o t ................................ R e c o m m e n d a t i o n s ................................ 249 249 252 254 A P P E N D I X ................................................. 256 LITERATURE CITED 296 ....................................... L I S T OF TABLES Table 12. 3. 4. 5. 6 . 7. 8 . 9. Page A v e r a g e concentrations of lagoon effluents in the M i d d l eville w a s t ewater ..................... 74 W a s t e w a t e r irrigation and nutrient loading rates at Middleville, 1972 and 1973 . . . . 76 C a l c u l a t i o n of ground w a t e r recharge according to T h o r n t h w a i t e 's W a t e r Budget Method at the 60 cm depth in plots receiving 25 mm/week of -wastewater irrigation, 1973 78 Estimated ground w a t e r recharge at two soil depths and four wastew a t e r irrigation rates o n a red pine p l a n tation at Middleville, 1972 and 1973 .......................................... 81 C o m p a rative computations of hypothetical N O 3 -N renovation using the direct and ground water recharge methods for a 25 mm/ w e e k irrigation r a t e .................................................. 83 P ercent nutrient renova t i o n using the ground w a t e r recharge me t h o d at 60 cm depth at Middleville, 1972 and 1973 ................. 84 P er c e n t nutrient renovation using the ground wa t e r recharge me t h o d at 1 2 0 cm depth at M i d d l e v i l l e , 1972 and 1 9 7 3 ................. 85 Internal reference standards of red pine for nutrient analyses, 1972 and 1973 ................. Ill Nitrogen, potassium, phosphorus, calcium, and m a g n e s i u m concentrations of red pine foliage for varying rates of w a s t e w a t e r irrigation, Middleville, 1972 and 1973 ................. viii 112 Table 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. Page Sodium, magnesium, iron, copper, boron, zinc, and aluminum concentrations of red pine foliage for varying rates of wastewater irrigation, Middleville, 1972 and 1973 . . 113 Average red pine needle growth with varying wastewater irrigation rates, Middleville, 1972 and 1973 123 Red pine diameter increments and reference height increments for varying rates of wastewater irrigation, Middleville, Fall, 1973 126 Red pine stem circumference as measured by band dendrometers on four sample trees per plot, Middleville, 1973 .................... 126 Estimation of red pine foliage biomass pro­ duction with varying rates of wastewater irrigation, Middleville, 1972 .............. 129 Estimation of red pine foliage biomass pro­ duction with varying rates of wastewater irrigation, Middleville, 1973 .............. 130 Estimation of red pine stem biomass pro­ duction with varying rates of wastewater irrigation, Middleville, 1972 .............. 133 Estimation of red pine stem biomass pro­ duction with varying rates of wastewater irrigation, Middleville, 1973 .............. 133 Average soil chemistry parameters of the Boyer sandy loam for the 0 - 1 2 0 cm depth at the Middleville red pine wastewater study, by irrigation rate, 1973 . . . . 136 Red pine humus survey by wastewater irri­ gation treatment, Middleville, 1973 . . . 155 Mean number of fungal fruiting structures/ 0.02 ha plot by irrigation rate, Middle­ ville, September to October, 1973 . . . 17 3 Estimation of total nitrogen budget in the red pine stand at Middleville, 1972 and ......................................... 1973 180 Table 22.. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. Page E stima t i o n of phosphorus budget in the red pine plantation at Middleville, 1972 and 1973 .......................................... 181 A ver a g e concentrations of sewage effluent and w e l l water used in Lott Woodlot, 1972 and 1 9 7 3 ....................................... 185 Wastewater irrigation and nutrient loading rates for Lott Woodlot, 1972 and 1973 . . 186 E stim a t e d ground water recharge calculated at two soil depths and four irrigation rates, Lott Woodlot, 1972 and 1973 . . . 188 P e r c e n t renovation for 1972 and 1973 using the ground w a t e r recharge me t h o d at the 30 c m depth in the L o t t Woo d l o t . . . . 189 P e rc e n t renovation for 1972 and 1973 using the ground w a t e r recharge me t h o d at the 60 c m depth in the L o t t Woo d l o t . . . . 190 V e geta t i v e abundance for 15 irrigated plots on Miami loam, L o t t Woodlot, 1972 and 1973 ................................ 219 Frequency and occurrence of vegetative cover for the 15 plots on Miami loam, L o t t Woodlot, 1973 and 1973 221 Influence of irrigation on actual vegetative count for the most commonly occurring ground cover species, Lott Woodlot, 197 2 and 1 9 7 3 ................................. 222 C omposite biomass of spring herbaceous species by wast ewater irrigation rate, Lott Woodlot, 1974 224 Leaf biomass of 10 randomly chosen sugar maple seedlings in e a c h plot of the Lott Wood l o t wastewater irrigation study, 1974 .......................................... 224 Foliar nutrient content of composite sample of 1 0 sugar m a p l e seedlings by irrigation rate, Lott Woodlot, 19 74 225 x Table 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. Page Composite nutrient content of spring her­ baceous species by irrigation rate, Lott Woodlot, 1974 .................................. 226 Average soil chemistry parameters of Miami loam for 0-60 cm depth, Lott Woodlot, after two years of irrigation treatments . . . . 228 Soil oxygen diffusion in Miami loam, Lott Woodlot, 1973 .................................. 244 Humus accumulations by irrigation rate, Lott ........................ Woodlot, August, 1973 246 Estimation of total nitrogen and total phos­ phorus budget, Lott Woodlot, 1972 through 1973 ............................................. 247 Mean monthly air temperature for Middleville using data from Grand Rapids and Hastings. 2 56 . Mean monthly ammonia nitrogen at 60 and 120 cm at Middleville, 1972 and 1 9 7 3 ................. 257 Mean monthly nitrate nitrogen at 60 and 120 cm at Middleville, 1972 and 1 9 7 3 ................. 258 Mean monthly organic nitrogen at 60 and 120 cm at Middleville, 1972 and 1 9 7 3 ................. 259 Mean monthly total nitrogen at 60 and 120 cm at Middleville, 1972 and.1 9 7 3 ................. 260 Mean monthly total phosphorus at 60 and 120 cm at Middleville, 1972 and.1 9 7 3 ................. 261 Total nitrogen and total phosphorus renovation at the 60 cm depth at Middleville computed by the ground water recharge method, 1972. . 262 Ammonia nitrogen, nitrate nitrogen, and organic nitrogen renovation at the 60 cm depth at Middleville computed by the ground water recharge method, 1 9 7 2 . . . 263 Total nitrogen and total phosphorus renovation at the 120 cm depth at Middleville computed by the ground water recharge method, 1972. . 264 xi . 'age Ammonia nitrogen, nitrate nitrogen, and organic nitrogen renovation at the 1 2 0 depth at Middleville computed by the ground water recharge method, 1972 . cm 265 Total nitrogen and total phosphorus renovation at the 60 cm depth at Middleville computed by the ground water recharge method, 1973. 266 Ammonia nitrogen, nitrate nitrogen, and organic nitrogen renovation at the 60 cm depth at Middleville computed by the ground water recharge method, 1973.. ........................ 267 Total nitrogen and total phosphorus renovation at the 120 cm depth at Middleville computed by the ground water recharge method, 1973. 268 Ammonia nitrogen, nitrate nitrogen, and organic nitrogen renovation at the 1 2 0 cm depth at Middleville computed by the ground water recharge method, 1973 ........................ 269 Changes in (A) pH and (B) available phosphorus with soil depth and wastewater irrigation rates, Middleville, 1973 ..................... 270 Changes in (A) extractable potassium and (B) extractable calcium with soil depth and wastewater irrigation rates, Middleville, 1973 ............................................. 271 Changes in (A) extractable magnesium and (B) total Kjeldahl nitrogen with soil depth and wastewater irrigation rates, Middleville, 1973 ............................................. 272 Changes in (A) loss on ignition and (B) boron with soil depth and wastewater irrigation ..................... rates, Middleville, 1973 273 Changes in (A) mean humus depth, (B) fine humus dry weight, and (C) total humus dry weight in red pine by irrigation rate and distance from plot center, Middleville, 1973 ............................................. 274 xii Table 58. 59. 60. 61. 62. 63. 64. 65. 6 6 . 67. 6 8 . 69. Page N utr i e n t con t e n t of the litter layer in red pine, Middleville, 1973 ....................... 275 M e a n monthly temperatures in E a s t Lan s i n g and total mon t h l y precipitation at the Michigan State U n i v ersity Tree Research Center, 1972 and 1973 ....................................... 276 M e a n monthly ammonia nitrogen at 30 and 60 cm depth, Lott Woodlot, 1972 and 1973 . . . 277 M e a n mont h l y nitrate nitrogen at 30 and 60 cm depth, Lott Woodlot, 1972 and 197 3 . . . 278 M e a n m o n t h l y organic nitrogen at 30 and 60 cm depth, Lott Woodlot, 1972 and 1973 . . . 279 M e a n mon t h l y total nitrogen at 30 and 60 cm depth, Lott Woodlot, 1972 and 1973 . . . 280 M e a n m o n t h l y total phosphorus at 30 and 60 cm depth, Lott Woodlot, 1972 and 1973 . . . 281 Total nitrogen and total phosphorus r e n o ­ vations at 30 cm depth, L o t t Woodlot, com­ puted by the ground w a t e r recharge method, 1972 ........................................ 282 A mm o n i a nitrogen, nitrate nitrogen, and organic nitrogen renovations at 30 cm depth, Lott Woodlot, computed by the ground water recharge method, 1972 . . . 283 Total nitrogen and total phosphorus r e n o ­ vations at 30 c m depth, Lott Woodlot, c o m ­ puted by the ground w a t e r recharge method, 1973... .......................................... 284 A mm o n i a nitrogen, nitrate nitrogen, and organic nitrogen renovations at depth, Lott Woodlot, computed by the ground w a t e r recharge method, 1 9 7 3 ................. 285 Total nitrogen and total phosphorus r e n o ­ vations at 60 c m depth, L o t t Woodlot, c o m ­ puted by the ground w a t e r recharge method, 1972 xiii 286 Table 70. 71. 72. 73. 74. 75. 76. 77. 78. Page Amm o n i a nitrogen, nitrate nitrogen, and organic nitrogen renovations at 60 cm depth, L o t t Woodlot, computed by the ground w a t e r recharge method, 19 72 . . . . 287 Total nitrogen and total phosphorus r e n o ­ vations at 60 cm depth, L o t t Woodlot, c o m ­ puted by the ground water recharge method, 1973 .............................................. 288 Amm o n i a nitrogen, nitrate nitrogen, and organic nitrogen renovations at 60 cm depth, Lott Woodlot, computed by the ground water recharge method, 1973 289 Changes in (A) pH and (B) available phosphorus w i t h soil de p t h and wa s t e w a t e r irrigation rates, Lott Woodlot, 1973 ..................... 290 C hanges in (A) extractable p o t a s s i u m and (B) extractable calc i u m w i t h soil d e p t h and wastew a t e r irrigation rates, Lott Woodlot, 1973 .............................................. 291 Changes in (A) extractable m a g n e s i u m and (B) total Kjeldahl nitrogen w i t h soil d e p t h and w astew a t e r irrigation rates, Lott Woodlot, 1973 .............................................. 292 Changes in loss o n ignition w i t h soil depth and wastew a t e r irrigation rates, L o t t W o o d ­ lot, 1973 293 Soil moisture tension in the 30-60 c m depth of Miami loam, Lott Woodlot, June 27 to A u g u s t 17, 1973 294 Soil mois t u r e tension in the 30-60 cm depth of Miami loam, Lott Woodlot, A u g u s t 24 to November 20, 1 9 7 3 ................................ 295 xiv LIST OF FIGURES Figure 1. 2. 3. 4. 5. 6 . 7. 8 . 9. 10. 11. 12. Page The nitrogen cycle in a forest wastewater renovation system ........................... 17 Layout of the wastewater treatment facility at Middleville, M i c h i g a n .................... 26 Soil horizon description for the typifying pedon of the Boyer series (Soil Conser­ vation Service, 1 9 6 6 ) ....................... 30 Wastewater irrigation plots in the 20-yearold red pine plantation at Middleville, M i c h i g a n ...................................... 33 Polyethylene hose distribution system in the Middleville red pine s t a n d ................. 36 Adjusting pressure on a Rainbird 9-25A-FPTNT impact-haimner sprinkler using pressure gage and control v a l v e ..................... 39 Water Quality Management Area at Michigan State U n i v e r s i t y ........................... 42 Soil profile description for the typifying pedon of the Miami series (Soil Conser­ vation Service, 196 6 ) ........................ 47 Location of the trickle irrigation plots in the Lott W o o d l o t ........................... 50 Trickle irrigation system in the Lott W o o d ­ l o t ............................................. 53 Water discharge from trickle irrigation system using PVC p i p e ........................ 55 Tank and pump for delivery of wastewater to the Lott Woodlot irrigation site . . . . xv 55 Figure 13. 14. 15. 16. 17. 18. 19. Page S uction lysimeter: (A) access tubing used to remove w a t e r samples and (B) porous cup embedded in s o i l ................................ C ollecting soil w a t e r samples from suction lysimeters at M i d d l eville by means of a hand pump and v a c u u m flask assembly. . . . 2 The 300 cm core cutter used for collection of forest floor s a m p l e s ......................... N H 3 -N, N O 3 -N, Organic N, and Total N c o n c e n ­ trations at the 60 cm de p t h for the 50 mm/ w e e k irrigation rate at Middleville, 1972 and 1973 90 N H 3 -N, N O 3 -N, Organic N, and Total N c o n c e n ­ trations at the 60 cm depth for the 8 8 mm/ week irrigation rate at Middleville, 1972 and 1973 93 N H 3 -N, N O 3 -N, Organic N, and Total N c o n c e n ­ trations at the 120 cm de p t h for the 25 mm/ week irrigation rate at Middleville, 1972 and 1973 97 21. N H 3 -N, NO3-N, Organic N, Total N concentrations at the 1 2 0 cm depth for the 8 8 mm/ w e e k irri­ gation rate at Middleville, 1972 and 1973. . 24. 68 88 N H 3 -N, N O 3 -N, Organic N, and Total N c o n c e n ­ trations at the 120 cm depth for the 50 mm/ w e e k irrigation rate at Middleville, 1972 and 1973 23. 62 N H 3 -N, N O 3 -N, Organic N, and Total N c o n c e n ­ trations at the 60 cm depth for the 25 mm/ week irrigation rate at Middleville, 1972 and 1973 20. 22. 59 103 Total P concentrations at the 60 cm d e p t h at Middleville, 1972 and 1 9 7 3 ...................... 107 Total P concentrations at the 120 cm d e p t h at Middleville, 1972 and 1 9 7 3 ...................... 109 Red pine foliage nutrients exhibiting sig­ n ificant differences between wastewater irrigation rates: (A) boron, (B) potassium, (C) aluminum, and (D) n i t r o g e n ................. 117 xvi Figure Page 25. Necrosis of red pine needles showing boron toxicity induced by wastewater irrigation at M i d d l e v i l l e ..................................... 119 26. Changes in (A) pH and (B) available phosphorus with soil depth and wastewater irrigation rates, Middleville, 1 9 7 3 ......................... 138 Changes in (A) extractable potassium and (B) extractable calcium with soil depth and wastewater irrigation rates, Middleville, 1973 144 Changes in (A) extractable magnesium and (B) total Kjeldahl nitrogen with soil depth and wastewater irrigation rates, Middleville, 1973 146 Changes in (A) loss on ignition and (B) total -boron with soil depth and wastewater irri­ gation rates, Middleville, 1973 150 Comparison between branch litter in unirrigated (top) and irrigated (bottom) red pine plots showing the loss of bark occurring with irrigation, Middleville, 1973 .................... 154 27. 28. 29. 30. 31. 32. 33. 34. 35. Mean humus depth in red pine at Middleville by irrigation rate and distance from plot center, 1 9 7 3 ..................................... Interaction effects of wastewater irrigation rate and distance from plot center on (A) total humus weight and (B) fine humus weight 158 . 161 Amounts of calcium, magnesium, nitrogen, p h o s ­ phorus, and potassium in red pine fine humus at Middleville, 1973............................. 164 Aluminum, boron, copper, iron, manganese, sodium, and zinc contents of fine humus in the red pine plantation at Middleville, 1973 167 Typical fungi reproductive structures in the red pine stand at Middleville, 1973: (A) basidiomycete of the genus Lycoperdon and (B) basidiomycete of the genus A g a n c u s . . xvii . 172 Figure 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. Page Mean number of fungal fruiting structures/ 0.02 ha plot by irrigation rate, Mi d d l e ­ ville, September to October, 1973 . . . . 175 Summation on plots with highest individual fungal fruiting body counts, Middleville, September to October, 1973 1 NHt-N, N 0 3 “N, Organic N, and Total N concen­ trations at the 30 cm depth for the 50 mm/ week of well water irrigation rate, Lott Woodlot, 1972 and 1973 193 N H 3 -N, N O 3 -N, Organic N, and Total N concen­ trations at the 30 cm depth for the 25 mm/ week of wastewater irrigation rate, Lott Woodlot, 1972 and 1973 196 N H 3 -N, N O 3 -N, Organic N, and Total N concen­ trations at the 30 cm depth for the 50 mm/ week of wastewater irrigation rate, Lott Woodlot, 1972 and.1 9 7 3 ........................ 199 N H 3 -N, N O 3 -N, Organic N, and Total N concen­ trations at the 30 cm depth for the 75 mm/ week of wastewater irrigation rate, Lott Woodlot, 1972 and.1 9 7 3 ........................ 201 N H 3 -N, N O 3 -N, Organic N, and Total N concen­ trations at the 60 cm depth for the 50 mm/ week of well water irrigation rate, Lott Woodlot, 1972 and 1 9 7 3 ........................ 204 N H 3 -N, N O 3 -N, Organic N, and Total N concen­ trations at the 60 cm depth for the 25 mm/ week of wastewater irrigation rate, Lott Woodlot, 1972 and 1 9 7 3 ........................ 206 N H 3 -N, N O 3 -N, Organic N, and Total N concen­ trations at the 60 cm depth for the 50 mm/ week of wastewater irrigation rate, Lott Woodlot, 1972 and 1 9 7 3 ........................ 209 N H 3 -N, N O 3 -N, Organic N, and Total N concen­ trations at the 60 cm depth for the 75 mm/ week of wastewater irrigation rate, Lott Woodlot, 1972 and 1 9 7 3 ........................ 211 xviii Figure 46. 47. 48. 49. 50. 51. 52. Page Total P concentrations at the 30 cm depth, Lott Woodlot, 1972 and 1973 . . . . . . 215 Total P concentrations at the 60 cm depth, Lott Woodlot, 1972 and 1973 .................. 217 Changes in (A) pH and (B) available phosphorus with soil depth and irrigation rates, Lott Woodlot, 1973 ............................... 231 Changes in (A) extractable potassium and (B) extractable calcium with soil depth and irrigation rates, Lott Woodlot, 1973 . . . 234 Changes in (A) extractable magnesium and (B) total Kjeldahl nitrogen with soil depth and irrigation rates, Lott Woodlot, 1 9 7 3 ............................................. 237 Changes in percent loss on ignition w i t h soil depth and irrigation rates, Lott Woodlot, 1 9 7 3 ............................................. 240 Soil moisture tension for 0, 25, and 75 mm/ week wastewater irrigation rates, Lott Woodlot, 1 9 7 3 .................................. 243 xviv VITA DANIEL GEORGE NEARY Candidate for the degree of Doctor of Philosophy PINAL EXAMINATION: September 17, 1974 GUIDANCE C O M M I T T E E : Dr. Gary Schneider (Chairman), Department of Forestry Dr. Donald White, Department of Forestry Dr. Earl Erickson, Department of Crop and Soil Science Dr. .Dean Urie, U.S. Forest Service DISSERTATION: Effects of Municipal Wastewater Irrigation on Forest Sites in Southern Michigan BIOGRAPHICAL ITEMS: Born October 1, 1946, Chippewa Falls, Wisconsin Married August 29, 1970, to Vicki Oien EDUCATION: University of Wisconsin at Eau Claire, Michigan State University, B.S., 1969 Michigan State University, M.S., 1972 1964-1967 PROFESSIONAL E X P E R I E N C E : September 1973 — Present Graduate Assistant, Department of Forestry, Michigan State University September 1970 — September 1973 NDEA Fellow, Department of Forestry, Michigan State University August, 1969 — May, 1970 Ensign, U.S. Naval Reserve Summer, 1968 Crew Chief, C.F.I. Project, Plumas National Forest, Quincy, California Summer, 1967 Field Biologist, Clear Creek Camp, Philmont Scout Ranch, Cimarron, New Mexico xx September, 1965 — June, 1967 Biology Teaching Assistant, University of Wisconsin at Eau Claire, Eau Claire, Wisconsin O R G ANIZATIONS: Society of American Foresters Soil Science Society of America Xi Sigma Pi Michigan Academy of Science, Arts, and Letters xxi 4 C HA P T E R I INTRODUCTION Background Water is one of man's most important natural resources. The development of civilizations is linked to water abundance and man's ability to exert physical and political control over it. the 2 0 Water utilization in th century has been both varied and extensive. Surface waters are the major source of water supplies in the U.S. west). (91% in the humid east and 69% in the arid Water is used for domestic purposes, crop irri­ gation, cooling, manufacturing, recreation. transportation, and These uses, coupled with a rapidly growing demand for clean water, have led to deteriorations in the quality of surface water supplies in many regions of the country. Since the early 1 9 0 0 *s, advancements in chemistry and biology have permitted adequate treatment of surface waters. Most cities have been able to deliver unlimited volumes of high quality water which is disease hazard, taste, (1 ) free from (2 ) lacking any offensive odors or (3) devoid of color or turbidity, 1 (4) free 2 from harmful minerals, and (5) reasonably cool in temperature, (6 ) aesthetically acceptable. In fact, an "Ostrich Philosophy" has developed around the handling of wastewater. The viewpoint is that any problem which is out of sight and therefore out of mind ceases to be of concern. People fail to associate the streams in which they dump their wastes with the water that comes out of their f a u c e t s . Thus almost totally raw sewage has been placed into streams and lakes for many y e a r s . While populations were small, streams were able to purify waste loads naturally before reaching another municipality. cities grew, But as new towns were built and existing the loads imposed on many rivers exceeded their capacity to adequately process the wastes. Con­ sequently, surface water quality often reached such low levels that cities had to invest large amounts of capital for water purification prior to its public consumption. The demand for high quality water in the United States is growing rapidly. It is expected to rise from present amounts of 1.5 billion cubic meters per day (BCMD) (400 billion gallons per day BCMD (1000 BGD) by the year 2000. [BGD]) to over 3.8 With an estimated average daily surface runoff of 2.6 BCMD (700 BGD), extensive re-use of surface water will have to be 3 accomplished to make up for the proje c t e d deficit between de m a n d and runoff. A l t h o u g h ground w a t e r can provide for some of the deficit, upon to supply all of it. it should not b e reli e d To do so w o u l d be a serious threat to ground w a t e r supplies. In the G r e a t Lakes Region a similar r u n o ff-demand deficit w i l l occur by the year 2000 in spite of w a t e r abundance. In addition, this r egion is expected to have to handle a municipal sewage load two or three times that of pre s e n t levels {Todd, 1970). Water Treatment W i t h large projected w a t e r usages in the Grea t Lakes d rainage basin, steps m u s t now be taken to preve n t further surface w a t e r deteriorations. Municipalities and industries m u s t begin improving their w a s t e t r e a t ­ ment systems, and tertiary treatment w i l l be required. A complete tertiary w a s t e w a t e r treatment system consists of three stages. The first or pri m a r y stage accomplishes the separation of settlable solids. The second stage is designed to satisfy the biolog i c a l and chemical demand created by the presence of d i s s o l v e d and s u s pended organic compounds. It also removes some of the nutrients present in the wastewater. The third stage removes most of the remaining nutrients and p r o ­ duces a high quality effluent effectively free of the materials introduced into the original water. 4 There are two major methods of achieving tertiary wastewater treatment. The first method is the tradi­ tionally used completely mechanical biological-chemical treatment system. Such systems are operational year- round, occupy a minimum of land space, and result in excellent wastewater renovation. However, expensive to construct and operate. they are Another method utilizes the natural waste processing abilities of terrestrial ecosystems in conjunction with some degree of primary or secondary treatment. While this natural system utilizes much more land area and operates at peak efficiency only during the normal growing season, it can provide excellent wastewater renovation with a minimum amount of investment. Such systems have been labelled the "living filter." The "living filter" concept gained national attention through the Pennsylvania State University wastewater recycling studies. It is by no means a new concept but does differ in that the wastewater is c o n ­ sidered a resource rather than a waste. The treatment objective of this natural process is to provide maximum water renovation while maintaining system durability and longevity. Using controlled rates of application, nutrients present as pollutants in wastewater can be removed by microbial degradation and transformation, ion exchange, chemical precipitation, and absorption 5 through soil and plant root systems. Thus polluted water is processed into relatively pure water. mately, Ulti­ this type of wastewater treatment system promotes the maximum re-use of local water resources. The "living filter" approach operates best with a vegetative cover that can be harvested at frequent intervals. This allows for continuous nutrient removal from the site and thus precludes nutrient buildup which might otherwise result in toxicity conditions or sudden unwanted surges of nutrients into the ground water. Agricultural food crops meet these restricted requirements since they are harvested annually. forests have a longer crop rotation period, Although they also have properties that make them a desirable terrestrial system for wastewater renovation. resort areas, parks, In locations such as state and national forests, and other similar nonagricultural regions, trees are the only major vegetation type available for processing wastewater. Forest sites are generally adapted to wastewater application since they have high humus levels and high infiltration rates. Furthermore, concerns over disease transmission through the irrigated vegetation are virtually eliminated since no direct human consumption of the vegetational material occurs. 6 A great deal of information still needs to be obtained about the potential uses of forest lands for renovating wastewater. L o n g - t e r m effects created by applying w a s t e w a t e r o n land sites need further study. The "living filter" conc e p t for wastew a t e r renovation involves a complex ma t r i x of d i f f e r e n t plants, climate regimes, soils, and effluents w h o s e interactions need more clarification. Evans (1973) identified a w h o l e spectrum of wa s t e w a t e r research topics including long­ term effects of wastes on v e g e t a t i o n and soils, quantity and quality of ground w a t e r recharge, and the recycli n g of microorganisms in w a s t e w a t e r recycling. Study Objectives The objectives of this study are to evaluate changes in the vegetation, properties, soil physical and chemical and soil w a t e r qua l i t y resulting from municipal w a s t e w a t e r irrigation in two forest stands in southern Michigan. A t the first site, plantation near Middleville, a red pine the study involves m o n i t o r ­ ing for changes in red pine growth and nutr i e n t content, soil chemistry status, humus development, and nitrogen and phosphorus concentrations of soil water. The second site is a m a p l e - b e e c h hardwood stand near East Lansing w h i c h is being evaluated for alterations in 7 herbaceous plant and tree seedling growth and nutrien t content, soil chemi s t r y status, soil aeration, litter weights, and soil w a t e r nitrogen and phosphorus contents. CHAPTER II LITERATURE REVIEW Historical Perspective The application of wastewaters to terrestrial ecosystems as an alternative to existing methods of tertiary wastewater treatment has become a subject of great current interest. points out, However, as Thomas (1973) the use of land sites for disposing of wastewaters is nothing new. What is new is the change in attitude towards utilizing land sites for wastewater processing; a shift from one of mere disposal to that of treatment and re-use. The natural tendency with the disposal approach to sewage effluent is to apply as much waste as possible in a limited area at rates higher than the soil can process (Heukelekian, 1957). With a treatment and re­ use approach, wastewaters are applied to the land under proper climatic and soils conditions and sensible management control. Wastewaters need not create nuisance conditions, health hazards, or "poisoned" landscapes. Thus, discarded wastewaters can be renovated by the combined action of plants, 8 9 microorganisms and soil to a good quality water. Such water can then be safely returned to the ground water reservoir (Kardos, 1970). The recycling of wastewater has generally been accepted by the public in locations where water shortages have become serious (Hunt, 1954). Buswell (1928) reported that a crop irrigation project was designed to treat wastewaters from Bunslav, Prussia, in 1559 and operated for 300 years. Municipal sewage farms have been operating in England, Germany, France, and Australia since 1890. Italy, The first use of domestic sewage for irrigation in the United States was at Cheyenne, Wyoming, in 1883 (Hunt, 1954). By 1935, 113 localities in 15 western states practiced crop irrigation as a means of renovating and reusing scarce water resources (Hutchins, 19 39). Hutchins (1972) recently reported 571 land application wastewater treatment systems in operation in 3 2 states. Of those, 55% were located in 13 western states. Not included in Hutchins survey were the approxi­ mately 1300 industrial facilities currently utilizing land sites as wastewater treatment systems. The food processing industry is the largest user of land sites, accounting for about 72% of the industrial use of ter­ restrial wastewater treatment systems. and Rose Monson (1958) (19 71) have documented these uses for treating cannery wastes. 