THE EFFECTIVENESS 0F ROCK PHOSPHATE MD SUPERPEfieSFHATE 9N WELD AND CQMPOSEUQN 0F CROPS Thesis for tin Degree 0% pk. D. MECHEGAN STATE UNIVERSETY John R. Gattay 1959 This is to certify that the thesis entitled The Effectiveness of Rock Phosphate and Superphosphate on the Yield and Composition of Crops presented by John R. Guttay has been accepted towards fulfillment of the requirements for Ph.D. degree in_S_Qi]. Science -\ i ' " . -/2 G L“ L's-1K Major professor Dace May 111 1959 0-169 LIBRARY Michigan State University THE EFFECTIVENESS OF ROCK PHOSPHATE AND SUPERPHOSPHATE ON YIELD AND COMPOSITION OF CROPS By JOhn R0 mitt” AN ABSTRACT Submitted to the School of Graduate Studies of Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Soil Science Year 1959 Approved gZ:L_.E:m-v7€9 John R. Guttay ABSTRACT Research information up until 1950 on the relative effectiveness of rock phosphate and superphosphate was limited and difficult to inter- polate over wide areas of the country. There was a definite need for a more uniform research program. Accordingly. in 1950. a project was or- ganized for the north central region in which 8 member states (Michigan. Ohio. Indiana, Illinois. Minnesota. Iowa. Kansas, Nebraska) participated. This report summarized the results of the Michigan experiments. Field experiments comparing an initial rock phosphate application of 320 pounds of P205 per acre to annual applications of superphosphate at 10 and 20 pounds of P205 per acre were carried out over an eight year period. Fried and Dean “A" values of the residual availability of the rock phosphate and superphosphate were calculated by radio- chemical analyses of greenhouse grown plants. Rock phosphate did not increase yields of corn even though signif- icant increases were obtained with superphosphate. Soil tests made by the Bray ”adsorbed phosphorus" (P1) method. gave better estimates of the response of corn to phosphate in all cases. than did the Spurway "reserve.” The small grains exhibited some response to rock phosphate but less than to superphosphate and. generally. to a non-significant degree. The alfalfa-brows hay crops were more responsive than the other crops to rock phosphate. particularly to second-year hay. but the response was no greater than to superphosphate. In terms of net increase in yield of cats per pound of applied P205, John R. Guttay superphosphate was. on the average of the four field experiments. 15 times more effective than rock phosphate in increasing yield. On first- year hay superphosphate was 12 times more and on second-year hay 8 times more effective than rock phosphate. In comparing the rock phosphate responsive crops in the four field experiments. superphosphate was 12 times more effective. on the average. than rock phosphate in increasing yield per pound of applied P205. Fried and Dean ”A” values of available phosphorus in the soil did not give consistent differences between the two sources of phosphorus and conclusions based on this value could not be drawn. little significant difference between phosphate treatments on phosphorus content of plants was observed. THE EFFECTIVENESS OF ROCK PHOSPHATE AND SUPERPHOSPEATE ON YIELD AND COMPOSITION OF CROPS By @‘X John R Eb Guttay A THESIS Submitted to the School of Graduate Studies of Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Soil Science 1959 0 A573 9 b//9/é:5 ACKNOWLEDGMENTS The author wishes to express his sincere thanks to Dr. R. L. Cook for his inspiration. instruction and fellowship during the course of this investigation. to Dr. L. M. Turk. for providing the opportunity of working toward an advanced degree and to Dr. Kirk Lawton for guidance. particularly through the greenhouse phase of this investigation. To all members of the Soil Science Department. without whose aid this investigation could not have been accomplished. this thesis is dcdicated e Andrew John Robert Guttay candidate for the degree of Doctor of Philosophy Final examination. May 11. 1959. 1:30 P.M.. 210 Agricultural Hall Dissertation: The Effectiveness of Rock Phosphate and Superphosphate on Yield and Composition of Crops Outline of Studies Major subject: Soil Science Minor subjects: Geology. Farm Crops Biographical Items Born. May 12. 1921+. los Angeles. California Undergraduate Studies. Mayne State University 19h2-l9h3. 19h6-l9h7 University of Maine. 19h3. Michigan State University. 