10 Industrial and municipal wastewaters have been applied to land sites by three application modes: overland runoff, rapid infiltration, and spray irri­ gation. Overland runoff is the controlled application of irrigation wastes onto the land with the path of flow being downslope Gilde, 1971). (Foster, 1965; Bendixen et a l ., 1969? Rapid infiltration utilizes high rate infiltration and percolation after application by flood­ ing (Parkhurst, 1970; Bouwer, 1968). Spray irrigation utilizes slow rate sprinkler application with the major flow pathway being by infiltration and percolation (Luley, 1963; Law, 1969? Sepp, 1971? Kardos and Sopper, 1973). Of the three application methods, spray irri­ gation presents the greatest potential for reliability and longevity, and accounts for about half of the current terrestrial wastewater treatment systems operating in the country (Reed et a l ., 1972). Deaner (1971) reported that spray irrigation was the dominant wastewater appli­ cation mode in California. Wastewater treatment systems in Michigan which incorporate spray irrigation on land sites are currently in operation, undergoing pre­ operations testing, or are in the planning stage at Middleville, Belding, Harbor Springs, Cassapolis, East Jordan, Fremont, Michigan State University at East Lansing, and Muskegon (Urie, 1971). 11 Forests and Wastewater Recycling The use of forest stands for wastewater renovation has thus far been limited. It is undergoing rapid expansion, however, as the technology for renovating wastewaters on forest ecosystems is improved and has been increasingly adopted by recreational developments, municipalities, and industries. One of the earliest reported studies of the use of forested lands for w a s t e ­ water disposal was by Mather (195 3). He documented the use of vegetable processing waste from the Seabrook Farms plant at.Bridgeton, New Jersey, black oak stand stand. in a mixed white and (Quercus alba L. and Q. velutina L.) Little et al. (1959) discussed the irrigation effects after the Seabrook Farms system had been operating for seven years. Rudolph and Dils (1955) and Rudolph (1957) reported on cannery wastewater irrigation at Fremont, Michigan, utilizing box elder wood (Acer negundo L.), cotton­ (Populus deltoides B a r t r . ) , willow M a r s h . ) , and balsam poplar seedlings. (Salix nigra (Populus balsamifera L.) Forested areas have also been used to some extent for treating pulp and paper mill wastes 1956; Crawford, 1958; McCormick, (Voights, 1959; Jorgensen, Vercher et a l ., 1965; Flower, 1968). 1965; Effects of municipal sewage effluent on a forest site at Detroit Lakes, Minnesota were observed by Larson (1960). 12 The m o s t intensive investigation of the abili t y of forests and forest soils to process munic i p a l w a s t e ­ waters has been done b y W i l l i a m E. Sopper and his associates at Pennsylvania State University. in 19 66 (Sopper and Sagmuller, through the present 1966) and contin u i n g up (Kardos and Sopper, 1973), studies have utilized plantations of red pine resinosa A i t . ) , w h i t e pine larch these (Pinus (P. strobus L . ) , European (L a r i x decidua L . ) , white spruce Muench. Voss.), Starting Japanese larch and Z u c c . ] G o r d . ) , pitc h pine (Picea glauca (Larix leptolepis [Sieb. (Pinus rigida M i l l ) , as well as a mixed stand of wh i t e oak, black oak, oak (Q u ercus rubra L.) and scarlet oak red (Q. coccinea Muench). Urie (1973) discussed the ability of a jack pine (Pinus banksiana Lamb.) stand near Cadillac, Michigan, to renovate municipal sewage effluent. The use of a mixed h ardwood and conifer forest for the renovation of w a s t e w a t e r from the recreational d e v e lopment at Mount S u napee State Park in N e w Hampshire w a s described by Frost et al. (1973). Ol s o n and Johnson (1973) reported that 26 sites in national forest located in 14 states w e r e being considered for land application of waste waters by spray irrigation or rapid infiltration. 13 Hydrological Considerations The primary goal of irrigating wastewater in any terrestrial plant association is one of producing quality water which is free from the nutrients added by man. Thus appropriate monitoring facilities must be available to record changes in ground water quality. Parizek (1973) discusses many of the factors which need to be considered when monitoring unconfined or confined ground water aquifers. Many of these same ground water components are analyzed by Born and Stephenson (1969). Where regional ground waters exist at great depths or adequate funding does not permit the use of monitoring wells, soil water lysimeters allow for a reasonable on-site monitoring of recharge water quality. Parizek and Lane (1970) described the use of pan and suction lysimeters for monitoring the quality of the irrigation water percolating through the soil at the Penn State project. The porous cup or suction lysimeter has provided an especially direct and simple method of collecting soil water samples (Wood, 1973). The theory of the suction lysimeter was developed by Wallihan Wagner (1940), Colman (1962) (1946) , and Cole (1958) . reported on the design and use of a suction lysimeter developed by the Soil Moisture Equipment Company, Santa Barbara, California. 14 Porous cup lysimeters, while providing a simple and direct means of collecting soil water, do have their limitations. Such factors as lysimeter size and depth, porous cup wall thickness, and vacuum system or falling) (constant can affect the amount and nutrient concen­ tration of soil water samples obtained. cesses such as sorption, Physical p r o ­ leaching, screening, and plugging which can take place in conjunction with the porous cup also affect sampling (Hansen and Harris, U.S. Forest Service, personal communication, 1974) . Nevertheless, porous cup lysimeters are useful tools in instances where direct sampling of an unconfined aquifer is impossible. Important Nutrients One of the desired goals of terrestrial w a s t e ­ water irrigation operations is a product water whose quality should approach drinking and irrigation water standards. Reed et al. (1972) discussed the parameters of water quality in relation to the amount of uptake needed by the soil-plant-microbe association necessary to produce acceptable water. From the list of chemical and biological constituents of sewage effluent noted by Hunter and Kotalik (1973) it is obvious that sewage has a complex makeup and that water quality can no longer be defined by several parameters. Shuval and Gruener 15 (1973) have aptly pointed out specific hazardous c o n ­ taminants entering our wa t e r supplies w h i c h are not being routinely monitored. O f t e n budgetary, equipment, or m a n power restrictions a l l o w only a few w a t e r qualit y parameters to be measured. Two of the nutrients commonly found in wa s t e w a t e r which play domin a n t roles in wa t e r pollu t i o n are nitro g e n and phosphorus (Kardos, 1970). Phosphorus occurs p r e ­ dominantly in the inorganic phosphate form. is found as ammonia, nitrate, Nitrogen nitrite, and numerous organic nitrogen forms such as urea, amino acids, and proteins. The nitrogen cycle in a forest w a s t e w a t e r irri­ gation site is depicted in Figure 1, w i t h the pre d o m i n a n t nitrogen input coming from the w a s t e w a t e r Keeney, 1970). The m a j o r outputs from the system are: (1) plant uptake and biomass harvest, cation, and (3) (adapted from (2) d e n i t r i f i ­ loss to the ground water table. Proper m a n a gement of a terrestrial w a s t e w a t e r renovation system w o u l d be aimed at maximi z i n g outputs 1 and 2 while m inimi z i n g ou t p u t 3. The major components of the nitrogen cycle consist of ammonification, denitrification, and immobilization. as d e fined b y Alexander (1961), nitrification, Ammonification, is the conver s i o n of organic nitrogen to inorganic nitrogen. It is con­ ducted by numerous heterotrophic microbes under a wide Figure 1. The nitrogen cycle in a forest wastewater renovation system. BIOMASS HARVEST Output #1 ANmALS ATMOSPHERIC PLANTS NITROGEN BACTERIA Output n DENITRIFICATION DECAY N FIXATION ORGANISMS WASTEWATER H NITROGEN PROTEIN SYNTHESIS INPUT NITRATE NITRIFICATION ORGANIC AMMONIA AMMONIFICATION NITROGEN NITROGEN Output #3 Output #3 GROUND WATER NITROGEN Output #3 TABLE i 18 range of pH, temperature, (Bartholomew and Clark, and m o i s t u r e conditions 1965). In nitrification, am m onium is converted to nitrate. Since nitrogen from many secondary treatment plants is in the ammonium form, this is a m o s t important step in wa s t e w a t e r management. The n i t r ification process had b e e n reviewed extensively b y Quastel and S c h o l efield (1965), Camp b e l l and Lees (1970), H u n t cation, (1967), Ke e n e y and Gardner (1972), and B r o a dbent cont r a r y to mineralization, to pH, aeration, Nitrate, (1951), A l e x a n d e r temperature, (1973). Nitrifi­ is very sensitive and moist u r e conditions. the end pro d u c t of nitrification, is of great concern since it is highly soluble in w a t e r and r e l a ­ tively inert in soil chemical reactions. It thus becomes readily available for b o t h plant uptake and loss to the g round w a t e r (Corey et a l ^ , 1967). D e n i trification is the process of converting nitrate or nitrite to elemental nitrogen and nitrogen oxides (Broadbent, 1973). It is the m a j o r pathway w h ereby nitrogen is returned to the atmosphere. Immo­ biliza t ion completes the nitro g e n cycles as it consists of plant or microbial a b s o rption of nitr o g e n in the nitrate form and subsequent incorporation into cellular material (Bartholomew, 1965). Phosphorus does not undergo m u c h change in chemical form w i t h cycling throughout the environment. 19 As a prominent part of nucleic acids and energy transfer compounds, it functions as an essential plant and animal element. In aquatic ecosystems, phosphorus often becomes a limiting factor. Thus the introduction of even modest quantities of phosphorus in sewage effluent often results in lake and stream eutrophication. Fortunately, most terrestrial wastewater dis­ posal sites have high phosphorus renovation capacities. Phosphorus compounds are fairly insoluble in soil, and are made unavailable by iron and aluminum compounds {Lindsay and Moreno, 1960; Woodruff and Kamprath, 1965; and Humphreys and Pritchett, 1971). Plant uptake of phosphorus can also be very significant as indicated by Law (1970), Gilde (1971), and Hook et al. (1973). The ability of terrestrial wastewater treatment sites to renovate nitrogen and phosphorus-bearing w a s t e ­ waters has been investigated. Forest sites at P e n n ­ sylvania State University which were utilized for spray irrigation have exhibited 99% phosphorus removal and 85% nitrogen removal over seven years. Corn and reed canary grass sites at the same location proved even more effective in removing nitrogen. Bouwer (1973) reported 80% nitrogen and 50% phosphorus renovation levels for the rapid infiltration project at Flushing Meadows, Arizona. The spray irrigation system at Cadillac, Michigan, described by Urie (1973) gave 98% phosphorus 20 removal and greater than 90% nitrogen renovation (except for two months at the end of the irrigation season when nitrate b e g a n moving into the ground w a t e r ) . Frost (197 3) reported 95% phosphorus removal and only 16% nitrate removal from forest sites irrigated in New Hampshire. A n agricultural site at Paris, Texas, irr i ­ gated w i t h c a n n e r y w a s t e w a t e r achieved 86-93% nitroge n and 50-88% phosphorus renova t i o n Hill (1972) (Law et a l ., 1970). descr i b e d a sy s t e m for irrigating swine waste w h i c h was able to achieve 99.5 and 99.8% removal of n i t rogen and phosphorus respectively. The abilities of diffe r e n t terrestrial ecosystems to remove nutrients applied in w a s t e w a t e r are quite marked. A reed canary grass crop at Penn State, gated w i t h 50 mm/ w e e k of wastewater, irri ­ removed 457 kg/h a of n i t rogen and 63 kg/ha of phosphorus after three h a r ­ vests d uring 1970. Under the same conditions a corn silage crop w i t h d r e w 180 kg/ha of nitrogen and 47 kg/ha of p hosphorus from the irriga t i o n site. In contrast, uptake of nitrogen and phosphorus in an irrigated h a r d ­ wood forest averaged only 104 and 9 kg/ha respectivel y (Sopper and Kardos, 19 73). Some investigators have stated that b o r o n is a potential p r o b l e m in terrestrial w a s t e w a t e r irrigatio n schemes and requires more study Baier and Fryer, 1973). (Richard, Ellis and Kn e z e k 19 72, and (1972) 21 reviewed the absorp t i o n mechanisms of b o r o n in soils. Wear and P a t t e r s o n (1962) showed that p l a n t upt a k e of w a t e r - s oluble b o r o n is grea t e s t w h e n the soil is low in pH and coarse in texture. Ag r o n o m i s t s have agreed that b oron is an essential element for higher plants. However, the crit i c a l b i o c hemical role of b o r o n has not yet been isolated. D i f f erent hypotheses exist as to what the function of b o r o n in plants is 1972). Oertli and Kohl (1961) (Price et al^., have s u b s t antiated the hypothesis that bo r o n is m o v e d b y the tran s p i r a t i o n stream and c o n c entrated in the p l a n t extremeties as water is lost through evapotranspiration. This w o u l d correlate well w i t h o b s e rvations by Stone and Baird (1956) that b o r o n toxicity symptoms commonly o c c u r at the top and perip h e r y of the c r o w n in red and w h i t e pine. Soils and V e g e t a t i o n Considerations The w a s t e w a t e r renova t i v e capacity of terrestrial ecosystems results from the dynamic processes o c c u r r i n g in soils. A com p l e x interaction of physical, chemical, and b i o logical processes function in removing chemicals from wastewater. Murr m a n n and Koutz cussed the roles of c a t i o n exchange, adsorption, oxidation-reduction, (19 72) have d i s ­ precipitation, plant uptake, and m i c r o b i o l o g i c a l u t i l ization in reclaiming w a s t e w a t e r applied to terrestrial ecosystems. The effects of w a s t e w a t e r o n the chemical and physical properties of 22 soils have been investigated by Steel and Berg Thomas et al. Day et al. (1966), McGauhey and Krone (1970). Hajek (1969) (1954), (1967), and and Ellis (1973) have reviewed the chemical interactions which allow the soil to serve as a filtering system for chemicals found in wastewaters. Kardos and Sopper (1973) reported that wastewater irrigation caused significant changes in the principal exchangeable cations of only magnesium and sodium. Distinct increases also occurred in pH, manganese, and extractable chloride. One key item of concern in the management of a terrestrial wastewater treatment system is the maintenance of the botanical component. Rickard (1972) points out that while plants have a high nutrient absorption capacity, they also are susceptible to nutrient toxicity. Little et al. Fryer (1973) (1959), Cole et al. (1969), and Baier and have cited undesirable plant responses to wastewater irrigation. Sopper and Kardos (1973) dis­ cussed the growth and nutrient responses of a variety of agricultural crops and tree species. In general, wastewater irrigation increased the height and diameter of mature forest stands and greatly improved the sur­ vival and height growth of tree seedlings. The only exception to this was red pine which initially responded well to irrigation rates of 25 and 50 mm/hour but then exhibited a negative response at 50 mm rate. This they 23 felt was due to boron toxicity which developed in the red pine after six years of wastewater irrigation. Needles on trees containing 33 ppm boron turned yellow. Stone and Baird (1956) observed stepwise needle necrosis of red and white pine fertilized with as little as 11 kg/ha of borax. High correlations existed between the amount of borax applied to the sandy loam soil and the boron content of red pine foliage. CHAPTER III STUDY SITES A. Middleville Geography Middleville, Michigan has a population of about 2,500 and is located approximately 24 km southeast of Grand Rapids in Barry County. It sits astride the Thornapple River, a tributary of the Grand River. The drainage basin of the Grand River is the dominant watershed in southern Michigan. It drains an area of 12,740 k m 2 . In 1971, Middleville constructed a 24 ha sewage treatment facility to the east of town in the NE 1/4 and SE 1/4, Section 23, Township 4 North, Range 10 West, Michigan Meridian. Prior to 1971, all municipal waste ­ water was given primary treatment and then dumped into the Thornapple River. consists of two, The new sewage treatment facility 4.4 ha, sewage stabilization ponds, a pump house and chlorination chamber, a 14 ha crop irrigation site, and an adjacent 20 ha area of conifer plantations and hardwood stands 24 (Figure 2). 25 Figure 2. L a y o u t of the w a s t e w a t e r t r e a t m e n t f a c i l i t y at M i d d l e v i l l e , M i c h i g a n . 26 N Sec 23, T4N, R10W t Lagoon 1 Scale Red Pine 1 cm = 123 m Lagoon 2 | m 1 * P Jl pump housi ---- Crop j Irrigation — Istudy site Village of Middleville 27 This site was chosen for study because of the availability of sewage effluent for irrigation, and the presence of forest stands on characteristic soils. Geology The Middleville sewage stabilization pond facility is located on gentle rolling to hilly topography bordering a recessional moraine. The surface geologic formation consists of unconsolidated glacial drift of the Wisconsinan stage. It is characterized by sorted and unsorted sands and gravels with heterogeneous inclusions of clay till. About 30 m of glacial drift overly the bedrock of Mississippian aged Napolean sand­ stone (Martin, 1936). The regional ground water table slopes to the west down to the Thornapple River. 18 m below ground surface. It lies from 9 to Most individual wells utilize this surface aquifer for a water supply. Soils The portion of the sewage treatment facility occupied by the red pine plantation is underlain by a Boyer sandy loam. Boyer soils are typic hapludalfs which formed in loamy sand and sandy loam outwash overlying calcareous coarse sand and gravel. Such soils occur on outwash plains, old glacial d r a i n a g e w a y s , and on moraines. The original vegetation found on them 28 consisted of oak, hickory, and white pine stands, but is predominantly under cultivation for grain and forage crops. Soils of the Boyer series are well drained and have a moderately rapid permeability of 60 to 250 mm/hr. Surface runoff is slow on gentle slopes and rapid on steep slopes. These soils tend to have a low available moisture capacity and moderately low natural fertility. The pH of the Boyer series ranges from 5.3 to 6.3. The productivity of trees growing on Boyer soils is m e dium to high for pine, and low to medium for hard­ woods. White pine, red pine, and white spruce are the most desirable plantation species. These species present few management problems when located on Boyer soils. Occasional droughtiness is the only soil limi­ tation of any concern. A typical soil profile description of a Boyer loamy sand is shown in Figure 3. Climate The climate at Middleville alternates between continental and semi-marine. The influence of Lake Michigan to the west results in the marine-like climate during periods of strong wind flow. At other times the continental climate characteristic of interior North America prevails. 29 F i gure 3 Soil Hor i z o n description for the typifying pedon of the Boyer series Service, 1966). (Soil C o n s e r v a t i o n 30 T ypif y i n g Pedon: SOIL P R O F I L E : A 00-18 Boyer Loamy Sand DESCRIPTION cm ^ Dark grayish b r o w n (10YR4/2) loamy sand; very w e a k fine granular structure; very friable; numerous roots; slightly acid; abrupt smooth boundary; 15 to 25 cm thick. A2 18 - 30 cm Brown (10YR5/3) loamy sand; very w e a k m e d i u m granular structure; very friable; m e d i u m acid; clear wavy boundary; 8 to 2 5 cm thick. B1 30 - 45 cm Y e l l o w i s h br o w n (10YR5/3) loamy sand; w e a k fine subangular blocky structure; v e r y friable; 2 to 4% gravel; m e d i u m acid; clear w a v y boundary; 10 to 30 cm thick. B21t 45 - 77 cm Dark brown (7.5 YR4/4) sandy loam; w e a k coarse subangular bl o c k y structure; firm; few thin clay films; 15% fine and m e d i u m gravel; slightly acid; gradual w a v y boundary; 20 to 38 cm thick. B22t 77 - 86 cm Dark brown (7.5YR4/4) sandy clay loam; w e a k coarse subangular blocky structure; firm; 15% gravel; common thin and m e d i u m clay films; neutral; ab r u p t irregular boundary; 1 to 15 c m thick. IIC 86 - 130+cm Grayish br o w n (10YR5/2) stratified gravel and coarse sand; single grain; loose; calcareous. 31 The m e a n annual t e m p e r a t u r e for this site is about 8.9°C w i t h the e x t r e m e s a v e r a g i n g - 8 . 9 ° C in J a nuary and 28.5°C in July. The a v e r a g e l e n g t h o f the g r owing s e a s o n is a b o u t 160 days. P r e c i p i t a t i o n is u n i f o r m l y d i s t r i b u t e d t h r o u g h o u t the year. Annual precipitation averages the m o n t h s o f A p r i l - October, 820 mm. During rainfall averages 546 mm, w i t h m o n t h l y e x t r e m e s of 209 and 4 m m h a v i n g o c c u r r e d w i t h i n the p a s t six years. The m a x i m u m 24- h o u r r a i n f a l l in the c u r r e n t 3 0 - y e a r p e r i o d o f r e c o r d w a s 84 m m in June of 1972. M e a s u r a b l e p r e c i p i t a t i o n o c c u r s on an a v e r a g e of 140 days each year. A b o u t 80% of the days d u r i n g the y e a r a r e c l o u d y or p a r t l y cloudy. The r e l a t i v e h u m i d i t y g e n e r a l l y a v e r a g e s a b o u t 80% in the m o r n i n g and 65% d u r i n g the a f t e r n o o n (Strommen, 1971). S t u d y De s i g n The w a s t e w a t e r i r r i g a t i o n s t u d y w a s e s t a b l i s h e d at M i d d l e v i l l e in the fall of 1971 and the s p r i n g of 1972. T w e l v e c i r c u l a r 0.02 ha plots w e r e laid o u t in a 2 0 - y e a r - o l d red pine p l a n t a t i o n (Figure 4). A ran­ d o m i z e d b l o c k d e s i g n w a s u s e d to a c c o u n t for s l o p e variations from n o r t h w e s t to s o u t h e a s t across the plots. The d e s i g n c o n s i s t e d of three r e p l i c a t i o n s of four treatments: (1) cont r o l (plots 1, 5, and 11), 32 Figure 4 Wastewater irrigation plots i n the 20-year- old red pine p l antation at Middleville, Michigan. 33 2 5 mm/wk 0 mm/wk 0 mm/w k 0 mm/wk 25* TRjji/wk 88 m^/wk .. 10 5 m»/wk MAP LEGEND ----------------- 50.8 m m P o l y e thylene Pipe ----- 31.8 m m P o l y e thylene Pipe .................. 18.1 m m Rubberized Hose Scale: 1 cm = 12 m 34 (2) 25 nun of w a s t e w a t e r / w e e k (3) 50 m m/ w e e k (plots 4, 8, and 10), (plots 2, 3, and 12) , and (plots 6, 7, and 9). (4) 100 mm/wee k The 100 mm/w e e k plots actually turned out to receive 88 nun/week beca u s e of insufficien t line pressure, and hence are referred to as 8 8 nun/week treatment plots. Trees w i t h i n the 8.02 m plot radius were flagged and pruned to a height of 3 m . A metal post w i t h a plot identity tag was positi o n e d in each p l o t center. The entire study area was fenced off and posted w i t h w a r n i n g signs. Irrigation S y s t e m The irrigation system for the study was c o n ­ structed in the spring of 1972. semi-portable, (2-inch) It is a solid-set, spray irrigation design. A 50.8 m m diam e t e r polyethylene pipeline delivers effluent from the nea r e s t 212.4 m m (6-inch) a m a n h o l e w e s t of the plantation. From a tee near plot 3, a 31.8 m m 18.1 m m (1 1/4-inch) (3/4-inch) p o l y ethylene pipe and rubberized hose complete the d i s ­ tribution system to the irrigated plots In the center of each irrigated plot, 122 m m (48-inch) header in (Figure 5). a post-supported riser branches off the dist r i b u t i o n line by means of a saddle tee. The sprinklers, mounted o n the galvanized steel risers, are Rainbird single nozzle impact-hammer types. Figure 5. Polyethylene hose distribution system in the Middleville red pine stand. 37 The 25 nun/week plots have Rainbird 3-25A-FP-TNT sprinklers with a l um i n u m hammers and 3.2 mpi {1/8-inch) H i - L o nozzles. The 50 m m and 88 mm/ w e e k plots have Rainbird 9-25A-FP- T N T sprinklers w i t h bronze hammers and 4.3 m m Hi-Lo nozzles (Figure 6). (11/64-inch) Two of these sprinklers are tee m o unted in the 88 mm/ w e e k plots to deliver the designed irrigation rate. a pressure of 3 5 to 40 PSI. Sprinklers w e r e operated at The Hi-Lo nozzles allowed adjustment to cover all areas w i t h i n a plot radius. Sprinkler c a l i b ration was conducted at the beginning of each irrigation season by a network of rain gage cans located on each plot. O p e r a t i o n of the irrigation sy s t e m is designed to be d i re c t e d through a Buckner electronic control panel in the pump house. In 19 72 a separate pumping a n d con ­ trol s y stem had to be established to provide w a s t e w a t e r for the tree irri ga t i o n pro j e c t due to the fact that the main ir riga t i o n sy s t e m was not operating. T h e normal irrigation sc hedule called for eight hours of irrigati o n one day/week. Plots w e r e irrigated from late J u l y to mid-October in 19 72, and from late May to mid-October in 1973. Irriga t i o n was continued in 1974. However, data from the 19 74 irrigation season were not included in the t h e s i s . 38 Figure 6 Adjusting pressure on a Rainbird 9-25A-FP-TNT i m p a c t - h a m m e r s p r i n k l e r u s i n g p r e s s u r e ga g e and con t r o l v a l v e . 39 40 B. L o t t Wood l o t Geography The L o t t W o o d l o t is located on the south edge of the Michi g a n State Univer s i t y campus in Section 6, Township 3 North, Range 1 West, M i c h i g a n Meridian. It is approximat ely 4.8 km south of the m a i n campus at East L a nsing in Ingham Cou n t y (Figure 7). East Lansing is a major suburban community in the greater Lansing m e tropolitan area. Mich i g a n State lies w i t h i n portions of the Sycamore Cr e e k and Red Cedar River watersheds. These two streams empty into the Grand River, w h i c h flows through L a n s i n g and west w a r d to Grand Rapids and its junction w i t h the Thorna p p l e River. The 26 ha L o t t W o o d l o t is part of a 200 ha research area designated as the M i c h i g a n State University Water Q uality M a n a gement A r e a (WQMA). The Institute of Water Research at Michigan State Univer s i t y plans to conduct long-range studies on the many aspects of using aquatic and terrestrial sites to renovate municipal wastewaters. day (2mgd) (11 mgd) It is desi g n e d to process 7,600 m per of the approximately 41,800 m 3 per day of w a s t e w a t e r handled b y the East Lansing Sewage Treat m e n t Plant. Effl u e n t for the W Q M A will be taken off the secondary treatment final clarifiers in the E a s t Lansing plant and pumped 8 km to a series of 41 Fi g u r e 7 W a t e r Q u a l i t y M a n a g e m e n t A r e a at M i c h i g a n S t a t e U n i v e rsity. ^To: MSU Main Campus (4.8 km) Jolly Road N Lake 2 Lake 4 Lake 3 \ t 1-96 Expressway pm..,..' Tl Irrigation Area <0 o « o 0) WOQfllO 0 u «• • • Scale Sand Hill Road 5 cm = 537 m To: Sycamore Creek If 43 four 4.0 ha oxida t i o n ponds. Part of the w a t e r from these ponds will then be pumped to a 120 ha irrigation site (Figure 7). doned farmland, The irriga t i o n area consists of a b a n ­ and the L o t t Woodlot, a second growth sugar m a p l e - b e e c h hardwood stand w h i c h w a s heavily cut over by its former owners. Starting operations of the WQMA are expe c t e d to commence dur i n g the summer of 1974 as c o n s t ruction and e q u i p m e n t testing are completed. The L o t t Wood l o t site was chosen for this study to obtain p r e l i minary data o n the ability of this p a r ­ ticular forest site to renovate munic i p a l wastewater. Geology The Lott Woo d l o t is located on the gently rolling topography of a glacial till plain. is unsorted drift, age. The till loamy in texture, and of W i s c o n s i n a n The regional ground w a t e r table lies from 3 to 7 m below g r ound surface. It slopes to the south and east towards Syca m o r e Creek and Felton Drain. dated b e d r o c k aquifer, The c o n s o l i ­ located ab o u t 15 to 20 m below ground surface, is the P e n n s y l v a n i a n aged S a g i n a w sand­ stone f o rmation (Martin, 19 36). Soils The study portion of the L o t t W o o d l o t is under ­ lain by Miami loam (typic h a p l u d a l f ) . Miami series formed in calcareous loam, Soils of the silt loam, or 44 light clay loam till. They occur on level to steep morainal areas and on till plains t h r o u g h o u t southern Michigan. maple The original vegetation c o n s i s t e d of sugar (Acer saccharum M a r s h . ), Ameri c a n b e e c h (Fagus grandifolia E h r h . ) , A m e r i c a n elm (Ulmus americana L . ) , white o a k (Quercus alba L .) , red oak shagbark hickory (C a r y a ovata [Mill.] (Fraxinus americana L . ) , basswood and green ash (Quercus rubra L.) , K. Koch), w h i t e ash (Tilia americana L . ) , (Fraxinus pennsylvanica M a r s h . ) . M u c h of the area occupied b y Miami soils is n o w utilized for grain crops or pastures. Miami soils are typically well drained w i t h a moderate permeability of 20 to 63 mm/hour. Permeabili t y may be h i g h e r in well-s t r u c t u r e d soil bodies such as forest areas. Runoff is m e d i u m on low slopes and very rapid on steep slopes. Both the available m o i s t u r e capacity and natural fertility are m o d e r a t e l y high due to the fine texture of this soil. slight to moderate. The erosion hazard is Normal soil pH ranges from 6.1 to 6.4. Soils possessing physical and chem i c a l c h a r ­ acteristics similar to that of the Miami have a very high potential productivity for better hardwoods such as black cherry (Prunus serotina L . ) , tulip poplar (Liriod e ndron tulipifera L . ) , basswood, red oak, w h i t e oak, and white ash. sugar maple, W h i t e spruce, 45 Norway spruce (Picea abies L . ), and white pine also have high growth rates and are frequently planted. The only management limitation is weed competition. A representative soil profile description of a Miami loam soil is presented in Figure 8. Climate The Lansing climate is similar to that of Midd l e vi.lle in that it alternates between continental and s e m i ­ marine. Despite its location in the middle of the lower peninsula, Lansing is influenced by the proximity of Lake Michigan to the w e s t and Lake H u r o n to the east. However, the wea t h e r tends to be somewhat m o r e c o n t i ­ nental . The m e a n annual temperature for Lansing is abo u t 8 .6°C. Yearly extremes average — 9.3°C in January and 28.1°C in July. The average growing season is about 154 days. The annual precipitation of 772 m m is fairly uniformly distributed. through October, During the months of April rainfall averages 514 mm, w i t h monthly extremes of 20 2 and 4 m m having occu r r e d in the past six years. The max i m u m 24—hour rainfall in the past 30-year period of record was 110 m m in June of 1963. Measurable precipitation occurs on an average of 137 days each year. A b o u t 79% of the days during 46 F i gur e 8 S oil p r o f i l e d e s c r i p t i o n for the t y p i f y i n g p e d o n of the Mi a m i series Service, 1966). (Soil C o n s e r v a t i o n 47 Typif y i n g Pedon: SOIL PROFILE: Miami Loam DESCRIPTION Ap 00 - 20 c m Dark grayish b r o w n (10YR4/2) loam; weak, medium, and coarse, granular structure; friable; slightly to m e d i u m acid; abrupt smooth boundary; 15 to 28 cm t h i c k . A2 20 - 30 cm Light yello w i s h b r o w n (10YR6/4) to br o w n (10YR5/3) loam; weak, medium, platy to weak, coarse, granular structure; friable; m e d i u m to s trongly acid; clean w a v y boundary; 5 to 15 cm t h i c k . B1 30 - 38 cm Yello w i s h br o w n (10YR5/4) to dark b r o w n (10YR4/3) loam or clay loam; thin clay coatings on a few ped faces; moderate, fine, subangular bl o c k y structure; friable to firm; m e d i u m to strongly acid; clear wavy boundary; 5 to 12 cm thick. B21t 38 - 60 c m Dark yello w i s h brown (10YR4/4) or dark brown (7.5YR4/4) clay loam; clay coatings on many ped faces; moderat e to strong, m e d i u m and coarse, subangular blocky structure; firm; m e d i u m to strongly acid; clear irregular boundary; 18 to 38 cm thick. B2 21 60 - 71 cm Dark b r o w n (7.5 YR4/4) to (10YR4/3) clay loam; clay coatings on most ped faces; w e a k to moderate, coarse and very coarse subangular blocky structure; firm; slightly acid to neutral; abrupt irregular boundary; 2.5 to 12.5 c m thick. 71 + cm Light yello w i s h b r o w n (10YR6/4 2.5YR6/4) to brown (10YR5/3) loam or silt loam; mas s i v e (structureless) to very weak, very coarse subangular blocky structure; firm; calcareous. 48 the year are cloudy. Relative humidity averages about 81% in the morning and 66% in the afternoon (strommen, 1971) . Study Design The pilot wastew a t e r renovation study in Lott Woodlot was established during the spring and summer of 19 72. The design consisted of three replications along the w e s t e r n edge of the woo d l o t (Figure 9). Each block in the randomized block design consists of five plots with the following treatments: of well water/week (1) control, (4) (mil-acre) in size. clear of large trees, composition. 25 m m of sewage 50 m m of effluent/week, 75 m m of effluent/week. ha 50 mm (well w a t e r taken from the Michigan State University water s y s t e m ) , (3) effluent/week, (2) and Each plot is square, (5) and 0.0004 All plots were on level ground, and fairly similar in ground cover Each plot was entrenched w i t h 3 mil black plastic to a soil depth of 30 cm to ensure vertical infiltration of the irrigation water. Irrigation System The irrigation system in Lott Woodlot was a gravity— feed trickle irrigation type. This was neces­ sitated by the lack of pumped sewage effluent on the irrigation site, and the physical constraints of e stablishing a portable pumping system for spray irri­ gation to each plot. 49 F i g u r e 9. L o c a t i o n of the t r i c k l e i r r i g a t i o n plots in the Lott Woodlot. 50 *Boyer Road Miami Loam Stendy L o a m Block III Conover Woo d l o t Loam Boundary Blook II Road Miami Loam Brookston Loam Spinks Fox Sandy Sandy Loa m Loam Block I Spinks Conover Brooks toV* Loam Spinks Loam f S andy L o a m * Sandy Loam el ton Drain 51 The trickle system consisted of metal reservoirs, a control valve, pipe (Figure 10). and 12 m m diameter PVC dist r i b u t i o n Combinations of two, four, and five barrels w e r e connected to del i v e r a given volume of water over the plots. The barrel systems were calibra t e d in the lab to del i v e r 101, to correspond to the 25, 202, and 303 liters of w a t e r 50, and 75 m m design rates. The PVC pipe w a s drilled a t 15 cm intervals w i t h 2 m m holes to disp e r s e the irrigation w a t e r (Figure 11). Water d i spersal over the plots, w h i l e not as u n i f o r m as spray irrigation, was suffic i e n t to w e t down the entire plot surface. The control valve had to be kept open to obtain adequate dispersal of the w a t e r away from the plastic pipe. This resulted in high hourly application rates of 25 to 50 mm/hour. Plots w e r e irrigated one day/ w e e k during the growing season. A truck-mounted 2,500 liter tank hauled the chlorinated secondary treat m e n t effl u e n t from the East Lansing Sewage Treatment Pl a n t to the Lott Woodlot (Figure 12). The irrigation reservoirs were pumped full from an access road by aircraft fueling hose. Sewage e ffluent and well w a t e r w e r e deliv e r e d by separate hoses and hauling containers to avoid w e l l water contamination. Irrigation started in July of 19 7 2 and continued to mid-October of that year. In 1973, irrigation was Figure 10. Trickle irrigation system in the Lott Woodlot. reservoir and PVC distribution lines. Note storage 53 54 F i g u r e 11. Water discharge from trickle irrigation s y s t e m u s i n g PVC pipe. F i g u r e 12. Tank and p u m p for d e l i v e r y of w a s t e w a t e r to the Lott W o o d l o t i r r i g a t i o n site. 56 started in June and ended in mid-October. ticular pro j e c t was not c o n t inued in 1974. This p a r ­ It was d esigned as a p i l o t study for research in the period preceding the o p e r a t i o n of the m a i n spray-i r r i g a t i o n system in the WQMA. W a s t e w a t e r w a s available for irri ­ gation through the m a i n sys t e m during the summer of 19 74. C H A P T E R IV METHODS A N D MEASUREMENTS A. M i d d l e v i l l e Wa t e r Quality A n a l y s i s The o b j e c t i v e in utilizing the "living filter" of soil, microorganisms, and plants is to provide a recharge of puri f i e d wa t e r into the ground w a t e r aquifer. Such water, w h i l e not p u r e in the strict sense of the word, is relatively free of the nutrients acquired through use. Porous cup lysimeters w e r e used to sample soil w a t e r at Mid d l e v i l l e since the ground water table is too far be l o w ground surface for adequate sampling. The porous cup or suction lysimeter c o n s i s t e d of a 5 cm diam e t e r PVC plastic pipe of two lengths (60 or 120 cm) end. w i t h a porous clay cup epox y e d to one The top end is sealed w i t h a rubber stopper that contains access tubing used for appl y i n g a v a c u u m to w i t h d r a w samples (Figure 13) . The lysimeter i n s t allation was at 60 and 120 cm depths, 5 m from the sprinkler heads, 57 a co m p a r a b l e 58 F i g u r e 13. S u c t i o n lysimeter: (A) access to r e m o v e w a t e r samples a n d e m b e d d e d in soil. (B) tubing used porous cup 59 60 distance from the sprinklers as were the initial c a l i ­ bration cans. A 7.5 cm diameter soil auger was used to dig the holes for the lysimeters. C a r e was taken to ensure that the cups w e r e prop e r l y seated using fine sand. The auger holes w e r e then backfi l l e d w i t h soil corresponding to the original profile. A plastic apron was located around each lysimeter at the soil surface to p r event w a t e r seepage down the side. A m e t a l can was also pl a c e d over the lysimeter to further reduce possible sideways w a t e r flow. W a t e r samples were obtained w i t h a v a c u u m of 3 3 cm of mercury. Sampling procedures involved: (1) p u t t i n g a v a c u u m on the lysimeters, for 8 hours, and (2) irrigated (3) removing the samples one week later prior to irrigation (Figure 14). Water collecte d from the lysimeters was placed in plastic bottles, served w i t h 40 mg/1 H g C ^ , State University. pre­ and b r o u g h t b a c k to Michiga n Samples w e r e placed in cold storage until chemical analysis could be completed. W a t e r samples collected from both lysimeter and lagoon w e r e analyzed for nitrate nitr o g e n ammonia nitrogen (NO^-N), (NH^-N), total Kjeldahl nitr o g e n and total phosphorus (Total P ) . NO^-N was determined by the b rucine sulfate method, NH^-N b y the phenol hypochlorite method, (TKN), TKN by m i c r o-Kjeldahl method, Figure 14. Collecting soil water samples from suction lysimeters at Middleville by means of a hand pump and vacuum flask assembly (center). 63 and Total P by persul f a t e diges t i o n using Standard Methods for the E x a m i n a t i o n of W a t e r and Wastewater, 13th Edition. Red Pine Gr o w t h and Nutr i e n t Status Addit i o n s of w a t e r and nutrients from w a s t e w a t e r irrigation w o u l d m o s t likely affect tree growth. document such change, DBH, height, To and needle growth, and foliage nutri e n t level w e r e m o n i t o r e d du r i n g 1972 and 1973. DBH was meas u r e d at the end of each growing season. A l l trees in each p l o t w e r e m e a s u r e d using a diameter tape. In addition, two trees o n e a c h plot were m o n it o r e d mon t h l y during the 1973 growing season with band d e n d r o m e t e r s . The heights of all trees w e r e meas u r e d in 1972 and 1973 using a H a g a altimeter. Great d i f f i c u l t y was encountered in locating the tree tops in the thick, closed canopy. A n accurate assessment of the height growth response of the trees to the irriga t i o n was therefore not possible. A limited sample of trees wit h visible tops was selected for me a s u r e m e n t of the 19 72 and 19 7 3 whorl heights above the ground. Needle growth was determined by collecting b ranch samples from the top 2 or 3 wh o r l s on the south side of 4 sample trees in each plot. Sample trees 64 were located at the 4 directional axes of each plot and so marked. removed, The current year's lateral growth was labelled, placed in a plastic bag, back to MSU for analysis. and brou g h t From the basal por t i o n of each sample 100 fascicles were removed, meas u r e d for length, and placed in a separate envelope. Remaining needles were stripped off and placed in a paper bag. Foliage was oven dried at 7 0 °C for 24 hours. Terminal bud length of each sample br a n c h was also measured. Oven-d r i e d needles were ground in a Wiley Mill with a 20 mesh screen for nutrient analysis. Total Kjeldahl nitrogen was determined using the macro-Kje l d a h l method. Water extraction and flame spectrophotometry were used for potas s i u m determination. A mass spect r o ­ graph was used to determine foliar content of sodium, calcium, magnesium, manganese, aluminum, iron, cooper, boron, zinc, and phosphorus. Soils Soil samples w e r e collected in the fall of 19 7 3 to d e t ermine changes in soil chemistry. was used to collect soil from the 0-15, and 105-120 cm depths. A bucket auger 15-30, 45-60, Four sampling points were selected in each plot and samples then combined into a p l o t composite sample. Soil samples w e r e air dried, sieved to pass a 2 mm screen, soil c hemi s t r y lab. and analyzed at the MSU Soil pH was determ i n e d by glass 65 electrode. Calcium, potassium, and m a g n e s i u m were m easured by atomic a b s o rption analysis after extracti o n with a m m o n i u m acetate. Phosphorus was analyzed by extraction w i t h Bray's P^ solution and quan t i t a t i v e determination by spectrophotometry. Boron analyses we r e done b y the W i s c o n s i n state soil testing lab using the cucurmin method. M a c r o - K j e l d a h l techniques w e r e used to o b t a i n the total Kjeldahl nitrogen, matter was m e a s u r e d using Davies on-ignition, and soil organi c (1974) me t h o d for loss- both operations p e r f ormed in the D e p a r t m e n t of Forestry soils lab. Humus The forest floor (0 horizons) bene a t h a red pine stand c onsists of organic matter in vary i n g stages of decomposition. This organic matter, called humus, is composed of rece n t l y depos i t e d litter such as needles, branches, and cone parts, parti a l l y d e c o mposed b u t still recognizable litter, and organic mate r i a l in more advance stages of decomposition. The physical, chemical, and b i o l o g i c a l characteristics of the u n d e rlying soil are s t r ongly influenced by the properties of the humus. A study of the duff mull humus 1956) (Trimble and Lull, in the red p i n e stand at M i d d l eville was conducted towards the e n d of the 1973 growing season. Subplots were e s t a b l i s h e d o n the cardinal axes of each plot at 2, 4, and 6 m distances from the plot center and marke d 66 by plastic stakes. A 300 c m delineated such p l o t s . 2 core cutter (Figure 15) Orga n i c mate r i a l above the A p horizon was removed and placed in labelled bags. A 50% sand/humus ratio was used as the end p o i n t for the lower limit of the forest floor w h e n the b o u n d a r y was diffuse. During the actual sampling, measurements were taken. several d i r e c t For e s t floor d e p t h was measured at six locations around the c i r c u mference of the sampling core. Mycelial m a t and e a r t h w o r m counts were used as indicators of d e c o m p o s i t i o n acti v i t y of fungi and annelids in rela t i o n to w a s t e w a t e r irrigation. These counts are indices and do not represent absolute numbers. Pres e n c e or a bsence of these organisms w i t h i n the sampling core was recorded simply by means of a "yes" or "no." The index for myce l i a l mats and e a r t h ­ worms ranged from a m i n i m u m value of 0 to a m a x i m u m of 12 (based on 12 subplots per p l o t averaged by t r e a t m e n t ) . Samples of the duff mull humus were o v e n dried at 70°C for 24 hours, a nd the w e i g h t of the w o o d y litter and incorporated mineral soil measured. was hand separated and weighed. W o o d y material Mineral soil was e s t i ­ mated by sieving the samples through 16 and 32 mesh screens and ashing the material w h i c h passed through the sieves. Needle litter and d e c o mposed organic matter w eight was determined b y subtracting the wei g h t s of the mineral soil and wo o d y litter from the total forest floor weight. Figure 15. The 300 cm 2 core cutter used for collection of forest floor samples. 69 Fungi Count A survey of the number of fungal fruiting bodies present in the study plots at Middleville was conducted from m id-Au g u s t through October of 1973. Representative fruiting bodies were collected for i d e n t ification but total counts in each plot w e r e combined for all species. B. MSU Lott Woodlot Water Quality Analysis The water sampling and analytical procedures used in the Lott Wood l o t were the same as those described for Middleville. Lysimeters, however, were positi o n e d at 30 and 60 cm depths. Herbaceous Vegeta t i o n Although the herbaceous and tree seedling understory is quite variable throughout the Lott Woodlot, studies were initiated to assess the response of this stratum to wastewater irrigation. Analysis was a c c o m ­ plished through two count surveys and a combination b i o m a s s -nutrient study. A general vegetation survey was conducted in 1971 when permanent vegetation sample plots were e s t a b ­ lished. This survey gives the species c o m p o sition of the overstory, shrub, and understory components. In Au g u s t of 1972 and 1973 a count of the number of individual plant species was conducted on each of the 70 fifteen 0.0004 ha irrigation plots. Sp r i n g flora and number of individuals flowering throughout a two-month period was u n d e rtaken in the spring of 19 73 and 19 74. In May, 1974, the new growth of 10 randomly selected sugar m a p l e seedlings in e a c h p l o t was c o l ­ lected. The collected samples w e r e weighed, oven dried at 7 0 °C for 24 hours, and reweighed to deter m i n e w e t weight, dry weight, and perc e n t moisture. The dried samples w e r e then ground up in a W i l e y Mill w i t h a 20 mesh screen and subsequently analyzed for nutrient content as descr i b e d in the section o n red pine growth and nutrient status. C o m p a r a b l e data w e r e collected on 2 all herb species found on a 0.25 m area in the n o r t h e a s t quadrant of each plot. Soil Soil m o i s t u r e w a s m o n i t o r e d throughout the second irrigation season using t e n s i o n m e t e r s . Tensionmeters were p l aced at 30 and 60 cm depths in the control, 25 m m of effluent and 75 m m of effluent treat m e n t plots of Blocks 1 and 2 of the replicated study. We e k l y m e a s u r e ­ ments of soil mois t u r e tension w e r e m a d e in centibars. Tensionmeters w i t h br o k e n water columns w e r e assumed to have attained 100 centibars of tension. Soil samples from the irrigation plots w e r e co l ­ lected in the spring of 1974. plot at 15, Two sample points per 30, and 60 cm depths c o n s tituted a plot 71 composite sample. The soil mate r i a l w a s then air dried, sieved to pass a 2 m m m e s h screen, and analyzed in the same m anner as the M i d d l eville soil samples. O xygen diffu s i o n m e a s u rements w e r e m a d e during the 1973 irrigation season to determine the affects of irrigation on soil aeration. A Jensen Ox y g e n Dif­ fusion Ratemeter was used to mon i t o r soil oxygen flux at 10 and 30 cm depths (Lemon and Erickson, 1952). Measure­ ments were made be f o r e and after irrigation in m i d - J u l y and early August. Humus The forest floor in a hard w o o d forest horizons) (01 and 02 consists mainly of recent leaf and b r a n c h litter and parti a l l y d e c o mposed litter. Most of the organic m a t t e r in advanced stages of decay is incor­ porated into the Al hor i z o n by e a r t h w o r m activity. This type of a forest floor is classi f i e d as a coarse mull humus (Trimble and Lull, 1956). A survey of the humus w i t h i n the Lott W o o d l o t wastewater irrigation study was condu c t e d in the fall of 197 3 b efore leaf fall. Four subplots w e r e e s t a b ­ lished in the four quadrants of each plot, m i d w a y from 2 the plot center to the respec t i v e corners. A 300 cm core cutter was used to def i n e the boundaries of each subplot. Humus w i t h i n the core was removed and 72 ovendried at 7 0 °C. The d r i e d humus was then separated and w e i ghed by w o o d y and nonwoody c o m p o n e n t s . CHAPTER V RESULTS A N D DISCUSSION A. Middleville Water Quality Wastewater was applied to the red pine stand at M iddle v i lle during the summer and early fall of 1972 and 1973. The 1972 i r r i gation season b e g a n on July 7th and ran to October 31st w i t h a two-week shutdown in the last half of July due to low lagoon levels. During 1972 the red pine irrigation system o p e r a t e d from a separate intake and pumping arrangement w h i c h could not draw effluent during low lagoon stages. In 197 3 the main Middle v i lle pumping facility was utilized. The 19 7 3 irrigation season was initiated on May 24th and con­ tinued to Oct o b e r 14th w i t h another two-week shutdown in mid-July. The halt in the 1973 operations was caused by lightning damage to the pumping electrical system. Under normal operating c o n d i t i o n s , w a s t e w a t e r irrigation in forest stands can b e g i n in late A p r i l or early May. A t that time m o s t n o n c a pillary pores are open and moisture stress in coarse textured soils 73 74 begins. In m o s t situations, w a s t e w a t e r irrigation can be resumed earlier and continued longer in forest sites than in cropped f i e l d s . Wastewater Inputs During both irrigation seasons the lagoon effluent was monitored for c o n c e ntrations of ammonia nitrogen (NH^-N), nitrate nitr o g e n nitrogen (Organic N ) , total nitrogen total phosphorus (Total P ) . (N03~ N ) , organic (Total N ) , and Table 1 presents the values of these nutrient forms for each year. Table 1. Year Ave r a g e concentrations of lagoon effluents in the M i d d l eville wastewater. NH^-N N 0 3-N Organic N ------------------------------ Total N Total P mg/l-------------------------------- 1972 1.2 0.8 6.4 8.4 3.8 1973 0.7 2.0 4.4 7.1 2.4 Concentrations w e r e variable over the two irrigation seasons. Decreases were noticed in N H 3*-N, Org a n i c N, 3 Total N, and Total P wh i l e NO -N increased. These d i f ­ ferences w e r e probably due to changes in the o p e r a t i o n of the lagoons. For example, in 1972 the corn irrigation area was not receiving wastew a t e r and all the effluent entered the south lagoon while the north one w a s being repaired. High levels in N H 3~N, Organic N, Total N, and 75 Total P w o u l d thus be expected due to a lack of any sig­ nificant n u t r i e n t ou t p u t and further c o n c e n t r a t i o n by evaporation. L o w N O ^ - N levels re s u l t w i t h improper water circu l a tion and aeration. In 1973, the entire wa s t e w a t e r treatment facility was o p e r a t i n g normally. Thus, NO^-N levels rose w h i l e other nutrient forms decreased. b i lity w i t h i n each year was also noted. Varia­ For instance, in 1973 NO ^ - N fluctuated from a low of 0.10 m g / 1 to a high of 4.0 mg/1. However, m o s t lagoon determinations for N O ^ -N w e r e w i t h i n ±1.0 mg/1 of the m e a n for the i r r i ­ gation season. W e e k l y m o n i t o r i n g o f the app l i e d effluent may thus be c o m e advisable to ob t a i n a reliable estimate of n u t r i e n t loading. N u t rient Loading Table 2 shows the w a t e r and nutr i e n t loading rates for the two years of irrigation. The addi t i o n of the w a s t e w a t e r s i g n i fic antly altered the p r e c i p i t a t i o n regime. by 40, It had the ef f e c t of increasing p r e c i p i t a t i o n 80, and 140% in 1972 and by 55, 110, and 190% in 19 7 3 over the yea r l y p r e c i p i t a t i o n means of 955 and 866 m m respectively. It should be noted that since the w a s t e w a t e r irrigation came during the months of May through July, its impact on p r e c i p i t a t i o n dur i n g those months was p r o p o r t i o n a t e l y greater. The n u t r i e n t load­ ings in kg/ha w e r e dete rmined by using the following equation: 76 Table 2. Wastew a t e r irrigation and nutri e n t loading rates at Middleville, 1972 and 1973. (A) A m o u n t of i r r i gation and precipitation. W a s t e w a t e r Irrigation Rainfall Year --- 25 50 88 mm ---- 1972 955 375 750 1320 1973 866 475 950 1672 (B) A v e r a g e nutr i e n t loading rate w i t h d i f f e r e n t levels of w a s t e w a t e r irrigation. 1972 Nutrient 25 — 1973 50 — — jvy/na 88 25 50 88 " nh 3- n 4.5 9.0 15.8 3.3 6.6 11.7 no 3- n 3.0 6.0 10.5 9.5 19 .0 33.4 Organic N 24 .0 48.0 84 .5 20.9 41.8 73.6 Total N 31.5 63.0 110.8 33.7 67.4 118.7 Total P 14.3 28.5 50.2 11. 