1947-1948. 3.5. Graduate Studies. Iowa State College. l9h8-1950. M.S. Michigan State University 1953 to 1959. Experience: U. 5. Army. 19h3-19h6. loath Infantry Regiment. 26th Division. Third Army. European Campaign. Land Use Spec. Michigan Dept. of Conservation 1950-1951. Instructor (Research) Michigan State University 1951- 1958. Agronomist. National Plant Foo ‘Institute. 1958- to present. a Member:. American Society of Agronomy. Soil Science Society of America. International Soil Science Society. Society of Sigma Xi. Alpha Zeta. TABLE OF CONTENTS Page momICTIONQOOOOOOOOOOOOOOOOOOOOOOOOOOOOO0.000000000000000000IOOOOOO 1 REVIEW’OF LITERATURE..FACTORS AFFECTING ROCK PHOSPHATE USE........... Inherer‘t FactorSOOeeeeeeeeeOooeoe00.000.00.0000000eoeogeeeeoeoe. 6 6 FinenQSSOOIeeeeeeceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeceeeeoeo 6 Fluorine Content.......................................o..o 6 Source Of mosphateceeooeooooooeoooe0.000000000000000000000 7 8 8 son FactorSOOOOOOOOOO0.0.000000000000000000COOOOOOOOOOOOOOOOOOO Organic Mattereeeeeeeeeoeeoeeeeeeeeeoeceeeeeeeeeeeeoeceeeee $011 Reaction.....o..............o......................o.. 9 Incubatian POTiOdeoeeeeeeeeeeeeeeeceeoeeeeoe00000000000000. 10 Placement.......o......................................oo.. 10 Crop Factors...............o.........o..............o.o.o...o... 11 Relative Effectiveness of Rock Phosphate and Superphosphate..... 11 Residual Effect................................................. 1“ EXPERIMENTAI.METHODS AND RESULTS..................................... 18 Field.Emperiments............................................... 18 Ekperimental Procedure....o................................ 18 Kalamazoo County.....o..............o...................... 19 Corn.....o............................................ 21 Oats........................o.o....................... 25 Hay..........o..............o..............o........oo 31 Genesee County......................o....................oo 35 Corn.....................................o.......o.... 36 Oats................o.......o..............o..oooo.ooo “1 Hayeeeeoeeeeeeeeeeeeeeeeeeee-eoeeeeeeeeeeeeeeeeeeeeeee “5 IOBCO County.......................o..............ooooo...o 5h corneoeeeeeeeeeeeeeeeeeeeeeeeeecoo-00000000000000.0000 56 whgateeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee... 56 HayeOeeeeeeeeeeeeeceeeeeeeeeeeeoeeceeeeeeeeeeeeeeeeeee 60 Grand Traverse county.eeeeeeeeceeoeeeeeeeeeeeeeeeeeeeeeeooo 63 Corn.................................o.....o......o... 66 Oats................o..........................o....o. 72 HQOOOOO...0..00......COIOOCOOOCOOOOOCOOO0.0.0.0...0.. 78 TABLE OF CONTENTS - ntinued Greenhouse merinentSOOCO0.00000000000COOOOOOOOOOOOOOOOOOOOOOOOO 86 mermmtal ProcedureCOOOOOOOOO.O...OOOOOOOOOOCOOOOOOOOIOO. 87 Availability Of New Application Of ROCR “losphameeeeeeeeooe 88 Residual Effect of Treatments on Soils from the Field Plots. 92 Kalamazoo county.eeeeeeoeeeeeeeeeeeeeeeeeeeeeeoeeeeoeee 92 00110308 countyeeeeeeeeeeeeeeeeeeeeeeeeeoeeeeeeeeeeeeeo. 96 SUMY AND CONcmSIONSeoeeeeeeoeeeeeeoeeeccoo-000.00.000.00000000.... 99 11mm CITEOOOOOOOIOO0.000......O...0..00......OOOCOOOOUOCCOOCOOQIOZ LIST OF TABLES Table Page 1. Yield of Corn at the Kalamazoo County Location.................. 23 2. Available Soil Phosphorus Prior to Corn Planting at the Kamoo comty mat1WOOOOOOOOOCOOO...OOOOOCCOOOOOOOOOOQOOIOO 2h 3. Total Phosphorus in the Green Tissue and Harvested Grain of the 1956 Corn Crop. Kalamazoo County............................ 26 h. Yield of Cats at the Kalamazoo County Location.................. 27 5. Net Increase in Yield of Oats in 6 Years Produced by Phosphate Fertilization at the Kalamazoo County Location.................. 29 6. Total Phosphorus in Cats Sampled at Heading Time at the Kalamazoo county beat1°n°0....0...’......O00......OOCOQOOOOOOQO 7. Yield of First Year Alfalfa-Drone at the Kalamazoo County locatim00000000.0.0....0......0.0.0...OOOOOOOOOCOOCOOOOOOCOO0.. 32 8. Yield of Second Year Alfalfa-Drone at the Kalamazoo County Iocation..................................................o.o... 33 90 ‘Iield or corn at the Genesee County location.................... 38 10. Net Increase in Yield of Corn in 8 Years Produced by Phosphate Fertilization at the Genesee County location.................... 