4 2 2 .8 40.1 77 (Equation 1) N = C- m- v- D » l - a where: N « nutrient loading in kg/ha C = effluent c o n c e n t r a t i o n in mg/1 m = mass conver s i o n factor (10 ® kg/mg) —3 3 v = volume conver s i o n factor (10 1/cm ) D = amount of effl u e n t applied in m m / y e a r 1 = length conver s i o n factor a - area c o n v e r s i o n factor (10 ^ cm/mm) (10 8 2 c m /ha) Of notable interest is the increase in the NO^-N loading levels. The rise in 1973 lagoon NO^-N concentrations coupled w i t h the larger amounts of irrigation water resulted in a three-fold rise in NO^-N loading. Of the Total N applied to the M i d d l e v i l l e site in 1972, 10% was in the NO^-N form. In 1973, 30% of the Total N loading was in the highly mob i l e NO^-N form. Ground W ater Recharge To interpret the trends in the m o v e m e n t of nit r o ­ gen and phosphorus in the soil w a t e r bene a t h the red pine stand at Middleville, it is necessary to compute the water b u d g e t utilizing T h o r n t h w a i t e *s Potentital E v a p o t r anspiration Formula 19 57). (Thornthwaite and Mather, Table 3 contains computations used to o b t a i n an e s t i mated ground w a t e r recharge m o v i n g p a s t the 78 Table 3. Calculation of ground water recharge according to Thornthwaite*s Water Budget Method at the 60 cm depth in plots receiving 25 mm/week of wastewater i r r i g a t ion , 1973. Month - 1 9 7 3 Water Budget Factor Apr May June July Aug Sept Oct 8.6 12.5 21.3 22.6 22.7 17.8 13.2 Mean monthly Temp. < v - ”c 2.27 4.00 8.97 9.82 9 .88 6.84 4.35 Unadjusted Daily Potential Evapotranspiration (PE) — mm 1.1 1.8 3.4 3.7 3.7 2.8 1.9 Latitude Correction Factor (LCF) 12 hr. units 33.6 37.8 38.4 38.7 36.0 31.2 28.5 Monthly Potential Evapotranspiration (PE) - m m 37 68 131 143 133 87 54 Monthly Rainfall (Pr ) - mm 54 38 26 31 60 116 70 0 50 100 50 125 100 50 Total Monthly Precipitation (P^) - mm 54 88 126 81 185 216 120 Net Precipitation (Pfc - PE) — mm 17 20 -5 -62 52 129 66 Accumulated Water Loss (AWL) - mm 0 0 -5 -67 0 0 0 100 100 95 50 100 100 100 Change in Soil Water Storage (ASS) - mm 0 0 -5 -45 + 50 0 0 Ground Water Recharge (GWR) - mm 17 20 0 0 2 129 66 Heat Index (I) Monthly Irrigation (P^) - mm Soil Water Storage (SS) - mm 79 60 c m lysimeters beneath the plots receiving 25 m m of w a s t e w a ter/week in 1973. m o nthly temperatures By k n o w i n g the estim a t e d m e a n (average of temperatures Grand Rapids and Hastings) ville, the h e a t index e v a p o t r anspiration (LCF) from and the latitude for M i d d l e ­ (I), unadju s t e d daily potential (pe) and latitude c o r r e c t i o n factor are determ i n e d using methods d e s c ribed by T h o r n t h ­ w aite and Ma t h e r (1957). The mont h l y potential e v a p o t r a n s p i r a t i o n the p r o d u c t of pe and LCF. (Pt) (Pi). is Total m o n t h l y preci p i t a t i o n is comp u t e d using rainfall loading (PE) (Pr) and irrigation The difference b e t w e e n Pt and PE p r o ­ duces the net p r e c i p i t a t i o n (Pt - P E ) . If Pt - PE is negative, an accumulated w a t e r loss total (AWL) results and remains so until Pt - PE becomes positive again. Soil w a t e r storage (SS) is e s t i mated to be 100 m m for the 60 c m soil profile and 200 m m for the 120 cm soil profile. These figures are b a s e d o n data w h i c h list sandy l o a m soil as having 150 m m of avail a b l e w a t e r per m of soil (Thornthwaite and Mather, 195 7). By inter­ p o l ating and rounding to the nea r e s t m u l t i p l e of 50 (i.e. 50, 100, 150, 200, 250, etc.) the figures of 100 and 200 m m for the two depths of soil are obtained. Using tables from Thornthwaite and Mather (1957) which give the soil moisture retained in a given soil after d i f f e r e n t amounts of potential evapo r t r a n s p i r a t i o n have 80 occurred, maximum, a SS value is determined. the ground w a t e r recharge be equal to net precipitation. GWR is assumed to be zero. again, W h e n the SS is a (GWR) When is assumed to - PE is negative, As P^. - PE becomes positive the excess p r e c i p i t a t i o n is used to satisfy the soil m o i s t u r e deficit. Once SS is back up to maximum, any r e m aining P fc - PE is tabulated as GWR. Ground w a t e r recharge compu t e d for the 19 72 and 197 3 g r owing seasons is prese n t e d in Tables 4A and 4B. Little ground w a t e r re charge occu r r e d du r i n g the period of April through October u n d e r u n i r rigated conditions. In 1973, only the 88 m m / w e e k irrigation rate p r o d u c e d ground w a t e r recharge each month. A p p l i c a t i o n s of 25, 50, and 88 mm/week of w a s t e w a t e r increased the ground water r echarge d u r i n g the growing season at the 60 cm depth by factors of 5, 9, and 16 in 1972 and 14, 41, and 8 3 in 1973. Calculations of Nutrient R enovation Several methods can be used in e v a l u a t i n g the nitrogen and phosphorus renova t i o n w h i c h o c c u r r e d w h e n w a s t e w a t e r irrigation was applied to the M i d d l eville red pine plantation. The ground w a t e r recharge method is fairly accurate since it compares the mass of each nutrient applied to the mass passing through the soil profile. The technique assumes knowledge of: (1) the 81 Table 4. E s t i mated ground w a t e r recharge at two soil depths and four w a s t e w a t e r irriga t i o n rates on a red pine planta t i o n at Middleville, 19 72 and 1973. Ground W a t e r Recharge 60 cm depth Month April 0 25 50 120 cm depth 0 88 25 50 88 73 73 73 73 73 73 73 73 May 0 0 0 0 0 0 0 0 June 0 0 0 0 0 0 0 0 July 0 0 0 83 0 0 0 81 August 0 94 24 6 464 0 84 249 464 September 0 137 237 389 0 137 237 389 October 15 121 216 373 0 121 216 373 Total 88 425 772 1382 73 415 775 1382 Ground Water Recharge (B) 1973 60 cm depth Month April 0 25 50 120 c m depth 88 0 25 50 88 17 17 17 17 17 17 17 17 May 0 20 70 146 0 20 70 146 June 0 0 95 247 0 0 95 247 July 0 0 0 64 0 0 0 64 August 0 2 165 367 0 0 165 367 September 0 129 229 381 0 122 229 381 October 0 66 116 192 0 66 116 192 17 235 692 1414 17 225 692 1414 Total 81 Table 4. E s t i m a t e d gro u n d w a t e r rech a r g e at two soil depths and four w a s t e w a t e r i r r i gation rates o n a red pine p l a n t a t i o n at Middleville, 1972 and 1973. Ground W a t e r Recharge 60 cm depth Month 0 50 25 120 c m depth 88 0 25 50 88 -mm-----April 73 73 73 73 73 73 73 73 May June 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 July 0 0 0 83 0 0 0 81 Au g u s t 0 94 246 464 0 84 249 464 September 0 137 237 389 0 137 237 389 October 15 121 216 373 0 121 216 373 Total 88 425 772 1382 73 415 775 1382 G round Water Recharge (B) 1973 60 cm depth Month 0 25 50 120 c m depth 88 0 25 50 88 -mm-----April 17 17 17 17 17 17 17 17 May 0 20 70 146 0 20 70 146 June 0 0 95 247 0 0 95 247 July 0 0 0 64 0 0 0 64 Au g u s t 0 2 165 367 0 0 165 367 September 0 129 229 381 0 122 229 381 October 0 66 116 192 0 66 116 192 17 235 692 1414 17 225 692 1414 Total 82 monthly irrigation in mm, (2) the average nutrient concentration of the wastewater in mg/1, (3) the monthly ground water recharge in mm, and (4) the mean monthly concentration of soil percolate in mg/1 col­ lected in the lysimeters. Using Equation 1, items 1 and 2 are used to compute (A) the wastewater loading for each nutrient form in kg/ha, and items 3 and 4 are used to compute (B) the amount of nutrient carried in the soil water collected in the lysimeters. cent renovation The per­ (C) is calculated by dividing B by A. A second and more direct method for calculating nutrient renovation would be to compare the concentration of each nutrient form in the lysimeters Ground Water Recharge Method) wastewater (item 4 in the with that of the irrigated (Item 2 in the Ground Water Recharge M e t h o d ) , The percent renovation for this method is computed by dividing Item 2 by Item 4. A hypothetical comparison of the use of these two methods in estimating wastewater renovation is pre­ sented in Table 5. recharge (August) For periods with low ground water the percent renovation calculated by the direct method is considerably lower than that of the other method. recharge During months with high ground water (September), the direct method produces a higher estimate of renovation. It is believed that the ground water recharge method is the most accurate 83 of the two methods since it accounts for the amount of water percolating through the soil profile. A high NO^-N content in soil water is of no concern if very little of the irrigated water reaches the ground water table. However a moderate NO^-N level in soil water is significant if the majority of the applied wastewater moves into the ground water aquifer. Table 5. Comparative computations of hypothetical NO^-N renovation using the direct and ground water recharge methods for a 25 mm/week irrigation rate. Month Parameter Item Units August September Irrigation 1 mm 125 100 Wastewater Content 2 mg/1 2.0 2.0 Wastewater Loading A kg/ha 2.5 2.0 Ground Water Recharge 3 mm 2 129 Lysimeter Content 4 mg/1 1.0 1.0 Lysimeter Loading B kg/ha 0.02 1.29 Ground Water Recharge Method Renovation C % 99 35 Direct Method Renovation D % 50 50 The nutrient renovations at Middleville during 1972 and 19 7 3 for the two soil depths are presented in Tables 6 and 7. These values are used in discussing changes in water quality monitored by the lysimeters. Table 6. Percent nutrient renovation using the ground water recharge method at 60 cm depth at Middleville, 1972 and 1973. 60 cm depth 1972 Month 1973 Kate NH--N 3 NO.-N 3 0r^ nic N Total N Total P n h 3- n n o 3- n --------------------- % ----- Jun Organic N ---- Total N Total P %---- 100 86 96 100 95 34 100 94 94 100 94 75 100 99 99 100 100 99 100 100 97 100 100 80 100 100 97 100 100 93 100 100 100 96 90 94 100 99 100 100 56 52 100 96 76 99 85 79 100 85 75 100 99 99 95 97 94 95 95 94 99 100 100 71 50 88 90 60 20 64 87 87 72 77 69 97 99 100 75 94 93 95 63 93 94 68 92 97 99 100 87 57 92 80 70 60 68 80 83 75 51 78 97 99 99 90 78 91 97 87 94 96 87 94 99 100 100 94 67 81 95 85 49 88 89 87 90 83 76 99 100 100 25 50 88 — — — — — — — — — — — — — — M ■* Jul 25 50 88 100 100 99 100 100 86 100 100 96 100 100 95 Aug 25 50 88 95 90 89 90 50 91 97 94 95 Sep 25 50 88 94 87 90 91 87 93 Oct 25 50 88 95 79 86 Mean 25 50 88 98 88 90 Table 7. Percent nutrient renovation using the ground water recharge method at 120 cm depth at Middleville, 1972 and 1973. 120 cm depth 1972 Month Rate mm/week -----------NH^_N n o 3-N Organic N 1973 Total N Total P ^ 3~ nn „ w 3-w % Organic N Total N Total P % — — — 100 57 84 100 47 87 100 95 94 100 88 91 100 94 98 100 100 94 100 100 97 100 100 97 100 100 100 100 100 95 100 100 89 100 100 94 100 100 98 100 100 100 93 93 91 0 25 91 91 91 95 76 85 94 99 97 99 100 0 74 100 72 62 100 89 90 100 78 81 100 97 99 25 50 88 83 87 93 0 12 89 84 91 92 73 89 92 99 93 99 57 50 92 45 65 6 95 77 53 93 71 44 98 99 99 Oct 25 50 88 88 79 93 75 81 93 89 85 93 88 90 93 97 86 99 0 71 67 0 80 74 95 70 71 92 85 72 98 97 98 Mean 25 50 88 91 89 92 0 47 92 90 91 94 82 89 94 99 93 99 87 40 82 64 64 59 98 87 81 97 81 76 99 97 99 25 50 88 — — — — — — Jul 25 50 88 100 100 90 Aug 25 50 88 Sep Jun 86 Nitrogen 60 cm: 25 mm/Week Average concentrations of NH^-N, NO^-N, Organi c N and Total N at the 60 cm d e p t h for the 25 m m / w e e k treatments are shown in Figure 16. In 1972, b o t h the NH^-N and N 0 3~N forms w e r e relatively stable w i t h average renovations of 98 and 90% respectively. NO^-N levels w e r e b e l o w 0.2 mg/1. All The Organic N c o n c e n ­ tration rose in late August, b u t the r e n o v a t i o n for the year r e mained h i g h at 97%. Total N renova t i o n was 96%. Nitrogen renova tions in 1973 w e r e g e n e r a l l y lower than in 1972. N H 3~N levels remained stable and very similar to those of the previous year, but renovation dropped slightly to 94%. N O ^ —N e x h i b i t e d the only increase in renova t i o n b y rising to 95%. and Total N showed lower renovations of respectively. Org a n i c N 88 and 90% A relatively large peak in Org a n i c N, w hich o c curred in early September, lower Total N renovation. accounted for the The high Org a n i c N levels coincided w i t h the resumption of ground w a t e r recharge {Table 4). 60 cm: 50mm/Week Figure 17 shows the average c o n c entrations of N H 3 -N, N 0 3 ~n, Organic N, and Total N in lysimeters at the 60 cm depth for the 50 mm/ w e e k irrigation rate. Figure 16. NH^-N, NO^-N, Organic N, and Total N concentrations at the 60 depth for the 25 mm/week irrigation rate at Middleville, 1972 and 1973. 4 2 1973 1972 Total mg / 1 Organic 1 A... 0 7-14 8-04 9-07 10-1 6-13 7-12 8-13 9-06 10-04 Figure 17. NH^-N, NO^-N, Organic N, and Total N concentrations at the 60 cm depth for the 50 mm/week irrigation rate at Middleville, 1972 and 1973. i m Total N Organic N 91 N H 3~N values were relati v e l y uni f o r m throughout 1972. Renovation was at an a c c e p t a b l e level of 8 8 %. N 0 3~N renovation during 1972 averaged about 12% lower than the 25 mm/ w e e k irrigation rate at 78%. N 0 3~N climbed steadily to a peak of about 0.8 mg/1 in early A u g u s t and then declined quite rapidly. Both the Organic N and Total N renovations averaged 87% in 1972. T h e high Organic N level on Oct o b e r 12th represented an erratic value in one plot. Lysimeters in plots of the other two treatments did not e x h i b i t similarly high values. In 1973, the renova t i o n efficiency for N H 3~N dropped off c o n s i derably to 67%. This was due primarily to a rise in N H 3~N levels bet w e e n July 7th and A u g u s t 13th. N 0 3~N r enova t i o n for 1973 (85%) improved over t h a t of 19 7 2 d e s p i t e two peaks above 1.0 mg/1. The 197 3 Organic N r e n o v a tion improved slightly to 89%. Total N r e n o ­ vation d ecreased to 83% due to the combined effects of rises in the N H 3 ~N, N 0 3 ~N, and Org a n i c N forms. 60 cm: 8 8 mm/Week Graphs of the levels of N H 3 ~N, N 0 3 *-N, Org a n i c N, and T otal N found soil w a t e r taken from lysimeters buried at 60 cm under plots receiving 88 irrigation are shown in Figure 18. mm/week of w a s t e w a t e r During 1972, N H 3~N concentrations w e r e fairly u n i f o r m at values less than 0.2 mg/1. Except for the first sampling date, N 0 3~n v a lues were unifo r m l y less than 0 . 1 all mg/1 . Figure 18. NH-j-N, N03-N, Organic N, and Total N concentrations at the 60 depth for the 88 mm/week irrigation rate at Middleville, 1972 and 1973. i 1972 1973 mg/1 Total N ID a n o 3~n "^ •- \ A V ■•* * 7-14 I"* 8-04 A »■ ■ I \ \ V " y 10-12 6-13 • . '>/ \ \ \ 1 ' I 1 9-07 * Organic N 7-12 8-13 \ \I NH7-N ■ nr 9-06 10-04 UJ 94 Renovation of the N H 3~N and N 0 3~N forms was q u i t e similar at 90 and 91% respectively. In 1972, O r g a n i c N and Total N e x h i bited trends very similar to those found in the 25 m m / w e e k irrigation rates. Organic N had a high peak of about 0.7 mg/1 in late A u g u s t and accoun t e d for much of the Total N throughout the 1972 irrigation season. However, the year. Organic N r e n o vation averaged 94% for Total N renova t i o n was the same as Org a n i c N. Renova t i o n of the various forms of nitrogen dropped o f f in 1973 for the 88 mm/week irriga t i o n rate as it did for the other two rates. NH^—N renova t i o n was 81% in 1973 prima r i l y due to a high level on A u g u s t 13th. 87%. (0.6 mg/1) Org a n i c N renovation fell off 7% to A high peak (1.7 mg/1) on Au g u s t 13th coincided with substantial increases in ground w a t e r recharge between July and A u g u s t and probably r e p r esented the flushing of w a s t e w a t e r Organic N and litter decay p r o ­ ducts. The largest drop in renovation w a s exhibited by NO^-N. The average NO^-N renovation in 19 7 3 fell by 42% to a low of 49%. June (over 3 mg/1) accounted for this. High peaks in the NO^-N curve in and in September (about 1.5 mg/1) These peaks occurred during periods of high ground w a t e r recharge (Table 4) and probably represented the flushing of residual N 0 3~N through the soil profile. As a result of the reduced renovations in N 0 3~N and Organic N, Total N renovation was reduced 95 to 76%. The three dist i n c t Total N peaks in 1973 (Figure 18) were due to pulses of N O ^ —N in the first peak, O rganic N in the second, and NO^-N in the third. NO^-N accounted for nearly 60% Total N loss 120 cm: (25.5 kg/ha) (15.1 kg/ha) of the in the high irrigation rate. 25 mm/Week Ave r a g e concentrations of NH^-N, NO^-N, Organic N, and Total N at the 120 c m depth for the 25 mm/week i r r i ­ gation rate are prese n t e d in Figure 19. In 1972, NH^-N levels w e r e relatively stable w i t h renovation averagi n g 91%. However, NO^-N was very erratic. Part of this was due to the fact that only one lysimeter produced these data points in 1972. 1972 was zero. Renovation for NO^-N in While Organic N at the 120 c m depth was more variable than at the 60 cm depth, still high at 90%. renovation was Despite poor NO.J-N renovation, overall removal of Total N was 82%. This was resulted from the fact that NO^-N loading accounted for a lower proportion of the Total N loading in relation to NH^-N and O r g a n i c N loading. Since o n l y single data points w e r e available in 1973 for NH^-N, Organic N, and Total N, rough a p p r o x i ­ mations of the renovations w e r e made using those data points as averages. by the lack This procedure of sufficient lysimeter was necessitated sample volumes Figure 19 . NH3-N, N03-n, Organic N, and Total N concentrations at the 120 depth for the 25 mm/week irrigation rate at Middleville, 1972 and 1973. mg/1 1973 Total Organic N • n o 3-n NH-.-N 7-14 8-04 10-12 98 needed to compl e t e the analyses for all nitrogen forms. A more complete picture of the N 0 3~N trend was availa b l e since sufficient sample volumes w e r e collected on four different dates to test for NO^—N. Consequently no concise interpretations of the d a t a can be made e x c e p t to note that NO^-N did fluctuate c o n s iderably from a high of about 3.8 mg/1 to a low of 0.0 2 m g / 1 . 120 cm: 50 mm/Week F igure 20 presents the NO^-N, Org a n i c N f and Total N trends for the 120 cm d e p t h lysimeters under plots w i t h a 50 mm/ w e e k irrigation rate. NH^-N was relatively stable in 1972 and had an average renovati o n of 89% for the year. N 0 3~N was erratic throughout 1972. A r enovation of 47% for N 0 3~N was an improvement over that found in plots receiving 25 mm/week, but was less than computed for the same treatment at the depth. 6 0 cm soil Part of the instability in N 0 3*-N values w a s due to the small volumes of samples d e l i v e r e d by one lysimeter out of a replication of three. Organic N levels oscill a t e d quite a bit b u t overall renovation was good at 91%. The Total N values reflected the peaks in N 0 3~N and O r g a n i c N, but the renovation was very satisfactory at 89%. During 1973 the renovation fell off for all nitrogen forms except N 0 3 ~N. N H 3—N exhibited an Figure 20 NH^-N, NO^-N, Organic N, and Total N concentrations at the 120 depth for the 50 ram/week irrigation rate at Middleville, 1972 and 1973. Total N H O o Organic N NO3-N n h 3-n 101 uncharacteristic increase up to 1.3 mg/1 in the first part of the irrigation season. was low at 40%. variability Renovation for NH^-N NO^-N conti n u e d to show considerable (low of 0 . 0 mg / 1 and a high of about 2 . 2 m g / 1 ) but the overall renova t i o n improved b y rising to 64%. Organic N renovat ion remained fairly high at 87%. Total N renovation decre a s e d to 81% as a result of the decreases in Organic N and NH^-N renovations. 1 2 0 cm: 8 8 mm/Week The NH^-N, NO^-N, Organic N, and Total N r e n o ­ vations for the 1 2 0 cm d e p t h and 88 rate are prese n t e d in Figure 21. mm/week irrigation N H ^ —N and NO^-N levels in 1972 w e r e stable b e l o w 0.2 mg/1 with renovations of 92%. O r ganic N concentrations w e r e higher than either NH^-N or NO^-N that same year but the overall renovation for it and Total N was high at 94%. In 197 3 the renovations for all nitrogen forms declined. While NH^-N levels increased only slightly, the average renovation dro p p e d to 82%. the largest decrease in renovation NO^-N suffered (92 to 57%). The poor N 0 3“N renova t i o n in 1973 resulted from the peak in September which accompanied high ground w a t e r recharge. Organic N renova t i o n d e c r eased only slightly to 87% despite high concentrations in September. Total N renovation (76%) The lower reflected the decreases in the other three forms of nitrogen. It is interesting to Figure 21. NH^-N, NO^-N, Organic N, Total N concentrations at the 120 cm depth for the 88 mm/week irrigation rate at Middleville, 102 1972 and 1973. 1972 1973 Total 103 ^ 7-14 8-04 9-07 10-12 6-13 7-12 8-13 9-06 10-04 Organic 104 to note that w h i l e Organic N applied to the red pine site was twice that of N O ^ —N, the nitrogen losses for each form w e r e almost identical. Nitrogen Summary From the data presented, the major p r o b l e m in applying municipal wastew a t e r to the red pine plantati o n is nitrogen in the form of N O ^ —N. This p r o b l e m may likely be directly related to the hourly rate of irri­ gation and not the total weekly application. All three weekly levels of wastewater are applied over the same eight-hour time period. Thus the 25, 50, and irrigation loadings occur at rates of 3, 6 8 3 mm/week , and 11 mm/hour. A n application rate of 11 mm/hour w o u l d tend to cause more NO^-N flushing than one of 3 mm/hour. Water can e asily infiltrate into the soil at rates greater than 11 mm/hour (Lull and Reinhart, 197 2), but w a s t e ­ water m o v i n g through the soil at such high ho u r l y rates allows very little time for NO^-N uptake by plants or denitr i fication by microorganisms before it reaches the lysimeter depths. Therefore it becomes diffi c u l t to compare the three irrigation treatments because it is impossible to differentiate whe t h e r the reduced N 0 3~N renovation for the 88 mm/week irrigation rate, as 105 measured b y suction lysimetry, is due to the total amount of nitrogen loading or the hourly rate at whic h the w a s t e w a t e r is applied. NH^-N and Organic N had acceptable renovation levels at all three irrigation rates throughout the study. Improved NO^-N r e n o vation might b e obtained at the h i g h rates of irrigation b y limiting the hourly rate to 3 mm/hour. Total P hosphorus Total P values at the 6 0 cm depth were variable in 1972 and exhibited several high peaks in 1973 (Figure 22). However, the average Total P renovation was 99, 100, and 100% during 1972 and 1973 for the 25, 50, and mm/week irrigation rates. 8 8 an e x c e l l e n t Total P renovation. This represented At the 120 c m depth considerable variations in Total P took place (Figure 23), but r e n ova t i o n at this depth during 1972 and 1973 was around 99%. Red Pine Fol i a r Nutrients Foliage samples were collected f r o m the upper one-t h i rd of the red pine crowns in early December of 1972 and mid-November of 1973 to determine if the dif­ ferent rates of w a s t ewater application w e r e affecting nutrient uptake. of trees, When evaluating the nutrient balance several factors have to be considered. First, Figure 22. Total P concentrations at the 60 era depth at Middleville, 106 1972 and 1973. f 1973 1972 20 • .16 ■ 107 mg/ 1 12- mm/week 08* 88 7-14 8-04 9-07 10-12 6-13 7-12 8-13 9-06 10-04 Figure 23 . Total P concentrations at the 120 cm depth at Middleville, 1972 and 1973. 108 1973 1972 6.0 4.0 109 mg/ 1 mm/week 8-04 10-12 7-12 10-04 110 the n u t r i e n t con t e n t varies by the tree component, w i t h the c o n c e n t r a t i o n per g r a m of dry w e i g h t d e c r e a s i n g in the order of foliage, bark, branches, (Nelson et a l ., 1970). Also, stem, and root the greatest elemental concentration existing in the foliage occurs in the crown extremities (Young and Guinn, 1966) . Thus, needles from the crown top become the m o s t sensitive indicators of changes in nutri e n t status. Tree stems accumulate the grea t e s t mass of elements in a forest stand despite their lower p e r c e n t composition. This is a di r e c t result of their greater stem to foliage ratio. in a coniferous Wh i l e the annual nutr i e n t retu r n forest is about 3 to amount incorporated, 6 % of the total this return is, however, p r e d o m i ­ nantly from the foliage. These nutrients are present in amounts indicating the following d e s c e n d i n g order of concentrations: phorus, nitrogen, and sodium calcium, potassium, p h o s ­ (Rodin and Bazilevich, 1967). A check on the analytical procedures was a c c o m ­ plished by utilizing an internal reference standard of red pine foliage. The reference standard analyses mad e during 1972 and 197 3 are p r e s ented in Table 8 . The elements w h i c h var i e d to any ex t e n t over the two-year period w e r e sodium, calcium, iron, zinc, and aluminum. A change in the c a l i b ration curves for the Hort i c u l t u r e Plant A n alysis Labora t o r y mass spectrograph which Ill occurred bet w e e n the 1972 and 197 3 d e t e r minations may have a c counted for the obse r v e d deviations. The calc i u m levels for the reference standard w e r e about three to eight times lower than normal. phenomenon can be offered. No e x p l a nation for this However, calcium percentages for the actual tissue samples w e r e w i t h i n expected ranges. Data for cal c i u m and the o t h e r elements w h i c h exhibited variations bet w e e n the 197 2 and 19 73 standard analyses can still be used to indicate treatment d i f ­ ferences w i t h i n each study year. Table B. Internal reference standards of red pine for nutrient analyses, 19 7 2 and 1973. N K P Na Ca Mg % % % ppm % % 1972 1.18 0.39 o • H Year 1973 1.18 0.44 0.14 63.4 0.03 0 . 1 0 171.0 0.07 0.09 Mn Fe Cu B Zn A1 p pm ppm ppm ppm ppm ppm 1972 158.8 13.2 0 . 1 10 .4 5.8 278 1973 133.0 34.0 0 . 1 10.3 11.7 152 Year W h e n comparing the results of independently run nutrient analyses, it should be remembered that eleme n t concentrations may vary bet w e e n d i f f e r e n t tree components, periods of the year, years, and soil types. The red pine foliage nutrient analyses for 1972 and 1973 are shown in Tables 9 and 10. 112 Table 9. Nitrogen, potassium, phosphorus, calcium, and m a g n e s i u m concentrations of red pine foliage for varying rates of w a s t e w a t e r irrigation, Middleville, 1972 a nd 1973. Wastewater Irriga t i o n in mm/week Element Year 0 25 50 88 % of dry w e i g h t N K P Ca Mg 1972 1.15 a 1 1.18 a 1 . 2 2 a 1.23 a 1973 1.33 w 1.44 w 1 . 6 6 w 1.70 1972 0.54 a 0.64 a 0.64 a 0.67 a 1973 0.47 w 0.52 wx 0.52 w x 0.54 1972 0.18 a 0.19 a 0.19 a 0.18 a 1973 0 . 2 2 w 0 . 2 2 w 0 . 2 2 w 0.19 w 1972 0 .21 a 0 . 2 1 a 0.23 a 0.13 a 1973 0 . 2 1 w 0.23 w w 0.19 w 1972 0.09 a 1973 0 . 1 2 w 0 . 2 1 X X a a 0.09 a 0 . 1 0 0.13 w 0.13 w 0.13 w 0 . 1 0 ^Means not followed by the same letter are sig­ nificantly diffe r e n t at the 5% level (Tukey*s test). 113 Table 10. Sodium, magnesium, iron, copper, boron, zinc, and a l u m i n u m concentrations of red pine foliage for var y i n g rates of w a s t e w a t e r irrigation, Middleville, 1972 and 1973. W a s t e w a t e r Irrigation in mm/week Element Year 25 0 50 f dry Na Mn Fe Cu B Zn A1 1972 58.3 a 1 88 t2 — — ■ weighiL. 80 .6 a 77.8 a 74 .7 a 1973 202.9 w 264.3 w 381.2 w 277.2 w 1972 480.8 a 474.4 a 465.9 a 450.1 a 1973 768.8 w 800.1 w 718.5 w 557.7 w a 1972 2 0 . 2 1973 78.7 w 26 a 16. 2 a 13.5 a 59.4 w 58. 6 w 54 .0 .8 w 1972 0 . 1 a 0 . 1 a 0 . 1 a 0 . 1 a 1973 0 . 2 w 0 . 2 w 0 . 2 w 0 . 2 w 1972 2 2 . 1 a 1973 28.1 ab 27.1 ab 33.4 b 27.0 w 54.9 X 66 .4 xy 75.2 Y 1972 11.3 a 1 1 . 8 1973 2 2 . 8 a 1 1 . 1 a 9.1 a w 19.5 w 17.2 w 17.2 w 1972 379.6 a 391.5 a 336 .2 a 331.9 a 1973 545.7 w 355.0 X 256.7 xy 106.2 y ^Means not followed by the same letter are si g ­ nificantly diffe r e n t at the 5% level (Tukey*s t e s t ) . 2ppm = pg/g 114 In 1972 elements exhibiting concentration increases related to the rate of wastew a t e r applicatio n were nitrogen, potassium, and boron. Nitrogen increased from 1.15% at the 0 m m rate to 1.23% for the 88 m m rate. Potassium had an increase from 0.54% to 0.67% over the same range of irrigation rates. None of these d i f ­ ferences betw e e n irrigation treatments were significant. However, the increase in b o r o n from 2 2.1 to 33.4 p p m with higher rates of irrigation was significant. Of the remaining elements, phosphorus, sodium, calcium, magnesium, iron zinc, and aluminum had no dis­ tinct trends related to irrigation. Copper was uniform over the four irrigation rates, while manganese exhibited a decreasing concentration with increased wastewater irrigation. The 1973 nutrient data indicate that many trends established during the 1972 irrigation season continued. Again, phosphorus and calcium showed no distinct patterns. Concentrations of sodium and magnesium, variable in 1972, exhibited clear increases up to 50 mm/week of wastewater irrigation and then decreases with the 8 8 mm rate. This indicates that an optimum nutrient uptake efficiency probably occurred at 50 mm/week. Decreases in nutrient concentration with increases in wastewater application were evident for manganese, iron, zinc, and aluminum. The copper content 115 of the foliage was const a n t across the range of irri­ gation rates. Nitrogen, potassium, and b o r o n continued to increase in c o n c e n t r a t i o n w i t h increases in irri­ gation rate. S i g n i ficant treatment differences for these elements and alum i n u m are illustrated in Figure 24. Boron The foliar b o r o n content increased dramatical l y since 1972. W h i l e control trees remained fairly c o n ­ stant, varying only 5 p p m from 22 to 27 ppm, the 75.2 ppm boron in needles of trees recei v i n g 88 wastew a ter/week was trols. m m of 300% greater than that of the con­ A l l three levels of irrigation produ c e d boron concentrations significantly greater than found in the nonirrigated trees. Stone and Baird (1956) reported toxicity symptoms in red pine containing m o r e than 4 5 p p m boron in the foliage. Sopper and Kardos (1973) noticed toxicity problems in red pine after six years of irri­ gation. They m e a s u r e d b o r o n levels of 23, 28, and 33 ppm in the foliage of trees receiving 0, 25, and 50 mm of wastewater/week. terminal 1 - 2 Toxicity symptoms c m of the needles) (necrosis of the w e r e first observed in the red pine at Middleville in late May of 1974 (Figure 25). Injury was most evid e n t on needles at 116 Figure 24. Red pine foliage nutrients exhibiting sig­ nificant differences bet w e e n w a s t e w a t e r irrigation rates: (C) aluminum, and (A) boron, (B) potassium, (D) nitrogen. 117 I r r i gation Rates (A) 0 = (B) mm/week 0 ^ = 25 m m / w e e k 80 • ■ = 50 mm/week (ppm) — 88 nun/week 60 dP *> H Boron to 01 id -p m O Q* 40 .5- 20 n 1972 I" 1973 1972 1973 (D) ) 8 Aluminum (ppm) 500 - 1.6 400 • / / fp C c 0) o 300 - // 1.4 u /✓ +J 1.2 200 1.0 100 « 1972 1973 1972 1973 Necrosis of red pine needles showing boron toxicity induced by wastewater irrigation at Middleville. 118 Figure 25. BORON TOXICITY OF RED PINE WASTEWATER IRRIGATION 88 mm /W e e k 0 mm / Week 119 1 YEAR OLD NEEDLES « 120 the extremities of the crown. W h i l e toxicity symptoms were m o s t acute in needles devel o p e d in 19 73, they wer e also noticeable as a slight y e l l o w i n g on the tips of newly developing needles. It is y e t to be determined what physiological effects this will have. Sensitivity to b oron toxicity could ultimately eliminate red pine as a tree species suitable to high rates of wa s t e w a t e r irrigation. Potassium The p o t a s s i u m content of the red pine foliage decreased in 197 3, but was higher in the irrigated plots. The 0.54% p o t a s s i u m found in the 8 8 mm/week plots was significantly greater than that of control trees at 0.47%. The p o t a s s i u m values in 1972 were somewhat similar, b u t not significantly so. P o t a s s i u m values reported b y Sopper and Kardos (1973) for wastew a t e r irrigated red pine differ con­ siderably from those re ported here. They found p otassium c o n c e ntration to decrease with increased irrigation. However, the method of a p p l i cation of wastew a t er also differed. The red pine at Penn State were irrigated from above the crown w h i l e those at Middleville w e r e irrigated from b e l o w the crown. Thus, the overhead irrigation wa t e r s probably leached excess potassium from the needles, concentrations. thereby reducing foliar 121 Aluminum The a l u m i n u m concentration of the red pine foliage changed radically from 1972 to 1973. While the a l uminum content increased in trees receiving no wastewater irrigation, trees receiving it dropped sharply for those mm/week. 88 The 106.2 p p m a l u m i n u m in the hig h e s t irrigation rate was significantly lower than the 545.7 and 355.0 p p m in the control and 25 mm/week treatments, respectively. A l l three irrigation treatments produced foliage w i t h alum i n u m levels lower than that of the controls. This decrease in foliage aluminum is associated w i t h changes in soil pH section on soil c h e m i s t r y ) . (see A f t e r two years of irrigation soil pH of the upper 30 cm w e n t from 5.5 in the control plots to 6.1, 6 .6 , and 7.4 in the 25, irrigation plots, respectively. 50, and 88 mm/week A l u m i n u m solubility is highest in acid soils and rapidly approaches zero as soil pH increases to pH 7. L o w foliar aluminum levels thus resulted from the insolubility of aluminu m b r o ught about by an increase in pH. (1973) State. Sopper and Kardos experienced similar alum i n u m decreases at Penn The red pine foliage there had 444, 142, and 9 7 ppm alumi n u m for the 0, 25, and 50 mm/week irrigation rates, respectively. 122 Nitrogen Foliar nitrogen levels exhibited considerable response to wastewater irrigation. Nitr o g e n c o n c e n ­ trations in the foliage of irrigated trees in 1972 wer e not significantly greater than the control trees. By the end of the 1973 irrigation season the foliage nitrogen levels in the two highest irrigation rates (1.70% and 1.66%) were significantly higher than those of the control and 25 m m/week irrigation rate and 1.44%). (1.33% The red pine thus responded favorably to irrigation b y absorbing considerable quantities of nitrogen found in the wastewater. Similar responses by red pine have b e e n reported by Sopper and Kardos (1973) . Red Pine Growth Responses The 20-year-old un-thinned red pine p l a n t a t i o n utilized in this w a s t e w a t e r renova t i o n study had a spacing of 2.4 x 2.4 m, and an average basal area of 2 7.5 m / ha. M e a n tree he i g h t and DBH w e r e 11.6 m and 14.8 c m respectively. Growth responses to we e k l y irrigation rates during 1972 and 1973 are prese n t e d in Table 11. Needle Length The average needle length for the red pine stand in 1972 was 144.9 m m w i t h no significant differences 123 between irrigation r a t e s . gation schedule (July 15) The late start in the irri ­ prob a b l y accounts for this. Red pine has a determinate gr o w t h pat t e r n w h e r e b y m o s t of the growth occurs during June and early July et a T ., 1972). (Neary Little foliage growth thus o c c u r r e d during mid- J u l y to September despite irrigation. Table 11. Ave r a g e red pine needle growth w i t h v a r y i n g w a s t e w a t e r irrigation rates, Middleville, 1972 and 1973. m m of w a s t e w a t e r irrigation/we e k P a r a meter Year 25 0 88 146.0 a 155.0 a 136.2 a 136.4 wx 154.9 xy 164.4 y 68.67 a 64.17 a 64 .46 a 1973 68.97 w 74.76 wx 9 5.23 xy 107.40 y 1972 26.6 a 24.0 a 23.7 a 24.2 a 1973 28.2 w 24.5 x 27.8 w 30.2 w Needle length (mm) 1972 142.6 a 1 1973 1 2 1 . 0 Dry W e i ght per fascicle (mg) 1972 Terminal Bud L e ngth (mm) 50 w 62.19 a 1 Means not followed by the same letter are sig nificantly d i f f e r e n t at the 5% level (Tukey*s test). In 1973, however, there w e r e significant d i f ­ ferences in needle growth w h i c h related to irrigation rate. Needle lengths increased 12, 28, and 36% over control plots with increasing irrigation levels, going from 121.0 m m for the n o n i r rigated trees to 164.4 mm for trees receiving the grea t e s t amounts of wastewater. The decrease in needle length for control trees from 1972 to 1973 is attributed to the low rainfall in 124 June, 1973, (110.5 mm) (100 (26.9 rum) compared to that of June, 1972, which is close to the 30-year m e a n for June mm). Branch Buds Branch terminal bud lengths exhibited no sig­ nificant variations in 1972 w h i c h could be related to irrigation. In 1973, trees receiving 25 m m of w a s t e ­ water/week had significantly smaller terminal buds. It is unlikely that this was related to amounts of irri­ gation since similar reductions w e r e not evident at higher irrigation rates. Branch terminal bud length does not appear to be a good indicator of red pine response to irrigation. Main stem terminal bud length, however, has been reported to be a more sensitive indication of irrigation response (Clements, 1970). However this technique is feasible only with small trees. Dry W e i g h t per Fascicle Growth trends in the dry w e i g h t per fascicle parallel that of needle length. variations No significant from the m e a n of 64.87 mg/fascicle were evident in 1972. The 1973 data show that the average needle dry we i g h t increased by 8 controls w i t h application of 25, sewage effluent. , 38, and 56% over 50, and 8 8 m m of The significant differences occurred 125 between the two hig h e s t irrigation rates and the control. The 88 m m/week plots were also significantly higher than the 25 m m/ w e e k p l o t s . The increase in both needle dry we i g h t and length in trees irrigated w i t h w a s t e w a t e r suggests potential increases in photosynthetic capabi l i t y and nutrient uptake capacity. This increase in total energy fixation could be expressed in greater he i g h t and/or diameter growth which would in turn increase the capacity for red pine to tie up excess wastew a t e r nutrients. Diameter Increment The mean DBH increments tabulated from all trees during the 1973 growing season are shown in Table 12. The average height increments of 15 sample trees per treatment are included for reference. No significant trend in DBH increment has yet appeared but may in sub ­ sequent y e a r s . Monthly increases of DBH during 1973 by irri­ gation rate are given in Table 13. C i r c u mference growth was m o n i tored by band dendrometers and it appears that wastewater irrigation prolonged the period of diameter increment. Greatest increment took place in May and June for the controls and July and A u g u s t for the irrigated plots. Alth o u g h no statistically significan t differences were present in m e a n circumference growth, 126 Table 12. Red pine diameter increments and reference h e i g h t increments for varying rates of w a s t e ­ wa t e r irrigation, Middleville, Pall, 1973. Irrigation Rate DBH Increment Hei g h t Increment m m ------ m m / week m 3.99 a 1 0 . 6 8 25 4.11 a 0. 65 50 4.67 a 0.71 88 4.09 a 0.69 0 ^Means not followed by the same letter are significantly d i f f e r e n t at the 5% level (Tukey's t e s t ) . Table 13. Red pine stem circumference as measu r e d by band d endrometers on four sample trees per plot, Middleville, 1973. Circumference Increment^ Growth Period 0 25 50 88 May - June 4.95 a 3.30 a 1.70 ab 1.91 b July - August 2.24 a 3.68 ab 5.00 b 2.84 a September - O c t o b e r 0.97 a 1 . 0 2 a 2.24 a 1.57 a Total C ircumference Increment 8.18 a 7.95 a 8.94 a 6.48 a (2.61)a (2.53)a (2.85)a (2.06)a {Total DBH Increment) ^Heans not followed by the same letter are si g ­ nificantly diffe r e n t at the 5% level (Tukey's test). 127 the 8 8 nun/week irrigation treatment produced the lowest increment (6.48 mm). This may be a negative response by red pine to the high irrigation rate. Kardos (1973) Sopper and also noticed that wh i l e trees receiving 50 m m of w a s t e w a t e r / w e e k had an average annual diameter increment of 1.52 mm, the controls and 25 mm/week trees had increments of 1.65 and 4.32 m m respectively. Thus, to ensure m a x i m u m diameter gro w t h on sandy loam soils similar to Middleville, a m a x i m u m irrigation rate of 50 m m /week is required wh i l e loamy soils like those at Penn State should receive 25 mm/week. The DBH increments computed from circumference growth as measured by the band dendrometers were con­ siderably less than those determined by direct DBH measurement. These differences are due to factors inherent in each method. The di r e c t DBH was measured with diameter tape to the nearest 2.5 mm, w h i c h is about the magni t u d e of the vari a n c e in the D B H 1s reported in Tables 12 and 13. These results are most likely an o v e r e stimation of the actual increments. The diameter and foliage growth of red pine resulting from wastew a t e r irrigation are important factors to consider in the renovation efficiency of the w a t e r reclamation system. Increases in tree biomass production permits additional nutrients to be absorbed by forest stands that receive irrigated 128 wastewater. changes, To assess the impact of observed growth estimations of total foliage and stem p r o ­ duction w e r e made. Needle biomass produced by the red pine at Middleville during 1972 and 1973 is estimated in Tables 14 and 15. Needle Biomass Estimations of total needle biomass were computed by adapting a method discu s s e d by Brown (19 6 3) for d e t e r ­ mining crown weights of red pine stands in the Lake States. This method assumes that: plantation occupies a good site and a high density (1) the red pine (2 ) the stand has (1,000 - 2,500 trees/ha). Total crown weight / tree is first computed by Equa t i o n 2: (Equation 2) Lt c w = .9072 + .1087 D where: L T C W = Logr t*ie crown w e i g h t (pounds, dry weight) D = DBH in inches Then the needle biomass/ha on dry w e i g h t basis is d e t e r ­ mined by Equation 3: 129 Table 14. Estima t i o n of red pine foliage biomass p r o ­ duction w i t h varying rates of w a s t e w a t e r i r r i ­ gation, Middleville, 1972. mm wastewater/week P arameter Units 25 50 88 5.76 5.58 6 . 1 0 5.89 0 DBH inches DBH cm 14 .63 14.17 15.49 14.96 Crown W e i g h t lb/tree 34.14 32.64 37.18 35.27 Crown W eight kg/tree 15.49 14.81 16.86 16.00 Trees/ha # 1780 1780 1780 1780 Total Crown Weight kg/ha 27,570 26,360 30,010 28,480 Factor for Needle Crown Weight Unadjusted Needle Crown Weight .51 kg/ha 1972 Needle Factor — 1972 Needle Weight 14 ,060 .51 13,440 .51 15,300 .51 14,520 .33 .33 .33 . 33 kg/ha 4,600 4 ,400 5, 050 4,790 Dry W e i ght/Fascicle A djusted Factor — 1 . 0 0 .93 .94 .91 Actual 1972 Needle Weight kg/ha 4,600 4 ,100 4 ,700 4,400 130 Table 15. Estima t i o n of red pine foliage biomass pro ­ duc t i o n w i t h var y i n g rates of wa s t e w a t e r i r r i ­ gation, Middleville, 1973. m m wa s t e w a t e r / w e e k Parameter Units 25 50 88 5.92 5.75 6.28 6.04 0 DBH inches DBH cm 15.04 14.61 15.95 15.34 Crown W eight lb/tree 35.49 34.06 38.89 36.62 Crown W e i g h t kg/tree 16.10 15.45 17.64 16.61 Trees/ha # 1780 1780 1780 1780 Total C r o w n Weight kg/ha 28,660 27,500 31,400 29,570 Factor for Needle Crown Weight Unadjusted Needle Crown Weight — kg/ha 14,020 .51 16,010 .51 15,080 .33 .33 .33 kg/ha 4 ,820 4,630 5,280 4,980 — 1 . 0 0 1.08 1.38 1.56 kg/ha 4 ,800 5, 000 7,300 7,800 — 1973 Needle Weight Actual 1973 Needle Weight 14,610 .51 .33 197 3 Needle Factor Dry Weight/Fascicle Adjust ment Factor . 51 131 (Equation 3) BN = T C W - K ■ DH • PN where: = crown needle biomass in kg/ha T C W = total crown w e i g h t per tree in pounds Djj ~ tree density per hectare = needle per c e n t of total crown weight K = pounds to kilo g r a m conver s i o n factor (.4536 kg/lb) The needle biomass computed by Equa t i o n 3 is further adjusted by m u l t i plying by a (1 ) needle factor and (2 ) dry w e i g ht / f a s c i c l e factor. The needle factor accounts for the propor t i o n of needles produced in any one year. In this instance a needle factor of 0.33 is assumed. The dry w e i g h t / f a s c i c l e factor is a ratio of the dry weight/fascicle for the 25, gation treatments each year. 50, and 8 8 mm/w e e k irri­ to that of the control treatment for The resultant figure is an e s t i mation of the dry w e i g h t needle produc t i o n during any growing season on a kg/ha basis. During the 197 2 growing season, needle production in red pine on the control plots was 4,60 0 kg/ha. duction on plots receiving 25, 50, and 88 Pro­ m m of w a s t e ­ water/week over the same period was — 13, + 2 , and - 6 % in 132 contrast to the nonirrigated trees. Needle biomass production in 1973, however, was greatly increased in trees r eceiving wa s t e w a t e r irrigation. Red pine on the control plots produced a new needle biomass of 4,800 kg/ha, an increase of 200 kg/ha from 1972 to 1973. Meanwhile, and 88 needle biomass produc t i o n for the 25, 50, mm/ w e e k irrigated trees was 4, 51, and 61% greater at 5,000, 7,300, and 7,800 kg/ha. Stem Biomass No data on br a n c h growth w e r e colle c t e d from the Middleville site in 1972 and 1973. However, the production of stem biomass during this time is presented in Tables 16 and 17. Stem biomass production was d e t e rmined by a p p l y ­ ing w o o d density and taper factors to a cylinder volume formula and subtracting the biomass computed at the start of the growing season from that determined at the end of the growing season. Stem biomass p r o d u c t i o n was calculated w i t h Equa t i o n 3: {Equation 3) B„ S - it * r2 • h • d • T • K g • D„ H where: Bg = stem biomass produc t i o n in kg/ha 7t = 3.1416 133 Table 16. Estima t i o n of red pine stem biomass product i o n with var y i n g rates of w a s t e w a t e r irrigation, Middleville, 1972. m m w a s t e water/week .fardine UIIXI. 0 25 50 88 Initial DBH cm 14.21 13.75 15.07 14 .54 Initial Height m 10.44 10.53 11.35 11. 37 DBH Increment cm 0.42 0.42 0.42 0.42 Final DBH cm 14.63 14.17 15.49 14.96 Final H e ight m 1 1 . 1 2 11.18 1 2 Biomass Increase per Tree kg Trees/ha # 1780 1780 1780 1780 Total S t em Biomass Increase kg/ha 9,600 9,000 1 1 , 2 0 0 10,600 Table 17. 5.414 5.055 .06 6.289 1 2 .08 5.965 Estima t i o n of red pine stem biomass production w i t h varying rates of w a s t e w a t e r irrigation, Middleville, 197 3. m m w a s t e water/week Parameter Unit 0 25 50 88 Initial DBH cm 14.63 14.17 15.49 14.96 Initial Height m 1 1 . 1 2 11.18 12.06 12.08 DBH Increment cm 0.41 0.44 0.46 0.38 Final DBH cm 15. 04 14.61 15.95 15.34 Final Height m 11.80 11.83 12.77 12.77 Biomass Increase per Tree kg Trees/ha # 1780 1780 1780 1780 Total S t e m Biomass Increase kg/ha 1 0 , 2 0 0 9,900 12,600 10,700 5.735 5.578 7.066 5.999 134 r = tree m e a n radius at DBH h = m e a n height in trees in m d = den s i t y of red pine w o o d T = taper factor 3 (.507 g/cm ) (.5) Kg = grams to kilo g r a m c o n v ersion factor (1 X 10 _3 D jj = tree den s i t y per hectare Since data on red pine DBH from the fall of 1971 was unavailable, several assumptions in c o m p utation of the 1972 stem biomass produc t i o n w e r e made. Equivalen t DBH increments during 19 7 2 w e r e assumed for all four irrigation rates. The m e a n diameter increment from the 1973 g r owing season of .42 cm was also used as the 1972 increment. In 1972 the nonirrigated red pine stem biomass was e s t i mated at 9,600 kg/ha. The 25, 50, and irrigated trees had a stem biomass of 9,000, and 10,600 kg/ha, respectively. 8 8 mm/we e k 11,200, These amounts varied from the control by - 6 , +17, and +10%. The 1973 stem growth for the nonirrigated red pine was on the order of 10,200 kg/ha. The 25, red pine produced 9,900, 50, and 12,600, 8 8 m m / w e e k irrigated and 10,700 kg/ha in stem b i omass wh i c h varied from the control treatment by -3, +22, and +5% respectively. ) 135 Soil Chemistry The chemical bal a n c e of any u n d i s turbed pedon is a function of cli m a t e and v e g e t a t i o n acting on the parent mate r i a l over time. The addi t i o n of m u n i c i p a l sewage effluents to soil alters the soil chemical status due to the chemical, physical, and biological processes w h i c h filter varying chemicals o u t of the wastewater. Not o n l y do domestic and industrial w a s t e ­ waters contain div e r s e amounts of chemicals Kotalik, 1973; (Hunter and Reed e t > Depth Irrigation Rates 0 = mm/week 0 Soil = 25 nun/week ■ = 50 num/week # = 100 « 120 nun/week 88 ■ 0.5 T 1.0 ■ 2.0 1.5 Loss o n Ignition (cm) 20 2.5 (%) ■ 40 ■ Soil Depth Irrigation Rates 60 « 0 = mm/week 0 25 mm/week 80 ■ 50 nun/week 100 - 88 iran/week 120 « 0 4 2 Bo r o n (kg/ha) 6 151 of b o r o n in the red pine foliage pa r a l l e l e d comparable increases in the soil. A t 15 cm, the total b o r o n in the plots recei v i n g w a s t e w a t e r irriga t i o n was signif i ­ cantly higher than in u n i r r igated controls. years of irrigation, b o r o n climbed to 3.4, kg/ha for the 25, 50, and 88 After two 3.3, and 4.2 m m / w e e k irrigation rates compared to 1.0 kg/ha for u n i r r igated areas. These high boron increases in the upper soil horizons pose a threat to tree species such as red pine wh i c h are se n s i ­ tive to high b o r o n levels. tents of the 25 and 88 A t 30 c m depth, b o r o n co n ­ m m / w e e k irrigation plots w e r e still significantly higher than those of the controls. No statistically significant differences in soil bor o n content occurred at the 60 and c m depth, b u t plots 1 2 0 receiving irrigation remained a b o u t unirrigated soils. 1 0 0 % higher than in The undisturbed control plots had a u n iform b o r o n level throughout the soil profile, varying by no more than 0.2 kg/ha from the 15 to 120 depth. Bo r o n normally exists in soil solution as either u n d i s s ociated H^BO^ or as an anion. It is adsorbed in soils m o r e strongly than other anions such as the highly m o bile chloride or nitrate ions. A major site for adsorption of large quantities of b o r o n is freshly p r e ­ cipitated alumi n u m hydroxide (Hatcher et a l . , 1967). Indications that considerable amounts of aluminum h ydroxide have b e e n recently p r e c i pitated in irrigated 152 plots are evident w i t h the shift in pH and the large reductions in alum i n u m of red pine needles. Humus Survey Changes in the red pine duff mull humus were examined in 197 3 w i t h i n the irrigated plots. Alter­ ations from the normal prevai l i n g conditions were: (1 ) noticeable decreases in humus depth, (2 ) shifts in humus color from b r o w n i s h - r e d to gray-green, and (3) bark removal from bra n c h litter on the soil surface (Figure 30). Survey results are prese n t e d in Table 19. Soil O r ganisms The mycelial m a t index increased from 2.0 for the control treatment to 4.0 and 3.7 for the 25 and 50 mm/week irrigation treatments, respectively. However, the index for the hig h e s t irrigation rate then dropped 50% b e l o w control levels. The earth w o r m index rose from 0.7 for the control plots to 1.7 and 2.0 for the 25 and 50 m m / w e e k a p p l i cation rates. 88 The index for the m m / w eek rate plots then drop p e d to less than that of the 25 mm/ w e e k rate (index of 1.3). W astew a t e r a p p l i c a t i o n to the red pine stand apparently stimulated fungi and e a r t h w o r m activity. The h i g h e s t indices o c c u r r e d in plots receiving 50 mm/week. Despite treatment variations of up to 400%, Figure 30. Comparison between branch litter in unirrigated (top) and irrigated (bottom) red pine plots showing the loss of bark occurring with 153 irrigation, Middleville, 1973. 154 155 the m y c elial m a t and e a r t h w o r m indices did not produc e statistically s i g n i f i c a n t differences related to irri ­ gation rate. Table 19. Red pine humus survey b y w a s t e w a t e r irrigation treatment, Middleville, 197 3. m m w a s t ewater/wee k^ Units Parameter 0 50 25 88 Mycelial Mats Index 2 . 0 4.0 3.7 1 . 0 Earthworms Index 0.7 1.7 2 . 0 1.3 Mean Humus Depth cm 4.23 3.19 2.97 3.40 Total Humus W e i g h t kg/ha 23,590 23,420 22,340 21,530 Woody Litter kg/ha 3, 240 3,200 2,900 3,480 Mineral Soil kg/ha 4,310 6,040 5,880 4 ,940 Fine Humus kg/ha 16,040 14,190 13,570 13,140 5% level ^No significant differences w i t h treatment at the (Tukey's t e s t ) . Humus Depth Average forest floor d e p t h varied from a m a x i m u m 4.23 cm in u n i r r igated plots to 2.97 cm in plots receiving 50 m m of wastewater/week. Plots receiving an average depth of 3.4 cm. 88 mm/ w e e k had Depth for the control plots agreed w i t h those reported by Stutz b a c h e t ad. (19 72) for a 37-year-old red pine planta t i o n in N e w York. Humus depths of 4.52 and 3.15 c m w e r e reco r d e d for good (site index 64) respectively. and poor (site index 47) sites 156 Based o n the biolog i c a l activity index, the major amount of d e c o m p o s i t i o n occu r r e d in the 50 m m / w e e k t r e a t ­ ment. However, analysis of the w a s t e w a t e r application rate and sampling point interactions indicated that the forest floor depths for each level of w a s t e w a t e r a p p l i ­ cation w e r e affected by distance of the sampling point from the p l o t center (Figure 31). at distances of 2, 4, and 6 Those depths measur e d m from p l o t center differe d because of variations in total irrigation across the plot. For example, the humus depth at the 2-m sampling point decreased with increased amounts of irrigation. Total humus depth was about 4 c m on plots receiving no irri­ gation and 2.5 c m in plots irrigated w i t h wastewater/week. depth, 8 8 m m of The b i g g e s t change in forest floor 1.28 cm, occurred in the interval b e t w e e n the control and 25 mm/ w e e k treatments. at the 4 and 6 Mean depths m e a s u r e d m locations a p p r o ximately p a r a l l e l e d those of the 2-m location. The humus depths at the 2-m sampling point clearly reveal that w a s t e w a t e r irrigation has decreased forest floor thickness. This decrease was probably due to b o t h a physical compaction by the weight of the applied w a t e r as well as by actual d e c o m ­ position. Total Humus W e i g h t The extent of organic ma t t e r d e c o m p o s i t i o n on the forest floor as a result of w a s t e w a t e r irrigation 157 F i g u r e 31. M e a n h u m u s d e p t h in red p i n e at M i d d l e v i l l e by i r r i g a t i o n rate a n d d i s t a n c e center, 1973. from plot Distance From Plot Center Depth (cm) • 6m 4 m Humus 158 2 m I 1 0 25 I 50 Wastewater Irrigation (ntm/week) I 88 159 can be estimated b y examining the forest floor w e i g h t components (Table 19). Total humus wei g h t s d e c r e a s e d consistently w i t h increases in irriga t i o n rates. The o ven-dry w e i g h t of 23,590 kg/ha for the control plots was w i t h i n the w e i g h t range of 30,610 to 22,370 kg/ha reported by Stutzbach et al. (1972) red pine sites respectively. measured at the 4—m and ville were variable 6 for good and poor Total humus weights — m sampling points at M i d d l e — (Figure 3 2 A ) . the 2-m location w e r e m o r e u n i f o r m Those determ i n e d at (21,740 330 kg/ha at the lower irrigation treatments, b u t dro p p e d sharply to 14,840 kg/ha for the 88 mm/week r a t e ) . Fine Humus Fine humus matter) (needle litter and other organic d r y weights c o r r esponded in a similar manner, with gradual decreases of 16,040 to 13,140 kg/ha occurring over the range of irrigation treatments (Figure 3 2 B ) . the 4 and 6 These wei g h t s varied c o n s iderably at m sampling point. Humus weights at the 2-m locations decre a s e d u n i f ormly from 14,490 to 13,500 kg/ha b e t w e e n the 0 and 50 mm/ w e e k treatments, dropped more rapidly at the 88 and then mm/week rate to 9,630 kg/ha. A l t h o u g h all decreases in the duff m u l l humus weights and depth w e r e not statistically significant, d istinct trends w e r e present. If these trends continue. 160 F i g u r e 32. I n t e r a c t i o n e f f e c t s of w a s t e w a t e r i r r i ­ g a t i o n rate a n d d i s t a n c e on (A) from p l o t center total hu m u s w e i g h t and hu m u s weight. (B) fine 30 (10 kg/ha) 161 v 20 m Humus Weight N. Total Distance F r o m P l o t Center 4 m ■ 10 25 88 50 kg/ha) (10 15 13 (mm) Distance F r o m P l o t Center ▲ = 11 Fine Humus 17 Weight W a s t ewater Irrigation/week 9 0 25 88 50 Wastew a t e r I r r i gation/week (mm) 162 considerable changes in the forest floor w i l l occur. Further d e c o m p o s i t i o n and amelioration of the acidic red pine needle litter will probably hasten successional changes to a hardwood understory. In addition, the co n ­ tinued litter b r e a k d o w n will affect the w a s t e w a t e r renovation capacity of the site. Litter d e c o m p o s i t i o n will lead to an increase in organic matter of the soil surface and improve the cation exchange capacity. How­ ever, o rganic matter break d o w n will also create problems by m o b i l i z i n g additional nutrients, such as nitrogen, which m a y adversely influence the site's wa s t e w a t e r renovation efficiency. Nutrients A nutrient analysis of the red pine fine humus was made to relate its chemical status w i t h wa s t e w a t e r irrigation. The effects of increased rates of w a s t e w a t e r irriga t i on on the calcium, phorus, nitrogen, magnesium, phos­ and p o t a s s i u m contents of fresh and partially decomp o s ed needle litter is shown in Figure 33. Nitro g e n and p o t a s s i u m w e r e relatively u n i f o r m for all irrigation treatments w i t h averages of .83 and .12% respectively. Phosphorus showed a mode r a t e increase b e t w e e n the 25 and 8 8 m m / w e e k treatments w i t h the .15% phosphorus level for the higher rate b e i n g significantly greater than the other two treatments. The largest increases were 163 Fi g u r e 33. A m o u n t s of calcium, m a g n e s i u m , phosphorus, nitrogen, a n d p o t a s s i u m in red p i n e fine humus at M i d d l e v i l l e , 1973. 164 1 .6 « Ca 1.4 * ■ 1.0 Nutrient Composition (% Dry Weight) 1.2 4* < 3* 2 Mg / « —r 00 25 Wa s t e w a t e r Irrigation 50 (mm/week) -r 88 165 recorded for m a g n e s i u m and calcium. significant jump from .24, .24, and .07% for the 0 mm/w e e k rate to .26% for the 25, respectively. 50, and 8 8 m m / w e e k rates C a l c i u m significantly increased from .73% in the control plots to 1.40, the 25, Magnesium made a 50, and 88 1.56, and 1.50% for nun/week rates respectively. C a l c i u m and m a g n e s i u m increases w e r e due to absorption of those cations on organic ca t i o n exchange sites in the humus. Leac h i n g induced b y irrigation water, p robably k e p t p o t a s s i u m levels near normal. No signi f i c ant irrigation rate sampling p o i n t interactions were noted. Fluctuations in the levels of aluminum, boron, copper, iron, manganese, sodium, and zinc in the fine humus at Middleville are presented in Fig u r e 34. the e x c e ption of manganese, With nutrient increases were noted in all irrigated plots in c o m p arison to u n i r r i ­ gated plots. Manga n e s e exhibited a nonsi g n i f i c a n t d e c rease from 923.0 p p m for the control treatment to 644.6 p p m for that of the h i g h e s t irrigation rate. Of the other nutrients, o n l y copper had a nonsignificant increase over the range of irrigation rates. zinc levels g radu a l l y increased from 55.1 to 74.0 ppm, with low and high rates of irriga t i o n b e i n g significantly different. Iron followed a similar pattern, but a l u minum was m o r e variable, w i t h a general increase 166 F i g u r e 34- Alumi n u m , sodium, boron, copper, iron, mangan e s e , and zinc c o n t e n t s of fine h u m u s in the red p i n e p l a n t a t i o n at Mid d l e v i l l e , 1973. 