39 11. Available Soil Phosphorus Prior to Corn Planting at the 6930300 County’location......................................... #0 12. Total Phosphorus in the Green Tissue and Harvested Grain of Corn .t the GODOBCO County Location............................. “2 13. Yifild Of Oats at the Genesee County Location.................... “a 1“. Net Increase in Yield of Oats in 7 Years Produced by Phosphate Fertilization at the Genesee County Location.................... “A 15. Total Phosphorus in the Cats Sampled at Reading Time at the Genesee County 10¢at1°n......................................... “6 16. Yield of First Year Alfalfa-Brena at the Genesee County Location........................................................ “7' 17. 18. 19. 20. 21. 22. 23. 2h. 25. 26. 27. 28. 29. 30. 31. 32. 33- 3“- LIST OF TABLES - Contigggg Net Increase in Yield of First Year Hay in 6 Years Produced by Phosphate Fertilization at the Genesee County Location........ Total Phosphorus in the First Year Hay Crop at the Genesee co‘mw Imat1°nOOOOOOIOOOOOOOO0.00000....0.0ICOOOOOOOCQOCOCCCC0.0 Yield of Second Year Alfalfa-Drone at the Genesee County location...0......CO..OOOOOOOCOOOOOOOOOOOOOO0.0.0.0....0.0.0.0... Net Increase in Yield of Second Year Hay in 6‘Years Produced by Phosphate Fertilization at the Genesee County Iocation........ Total Phosphorus in the Second Year Hay Crop at the Genesee County Location.......................................... Yield of “heat at the Iosco County Iocation...................... The Net Increase in Yield of Wheat in 5 Experiments Produced by Phosphate Fertilization at the Iosco County Location.......... Yield of First Cutting Hay at the Iosco County Location.......... The Net Increase in Yield of First Year Hay in 2 Years Produced by Phosphate Fertilization at the Iosco County Location..........- The Net Increase in Yield of Second Year Hay in 2 Years Produced by Phosphate Fertilization at the Iosco County Location.......... Yield of Corn at the Grand Traverse County Location.............. The Net Increase in Yield of Corn in 7 Years Produced by Phosphate Fertilization at the Grand Traverse County Location.... Available Soil Phosphorus Prior to Corn Planting. Grand Traverse County.................................................. Total Phosphorus in the Green Tissue and Harvested Grain of Corn at the Grand Traverse County Location-cooeeeeeeeeeeeeeeeeee- Yield Of Oats at the Grand Traverse County Location.............. Net Increase in Yield of Cats in 6 Years Produced by Phosphate Fertilization at the Grand Traverse County Iocation.............. Total Phosphorus in the Cats Sampled at Heading Time at the Grand Traverse County Location............................... First Cutting Yields of First'Year Alfalfa-Brena at the Grand TraverBQ County Locatian................................... SO 52 53 55 58 59 61 67 68 71 74 75 79 35- 36. 37. 38. 39. “I. “2. #3. #5. LIST OF TABIES - Continued The Net Increase in Yield of First Year Hay in 6 Years Produced by Phosphate Fertilization at the Grand Traverse cmty mat1°n00000.COOOOOOCOOIOOOOOOCOOOOOOIOOOOODOOOOO..000... 81 Total Phosphorus in the First Cutting of the 1957 Ray Crop at the Grand Traverse County location".......................... 82 First Cutting Yields of Second Year Alfalfa-Brena at the Grand Traverse County location................................... 83 The Net Increase in Yield of Second Year Hay in.h Years Produced by Phosphate Fertilization at the Grand Traverse county locationOOOOOlOOOOOO00.00.000.000..OOOOCOOOCOOOOCOOOOOOOCC 85 The Yield of Greenhouse Grown Wheat. Percent Phosphorus in the Plant and A Values Of the $01.18...eeeeeeeeeeeeeeeeceeeeeeeeee 90 The Yield of Greenhouse Grown Mammoth Clover. Percent Phosphorus in the Plant and A Values of the Soils................ 91 The Yield of Greenhouse Grown Wheat. Percent Phosphorus in the Plant and A Values of the Soils from the Kalamazoo Comty Locationeeeeeeeeeeeeeeeeeeeeeoeeeeeeeeeeeeeoe0000000000000 93 The Yield of Greenhouse Grown Mammoth Clover. Percent Phosphorus in the Plant and A.Va1ues of the Soils from the mmzoo county locatiorIOOOOOO000......OOOOOOOOOOOOOOOOOOOOOOOCO 95 The Yield of Greenhouse Grown Wheat. Percent Phosphorus in the Plant and A Values of the Soils from the Genesee County location.................................................o 97 The Yield of Greenhouse Grown Mammoth Clover. Percent Phosphorus in the Plant and A Values of the Soils from the Genesee comw “cationOOOOOOOOOOOOO0.00COOOOOOOOOOOOOOOOOOO0.... 