167 A1 >o 1600 « Fe 1200 Nutrient Composition (ppm Dry Weight) 1400 1000 * . Na 800 Mn 600« 400 100 80 Zn 60 Cu 40 20 25 88 50 Wastewater Irriga t i o n (mm/week) 168 in c o n c entration w i t h increased irrigation. Sodium levels in the red pine fine humus rose significantly from 373.3 p p m in plots receiving no irrigation to 809.6 p p m in the 25 mm/ w e e k irrigation rate w h e r e they reached a plateau. Boron e x h i b i t e d a 440% increase from the n o n i r rigated plots of 16.2 p p m to 71.5 p p m for the 25 m m / w e e k rate, and then continued to climb to 90.0 ppm for the 88 mm/ w e e k irrigation rate. For boron, all three rates of w a s t e w a t e r app l i c a t i o n p r o d u c e d sig­ nific a n tly greater levels addition, the 88 (at 5%) than controls. In mm/week treatment was significantly hi g h e r than that of the 25 mm/ w e e k r a t e . Stutz b a c h et al. m i n i m u m nitrogen, (1972) phosphorus, r e p o r t e d m a x i m u m and potassium, calcium, and m a g n e s i u m concentrations in the forest floor layers of a 3 7 -year-old red pine stand in New York. The nitroge n and p h o sph o r u s levels at M i d d l eville w e r e w i t h i n those c o n c e n t ration ranges for all four w a s t e w a t e r treatments. However, d i f f e r e n t trends w e r e evident in the potassium, calcium, and m a g n e s i u m contents. The c a l c i u m c o n c e n ­ tration in control plots was well w i t h i n the range found in the N e w York stand, but, plots, in the w a s t e w a t e r irrigation the cal c i u m level w a s 59 to 70% higher than the m a x i m u m value reported by Stutzbach. P o t a s s i u m and m a g n e s i u m values in the fine humus of all four wastewa t e r 169 irrigation treatments at M i d d leville exceeded the maximums in the New Y o r k red pine stand. The a p p l i cation of municipal w a s t e w a t e r to the red p i n e stand at M i d d l e v i l l e has resulted in con­ siderable changes in the chemical bal a n c e of the forest floor. E x c e p t for nitrogen, potassium, and manganese, the levels of the m o n i t o r e d elements all increased. Nitro g e n remained u n a l t e r e d w h i l e p o t a s s i u m and m a n g a ­ nese d e c r eased in concentration. W h i l e no apparent n i t rogen decreases have occurred, the decom p o s i t i o n docume n t e d in the study has the p o t e ntial of contributi n g up to 133 kg/ha (8 kg/100 k g of fine humus) of total nitro g e n to the soil or ground w a t e r systems. This additional nitrogen flow m u s t be considered w h e n a n a l yzing the nitrogen pathways in a terrestrial w a s t e w a t e r disposal system. Fungal Frui t i n g Survey A n additional visible indica t i o n that wastewater i rriga t i o n induced litter d e c o m p o s i t i o n was the occur r e n c e of fungal fruiting structures. Normally the fungi produce a burst of r e p r o ductive structures in S e p t ember or Oct o b e r c o r r e sponding to the fall rainy season. In 1972 the fruiting activity w a s of such a short d u r ation that it could not be documented. However, 170 it did show early evidence of a fruiting b o d y n u m b e r — irrigation rate interaction. During the 197 3 irrigation season count of the total numbers of fungal r e p r o ductive structures on each plot was initiated on Septe m b e r 6 th. A scattering of fruiting structures of the genus Lycope r d o n spp. (Figure 35A) were noted w i t h i n several of the irrigated plots. They remained vis i b l e throug h o u t the entire fungal b o d y survey. Frui t i n g structures emerging later in October w e r e b a s i d i o m y c e t e s of the Agaricus spp. and A m a n i t a spp. (Figure 35B) or unidentified Fungi Imperfecti. W i t h the first appear a n c e of the fungal fruiting structures in early September, the normal late summer dry spell dominated the w e a t h e r picture. A t that time, fruiting structures w e r e found o n l y in irrigated plots. Rainfall increased by late Septe m b e r and on Oct o b e r 12th fungal reproductive structures occu p i e d a large p e r ­ centage of the forest floor area w i t h i n and out s i d e the irrigated plots. Wastew a t e r irrigation treatment effects on numbers of fungal r e p r o ductive structures in the fall of 1973 are presented in T a b l e 20 and Figure 36. S e p t ember 6 From th to Septe m b e r 27th, w a s t e w a t e r irrigation stimulated fungal fruiting. Lit t e r w i t h i n irrigated plots stayed moist throughout the w e e k w h i l e litter in 171 F i g u r e 35. Typ i c a l fungi r e p r o d u c t i v e s t r u c t u r e s in the red pine s t a n d a t M i d d l e v i l l e , 19 73: (A) b a s i d i o m y c e t e of the genus L y c o p e r d o n and (B) b a s i d i o m y c e t e of the g e n u s A g a r i c u s . 172 (A) 173 the unirrigated control plots was dry. The peak fruiting date for plots receiving wastewater was October 4th. Fungi in the u n i r r igated plots reached their peak one week later. Total numbers of fungi w e r e decli n i n g by O c tober 23, the last d a y of the survey. However, numbers in the irrigated plots w e r e higher than in control plots and d e clining at a slower rate. Table 20. M e a n number of fungal fruiting structures/ 0.02 ha plot by irrigation rate, Middleville, September to October, 1973. m m wastewa t e r / w e e k x1 50 25 0 s2 s X 88 s X s 2.7 1.5 38.0 57.4 51.3 69.2 43.0 57.4 X number 0 . 0 0 . 0 9/27 1.7 1.5 38. 7 10/04 145.0 44.5 100. 7 54 .9 197.7 149.1 8 8 . 0 56.3 1 0 / 1 2 197.0 2 0 . 0 70.7 51. 5 142.0 156.7 62.3 47.0 40.7 25.4 93.3 119.3 38.0 35.4 10/23 27.0 7.9 1.7 1.5 9/06 28 .1 ^x = mean 2s = standard deviation The data depicted in Figure 36 do not reveal the impact of the wastewater on the fungi reproduction in some of the plots. Large variations occurred w i t h i n each treatment and this is indicated by the high standard deviations listed in Table 20. By selecting the one plot Figure 36. Mean number of fungal fruiting structures/0.02 ha plot by irrigation rate, Middleville, September to 174 October, 1973. Irrigation Rates 0 = 0 ,\ ram/week ^ - 25 mm/week g = 50 mm/week 0 - 88 mm/week 10-04 10--12 10-23 176 in each treatment that produced the hig h e s t fungal fruiting body counts, a different picture arises. Figure 37 presents the total counts o n plots 11, and 9 as representing the 0, 25, irrigation rates. 50, and 8 8 4, 3, mm/week The values are summations of the individual counts on each of the five sampling dates. Several dist i n c t trends are noticeable in Figure 37. All three w a s t e w a t e r irrigation treatments stimulated fungi fruiting. Production of the fungal fruiting structures was m o s t rapid for all treatments between September 27th and October 12th. The plots receiving wastew a t er mainta i n e d their m a x i m u m fruiting b o d y p r o ­ du ction rates over the entire period w h i l e the control plot did so only during the last w e e k of that period. No significant interactions between irrigation rate and fungal fruiting body p r o d u c t i o n were noted. There was also little correspondence betw e e n the fruit­ ing b o d y count and the mycelial m a t count in the litter survey. It was evident that w a s t e w a t e r irrigation increased the time over w h i c h fruiting occurred. While this is a minor indication that w a s t e w a t e r irrigation stimulated litter decomposition, supportive one. it nevertheless is a A clearer picture of the effects of the wa s t e w a t e r o n fungal fruiting could prob a b l y be obtained by counting species of the L y c o p e r d o n genus separate from all others. These fungi dominated the Figure 37. Summation on plots with highest individual fungal fruiting body counts, Middleville, September to October, 1973. 800 ■ 600 ■ Irrigation Rates 0 = mm/week 0 ± = 25 mm/week g = 50 mm/week • = 88 inm/week 178 400 « Number of Fruiting (Summation) ■ Bodies 1000 200 ■ 9-06 9-27 10-04 Time {1973} 10-12 10-23 early September counts, w e r e m o s t prolific in plots irrigated w i t h wastewater, and occurred infrequently in the unirrigated control plots. This genus thus appears to be of value as an indicator species. Nutr i e n t Budget A focal point of this study has been the effects of w a s t ew a t e r irrigation on the nutrient status of the red pine ecosystem. water quality, Discussions have included soil soil chemistry, foliage nutrient levels, and elemental constituents of the litter. 22 Tables 21 and summarize individual observations of these components into a nutrient bu d g e t of the red pine system. Table 21 contains the total nitr o g e n bud g e t of the system. The bud g e t assumes that: changes in storage. inputs - outputs No attempt is m a d e to account for nitrogen already present in the system. Therefore, the primary concern is o n l y w i t h the fate of the nitrogen added via w a s t ewater irrigation. Other nitr o g e n inputs such as rainfall and bacterial fixation are disregarde d since no m e a s urements of these sources w e r e made. The m a i n items in the nitrogen bu d g e t include waste w a ter loading, needle litter decomposition, loss to the wa t e r table, foliage uptake, soil increase, item and the net balance. stem uptake, The w a s t e w a t e r loading (1 ) constitutes the input quan t i t y and has been discussed in the section o n water quality. Needle Table 21. Estimation of total nitrogen budget in the red pine stand at Middleville, 1972 and 1973. Wastewater Irrigation (mm/week) Budget Items Budget Relationship 25 50 88 ------------- kg/ha------------1. Wastewater loading Input - 61.8 -123.4 -217.0 2. Needle Litter Decomposition Storage A - 15.0 - 21.2 - 23.8 3. Loss to Water Table Output 4. Foliage Uptake 6. 7. 18.8 32.7 a) 1972 foliage uptake Storage A + 1.2 + 4.4 + 3.5 b) 1973 foliage uptake Storage A + 8.2 + 57.3 + 68.8 Stem uptake a) 1972 stem uptake Storage A 0.0 + 5.6 + 3.5 b) 1973 stem uptake Storage A 0,0 + 8.4 + 1.7 a) Estimated (sum of 1-5) Storage A + 63.2 + 50.1 +130.6 b) Measured Storage +612.4 +328.6 +328.6 +549.2 +278.5 +198.0 Soil Increase (0-60 cm) Net 180 5. 4.2 Table 22. Estimation of phosphorus budget in the red pine plantation at Middleville, 1972 and 1973. Wastewater Irrigation (mm/week) Budget Item Duuyeu Relationship 50 88 - 86.0 1. Wastewater Input Input in . CM 1 25 - 48.9 2. Needle Litter Decomposition Storage A - 2.6 - 3.2 - 3.2 3. Loss to Water Table Output + 0.1 + 0.1 + 0.3 4. Foliage Uptake a) 1972 foliage uptake Storage A + 0.4 + 0.5 b) 1973 foliage uptake Storage A + 0.4 + 5.5 + 5.7 a) 1972 stem uptake Storage A 0.0 + 0.1 + 0.1 b) 1973 stem uptake Storage A 0.0 0.3 + 0.1 a) Estimated (sum of 1-5) Storage A +26.2 + 45.6 + 83.0 b) Measured Storage A +49.5 +113.3 +229.5 +23.3 + 67.7 +146.5 5. 6. 7. 0.0 Stem Uptake Soil increase (0-60 cm) Net 182 litter d ecomposition (2 ) is a storage item w h i c h is negative if d e c o m position exceeds a c c u m u l a t i o n and p o s i ­ tive if the reverse is true. table Loss to the ground water (3) , the ou t p u t quantity, quality section. is discussed in the water The foliage uptake items (4a and 4b) are storage changes computed b y a two-step summation process using data from previously descr i b e d sections on red pine growth and foliar nutrients. The first step determines the amount of nitrogen generated by the irr i ­ gated red pine over that of the unirrigated control trees. The second step computes the mass of nitrogen accumulated in the new growth due to increases in needle nitrogen content. Nitrogen values are assumed to be zero if biomass production and percent nitr o g e n contents are b e l o w that of the control. S t e m uptake (5a and 5b) is calculated in a similar ma n n e r except that a constan t nitrogen level of 0.35% is assumed for the stem 1972). The estimated soil nitrogen increase (Neary, (6 a) is a d e rived value indicating the amount of soil nitrogen needed to balance the bu d g e t equation other terms to be v a l i d ) . increase (6 b) (assuming all M e a s u r e d soil nitrogen is computed by summing the soil nitrogen differences between the control and irrigation treat­ ments at 15 cm intervals from the 0-to-60 c m depth. A brief look at the net nitrogen values in Table 21 reveals considerable "noise" in this budget 183 equation. The 25, 50, and 88 m m / w e e k treatments p r o ­ duced a net nitr o g e n gain of about 5, 27, and 19 kg/ha. The values are cons i d e r a b l y higher than the estimated soil increases needed to balance the budget. One p ossible source of additional nitrogen is through b a c ­ terial fixation. However, it is unlikely that such large soil nitrogen increases resulted from fixation alone. Ano t h e r possible source of d i s c r epancy lies in the m e a s u r e m e n t of soil nitrogen. Nitrogen levels in the irrigated plots w h i l e consistently higher than in control plots were not significantly so. Table 22 estimates the phosphorus b u d g e t and consists of the same items as for nitr o g e n in Table 21. Phosphorus contents used in the stem calculations are from Rickard (19 72). The phosphorus budget comes closer to being balanced than d i d the nitr o g e n budget. the n i t rogen budget, As in soil increases throw the budget onto the additive side. The soil represents only available phosphorus and thus does not include the entire phosphorus content. However, the higher available phosphorus levels at the higher irrigation rates are m o r e readily explained. the s e ction on soil chemistry, As was indicated in the pH in the Boyer soil at Middleville rose from 5.9 to 7.5 w i t h wa s t e w a t e r irrigation. This w o u l d indicate conditions w h e r e p h o s ­ phorus tied up as insoluble precipitates wo u l d again go into solution. 184 B . Lott Woodlot W a t e r Quality Wastewater Inputs Wastewater from the E a s t Lan s i n g Sewage Treatment Plant and well w a t e r from the M i c h i g a n State Univer s i t y water s ystem were applied to plots w i t h i n L o t t Woo d l o t during the summer and early fall of 19 7 2 and 1973. 1972 irrigation was The from A u g u s t 1 through October 10 and in 1973 from June 8 to Oct o b e r 19. A v e r a g e concentrations of the ammonia nitrogen (NH^-W), nitrate nitr o g e n (NO^-N), organic nitrogen (Organic N ) , total nitrogen phorus (Total P) (Total N ) , and total p h o s ­ found in the sewage effluent and well water are presented in Table 23. E a c h wastew a t e r nutrient parameter exhibited some v a r i a bility over the two-year period. N 0 3~N showed the m o s t variation, from 5.2 mg/1 in 1972 to 0.8 mg/1 in 197 3. going However, nearly all nutrient values w e r e w i t h i n expected ranges for secondary effluent from the East Lans i n g sewage treatment plant (D'Xtri, 1973). Total P was slightly below the m i n i m u m values for secondary effluent. Nutrient values of the irrigated well wa t e r agreed with results reported b y D'Xtri (1973). 185 Table 23. Ave r a g e concentrations of sewage effluent and well w a t e r used in L o t t Woodlot, 1972 and 1973. NH--N N O - —N J Year Organic N Total N Total P mg/ 1 (A) Sewage Effluent 1972 4.8 5.2 1.5 11.5 1973 6.5 0 . 8 0.7 8 . 0 1 . 0 0.7 (B) Well Water 1972 0.04 0.04 0 .0 2 0 . 1 0 < 0 . 0 1 1973 0.04 0.04 0 . 0 2 0 . 1 0 < 0 . 0 1 Nutrient Loading The irrigation and nutr i e n t loadings achieved in Lott W o o d l o t during 1972 and 19 7 3 are presented in Table 24. The 1973 irriga t i o n was the most effective since it was applied over a longer period of time. Irrigation du r i n g 1973 at the rates of 25, 50, and 75 mm/week increased the annual effective p r e c i p i t a t i o n b y 62, 124, and 186%, respectively. A n interesting nutrient loading trend resulting from fluctuations in the sewage effluent nutrient concentrations involved the N H 3 ~N/ NO^-N ratio. was 0.75, During 1972, w h e n the N H ^ - N /NO^-N ratio the NH^-N fraction accounted for 38% of the total n i tr o g e n load. In 1973 this ratio abruptly changed to 8.13 w i t h N H 3~N accounting for a s i g n i ficant 81% of the n i t rogen load. 186 Table 24. Wastew a t e r irrigation and nutr i e n t loading rates for L o t t Woodlot, 19 72 and 19 73. (A) Depth of irrigation and precipitation Wastew a t e r Irrigation Year Rainfall 25 50 Well Water 75 50 mm mm 1972 949 250 500 750 1973 808 500 1000 1500 500 1 0 0 0 (B) A v e r a g e n u t r i e n t loading rate w i t h diffe r e n t levels of w e l l w a t e r and wastew a t e r irrigation 1972 Nutrient 25 s 50 s 75 s 1973 50 w 25 s 50 s 65.0 75 s 50 w lrr* /Via — nh 3- n 1 2 . 0 24.0 36.0 0 . 2 32. 5 no 3- n 16.0 32.0 48.0 0 . 2 4.0 3.8 7.6 11.4 0 . 1 Total N 31.8 63.6 95.4 Total P 2.5 5.0 7.5 Organic N 97.5 0.4 8 . 0 1 2 . 0 0.4 3.5 7.0 10.5 0 . 2 0.5 40.0 80.0 <0 . 1 3.5 7.0 1 2 0 . 0 10.5 0.5 <0 . 1 187 Ground Water Recharge Ground w a t e r recharge totals for Lott W o o d l o t during A p r i l through October of 1JJ7 2 and 1973 are shown in Table 25. A t the 60 cm depth, applications of 25, 50, and 75 m m of w a s t e w a t e r / w e e k increased the ground water recharge by factors of 3, 6 , 15, and 26 in 1973. 6 , and 9 in 1972 and Ground w a t e r rech a r g e totals during A pril through October at L o t t W o o d l o t w e r e lower than at M i d d l eville in 197 2 due to a later starting date, but h igher in 19 7 3 because irrigation at Mi d d l e v i l l e was suspended in July during the height of the e v a p o transp i r a tive d e m a n d period due to equip m e n t failure. Ground water recharge computed for L o t t Woo d l o t indicated no periods of soil mois t u r e def i c i t in 197 3 in plots receiving 25 or 50 m m of water/week. Middleville, In 197 3 at periods of soil moist u r e def i c i t occurred at both the 25 and 50 mm/ w e e k plots. Nutrient renovations at L o t t W o o d l o t du r i n g 1972 and 197 3 as measu r e d w i t h lysimeters buried at 30 and 60 cm depths are presented in Tables 26 and 27. The calculation of these renovations is approached from the p o i n t - o f - v i e w of total impact of the w a s t e w a t e r on soil wa t e r quality. A n alternative approach is to compute renovation on the basis of w a s t e w a t e r additions minus well w a t e r additions in order to separate the effects of w a s t e w a t e r nutrients from the w a t e r itself. 188 Table 25. Estim a t e d ground w a t e r recharge calcul a t e d at two soil depths and four irrigation r a t e s , L o t t Woodlot, 19 72 and 1973. G round Water Recharge 50 25 0 Month 75 30 60 30 60 30 60 30 60 86 86 86 86 86 86 86 86 May 0 0 0 0 0 0 0 0 June 0 0 0 0 0 0 0 0 July 0 0 0 0 0 0 0 0 August 0 0 17 0 152 1 2 0 277 245 September 0 0 142 127 242 242 342 342 16 0 93 93 118 118 (A) 1972 April October Total 1 0 2 86 68 68 313 281 573 541 823 791 (B) 1973 April 23 23 23 23 23 23 23 23 May 32 32 32 32 32 32 32 32 June 0 0 33 33 108 108 183 183 July 0 0 36 36 161 161 286 286 August 0 0 42 42 167 167 292 292 September 0 0 1 0 1 1 0 1 2 0 1 2 0 1 301 301 October 0 0 88 88 163 163 338 338 Total 55 55 855 855 1455 1455 355 355 Table 26. Percent renovation for 1972 and 1973 using the ground water recharge method at the 30 cm depth in the Lott Woodlot. 1972 Month June Jul Sep Oct Mean NH.-N N0,-N j Org. N Total N Total P Org. N Total N NH-.-N N0,-N J Total 0 0 0 0 50 50 w — — — — — 25 s — — — — — 98 0 96 78 99 50 s — — — — 98 0 0 57 98 75 s — — — — — 98 0 0 4 96 50 w — — — — — — 0 0 0 0 0 25 a — — — — — 98 70 93 95 99 — — 98 0 61 79 98 — — 97 0 38 65 96 50 s — — — 75 s — — — 50 w 0 0 0 C 0 0 0 0 0 0 25 3 99 78 98 90 99 98 0 97 73 99 50 s 97 5 58 51 96 96 45 0 59 98 75 s 98 0 93 26 99 97 0 31 43 96 50 w 0 0 0 0 0 0 0 0 0 0 25 s 98 0 73 0 97 94 0 14 0 93 96 50 s 98 0 60 0 97 94 0 29 52 75 s 93 0 44 19 97 96 0 10 0 96 50 w 0 0 0 0 0 0 0 0 0 0 25 s 83 0 0 0 98 98 0 80 0 92 50 s 92 0 75 0 84 97 0 0 59 92 75 s 92 0 55 0 94 97 0 0 19 94 50 w 0 0 0 a 0 0 0 0 0 0 25 s 97 0 76 24 98 97 0 77 14 97 50 s 97 0 61 13 96 96 0 77 63 97 75 s 96 0 70 9 98 97 0 15 28 ■ 96 189 Aug Rate mm/week 1973 Table 27. Percent renovation for 1972 and 1973 using the ground water recharge method at the 60 cm depth in the Lott Woodlot. 1973 1972 Month Rate mm/week June 50 w July Sep Oct Mean — n o 3-n Org. N Total N Total P NH3-N n o 3-n Org. N. Total N Total P — — — — 0 0 0 0 0 — — 99 0 60 80 99 25 s — — — 50 s — — — — — 99 0 36 69 96 75 s — — — — — 99 0 25 36 97 50 w — — — — 0 0 0 0 0 25 s — — — — — — 99 97 89 98 99 50 s — — — — 98 0 72 76 97 75 s — — — — — — 98 0 27 78 98 50 w 0 0 0 0 0 0 0 0 0 0 25 s 100 100 100 100 100 99 0 44 45 99 50 s 99 13 55 55 98 98 0 50 66 98 75 s 99 0 91 34 99 98 0 38 0 97 50 w 0 0 0 0 0 0 0 0 0 0 25 s 98 0 60 29 97 95 0 71 0 99 50 s 99 0 33 0 97 98 87 0 86 99 75 s 86 0 73 0 98 98 0 0 0 96 50 w 0 0 0 0 0 0 0 0 0 0 25 s 95 0 25 0 98 98 0 96 0 96 50 s 99 0 0 0 96 98 0 9 55 93 75 s 98 0 82 0 97 96 0 0 29 94 50 w 0 0 0 0 0 0 0 0 0 0 25 s 99 22 76 52 99 98 0 71 10 98 50 s 99 0 38 8 98 98 0 44 71 97 75 s 97 0 83 0 99 98 0 7 26 96 190 Aug n h 3-n 191 However, such an approach is unrealistic since irrigation alone can alter the qual i t y of the ground w a t e r aquifer by the flushing of nutrients normally pres e n t in the soil. Thus the total impact of w a s t e w a t e r nutrient constituents and irrigation w a t e r m u s t be considered in determining the effect upon ground wa t e r quality. Nitrogen 30 cm: 50 mm/week of Well Water The average concentrations of NH^-N, NO^-N, Organic N, and Total N in the soil solution sampled at 30 cm are shown in Figure 38. These values and those determined for the 60 cm depth (Figure 42) indicate the a mount of flushing which has taken place. instance, In every the concentrations of all four forms of nitrogen found in the soil water exceeds that in the well water used for irrigation. In 1972, NH^-N levels were very stable at c o n ­ centrations less than 0.25 mg/1. relatively uniform b e t w e e n 1 . 0 showed the m o s t variability. and Organic N was also 2 . 0 mg/1 . N 0 .J-N It started out quite high at about 13 mg/1 and then gradually receded throughout the remainder of the irrigation season. M o s t of the Total N content in the lysimeter samples was N 0 3 ~N. In 197 3, N 0 3~N continued the recession curve established in 1972 until it reached its low point in Figure 38, NH^-N, NO^-N, Organic N, and Total N concentrations at the 30 cm Woodlot, 1972 and 1973, 192 depth for the 50 mm/week of well water irrigation rate, Lott 1972 1973 20 « 10 9 8 . 6 ■ 193 mg/ 1 7■ 5* 4 3* 2 " 1 8-16 9-02 10-13 7-05 194 early August. However, even at that low level (0.35 mg/1), N 0 3~N was still m u c h higher than that found in the well water (0.04 mg/1). NH^-N levels rose somewhat in 19 73 but remained less than 0.5 mg/1. Organic N accounted for a larger propor t i o n of the Total N concentrations. Total N levels were lower in 1973 due to less N 0 3~N flushing. 30 cm: 2 5 mm/w e e k of Wastewater The renova t i o n of nitrogen in plots irrigated with 25 mm/ w e e k of w a s t e w a t e r was strongly influenced by N 0 3~N (Figure 39). In 197 2, Total N r e n o vation was 24% due to the lack of N 0 3~N renovation. Removal of N H 3~N and Organic N was 97 and 76% respectively. levels were consistently bet w e e n 8 . 0 and 1 1 . 0 N 0 3— N mg/ 1 throughout 197 2. During 197 3, N 0 3~N concentrations dropped som e ­ w h a t in July but then rose to well above the 10 mg/1 m a x i m u m limit allowed by the Public Health Service for w ater supplies. to those in 1972. N H 3~N and Organic N levels were similar Renovations were 97 and 77% for those two forms of nitrogen. As in 1972, the Total N contents of the soil solution were largely due to N 0 3 -N. Total N renovation was low at 14%. 30 cm: 50 mm/week of Wastew a t e r The 1972 N H 3 ~N, N 0 3 ~N, Organic N, and Total N levels in the soil solution collected in plots Figure 39 NH^-N, NO^-N, Organic N, and Total N concentrations at the 30 cm depth for the 25 mm/week of wastewater irrigation I 195 rate, Lott Woodlot, 1972 and 1973. Total N 1972 20 * 10 n o 3-n ■ 9« 8■ H 7 6* 5■ 4« 3 2 « 1" Organic N 1=M=4=^=HS/Vr 8-16 l-n*> 9-02 10-13 ^ 7-05 NH t -N 197 irrigated w i t h 50 irun/week of wa s t e w a t e r w e r e quite similar to those in plots r e c e iving 25 min/week of wastewater (Figure 40). N H ^ —N levels were v e r y stable and renovation was excel l e n t (97%). off d uring the irriga t i o n season. Organic N tapered Renovation was 61%. Total N contents of the soil w a t e r again w e r e strongly affected b y NO^-N. Re n o v a t i o n was poor at 13%. In 1973, Total N renova t i o n improved to 63% as NO^-N levels fell to less than 5.0 mg/1. N 0 3~N r e n o v a t i o n managed to increase to 45% in August, b u t a v e r a g e d 0% for the irrigation season. were good at 97 and 77%. N H ^ —N and Organic N renovations Some Organic N flushing occurred in late A u g u s t along w i t h NO-^-N flushing. 30 cm: 75 mm/week of W a s t e w a t e r The levels of the four forms of nitro g e n durin g 197 2 resembled those found in the 25 and 50 m m / w e e k of waste w a t er irrigation treatments (Figure 41). was high and accou n t e d for muc h (greater than 7.0 mg/1) of the Total N content in the l y s i m e t e r s . for N H 3~N (96%) and Organic N NO-j-N Renovation (70%) was similar to that of the other w a s t e w a t e r treatment plots at the same depth. Again, Total N renovation was low at 9%. In 1973, N 0 3~N exhib i t e d several distinct flushing pulses at a p p r o ximately monthly i n t e r v a l s . Total N renovation improved somewhat to 28%. N H 3~N Figure 40. NH-j-N, N03- N f Organic N, and Total N concentrations at the 30 cm depth for the 50 mm/week of wastewater irrigation 198 rate, Lott Woodlot, 1972 and 1973. 1973 1972 20 10 9 8 6 199 mq/1 7 5 4 Total 3 2 1 Organic 0 8-16 9-02 10-13 8-02 9-06 Figure 41. NH^-N, NO^-N, Organic N, and Total N concentrations at the rate, Lott Woodlot, 1972 and 1973. 200 30 cm depth for the 75 mm/week of wastewater irrigation i 1973 1972 20 ■ m g /1 10 - 201 Total Organic 8-16 9-02 10-13 7-05 8-02 9 16 - 202 levels continued very stable (97% r e n o v a t i o n ) . While Organic N concentrations were up only slightly above 1972 levels, renova t i o n decre a s e d to 15% as a result of lower Organic N in the wastewater. 60 cm: 50 m m / w e e k of W e l l Water A v e r a g e concentrations of NH^-N, NO^-N, Organic N, and Total N found in soil solution of plots irrigated w i t h 50 mm/ w e e k of well w a t e r are illustrated in Figure 42. All values during 1972 and 197 3 represent the amount of flushing of each nitrogen form that occurred w i t h irri­ gation. In 1972 N O ^ —N made up a greater propor t i o n of the Total N concentration. However, in 197 3 Org a n i c N accounted for m o r e of the Total N value than did NO^-N. N H ^ —N stayed fairly uni f o r m over the two-year period while N O ^ - N levels declined and Org a n i c N levels increased somewhat. 60 cm: 25 mm/week of Wastew a t e r Figure 4 3 presents the average values of NH-j-N, N 0 3 ~N, Organic N, and Total N for the 25 mm/ w e e k of wa s t e w a t e r plots at 60 c m depth. M o s t of the values during 1972 and 19 73 w e r e quite similar to those at the 30 c m d epth (Figure 39). and 52% in 19 72 and 98, Renovations were 99, 22, 76, 0, 71, and 10% in 1973 for the N H 3 ~N, N O ^ —N , Org a n i c N, and Total N forms respectively. Figure 42. NH^-N, NO^-N, Organic N, and Total N concentrations at the Lott Woodlot, 1972 and 1973. 203 60 cm depth for the 50 mm/week of well water irrigation rate, 1972 1973 20 1 204 mg/ 1 io H 5H Total 3H 2 H Organic 8-16 9-02 10-13 V 7-05 8-02 9-06 Figure 43. NH^-N, NO^-N, Organic N, and Total N concentrations at the rate, Lott Woodlot, 1972 and 1973. 205 60 cm depth for the 25 mm/week of wastewater irrigation 1972 ► 1973 Total N * no3»n 206 \ Organic N 207 Higher renova t i o n values in 1972 were due to the lack of ground w a t e r recharge in August. for that m o n t h w e r e all 60 cm: 1 0 0 Thus, the renovations %. 50 mm/week of Wastewater Figure 44 illustrates the changes in NH.J-N, NO^—N, Organic N, and Total N at 60 cm w i t h 50 mm/week of w a s t e w a t e r irrigation. The 1972 NO^-N values were typically high and accounted for much of the Total N in the soil solution. Renovations were 99, 0, 38, and 8 % for the N H 3 ~N, NO^-N, Organic N, and Total N forms respectively. In 1973 the NO^-N levels dropped considerably but still accounted for a large percentage of Total N. However, Total N r e n o vation improved considerably rising to 71%. Renovation for the other three nitrogen forms held fairly constant. 60 cm: 75 mm/week of Wastew a t e r Flush i n g of N O ^ —N was very p r o n ounced at the 75 m m / week ir r i g a t i o n rate during 1972 and 1973 45). In 1972, N O ^ - N values were consistently above 10 mg/1. As has been quite evident in many of the other rates and at b o t h lysimeter depths, concentrations w e r e fairly low. were 97 and 0 (Figure 8 N H ^ —N and Organic N Per c e n t renovations 3% for the NH^-N and Organic N forms, but % for the other two forms. Figure 44. NH^-N, NO^-N, Organic N, and Total N concentrations at the Lott Woodlot, 1972 and 1973. 208 60 cm depth for the 50 mm/week of wastewater irrigation rate, 4------ 1972 ► ^ -------------- 1973 ^ 20 « 10 ■ 9 ■ 8 ■ 6 1 209 mg/ 1 7■ 5* 4* 3 Total N 2 N°3-N A •■***•» 1 ■ ^ - OrganicT? NH-a-N 0 8-16 9-02 10-13 7-05 8-02 9-06 Figure 45. NH^-N, N03-N, Organic N, and Total N concentrations at the Lott Woodlot, 1972 and 1973. 210 60 cm depth for the 75 mm/week of wastewater irrigation rate, 1972 10 4 Total N n o 3- n Organic N 8-16 9-02 10-13 212 In 1973, the N O ^ - N flushing conti n u e d b u t was not as u n i f o r m across the irrigation season. Organic N concentrations increased despite lower Org a n i c N inputs (Table 24). NH^-N levels changed very little during the 197 3 i r r i gation season. and 26% for the NH^-N, Renovations w e r e 98, 0, 7, NO^-N, Organic N, and Total N forms r e s p e c t i v e l y . Nitrogen Summary The d o m i n a n t trend in the Lott W o o d l o t w a t e r quality data has been the N 0 3~N flushing. A perfect example of the overall flushing process can be seen in the data for the 75 mm/week of w a s t e w a t e r irrigation rate at 60 c m lysimeter depth during 1973. (97.5 kg/ha) A b o u t 81% of the nitrogen applied b y irrigation was in the NH-j-N form. However, 87% (76.9 kg/ha) of the Total N reaching the lysimeters was in the form of N 0 3 ~N. Since total NO^-N loading for that rate in 1973 was only 12.0 kg/ha, 64.9 k g / h a of the N 0 3~N had to therefore come from N H 3~N wh i c h was oxidized in normal soil n i t rogen transformations. W h i l e the L o t t Woodlot soil-plant filtering system prod u c e d a 96% renovation on the bulk of the nitrogen applied in the w a s t e w a t e r (NH 3 ~N) , m u c h of this was later lost as N 0 3 *-N. Nitrog e n losses as NC>3-N accounted for 64% of the Total N loading of 1 2 0 . 0 kg/ha. 213 The major factor cont r i b u t i n g to the loss of nitrogen as NO^-N in L o t t W o o d l o t is attributed to the hourly rate at w h i c h w a s t e w a t e r was applied. The gravity-feed irrigation sy s t e m used in the L o t t Woodl o t required that the valves on the reservoirs be operate d in the "wide-open" posi t i o n to insure adequate spread of irrigation water. Atte m p t s to reduce the flow p r o ­ duced m i n i m u m lateral disper s i o n from the PVC pipe d i s ­ tribution system. In the "wide-open" valve position, w astew a ter wa s di stributed on the plots at a rate of 50 mm/hour. M o s t w e l l - s t r u c t u r e d and drained forest soils can infiltrate p r e c i p i t a t i o n at rates m u c h greater than 50 m m /hour (Lull and Reinhart, 1972), however, such high infiltration rates also promote N 0 3~N flushing. NO^-N is a very mo b i l e form of nitrogen and moves quite easily w i t h any pulse of infiltrating water. Thus lysimeters in Lott W o o d l o t were sampling soil w a t e r containing NO^-N that was both o r i g i n a l l y pre s e n t in the w a s t e w a t e r and flushed out of the soil. Total Phosphorus Despite some initial var i a b i l i t y in 1972, Total P was g e n erally stable at b o t h the 30 and 60 cm soil depths (Figures 46 and 47). Renova t i o n was greater than 96% for all treatments except w i t h the 50 m m of Figure 46 . Total p concentrations at the 30 cm depth, Lott Woodlot, 214 1972 and 1973. 1973 mm/week P t 50s 215 / 75s 50w 25s 13 7 Figure 47. Total P concentrations at the 60 cm depth, Lott Woodlot, 216 1972 and 1973. 12« 1973 1972 mm/week mg/ 1 50w V 8-16 9-02 10-13 7-05 8-02 9-06 217 » 08" 218 well water. That partic u l a r treatment exhibited a flushing effect here w i t h Total P as it did w i t h the other four nutrient p a r a m e t e r s . Ve g e t a t i o n The L o t t Wood l o t is a typical second growth hardwood stand found on m a n y southern Mich i g a n farms. It is d ominated by sugar ma p l e slippery elm (A c e r sacch a r u m Marsh.), (Ulmus rubra M u h l ) , pri c k l y ash americanum M i l l . ) , A m e r i c a n be e c h Ehrh.), h o p h o r n b e a m black c herry (Fagus grandifolia (Ostrya v i r g iniana (Prunus serotina Ehrh.) (Acer n ig r u m Michx. (Zanthox y l u m [Mill.] K. K o s c h ) , and black maple F.) w h i c h make up 72% of the stand. High-graded by its former owners, the w o o d l o t contains numerous o v e r - mature hardwoods of low quality and a dense understory of small diam e t e r trees. In this pilot study, analysis of p l a n t response to wa s t e w a t e r irrigation w a s limited to tree seedlings and herbaceous plants found on the treatment plots. Summer Flora The herbaceous plants and tree seedlings occupying the wast ew a t e r irrigation plots w e r e surveyed in A u g u s t of 1972 and 1973 (Table 28). The 15 plots located on Miami loam were domin a t e d b y hairy blue violet (Viola sororia W i l l d . ) , sugar maple, stinging nettle (Urtica dioica L.), Virginia creeper (Parthenocissus 219 T a b le 2B. V e g e ta tiv e a b u n d a n c e f o r W o o d lo t, 1 9 7 2 a n d 1 9 7 3 . 15 ir r ig a te d p lo ts o n M ia m i lo a m , N u m b e r/O .0 0 6 h a 1 L o tt N u m b e r /h a S p e c ie s 1972 1973 C hange 1972 1973 C hange 266 1 5 ,8 6 5 6 0 ,2 8 7 + 4 4 ,4 2 2 + 3 ,5 0 7 95 361 114 135 + 21 1 9 ,0 3 8 2 2 ,5 4 5 11 10 - 1 1 ,8 3 7 1 ,6 7 0 9 9 0 1 ,5 0 3 1 ,5 0 3 0 19 19 0 3 ,1 7 3 3 ,1 7 3 0 S 9 + 4 835 1 ,5 0 3 + 668 17 20 + 3 2 ,8 3 9 3 ,3 4 0 + 501 2 2 0 334 334 0 60 119 + 59 1 0 ,0 2 0 1 9 ,8 7 3 + 9 ,8 5 3 p e lta tu m 44 72 + 28 7 ,3 4 8 1 2 ,0 2 4 + 4 ,6 7 6 p e n n s y lv a n ic a 1 1 0 167 167 0 1. A c e r a a c c h a ru m 2. C a re x p e n n s y lv a n ic a 3. C a ry a o v a ta 4. C aucus 5. Euonym ua 6. Fagus g r a n d ifo lia 7. F r a x in u s S. O s try a 9. P a r th e n o c is s u s c a ro ta spp. a m e r ic a n a v ir q in ia n a q u in g u e f o lia - 167 10. P o d o p h y llu m 11. P ru n u s 12. P. s e r o t in a 9 3 - 6 1 ,5 0 3 501 - 1 ,0 0 2 13. P. v ir g in ia n a 2 1 - 1 334 167 - 167 14. Q u e rc u s 1 2 + 1 167 334 + 167 15. Q. 1 2 + 1 167 334 + 167 16. R ib e s 10 26 + 16 1 ,6 7 0 4 ,3 4 2 + 2 ,6 7 2 17. S a m b u c u s c a n a d e n s is 3 3 0 501 501 0 IB . S a n g u in a r ia 13 31 18 2 ,1 7 1 5 ,1 7 7 + 3 ,0 0 6 19. S e n e c io 4 4 0 668 668 0 20. S m ila c in a 8 5 - 3 1 ,3 3 6 835 - 501 21. T h a llic t r u m 33 9 - 24 5 ,5 1 1 1 ,5 0 3 - 4 ,0 0 8 22. T ilia 2 2 0 334 334 23. T o x ic o d e n d r o n 43 48 + 5 7 ,1 8 1 8 ,0 1 6 + 835 24. U lm u s a m e r ic a n a 44 39 - 5 7 ,3 4 8 6 ,5 1 3 - 835 25. u r t ic a 112 147 + 35 I B , 704 2 4 ,5 4 9 26. V io la 14 17 + 3 2 , 338 2 ,8 3 9 + 501 27. V. e r io c a r p a 31 IB - 13 5 ,1 7 7 3 ,0 0 6 - 2 ,1 7 1 28. V. s o r o r ia 347 505 + 158 5 7 ,9 4 9 8 4 ,3 3 5 29. X a n t h a x y lu m 2 0 2 334 0 1 ,0 5 6 1 ,6 1 9 + S 63 1 7 6 ,3 5 2 2 7 0 ,3 7 3 a lb a ru b ra c y n o s b a ti c a n a d e n s is p la tte n s i9 s te lla ta d io ic u m a m e r ic a n a r a d ic a n s d io ic a c a n a d e n s is a m e r ic a n u m T o ta ls ^E ach p lo t is 0 .0 0 0 4 ha (1 m i l a c r e ) . + - 0 + 5 ,8 4 5 + 2 6 ,3 8 6 - 33 4 + 9 4 ,0 2 1 220 quinquefolia [L.] Planch.), M a y apple peltatus L . ) , poi s o n ivy and b l o o d r o o t (P o d o p h y l l u m (T o x i c o d e n d r o n radicans L . ) , (S a n g u inaria canadensis L.) . Changes in occurrence and perc e n t frequency have taken place w i t h irrigation over the two-year period (Table 29). The largest change in p e r c e n t frequency o ccurred in the following species: sugar maple, elm sedge hairy blue violet, (Carex p e n n s ylvanica Lam.}, A m e r i c a n (Ulmus A m e r i c a n a L . ) , Virgi n i a creeper, w h i t e ash (Fraxinus A m e r i c a n a L . ) , and smooth y e l l o w violet (Viola eriocarpa S c h w e i n . ) . A statistical analysis of these seven species was c o n ducted to determine significance of wa s t e w a t e r irrigation upon species abundance (Table 30)• While d istinct increases and decreases in species numbers were noted in cert a i n treatments, such differences were not s t a tistically significant. As w a s t e w a t e r irrigation treatments are con­ tinued, shifts in species composition may o c c u r . Several visible p l a n t responses to wastewater irrigation have been noted w h i c h may eventually lead to significant changes in the p l a n t composition, biomass, tribution. or d i s ­ During the droughty period of July and August, m o s t herbaceous plants outside of the irrigated plots consistently wi l t e d by m i d - a f t e r n o o n whereas plants w i t h i n the irrigated plots remained turgid. 221 T a b le 29. F re q u e n c y a n d o c c u rr e n c e o f v e g e ta t iv e c o v e r o n M ia m i lo a m , L o t t W o o d lo t , 1 9 7 2 a n d 1 9 7 3 . fo r O c c u rre n c e 1 th e 15 p lo ts % F re q u e n c y S p e c ie s 1972 1973 10 10 12 10 4 3 2 spp. g r a n d ifo lia C hange 1972 1973 0 67 67 0 - 2 80 67 -1 3 - 1 27 20 - 2 0 13 13 0 1 1 0 7 7 0 3 4 + 1 20 27 + S 8 + 3 33 53 +20 1 1 0 7 7 0 10 9 - 1 67 60 - p e lta tu m 3 5 + 2 20 33 +13 p e n n s y lv a n ic a 1 1 0 7 7 0 1 20 13 1. A cer s a c c h a ru m 2. C a re x p e n n s y lv a n ic a 3. C a ry a o v a ta 4. D aucus 5. E uonym us 6. Fagus 7. F r a x in u s 8. O s try a 9. P a r th e n o c is s u s c a ro ta a m e r ic a n a v ir g in ia n a q u in q u e f o lia C hange 7 7 7 10. P o d o p h y llu m 11. P ru n u s 12. P. s e r o t in a 3 2 13. P. v ir g in ia n a 1 1 0 7 7 0 14. Q u e rc u s 1 1 0 7 7 0 15. Q. 1 2 + 1 7 13 + 16. R ib e s 3 5 + 2 20 33 +13 17. Sam bucua 1 1 0 7 7 0 18. S a n g u in a r ia 3 3 0 20 20 0 19. S e n e c io 1 1 0 7 7 0 20. S m ila c in a 2 2 0 13 13 0 21. T h a llic t r u m 5 4 1 33 27 22. T ilia 2 2 0 13 13 23. T o x ic o d e n d r o n 3 2 1 20 13 24. U lm u s 10 10 0 67 67 25. U r tic a 3 2 1 20 13 26. V io la 4 4 0 27 27 0 27. v . e r io c a r p a 9 6 3 60 40 -2 0 28. V. s o r o r ia 12 12 0 80 80 0 29. X a n th o x y lu m 1 1 0 7 7 0 a lb a ru b ra c y n o s b a ti c a n a d e n s is c a n a d e n s iB p la tte n s is s te lla ta d io ic u m a m e r ic a n a r a d ic a n s a m e r ic a n a d io ic a c a n a d e n s is 1E a c h a m e r ic a n u m p lo t is .0 0 0 4 ha. (1 m ila c r e ) . - - - - + - - 7 6 6 0 - 7 0 - 7 f Table 30. Influence of irrigation on actual vegetative count for the most commonly occurring ground cover species, Lott Woodlot, 1972 and 1973.1 mm Irrigation per Week species iear 0 1. 2. 3. 5. 6. 7. 25 s 50 s 75 s 1972 7.0 4.6 5.3 5.7 9.0 1973 21.3 10.3 6.0 24.3 58.3 1972 16.7 6.7 10.7 10.7 3.3 1973 16.7 7.0 6.0 10.7 4.7 1972 0.7 0.7 1.7 2.7 0.0 1973 0.7 0.7 1.3 3.0 1.0 Parthenocissus quinquefolia 1972 6.0 0.3 1.3 3.0 9.3 1973 12.3 0.3 4.0 1.7 21.3 Ulmus americana 1972 5.7 5.3 0.7 1.7 1.7 1973 3.7 5.3 0.7 2.3 1.3 1972 3.0 1.3 4.3 0.7 1.0 1973 0.7 0.7 3.3 0.7 0.7 1972 10.7 1.3 38.0 36.7 29.0 1973 19.7 18.7 52.0 47.7 30.3 Carex pennsylvanica Fraxinus americana Viola eriocarpa V. sororia ^No significance at the 5% level (Tukey's test) with treatment. 222 4. Acer saccharum 50 w 223 Irrigation also appeared to extend the growing season in species such as P o d o p h y l l u m peltatus and Viola sororia. W h i l e m o s t plants in u n i r r igated plots die back by October 10th, such plants in irrigated plots were still vigorous. Spring Flora D omi n a n t spring plants on the study area in Lott Woodlot are: spring be a u t y (Clayt o n i a virginica L.), Anemone s p p . , Dutchman's breeches [L.] Vernh.), toothwart (Dentaria spp.), violets s p p .), y e l l o w a d d e r 1 s-tongue Ker.), b e d s t r a w (Dicentra cucullaria (Viola (E r y t h r o n i u m a m e r i c a n u m (Ga l i u m spp.), and sugar maple seedlings. To d e t e rmine the extent to w h i c h w a s t e w a t e r irrigation affected v e g e tative growth and nutrient content, 2 0.25 m sample was taken of ground cover plants a occupying the study plots in the spring of 1974. The data gathered in this sampling indicated that the i r r i gation treatments thus far had negligable effect on biomass produc t i o n (Tables 31 and 32). Leaf biomass for the sugar maple w a s somewhat lower in irri ­ gated plots, but the reductions w e r e not significant. The 50 and 75 m m of w a s t e w a t e r / w e e k treatments produced slightly higher herbaceous plant biomass but again not significantly. N u t r i e n t contents of the plants sampled for b i o ­ mass determinations are shown in Tables 33 and i 34. As 224 Table 31. Irrigation Rate Composite biomass of spring herbaceous species by w a s t e w a t e r irrigation rate, L o t t Woodlot, 1974.1 Irrigation Type Wet W e i g h t Biomass Dry Weight Biomass mm/week % Moisture ------ %------ None 328.7 78.1 396 50 Well water 204 .0 37.6 479 25 Wastewater 287.3 51.7 469 50 Wastewater 455.9 99.1 435 75 Wastewater 451.6 91.2 428 0 Table 32. Irrigation Rate Leaf biomass of 10 randomly chosen sugar m a p l e seedlings in each plot of the Lott Woo d l o t w a s t ewater irrigation study, 19 74.1 Irrigation Type mm/week 0 Wet We i g h t Biomass ----- None Dry W e i g h t Biomass % Moist u r e “ 9 — 11.9 4.0 196 50 Well water 8.9 3.0 203 25 Wastewater 9.7 3.2 196 50 Wastewater 3.8 2 0 1 75 Wastewater 3.1 198 5% level 1 1 . 8 9.5 ^No significant difference w i t h treatment at the (Tukey's test). 225 Table 33. Foliar nutr i e n t cont e n t of composite sample of 10 sugar m a p l e seedlings by irriga t i o n rate, Lott Woodlot, 1974.1 m m Irrigation/week Parameter Unit Control 0 Well Water Wastewater 50 25 50 75 N % 2 2. 29 2.17 2.37 2.15 2 K % 0.99 0.98 1.04 1.03 1 . 0 0 P % 0.15 0.15 0.18 0.16 0.15 Na ppm3 Ca % 0.48 0.58 0.50 0.49 0.45 Mg % 0.17 0.18 0.18 0.17 0.19 Mn ppm 130 .3 108.0 234.0 Fe ppm 90 .0 81.0 105.0 98.0 78 .0 Cu p pm 4.8 4.5 7.5 6.5 2.3 B ppm 16. 5 17.7 17.9 19.8 19 .8 Zn ppm 19.3 21.3 2 0 . 0 21.7 11.3 A1 ppm 450.7 1 . 0 602.3 1 . 0 1 496.3 1 . 0 462.7 422. 3 2 1 2 . 0 1 . 0 No significant difference w i t h treatment at the 5% level (Tukey's t e s t ) . 2 3 Percent of dry weight. p p m = pg/g. .28 58. 0 1 . 0 226 Table 34. Compo s i t e nutrient con t e n t of spring h e r ­ baceous species by irriga t i o n rate, L o t t Woodlot, 1974.1 m m of Irriga t i o n Per W e e k Parameter Unit Control 0 Well W ater W astewater 50 25 50 75 N % 2 2.23 2.39 1.87 2 . 0 1 2.18 K % 2 .0 1 2.48 2.36 2.27 2.47 P % 0.14 0.13 0.13 0.13 0.15 Na ppm3 Ca % 0.89 1.27 0.94 0 . 8 8 1.08 Mg % 0 .27 0.40 0.44 0.42 0.36 Mn ppm 92.0 56.0 94.3 75.0 72.0 Fe ppm 680 .0 290.7 785.3 424 .7 584.0 Cu ppm 16.1 8.3 46.9 8.9 26.1 B ppm 16 .8 14.9 17.1 15.2 16 Zn ppm 45.0 67.7 71.3 46.7 58.3 A1 ppm 253.3 940.0 428.7 613.0 648 .0 8 8 6 . 0 646.3 735.0 685.0 714.3 .1 ^No s i g n i ficant difference w i t h treatment at the 5% level (Tukey's test). 2 Percent of dry weight. 3ppm = ug/g. 227 for biomass, no significant treatment - r e l a t e d differences were noticeable. The sugar ma p l e leaves had higher manganese and b o r o n levels and lower potassium, calcium, magnesium, iron, copper, sodium, zinc, and a l u m i n u m levels than the herbaceous species. Nitr o g e n and p h o s ­ phorus levels w e r e compar a b l e in b o t h sugar maple and the c o m p osite of all the herbaceous species. Tree seedlings and herbaceous v e g e t a t i o n can exhibit considerable response to wa s t e w a t e r irrigation (Little et al^., 1959, and So p p e r and Kardos, 1973) . Such s i g n i ficant differences have not as yet been detected in the L o t t W o o d l o t study. to either This m a y be due (1 ) an insufficient length of irrigation or (2 ) the mode of applying the wastewater. Soil C h e m i s t r y The effects of two years of w a s t e w a t e r i r r i ­ gation on pH, available phosphorus, nitrogen, calcium, loss on ignition, total Kjeldahl and exchangeable potassium, and m a g n e s i u m are shown in Table 35. Con­ siderable variability exists in the L o t t W o o d l o t soil chemistry data and the d e t e c t i o n of existing trends thus becomes difficult. P a r t of this variability is undoubtably associated w i t h the me t h o d of w a s t e w a t e r application. Spray irrigation distributes w a t e r much more u n i f ormly than does trickle irrigation and does so over a more prolonged pe r i o d of time. [ Table 35. Average soil chemistry parameters of Miami loam for 0-60 cm depth, Lott Woodlot, after two years of irrigation treatments. Irrigation (mm/week) Parameter Units Control 0 pH 5.7 a — Wastewater Wellwater 50 25 50 75 6.1 ab 6.2 ab 6.4 b 6.7 b kg/ha 14.9 a 13.3 a 10.0 a 12.7 a 16.8 a K kg/ha 94.1 a 170.2 b 97.1 a 110.5 a 105.3 a Ca kg/ha 1458.0 a 2046.8 a 1668.9 a 1546.0 a 2002.8 a Mg kg/ha 139.7 a 355.2 b N kg/ha 2151.0 a 1852.2 a 1802.4 a 1493.7 a 1453.9 a 3.4 a 3.7 a 3.4 a 2.8 a 3.1 a Loss on Ignition % 224.1 ab 230.8 ab 278.9 b ^Means not followed by the same letter are significantly different at the 5% level (Tukey's test). 228 P 229 EH A p p l i c a t i o n of municipal w a s t e w a t e r to the Mia m i loam soil in the L o t t W o o d l o t altered the pH of the up p e r 60 cm of soil (Figure 4 8 A ) . the pH was uniform, to 5.8 at 60 cm. 75 mm/week, 6.8 In the u n i r r igated plots var y i n g from 5.7 in the upper 15 c m W i t h irrigation rates of 25, the pH at 15 cm increased to 6.4, respectively. water had a pH of 50, and 6.3, and The plots with 50 mm/w e e k of well 6 .6 . The magnitude of the increase in pH w i t h irrigation decre a s e d with increased soil depth for all four irrigation rates. However, the 50 mm/week of w e l l w a t e r rate decreased the m o s t with depth, and at 60 c m was lower than in the unirrigated control plots. None of the five treatments exhibited significant variations associated with soil depth. At 15 cm, irrigated plots w e r e significantly higher in pH than w e r e the control. But at 60 cm only the highest two w a s t e w a t e r irrigation rates had a pH significantly greater than the controls. Phosphorus The d i s t r i b u t i o n of available phosphorus w i t h i n the upper 60 c m of soil in L o t t Woodlot is illustrated in Figure 48B. No s i g n ificant differences w e r e noted between treatment of soil depth. The low available phosphorus levels, w h i l e unusual for this soil texture 230 F i g u r e 48. C h a n g e s in (A) pH and (B) a v a i l a b l e p h o s p h o r u s w i t h soil d e p t h and i r r i ­ g a t i o n rates, L o t t Woodlot, 19 73. 4 231 (A) Irrigation Rates 50s 25s (cm) 15 ■ Depth (mm/week) 50w 75s Soil 30 * 45 60 - 7.0 6.5 6.0 5.5 ® £H 0 Soil Depth (cm) 15 30 45 60 10 25 15 Avail a b l e Phosphorus (kg/ha) 232 and pH, are typical of forest stands w h i c h occupy sites with no previous history of cultivation. Under such conditions humic phosphorus normally ca n n o t b e extract e d with Bray's PI solution, although it is still available to plants. Potassium The extractable p o t a s s i u m con t e n t of the Miami loam soil in Lott W o o d l o t showed s i g n i f i c a n t differences related to soil d e p t h (Figure 4 9 A ) . week of w a s t e w a t e r irrigation, irrigation, Plots w i t h 25 mm/ 50 m m / w e e k of w e l l water and n o n i r rigated controls were significant l y higher in p o t a s s i u m at 15 cm depth than at 30 c m depth. The remaining treatments did not show any significant differences due to soil depth. No obvious treatment patterns w e r e observed for potassium content. of well water, A t 15 cm, 50 mm/w e e k and 25 mm/ w e e k of w a s t e w a t e r treatments were significantly higher kg/ha respectively) rate the control, (179.2, 241.9, and 170.2 than the 7 5 mm/w e e k of wastew a t e r (107.5 kg/ha). Calcium The levels of extractable c a l c i u m in the soil in Lott Woo d l o t ranged from 4190.0 to 2740.6 k g / h a at the 15 cm depth but w e r e not affected by wa s t e w a t e r irrigation. S i g n ificant differences w i t h i n treatments, 233 F i g u r e 49. C h a n g e s in (B) (A) e x t r a c t a b l e p o t a s s i u m and e x t r a c t a b l e c a l c i u m w i t h soil d e p t h and i r r i g a t i o n rates, L o t t Woodl o t , 197 3. Soil Depth (cm) 15 m 30 45 60 50 100 150 250 200 Extractable Potassium (kg/ha) Soil Depth (cm) 15 r 30 Irrigation Rates 0 = 0 mm/week □ = 50 m m / w e e k w e l l water 45 ^ = 25 nun/week w a s t ewater ■ = 50 m m / w e e k w a s t ewate r 60 • = 7 5 m m / w e e k wastew a t e r T 0 " T " 1000 2000 E x t r a ctable C a l c i u m -nr3000 (kg/ha) 4000 235 however, w e r e noted w i t h depth. C a l c i u m con t e n t was consid e rably higher at the 15 c m de p t h than at the 30 or 60 c m depths (Figure 4 9 B ) . M a g n e s i um Changes were evident in the e x c h a ngeable m a g ­ n esium contents of the Miami loam soil wh i c h reflected the application of irrigation waters (Figure 5 0 A ) . At 15 cm m a g n e s i u m levels in the soils o f all four irri­ gation treatments (678.8, 419.6, were h i g h e r than the control 362.9, and 482.2 kg/ha) (24 3.1 kg/ha). Magnesium in the 75 mm/ w e e k of wa stew a t e r and 50 mm/ w e e k of well w ater plots w e r e significantly higher than that of the control. A t 30 cm only the well w a t e r treatment was significantly higher in exchangeable m a g n e s i u m than the control. A t 60 c m the four irrigated plots were still h igher than the control but not significantly. The h i gher m a g n e s i u m levels associated w i t h the well w ater treatment, for both the 15 and 30 c m soil depth, when compared to the lower levels related to the w a s t e ­ w ater treatments is unexplained. Nitrogen Total Kjeldahl nitrogen exhibited considerable decrease w i t h increased depth (Figure 5 0 B ) . The nitro g e n content showed a gradual decline w i t h irrigation (510 8 . 6 kg/ha in control plots to 3465.5 kg/ha in the 236 F i g u r e 50. C h a n g e s in (B) (A) e x t r a c t a b l e m a g n e s i u m and total K j e l d a h l n i t r o g e n w i t h soil d e p t h an d i r r i g a t i o n rates, L o t t Woodlo t , 1973. 237 (A) 0 Soil Depth (cm) 15 30 45 60 0 200 400 (kg/ha) Depth (cm) "" Ex t r a ctable M a g n e s i u m 600 Irrigation Rates Soil 0 1000 = 0 nun/week □ = 50 nun/week w e l l water A = 25 m m / w e e k wastew a t e r ■ = 50 nun/week w a s t e w a t e r • = 7 5 mm/ w e e k w a s t e w a t e r 2000 Total Kjeldahl Nitr o g e n 4000 (kg/ha) 5000 238 75 nun/week irrigation rate plots) at the 15 c m depth but these differences w e r e n o t s t a t i stically significant. This trend continued at 60 cm except in the case of the 50 m m /week of w e l l w a t e r treatment. If the premise that n i trogen v a r i abili ty in forested l o a m soils will a pproach that indicated in Figure SOB, then the 200 kg/ha added by w a s t e w a t e r irrigation seems small by comparison. The two-year dura t i o n of this study was, however, insuf­ ficient to de t e c t any significant soil nitr o g e n changes. Loss on Ignition The loss on ignition in the Miami loam in the Lott W o o d l o t paralleled that of soil nitrogen (Figure 51). Significant differences w e r e noted w i t h i n e a c h treatment b e t w e e n the 15 and 30 cm depth. Otherwise, no signifi ­ cant differences existed bet w e e n individual loss on ignition values. A t 15 c m a trend of decrea s i n g loss w i t h increasing irrigation rate w a s observed. The p e r ­ cent loss w e n t from 7.1% for the control treatment to 5.8% for the high rate of w a s t e w a t e r irrigation. A l t h o u g h these decrea s i n g levels w e r e n o t significant, such values, if valid, w o u l d serve as an indicator of increasing organic mat t e r decomposition. Soil Moisture The a p p l i cation of w a s t e w a t e r to forest e c o ­ systems is capable of altering moisture regime to a 239 Figure 51. C h a n g e s in p e r c e n t loss o n i g n i t i o n w i t h soil d e p t h and i r r i g a t i o n rates, Woodlot, 1973. Lott 240 Soil Depth (cm) 15 30 Irrigation Rates 0 = 0 mm/ w e e k □ = 50 nun/week well water 45 ▲ — 25 m m / w e e k w a s t e w a t e r g = 50 m m / w e e k w a s t e w a t e r 60 * 0 - 75 m m / w e e k wa s t e w a t e r 2 4 Loss on Ignition 6 (%) 8 241 considerable extent. The fluctuations in soil m o i s t u r e tension in L o t t Woodlot, as m e a s u r e d b y tensionmeters, is shown in Figure 52. Soil mois t u r e tension in the control plots rose steadily after July 4th, peaking in early September. Similar rises were not e xhibited in the 25 and 75 mm/we e k of w a s t e w a t e r treatments until August. Soil m o i s t u r e tension in the unirrigated plots remained above 50 c e n ­ tibars for 91 days begin n i n g July 23 and en d i n g O c t o b e r 23. The 25 and 75 mm/week treatments exceeded the 50 centib a r mark for only 24 and 12 days, respectively. During July 18 to A u g u s t 24, and September 15 to Nove m b e r 4, soil m o i sture tension in one or both of the irrigated treatments was significantly lower than that of the control treatment. These data indicate that w a s t e w a t e r irrigation will have a considerable effect on the vegetative e v a p o transpirational processes in L o t t Woodlot. Oxy g e n Diffusion Soil oxygen diffu s i o n rates w e r e p e r i o dically m e a s u r e d in the Lott W o o d l o t w a s t e w a t e r plots during the 1973 irrigation season (Table 36). These m e a s u r e ­ ments w e r e taken to determine if the w e e k l y application of irrigation water was adver s e l y affec t i n g soil aeration. Figure 52. Soil moisture tension for 0, 25, and 75 mm/week wastewater 242 irrigation rates, Lott Woodlot, 1973. (centibars) 100 25 mm/week 40 ■ Soil Moisture 243 Tension 0 mm/week 75 ram/week •" 6-27 7-27 8-24 9-25 Time (1973) 10-18 11-20 244 Table 36. Soil ox y g e n diffu s i o n in Miami loam, Lott Woodlot, 1973. Irrigation in mm/week Control Wastewater Well Water 25 50 0 50 75 m ic r o g r a m s / c m ^ / m i n u t e 7/26 0.136 a 1 0.236 ab 0.236 ab 0.382 b 0.350 b 8/02 0 . 1 1 2 a 0.168 ab 0.327 be 0.267 abc 0.479 c 10/9 0.183 a 0.294 ab 0.495 c 0.430 be 0.534 c ■'‘Means not followed by the same letter are sig­ nificantly diffe r e n t at the 5% level (Tukey's test). The flux of ox y g e n was never lower in the irri ­ gated plots than in the unirrigated plots. one instance, In all b u t the ox y g e n diffusion in soils receiving 75 mm/week of w a s t e w a t e r was significantly hi g h e r than in all other treatments. This is the reverse o f what would normally be expected. Such readings are inherent in the p lat i n u m electrode me t h o d itself. The low ox y g e n diffu s i o n in the control plots resulted from the h i g h soil moixt u r e tension. Platinum electrodes respond only to that portion of their sur­ face covered w i t h wa t e r since the transfer of electrons occurs through water. Therefore, the oxygen d i f f u s i o n rates are u n d e r estimated in dry soil Erickson, 1966) . (VanDoren and 245 The ox y g e n d i f f u s i o n rates in the irrigated plots are w i t h i n accept a b l e limits soil. for the texture of Thus, additions of w a s t e w a t e r to the Mi a m i loam has thus far not altered its drainage properties to any detectable extent. Humus The forest floor under the L o t t W o o d l o t maplebeech stand is a coarse mull humus. consists of a By late fall it c m layer of recently fallen h a r d w o o d 2 - 1 0 leaves and w o o d y mater i a l in various stages of decay. At the end of the following summer much of the leaf layer is incorporated into the A1 soil hor i z o n by earthworms and o t h e r soil fauna. The activity of these organisms produces a highly p o r o u s , crumbstructured soil horizon. Plots in the w a s t e w a t e r renova t i o n study were surveyed to determine irriga t i o n effects on litter decomposition. Con s i d e r a b l e v a r i ation occu r r e d in the coarse mull humus (Table 37) b u t treat m e n t results were in all cases nonsignificant. Total humus va r i e d from a high of 4,900 kg/ha in the 25 m m / w e e k w a s t e w a t e r rate to a low of 2,4 70 kg/ha in the 50 mm/ w e e k treatment. Much of this v a r i a bility w a s due to the w o o d y litter component, that accounted for as much as 50% of w a s t e w a t e r rate) and as little as 15% (25 mm/wee k (50 mm/ w e e k of 246 well w a t e r rate) of the total humus. Leaf litter con­ tributed the largest p o r t i o n of the total litter in all treatments. Table 37. Humus accumulations by irrigation rate, Lot t Woodlot, August, 1973.^ Irrigation Type Total Humus control 3,270 940 2, 330 50 well w a t e r 3, 630 570 3,060 25 wastewater 4 ,900 2,360 2,540 50 wa s t e w a t e r 2,470 830 1,640 75 wastewater 2,843 1,163 1,680 I rrigation Rate Leaf L it t e r Woody Litter m m /week 0 5% level ■^No s i g n i ficant differ e n c e w i t h treatment at the (Tukey's test). Leaf litter exhibited a general trend of decrea s i ng mass w i t h increasing levels of w a s t e w a t e r irrigation b u t differences w e r e not statistically sig­ nificant. The h i g h e s t leaf litter w e i g h t was noted in plots r e ceiving 50 mm/ w e e k of w e l l w a t e r irrigation. To date it is diffi c u l t to say w h e t h e r continued irrigation will affect the coarse mull humus. So far, no s i g n i ficant trends have b e e n es t a b l i s h e d but a tendency does exist for w a s t e w a t e r irriga t i o n to hasten the d e c o m p o s i t i o n process as noted in the duff mull 247 litter at Middleville. Certainly, irrigation does establish ideal conditions for decay organisms to operate. N u t r i e n t Budget A deta i l e d nutri e n t bu d g e t could not be computed for Lott W o o d l o t due to a lack of sufficient data to characterize the storage components. contains, in general terms, However, Table 38 the input and ou t p u t data for total nitro g e n and total phosphorus as determined by s u ction l y s i m e t e r s . Table 38. Estima t i o n of total nitr o g e n and total p h o s ­ phorus budget, L o t t Woodlot, 1972 through 1973. Irrigation Rate Budget Item Budget Relation­ ship Well Water (mm/week) Wastewater 50 25 50 75 -kg/haNitrogen: Wastewater Loading Input Loss to Water Table Output 68.8 137.6 206.2 8 50.0 76.0 180.7 6.2 12.0 18.1 0.1 0.2 0.4 1.6 26. Phosphorus: Wastewater Loading Input 0.1 Loss to W a t e r Table Output 0 .3 < E vid e n c e of the nitr o g e n flushing that has gone on in L o t t W o o d l o t is quite apparent from the well water irrigation levels. While 1.6 kg/ha of nitrogen was 248 added by well w a t e r irrigation, (26.8 kg/ha) a s i g n i ficant amount was flushed through the soil. This quan t i t y is in close agreement to the average of 28 k g / h a esti­ mated to be lost from harve s t e d crop land in the United States (Lipman and Conybeare, 19 36). The 25 nun/week of w astew a t er irrigation treat m e n t lost 50 kg/ha of the 6 8 . 8 kg/ha of total n i t r o g e n applied. The 50 mm/week w astew a t er treatment had the least p e r c entage loss of nitrogen b u t still lost 33% more than the 25 mm/week rate. The hig h e s t irriga t i o n rate had as an o u t p u t 180.7 kg/ha of the 206.2 kg/ha applied. The total phosph orus budget indicates that a greater o u t p u t over input value occu r r e d only for the well w a t e r treatment. For the w a s t e w a t e r treatments, outputs ex ceeded inputs by only 1 .6 , 1 .6 , and 2 .2 %. C H A P T E R VI SUMMARY AND RECOMMENDATIONS A. Middlevi l l e E ffluent from sewage stabilization ponds at Middleville was spray irrigated only a 20-year-old red pine plantation du r i n g the summer and early fall of 1972 and 1973. The w a s t e w a t e r typically contained from 7.1 to 8.4 mg/1 total nitr o g e n and 2.4 to 3.8 mg/1 total p h o s p h o r u s . Irrigation du r i n g the two years delivered a total a p p l i cation of 61.8, 123.4, and 217.0 kg/ha of nitr o g e n and 24.5, 48.9, and 86.0 kg/ha of phosphorus 88 for the 25, 50, and m m / w e e k irrigation rates, respectively. The ability of the red pine plantation site to renovate the nitrogen and phosphorus applied by irri­ gation was monitored by porous cup soil moisture samplers at depths of 60 and 120 cm. Renovation of phosphorus generally exceeded 99% for all irrigation rates at both depths during the years of irrigation. Total nitrogen renovation was 96, 87, and 94% at 60 cm and 82, 89, and 94% at 120 cm in 1972 for the 25, 50, and irrigation rates, respectively. 249 88 mm/week In 19 73, total nitrogen 250 renovation d e c r eased for the two hig h e s t irriga t i o n rates to 83, and 76% at 60 cm a n d 81 and 76% at 120 cm. Much of the r educ t i o n in renovation w a s due to leaching of N 0 3 -N. The hourly rates of irrigation mm/hour for the 25, respectively) 50, and 88 (3, 6 , and 11 mm/week loading rates, probably contributed to the leaching dif­ ferences bet w e e n t r e a t m e n t s . The red pine foliar nutrient c o n c e ntrations of boron, aluminum, potassium, significant changes. and nitrogen have undergone B o r o n levels have risen from about 27 ppm in unirrigated trees to 55, the 25, tively. 50, and 8 8 6 6 , and 7 5 p p m for mm/week irrigation rates, respec­ These increases in foliage boron resulted in the appearance of toxicity symptoms. A l u m i n u m levels have dropped by a factor o f five from 545.7 p p m in unirrigated trees to 106.2 ppm in trees receiving the greatest amount of w a s t ewater application. Wastewater irrigation has resulted in p o t a s s i u m increases of 0.07% over the range of irrigation rates. The nitrogen c o n ­ tent of the red pine needles increased in both years. In 1973, the nitrogen levels were 1.33, 1.70% for the 0, 25, 50, a n d 88 1.44, 1.66, mm/ w e e k rates, r e s p e c ­ tively. The wastew a t e r irrigation had its most p r o ­ nounced e ffect on red pine growth in 1973. Needles from the upper one-third of the crown increased in length from an average of 1 2 1 . 0 and m m in unirrigated 251 trees to 136.4, 88 154.9, and 164.4 m m for the 25, mm/week irrigation rates. 50, and Dry w e i g h t s / n e e d l e fascicle increased in a similar fashion, rising from 68.97 mg to 107.4 0 mg over the range of irriga t i o n rates. Diameter and height growth have not as y e t responded significantly to the wastewater. The Boyer sandy loam soil underl y i n g the red pine plantation at Middleville underwent s i g n i ficant changes in pH and bo r o n content during the two years of w a s t e ­ water irrigation. The pH in the upper 120 cm of soil climbed significantly from 5.9 in unirrigated plots to 6 .6 , 7.0, and 7.5 for the 25, 50, and gation rates. to 2 . 6 88 mm/ w e e k irri­ Boron concentrations increased from 0.8 kg/ha over the range of irriga t i o n rates. Available phosphorus and exchangeable p o t a s s i u m and magne s i u m contents of the soil showed significant increases in the 0 to 15 cm depth. Calcium, nitrogen, and p e r c ent loss on ignition values w e r e not signifi­ cantly d ifferent between irrigation rates. Wastewater irrigation has enhanced decompositio n of the humus layer in the red pine plantation. A 20% decrease in humus w e i g h t and a 1.5 cm reduction in humus depth have resulted from irrigation. Cha n g e s in the activity of soil m i c r o organisms were refle c t e d by increases in their number and duration of appearance. 252 B. L o t t W o o d l o t Wastew a t e r from the East L a n s i n g secondary treatment plant has been trickle irrigated onto plots within a ma p l e - b e e c h hardwood forest dur i n g the summer and e arly fall of 197 2 and 1973, C o n c e ntrations of total n i trogen and phosphorus in the sewage effluent ranged from 8.0 to 11.5 mg/1 for nitr o g e n and 0.7 to 1.0 mg/1 for phosphorus. trol treatment contained Well w a t e r applied on a c o n ­ 0 . 1 0 mg/ 1 total nitro g e n and less than 0.01 mg/1 total phosphorus. Total nitrogen loadings over the two-year period w e r e 1.0, 143.6, 25, 71.8, and 215.4 kg/ha for the 50 mm/ w e e k well, water, 50, and 7 5 m m / w e e k of w a s t e w a t e r treatments, respectively. treatments were Total phosphorus loadings for the same 0 .0 1 , 6 .0 , 1 2 .0 , and 18.0 kg/ha. Renovation of the nitrogen and phosphorus applied via w a s t e w a t e r irrigation was ascertained by porous cup soil m o i s t u r e samplers at depths of 30 and 60 cm. Total phosphorus renovation averaged above 96% at both depths for all treatments over the two years. Total n i trogen renovatio n was quite variable and gen­ erally less than 50% for all treatments, depths, and years. This was primari ly due to the N O ^ - N renovation (the m o s t common form of nitrogen sampled in the soil solution) being generally 0%. As at Middleville, the leaching of NO^-N m o s t likely resulted from the high 253 hourly a p p l ication rate NH^-N (in excess of 50 m m / h o u r ) . (the m o s t commo n l y applied form of nitrogen} renovation was above 96% in all instances. Ground cover vegetation response to wa s t e w a t e r irrigation was inconclusive. No appa r e n t growth, vival, or nutrient uptake response was detected. ever, sur­ How­ there was a noticeable lack of w i l t i n g du r i n g dry weather and a delay of leaf senescence in the fall. A general decrease in leaf litter w i t h increasing rates of w a s t e w a t e r irrigation was noted, although none of the differences in treatment w e r e s t a t istically sig­ nificant. Leaf litter w e i g h t was hig h e s t in plots receiving 50 mm/ w e e k of well w a t e r irrigation kg/ha) (3,060 and lowest in plots receiving the same amount of w a s t e w a t e r (1,640 kg/ha). Wo o d y litter varied from 570 to 2,360 kg/ha across the range of treatments. Soil chemistry data for L o t t Woo d l o t was incon­ clusive. Significant increases in pH and extractable m a g n e s i u m w e r e recorded. However, no differences between the well w a t e r and w a s t e w a t e r irriga t i o n were noted. Irrigation water per se tended to be the pre­ vailing factor rather than the wastew a t e r constituents. Wastewater irrigation significantly reduced soil m oisture tension and improved soil wa t e r relations throughout the summer. 254 Recommendations Data gathered during this research pro j e c t and others of a similar nature have indicated that forest ecosystems are readily able to renovate munic i p a l w a s t e ­ water. However, ecosystems, it m u s t be remembered that terrestrial like aquatic ones, have physical limits to their w astew a t e r proces s i n g ability. Thus, the follow ­ ing r ecommendations are made for w a s t e w a t e r irrigation in forest stands in M i c h i g a n similar to those discussed here: 1. A p p l i c a t i o n rates should be k e p t b e l o w 3 mm/hour. Low hourly rates produce high w a s t e w a t e r r e n o ­ vations and simplify operation of irrigation equipment. 2. Weekly w a s t e w a t e r loadings up to 50 m m are acceptable in coarse textured forest soils as long as renova t i o n standards are met. 3. The manage m e n t objectives of a wa s t e w a t e r irri ­ gation system will definitely affect the amount of vegetative growth. While max i m i z a t i o n of tree growth does not necessarily have to be an objective, the tree cover m u s t be mainta i n e d in a viable condition; and this in turn will d etermine the allowable amounts of irrigation per unit area. 255 4. Some tree species, such as red pine and white pine, are highly sensitive to boron and will e xhibit toxicity symptoms w i t h normal levels of bo r o n in wastew ater {1 p p m ) . If such toxicity conditions persist and produce stand d e t e r i o r ­ ation, irrigation should be discontinued. This and similar studies have shown that forest ecosystems are capable of removing nutrients from municipal wastewater. However, w a s t e w a t e r disposal by spray irrigation should not be approached w i t h the idea of disposing of the m a x i m u m amount of w a t e r o n the least area of land. It should be handled in relation to the ultimate goal of removing the highest amount of nitrogen and phosphorus while maintaining site longevity and renovation efficiency. APPENDIX APPENDIX Table 39. Mean monthly air temperature for Middlevill e using data from Grand Rapids and Hastings. M e a n mon t h l y temperature Grand Rapids Hastings (°C) M i d d l eville 1972 1973 1972 1973 1972 1973 January -6.3 -2 . 6 -5.0 -2 . 1 -5.7 -2.4 February -5.7 -5.2 -4.3 -3.8 -5.0 -4.5 March -1.3 5.5 -0 . 2 6 . 1 -0 . 8 5.8 April 5.8 8.3 6 . 8 9.0 6.3 8 . 6 May 15.3 1 2 . 2 15.6 1 2 . 8 15.4 12.5 June 17.6 2 1 . 2 18.6 21.4 18.1 21.3 July 21.4 2 2 . 6 2 1 . 8 22.7 2 1 . 6 2 2 . 6 August 2 0 . 6 2 2 . 8 2 1 . 1 2 2 . 6 2 0 . 8 22.7 September 16. 8 17.6 19.9 17.9 18.4 17.8 October 7.9 12. 9 13.4 8.4 13. 2 November 2 . 2 4.4 3.0 5.2 December -3.0 -3.2 -2.4 -2 . 6 8 . 8 256 2 . 6 4.8 -2 . 8 -2.9 (mean) 257 Table 40. M e a n m o n t h l y ammonia nitrogen at 60 and 120 c m at Middleville, 1972 and 1973. M e a n lysimeter values 2 5 mm/ w e e k 50 mm/w e e k 88 mm/we e k Month 60 cm 1 2 0 cm 60 cm 1 2 0 cm 60 c m 1 2 0 cm -ppm (mg/ 1 ) (1972) Jun m M m M Jul 0 . 0 2 0.19 0 . 2 0 0.08 0 . 0 2 0 . 2 0 Aug 0.09 0.14 0 . 1 1 0 . 1 0 0.13 0 . 1 0 Sep 0.05 0.13 0.13 0 . 1 2 0 . 1 0 0.07 Oct 0.05 0 .08 0 .25 0. 25 0.15 0.07 Jun 0 . 1 0 0 .2 1 * 0 0 . 6 8 0.04 0.15 Jul 0.14 0 .2 1 * 0.44 0.76 0.14 0.09 Aug 0.06 0 . 2 1 0.49 1.30 0.41 0 . 2 1 Sep 0 . 1 2 0 .2 1 * 0.30 0. 30 0 . 08 0.04 Oct 0.08 0 .2 1 * 0 0 .20 0.07 0.23 (1973) .16 .2 2 Due to mis s i n g data, irrigation season was used. the mean value for the 258 Table 41. M e a n mon t h l y nitrate nitrogen at 60 and 120 cm at Middleville, 1972 and 1973. M e a n lysimeter values Month 2 5 60 c m mm/week 1 2 0 50 mm/week cm 60 c m 1 2 0 88 cm mm/wee k 60 c m 1 2 0 cm •ppm (mg/ 1 ) (1972) — Jun — — — — — Jul 0.16 0 . 1 0 0.08 1.17 0.24 0 . 1 0 Aug 0 . 1 2 2.15 0.40 0 . 62 0.06 0.06 Sep 0.05 1.13 0.07 0.60 0.05 0.08 Oct 0.13 0.18 0.05 0.24 0.06 0.06 Jun 0.06 0.80 0.26 0 . 6 6 2.15 0.36 Jul 0.18 0.93 0.61 0.56 1.04 0 . 6 6 Aug 0 . 0 0 0.03 0 . 1 2 1.18 0 .58 0.90 Sep 0 . 1 2 0.93 0.71 0.63 1.46 1.72 Oct 0.24 2 .0 0 0.54 0.32 0.71 0.46 (1973) * A Due to m i s s i n g data, irrigation season was used. the m e a n value for the 259 Table 42. M e a n mon t h l y organic nitr o g e n at 60 and 120 cm at Middleville, 1972 and 1973. Mean lysimeter values 25 mm/w e e k Month 60 cm 1 2 0 50 mm/week cm 60 c m 1 2 0 cm 8 8 60 cm mm/we e k 1 2 0 cm -ppm (mg/ 1 ) (1972) Jun MM MM Jul 0 . 1 2 0.73 0.16 0.07 0.56 0.32 Aug 0 . 2 1 0.78 0 .37 0.57 0. 32 0.30 Sep 0.19 0.75 0.15 0.52 0.36 0.43 Oct 0 . 2 2 0.56 2.16 0.90 0.41 0.44 Jun 0.38 0.19* 0.50 0.41 0.38 0.38 Jul 0 . 1 2 0.19* 0.40 0 .56 0. 27 0.75 Aug 0 . 2 1 0.19 1 . 0 1 0. 74* 1.13 0.52 Sep 1.28 0.19* 0.46 0 . 8 6 0.52 1.91 Oct 1.06 0.19* 0.80 1 . 1 2 0 . 6 6 1.14 (1973) Due to missi ng v a l u e s , the m e a n value for the irrigation season was used. Table 43. M e a n mon t h l y total nitr o g e n at 60 and 120 cm at Middleville, 1972 and 1973. M ean lysimeter values 25 mm/w e e k Month 60 c m 1 2 0 50 mm/ w e e k cm 60 c m 1 2 0 88 cm mm/wee k 60 c m 1 2 0 cm •ppm (mg/ 1 ) (1972) Jun — — — — — — Jul 0.30 1 . 0 2 0.44 1.32 0.82 0 Aug 0.42 2.96 0 . 8 8 1.29 0.51 0.45 Sep 0.28 1.60 0.35 0.75 0.46 0.58 Oct 0.40 0.82 2.46 1.39 0.62 0. 57 Jun 0.53 0.43* 0.92 1.76 2.57 0 . 8 8 Jul 0. 34 0.43* 1.44 1.70 1.45 1.48 Aug 0.27 0.43 1.63 1.72* 2 . 1 2 1. 64 Sep 1.52 0.43* 1.46 1.79 2.06 3.67 Oct 1.38 0.43* 1.55 1.64 1.43 1.83 .62 (1973) 4 Due to mis s i n g data, irrigation season was used. the m e a n value for the 261 Table 44. M e a n mon t h l y total phosphorus at 60 and 120 c m at Middleville, 1972 and 1973. M e a n lysimeter values 25 mm/week Month 60 c m 1 2 0 50 mm/week 60 cm cm — — PPm 1 2 0 88 cm mm/week 60 cm 1 2 0 cm img/ _l ;---- (1972) — Jun — — — — — Jul 0 . 0 2 0.67 0 . 2 0 5.32 0.18 0.05 Aug 0 .0 2 0.06 0.03 0.13 0 . 0 1 0. 03 Sep 0 . 0 1 0.05 0 . 0 1 0.31 0 . 0 1 0.04 Oct 0 . 0 2 0.05 0 . 0 2 0.43 0 . 0 1 0.04 Jun 0 .05 0.05 0.05 0.36 0 .04 0.07 Jul 0 . 0 1 0.04* 0 . 1 0 0.23 0. 03 0.03 Aug 0 . 0 2 0.03 0.05 0.13 0.03 0 .04 Sep 0.05 0.04* 0.03 0.05 0 . 0 1 0 . 0 2 Oct 0.05 0.04* 0.03 0.05 0 . 0 2 0.04 (1973) ★ Due to mis s i n g data, irrigation season was used. the m e a n value for the Table 45. Total nitrogen and total phosphorus renovation at the 60 cm depth at Middleville computed by the ground water recharge method/ 1972. 60 cm depth Nutrient Form Amount Applied Lysimeter Content 25 50 88 25 88 25 50 88 Jun 4.2 8.4 14.8 0.0 0.0 0.7 100 100 95 Aug 10.5 21.0 37.0 0.4 2.2 2.4 96 90 94 Sep 8.4 16.8 29.5 0.4 0.9 1.8 95 95 94 Oct 8.4 16.8 29.5 0.5 5.3 2.3 94 68 92 31.5 63.0 110.8 1.3 8.4 7.2 96 87 94 Jul 1.9 3.8 6.7 0.0 0.0 0.1 100 100 99 Aug 4.8 9.5 16.7 . <0.1 < 0.1 <0.1 100 99 100 Sep 3.8 7.6 13.4 <0.1 <0.1 <0.1 99 100 100 Oct 3.8 7.6 13.4 0.1 <0.1 <0.1 97 99 100 14.3 28.5 50.2 0.1 < 0.1 0.1 99 100 100 Jun sum/mean 262 Jul sum/mean Total Phosphorus 50 -kg/ha- -kg/haTotal Nitrogen Renovation Month Table 46. Ammonia nitrogen, nitrate nitrogen, and organic nitrogen renovation at the 60 cm depth at Middleville computed by the ground water recharge method, 1972. 60 cm depth „ . . 2 _ Form Amount Applied Lysimeter Content Honth --------------- 25 50 88 25 -kg/ha-----Ammonia Nitrogen 88 kg/ha— ---- 25 50 88 ---- -— %--- — -- — — — — — Jul 0.6 1.2 2.0 0.0 0.0 < 0.1 100 100 99 Aug 1.5 3.0 5.3 < 0.1 0.3 0.6 95 90 89 Sep 1.2 2.4 4.2 < 0.1 0.3 0.4 94 87 90 Oct 1.2 4.5 2.4 4.2 < 0.1 0.5 0.6 95 79 86 9.0 15.8 < 0.1 1.1 1.6 98 88 90 Jun — — — — — — — — Jul 0.4 0.8 1.4 0.0 0.0 0.2 100 100 86 Aug 1.0 2.0 3.5 0.1 1.0 0.3 90 50 91 Sep 0.8 1.6 2.8 < 0.1 0.2 0.2 91 87 93 Oct 0.8 1.6 2.8 0.2 0.1 0.2 75 94 93 sum/mean 3.0 6.0 10.5 0.3 1.3 0.9 90 78 91 Jun — — — — — — Jul 3.2 6.4 11.3 0.0 0.0 0.5 100 100 96 Aug 8.0 16.0 28.2 0.2 0.9 1.5 97 94 95 Sep 6.4 12.8 22.5 0.3 0.4 1.4 95 97 94 Oct 6.4 12.8 22.5 0.3 4.7 1.5 95 63 93 24.0 48.0 84.5 0.8 6.0 4.9 97 87 94 sum/mean — — - - — — — — — — 263 Organic Nitrogen 50 Jun sum/mean Nitrate Nitrogen Renovation Table 47. Total nitrogen and total phosphorus renovation at the 120 cm depth at Middleville computed by the ground water recharge method, 1972. 120 cm depth Amount Applied Nutrient Form Month 25 50 Lysimeter Content 88 25 50 88 Renovation 25 50 88 % Total Nitrogen — Jul 4.2 8.2 14.8 0.0 0.0 0.5 100 100 97 Aug 10.5 21.0 37.0 2.5 3.2 2.1 76 85 94 Sep 8.4 16.8 29.5 2.2 1.8 2.3 73 89 92 Oct 8.4 16.8 29.5 1.0 1.7 2.1 88 90 93 31.5 63.0 110.8 5.7 6.7 7.0 82 89 94 Jul 1.9 3.8 6.7 0.0 0.0 < 0.1 100 100 99 Aug 4.8 9.5 16.7 . <0.1 0.3 0.1 99 97 99 Sep 3.8 7.6 13.4 <0.1 0.7 0.2 98 91 99 Oct 3.8 7.6 13.4 < 0.1 0.9 0.1 98 88 99 14.3 28.5 50.2 < 0.1 1.9 0.4 99 93 99 — Jun sum/mean 264 sum/mean Total Phosphorus — Jun Table 48. Ammonia nitrogen, nitrate nitrogen, and organic nitrogen renovation at the 120 cm depth at Middleville computed by the ground water recharge method, 1972. 120 cm depth Amount Applied Nutrient „ _ Form Month 25 50 Lysimeter Content 88 *kg/ha — — — Jul 0.6 1.2 2.1 Aug 1.5 3.0 5.3 Sep 1.2 2.4 Oct 1.2 sum/mean 25 50 88 -- ----- — ---- -%• w o . o Organic Nitrogen Jun kg/ha-— 88 0.0 0.2 100 100 90 0.1 0.2 0.5 93 93 91 4.2 0.2 0.3 0.3 83 87 93 2.4 4.2 0.5 0.3 88 79 93 4.5 9.0 15.8 0.4 1.0 1.3 91 89 92 Jun — — — Jul 0.4 0.8 1.4 0.0 0.0 < 0.1 100 100 94 Aug 1.0 2.0 3.5 1.8 1.5 0.3 0 25 91 Sep 0.8 1.6 2.8 1.5 1.4 0.3 0 12 89 Oct 0.8 1.6 2.8 0.2 0.3 0.2 75 81 93 sum/mean 3.0 6.0 10.5 3.5 3.2 0.8 0 47 92 Jun — — Jul 3.2 6.4 11.3 0.0 0.0 0.3 100 100 97 Aug 8.0 16.0 28.2 0.7 1.4 1.4 91 91 95 Sep 6.4 12.8 22.5 1.0 1.2 1.7 84 91 92 Oct 6.4 12.8 22.5 0.7 1.9 1.6 89 85 93 24.0 48.0 84.5 2.4 4.5 5.0 90 91 94 sum/mean — 265 Nitrate Nitrogen — 50 ■ —1 • o Ammonia Nitrogen 25 Renovation f Table 49. Total nitrogen and total phosphorus renovation at the 60 cm depth at Middleville computed by the ground water recharge method, 1973, 60 cm Lysimeter Depth Amount Applied1 Nutrient Form Month 25 50 88 Lysimeter Content 25 -kg/haTotal Nitrogen 88 25 -kg/ha- 50 88 ■%- 7.1 14.2 25.0 0.0 0.9 6.3 100 94 75 Jul 3.6 7.1 12.5 0.0 0.0 0.9 100 100 93 Aug 8.9 17.8 31.2 < 0.1 2.7 7.8 100 85 75 Sep 7.1 14.2 25.0 2.0 3.3 7.8 72 77 69 Oct 3.6 7.1 12.5 0.9 3.5 2.7 75 51 78 30.3 60.4 106.2 2.9 10.4 25.5 90 83 76 Jun 2.4 4.8 8.4 0.0 < 0.1 0.1 100 99 99 Jul 1.2 2.4 4.2 0.0 0.0 < 0.1 100 100 100 Aug 3.0 6.0 10.6 < 0.1 < 0.1 0.1 100 99 99 Sep 2.4 4.8 8.4 < 0.1 < 0.1 < 0.1 97 99 100 Oct 1.2 2.4 4.2 < 0.1 < 0.1 < 0.1 97 99 99 10.2 20.4 35.8 < 0.1 <0.1 0.2 99 100 100 sum/mean ^Sum for the amount applied does not include that applied in May, 266 Jun sum/mean Total Phosphorus 50 Renovation Table 50. Ammonia nitrogen, nitrate nitrogen, and organic nitrogen renovation at the 60 cm depth at Middleville computed by the ground water recharge method, 1973. 60 cm lysimeter depth Amount Applied-*- Lysimeter Content Renovation Month 25 50 88 25 50 88 25 50 88 Ammonia Nitrogen Jun Jul Aug 0.7 0.4 0.9 0.7 0.4 3.1 2.0 1.0 2.5 2.0 1.0 8.5 4.4 2.2 1.4 0.7 1.8 2.5 1.2 3.1 2.5 1.2 10.5 0.0 0.0 < 0.1 0.2 < 0.1 0.2 0.0 0.0 0.0 0.2 0.2 0.4 0.0 0.0 < 0.1 1.6 0.7 0.2 0.0 0.1 < 0.1 1.5 100 100 86 100 56 100 85 96 97 52 88 92 81 34 80 76 20 60 49 94 97 79 87 80 87 83 89 87 Sep Oct sum/mean Jun Jul Aug Sep Nitrate Nitrogen Organic Nitrogen Oct sum/mean Jun Jul Aug Sep Oct sum/mean 5.5 4.4 2.2 18.7 1.4 0.7 6.0 4.0 2.0 5.0 4.0 2.0 17.0 8.8 4.4 11.0 8.8 4.4 37.4 7.0 3.5 8.8 7.0 3.5 29.8 15.5 7.7 19.4 15.5 7.7 65.8 2.3 0.8 0.7 0.3 2.0 0.2 0.0 0.2 1.6 0.6 2.6 0.5 0.0 1.7 1.1 0.9 4.2 0.3 0.1 2.0 5.3 0.7 2.1 5.6 1.4 15.1 0.9 0.2 4.1 2.0 1.3 8.5 ^Sum for the amount applied does not include that applied in May. 100 71 87 94 100 100 100 90 80 95 100 100 99 64 68 88 50 57 67 95 100 96 60 70 85 94 267 Nutrient Form [ Table 51. Total nitrogen and total phosphorus renovation at the 120 cm depth at Middleville computed by the ground water recharge method, 1973. 120 cm depth Amount Applied1 Nutrient Form Month 25 50 88 Lysimeter Content 25 50 88 Renovation 25 ---- Total Nitrogen 88 ---%— ------ 7.1 14.2 25.0 0.0 1.7 2.2 100 88 91 Jul 3.6 7.1 12.5 0.0 0.0 0.3 100 100 98 Aug 8.9 17.8 31.2 0.0 3.9 6.0 100 78 81 Sep 7.6 14.2 25.0 0.5 4.1 14.0 93 71 44 Oct 3.6 7.1 12.5 0.3 1.9 3.5 92 85 72 30.3 60.4 106.2 0.8 11.6 26.0 97 81 76 Jun 2.4 4.8 8.4 0.0 0.3 0.2 100 94 98 Jul 1.2 2.4 4.2 0.0 0.0 < 0.1 100 100 100 Aug 3.0 6.0 10.6 0.0 0.2 0.1 100 97 99 Sep 2.4 4.8 8.4 < 0.1 0.1 < 0.1 98 99 99 Oct 1.2 2.4 4.2 < 0.1 < 0.1 < 0.1 98 97 98 10.2 20.4 35.8 < 0.2 < 0.7 < 0.6 99 97 99 sum/mean ^Sum for the amount applied does not include that applied in May 268 Jun sum/mean Total Phosphorus 50 Table 52. Ammonia nitrogen, nitrate nitrogen, and organic nitrogen renovation at the 120 cm depth at Middleville computed by the ground water recharge method, 1973. 120 cm depth Lysimeter Content Amount Applied^Nutrient Form 88 25 50 88 25 50 88 2.5 1.2 0.0 0.0 0.0 0.6 0.0 0.4 < 0.1 100 100 57 100 84 2.1 0.8 100 0.7 0.2 10.5 0.3 0.1 0.4 0.2 0.4 1.9 57 75 87 0 50 71 40 4.0 2.0 5.0 7.0 3.5 0.0 0.0 0.9 0.4 100 100 8.8 0.0 100 1.0 4.0 2.0 7.0 3.5 1.1 2.0 45 0 65 80 sum/mean 8.5 17.0 4.4 2.2 8.8 4.4 11.0 3.1 0.0 6.2 0.4 64 100 64 Jun Jul Aug 29.8 15.5 3.3 6.6 0.9 12.1 47 100 72 7.7 0.0 0.0 0.0 Month 25 50 Renovation --kg/ha— Ammonia Nitrogen 0.7 1.4 0.4 Aug Sep Oct 0.9 0.7 0.4 3.1 0.7 1.8 sum/mean Nitrate Nitrogen Jun Jul Aug Sep Oct Organic Nitrogen Sep Oct sum/mean 2.0 1.0 2.5 2.0 5.5 4.4 1.4 0.7 6.0 3.1 2.5 1.2 2.2 4.4 19.4 15.5 7.7 18.7 37.4 65.8 8.8 3.6 2.5 0.0 1.9 1.4 0.4 0.2 1.2 2.0 0.1 0.3 1.3 4.9 0.9 0.5 1.9 7.3 2.2 12.8 ^Sum for the amount applied does not include that applied in May. 100 100 95 95 98 95 100 95 74 92 67 82 87 89 62 6 74 59 94 70 94 90 53 71 87 81 89 77 269 Jun Jul 270 Table 53. T . Irrigation Rate Changes in (A) pH and (B) available phospho r u s w i t h soil d e p t h and w a s t e w a t e r irrigation rates, Middleville, 197 3. Soil D e p t h _______________________ 15 (cm)-L 30 m m / week 60 120 pH units- (A) pH 0 5.2 aw 5.5 abw 25 6.5 ax 6 50 7.1 abxy 6 . 6 8 8 7.4 ay 7.4 ay .1 awx axy 6.1 b c w 6.9 cw 6.3 aw 7.7 b w x 6.7 awx 7.7 b w x 7.4 ax 7.9 ax (B) A v a i l a b l e phosphorus ------------------- k g / h a ----------------------0 87.4 aw 76.9 aw 52.3 abw 15.3 b w 9 3.7 aw 59.0 abw 26.9 b w 25 101.6 awx 50 144.2 ax 92.6 b w 88 203.2 ay 121.7 b w 1 74.3 b c w 34.7 cw 83.3 b w 14.9 cw Means within the same column (w, x, y, and z) or line (a, b, c, and d) not followed by the same letter are significantly different at the 5% level (Tukey's test). 271 Table 54. Changes in (A) e x t r a ctable p o t a s s i u m and (B) extractable c a l c i u m w i t h soil depth and w a s t e ­ water irrigation rates, Middleville, 1973. Irrigation Rate mm/week Soil Depth 15 30 (cm ) 1 ___________________ 60 120 ----------------------k g / h a ----------------------- (A) E x t r a ctable Potassium 0 85.1 aw 4 9.3 a w 49.3 aw 57.1 aw 44.8 b c w 12.3 cw 62.7 b c w x 20.5 cw 25 138.9 awx 76.2 b w x 50 14 3.4 ax 107.6 abxy 88 161.3 ax 161.3 ay 107.6 ax 16.4 b w (B) E x t r actable C a l c i u m 0 24 2.4 aw 24 2.0 aw 290.5 aw 2161.8 aw 25 872.0 aw 290.2 aw 290.2 aw 2382.5 aw 50 968.7 aw 435.8 aw 242.4 aw 1476.2 aw 1308.1 aw 726.7 aw 484.3 aw 2514.0 aw 88 “Means w i t h i n the same column (w, x, y, and z) or line (a, b, c, and d) not followed by the same letter are significantly diffe r e n t at the 5% level (Tukey's test). 272 Table 55. Changes in (A) e x t r a ctable m a g n e s i u m and (B) total Kjeldahl nitr o g e n w i t h soil d e p t h and w a s t e w a t e r irriga t i o n rates, Middleville, 1973. Soil Depth Irrigatior l Rate 15 30 mm/week (cm) 1 60 1 2 0 “Ky/ na' (A) E x t r a ctable Magne s i u m 0 32.5 aw 39.6 aw 54 .2 aw 373.1 bw 25 219.6 ax 100.4 aw 46.3 b w 129.2 ax 50 236.8 ax 150.5 aw 68.3 aw 78.8 ax 88 256.2 ax 186.3 aw 139 .7 aw 121.7 ax (B) Total Kjeldahl Nitrogen 0 776.7 aw 448.1 bw 179 .2 bw 179.2 bw 25 1075.5 aw 597.5 b w 239 .0 bw 209.1 b w 239.0 bw 50 8 36.5 aw 537.7 abw 268.9 bw 88 8 36.5 aw 537 .7 abw 268.9 bw 59.8 bc w Means wi t h i n the same co l u m n (w, x, y, and z) or line (a, b, c, and d) not followed b y the same letter are significantly different at the 5% level (Tukey's test). 273 Table 56. Changes in (A) loss on ignition and (B) b o r o n w i t h soil depth and w a s t e w a t e r irrigation rates, Middleville, 1973. Irrigation Rate Soil Depth (cm) 30 15 1 60 1 2 0 mm/week (A) Loss on Ignition aw 1 . 2 abw 0 . 8 25 2.5 aw 1 . 6 bw 0.9 b w 1 . 2 50 1.9 aw 1.4 b w 0.9 b w 0.9 b w 88 2 . 2 aw 1.4 b w 1 . 0 bw 0.7 b w 0 1 . 8 bw 1.3 a b w bw (B) Boron xg/naaw aw 0 . 8 aw 0.9 aw 25 3.4 ax 2 . 1 bx 1 . 6 bw 1.4 b w 50 3.3 ax 1 . 8 bwx 1 . 1 bw 1.4 b w 88 4.2 ax 2 . 8 abx 1.9 b c w 0 1 . 0 0 . 8 1.4 cw Means w i t h the same co l u m n (w, x, y, and z) or line (a, b, c, and d) not followed by the same letter are significantly diffe r e n t at the 5% level (Tukey's test) . 274 Table 57. Changes in (A) m e a n humus depth, (B) fine humus dry weight, and (C) total humus d r y w e i g h t in red pine b y irrigation rate and d i s t a n c e from p l o t center, Middleville, 1973. Sample P o i n t Distance from Plot Center mm wastewater/week 2-m 4-m 6 -m cnv (A) M e a n Humus Depth 0 3.98 1 aw 4.16 aw 4.56 aw 25 2.71 aw 3.43 aw 3.42 aw 50 2.71 aw 2.96 aw 3.24 aw 88 2.4 8 aw 3.57 aw 4.16 aw (B) Fine Humus Dry Weight ------------------ k g / h a ----------------0 14,490 aw 16,390 aw 17,250 aw 25 13,990 aw 15,990 aw 12,590 aw 50 13,500 aw 12,880 aw 14,320 aw 9,630 aw 14,750 aw 15,060 aw 88 (C) Total Humus Dry Weight 0 21,310 aw 24,780 aw 24,690 aw 25 21,830 aw 27,850 aw 19,730 aw 50 22,070 aw 22,260 aw 22,680 aw 8 8 14,840 aw 23,100 aw 26,74 0 aw Means w i t h i n the same line (a, b, c, and d) or column (w, x, y, and z) not followed by the same letter are s i g n ificantly diffe r e n t at the 5% level (Tukey's test). 275 Table 58. Nutr i e n t con t e n t of the litter layer in red pine, Middleville, 1973. m m wastewater/week1 UU-L LS 0 25 50 88 N % .83 a .81a .86 a .82 a K % .13 a .13 a .11 a .11 P % .13 a .14 a .13 a Na ppm Ca % .73 a 1.40 b 1.56 b 1.50 b Mg % .07 a .24 b .24 b .26 b Mn ppm 923.0 a 742.4 a Fe ppm 815.9 a 1090.9 ab Cu ppm 29.8 a 35.0 a 31.2 a 50.6 a B ppm 16.2 a 71.5 b 80.1 be 90.0 c Zn ppm 55.1 a 63.9 ab 67.7 ab 74.0 b A1 ppm 1280.3 a 1581.9 ab 1761.3 b 373.3 a 809.6 b 1714.8 b 789.1 b 664.3 a 9 36.3 ab a .15 b 785.2 b 644.6 a 1273.1 b 1Means not followed by the same letter are sig­ nificantly diffe r e n t at the 5% level (Tukey's test). 276 Table 59. M e a n m o n t h l y temperatures in E a s t Lan s i n g and total m o n t h l y p r e c i pitation at the M i c h i g a n State Univer s i t y Tree Research Center, 1972 and 1973. East Lan s i n g Temp, Month 1972 1973 Tree Research Cent e r Precipitation 1972 1973 -----------O C -------- January -6 . 0 -2.5 22 29 February -5.7 -6 . 0 16 29 March -1.3 4.4 55 J 12 April 5.4 8 . 0 60 56 May 14.7 11.7 96 85 June 16. 2 0 . 0 81 81 July 20 .2 21.3 43 43 August 19.7 23.0 54 54 September 15.6 16.8 82 82 October 7.2 12.5 64 64 November 1 . 8 4.4 67 138 -3.0 94 88 December 6 -3.1 Table 60. Mean monthly ammonia nitrogen at 30 and 60 cm depth, Lott Woodlot, 1972 and 1973. Mean Lysimeter Values Well Water Month Wastewater 50 mm/week 30 cm 60 cm 25 mm/week 30 cm 60 cm 50 mm/week 30 cm 60 cm 75 mm/week 30 cm 60 cm ----------------------------------------m g / l ----------------------------------------- (1972) — — — — — — — — Jul — M — — — — — — M Aug 0.12 0.12 0.24 0.08 0.20 0.10 0.11 0.10 Sep 0.08 0.06 0.08 0.08 0.10 0.06 0.30 0.18 Oct 0.23 0.07 0.06 0.09 0.23 0.02 0.24 0.06 Jun 0.20 0.31 0.38 0.20 0.18 0.10 0.14 0.08 Jul 0.26 0.23 0.44 0.19 0.25 0.27 0.24 0.17 Aug 0.27 0.23 0.59 0.20 0.37 0.20 0.27 0.21 Sep 0.47 0.17 0.38 0.26 0.40 0.12 0.25 0.09 Oct 0.25 0.38 0.09 0.13 0.16 0.12 0.15 0.17 (1973) 277 Jun Table 61. Mean monthly nitrate nitrogen at 30 and 60 cm depth, Lott Woodlot, 1972 and 1973. Mean Lysimeter values Well Water Wastewater 50 mm/week Month 30 cm 60 cm 50 mm/week 25 mm/week 30 cm 60 cm 30 cm 60 cm 75 mm/week 30 cm 60 cm ----— mg/1 (1972) — — — — — — — — Jul — — — — — — — — Aug 13.02 1.93 8.48 7.31 8.08 9.42 11.20 11.36 Sep 5.16 2.08 8.81 5.91 8.99 11.03 7.15 13.24 Oct 3.10 2.60 10.12 7.78 10.15 10.95 15.40 13.50 Jun 2.07 1.04 3.52 2.82 3.50 2.65 8.42 5.60 Jul 0.67 1.05 0.79 0.09 1.83 2.37 2.83 1.47 Aug 0.59 0.84 5.86 11.79 2.63 3.28 4.99 9.66 Sep 2.29 0.19 11.10 21.40 2.87 0.12 8.20 8.20 Oct 0.45 0.53 20.00 8.10 2.02 2.60 3.55 2.85 (1973) 278 Jun Table 62. Mean monthly organic nitrogen at 30 and SO cm depth, Lott Woodlot, 1972 and 1973. Mean Lysimeter Values Well Water Wastewater 50 mm/week 30 cm 60 cm 25 mm/week 30 cm 50 mm/week 60 cm 30 cm 60 cm 75 mm/week 30 cm 60 cm ■mg/1 (1972) — — — — — — — — Jul — — — — — — — — Aug 1.66 0.57 0.19 0.41 1.08 1.40 0.13 0.19 Sep 1.35 0.66 0.28 0.45 0.49 0.82 0.72 0.34 Oct 1.56 0.39 0.68 0.48 3.19 1.12 0.43 0.15 Jun 1.89 0.86 0.07 0.49 1.08 0.66 0.87 0.66 Jul 0.43 0.80 0.17 0.32 0.44 0.34 0.58 0.65 Aug 0.67 i.60 0.07 1.13 1.87 0.54 0.62 0.56 Sep 0.86 0.48 0.55 0.22 0.49 0.89 0.62 0.83 Oct 0.70 0.47 0.12 0.02 0.81 0.60 0.59 0,76 (1973) 279 Jun Table 63. Mean monthly total nitrogen at 30 and 60 cm depth, Lott Woodlot, 1972 and 1973. Mean Lysimeter Values Well Water Wastewater 50 mm/week 30 cm 60 cm 25 mm/week 30 cm 50 mm/week 60 cm 30 cm 60 cm 75 mm/week 30 cm 60 cm mg / 1 (1972) — — — — —— **— — — Jul — — — — -- -- — — Aug 14.80 2.62 8.91 7.80 9.36 10.92 11.44 11.65 Sep 6.59 2.79 9.18 6.45 9.58 11.90 8.18 13.76 Oct 4.89 3.06 10.86 8.35 13.57 12.09 ■ 16.07 13.71 Jun 4.16 2.21 3.97 3.51 4.76 3.41 9.43 6.34 Jul 1.36 2.08 1.40 0.60 2.52 2.98 3.65 2.29 Aug 1.53 2.67 6.52 13.11 4.87 4.02 5.88 10.43 Sep 3.62 0.84 12.03 21.88 3.76 1.13 9.07 9.12 Oct 1.30 1.38 20.21 8.12 2.99 3.32 4.29 3.78 (1973) 280 Jun Table 64. Mean monthly total phosphorus at 30 and 60 cm depth, Lott Woodlot, 1972 and 1973. Mean Lysimeter Values Well Water Wastewater 50 mm/week Month 30 cm 60 cm 25 mm/week 30 cm 50 mm/week 60 cm 30 cm 60 cm 75 mm/week 30 cm 60 cm mg/1' (1972) — — — — — — Jul — — — — — — Aug 0.06 0.02 0.04 0.04 0.08 0.04 0.01 0.02 Sep 0.02 0.01 0.02 0.02 0.02 0.02 0.04 0.02 Oct 0.03 0.02 0.02 0.02 0.09 0.02 0.04 0.02 Jun 0.01 0.03 0.02 0.02 0.02 0.04 0.04 0.02 Jul 0.03 0.03 0.03 0.03 0.02 0.03 0.04 0.02 Aug 0.04 0.04 0.02 0.02 0.02 0.02 0.04 0.03 Sep 0.04 0.01 0.05 0.01 0.03 0.01 0.03 0.03 Oct 0.04 0.07 0.04 0.02 0.05 0.04 0.03 0.03 — — — (1973) 281 Jun Table 65. Total nitrogen and total phosphorus renovations at 30 cm depth, Lott Woodlot, computed by the ground water recharge method, 1972. 30 cm Depth Nutrient Form Total Nitrogen Amount Applied 50 w Renovation 25 s 50 s 75 s 50 w 25 s 50 s 75 s 50 w Jun 25 s 50 s __ __ 75 s .__ Jul 0.2 14.4 28.8 43.1 22.5 1.5 14.2 31.7 0 90 51 26 Sep 0.2 11.5 23.0 34.5 15.9 13.0 23.2 28.0 0 0 0 19 Oct < 0.1 2.9 5.8 9.6 4.5 7.4 12.6 19.0 0 0 0 0 0.4 28.8 57.6 86.2 42.9 21.9 50.0 78.7 0 24 13 9 — — Jun — — — — — — — ___ Jul — — — ___ _ _ __ Aug < 0.1 1.2 2.5 3.a < 0.1 < 0.1 0.1 < 0.1 0 99 96 99 S ep <0.1 1.0 2.0 3.0 < 0.1 < 0.1