98 The Relative Effectiveness of Superphosphate over Rock Phosphate per Pm Of Applied P205000eeeeoecoooOOOOOOOOOCOIee000100 LIST OF PLATES Plate ‘ Page 1. Timed. no phosphate. Plant 5 inches tall. Spurvay reserve P 27 lb/aC. Fmal yield 31 bu/aCOOOeQOOeeoeeeeeooooooooeeeeeeeeee 70 II. lined. rock phosphate. Plant 5 inches tall. Spurway reserve P 58 lb/ac. Final yield 26 bu/ac 70 III. Rock phosphate. no line. Plant 5 inches tall. Note character- istic phosphorus deficiency. Spurway reserve P 102 lb/ac. Final yield 22 b‘u/ac..."........................................ 70 IV. lined. 10 lb P 0; superphosphate. Plant 10 inches tall. Sway reservg M lb/ECe Final yield “'1 m/BCQOQOQeeeeeeeeeee 70 INTRODUCTION Phosphorus has been called the "master key to agriculture” (83) as well as the “bottleneck of the world's hunger" (92). Its importance in general farming is indicated by the fact that low crop production is due more often to the lack of phosphorus than to the lack of any other element (76). To illustrate the importance placed on phosphorus. the time devoted to its research should be considered. In the period from 1935-1950, 673 major articles were published in the United States alone on soil and fer- tiliser phosphorus (75). Phosphorus is found in every living cell and is essential in both animal and plant nutrition. In plants. phosphorus is found in largest concentration in the seeds. whereas in animals along with calcium. it is found in the skeleton. Adequate amounts of available phosphorus in soils favor rapid plant growth and development and play both a direct and in- direct role in their metabolism (67. 83). The use of phosphorus containing materials for improving soil pro- ductivity is not new. In fact. the practice of using bones or fish for improving the productivity of soils has no exact record as to its origin. As early as 1653. an English writer mentioned the use of bones in British agriculture. but it was apparently not until the time of the American Revolution that the practice became fairly general. Even at this later date the reason for the beneficial effect of bones was not understood (83). About lane the first clear and intelligent exposition was written on the role of minerals in plant growth (97). 1 2 . By about 1815 the English supply of bones was low and importations from other countries reached about 30.000 tons annually. showing that England was more alert to the need of phosphorus than other European countries. Liebig. in attempting to awaken the other European countries to the importance of bones wrote. ”England is robbing all other countries of the condition of their fertility.“ (83). The problem of supply of phosphorus did not diminish. for at the turn of the 20th century Van Hise wrote. "The problem of the conservation of our phosphates is the most crucial. the most important. the most far reaching with reference to the future of this nation of any of the problems of conservation” (106). The importance of phosphorus fertilisation has not diminished in recent times. In a message to Congress on May 20. 1938. President Franklin D. Roosevelt said. "the phosphorus content of our land. following gener- ations of cultivation has greatly diminished. It needs replenishing. I cannot overemphasize the importance of phosphorus not only to agriculture and soil conservation but also the physical health and economic security of the people of the nation. Mbny of our soil deposits are deficient in phosphorus. thus causing low yields and poor quality of crops and pastures" (91). In 1867 deposits of rock phosphate were discovered in South Carolina and in the 1880's additional deposits were discovered in Florida (97). These discoveries gave American industry the opportunity to take the lead in the mining of rock phosphate. With the later discoveries of phosphate rock in Tennessee and in the western states it has been variously esti- mated that within the continental United States from about one—third to one—half of the known world reserves of phosphates are located (43. u“). 3 The principal types of phosphate deposits and mineral constituents are (58): l. Igneous apatites (fluorapatite) 2. Marine phosphorites (carbonate-fluorapatite) 3. Residual phosphorites (carbonate-fluorapatite) 4. River pebble (carbonate-fluorapatite) 5. Phosphatized rock (carbonate-hydroxyl-fluorapatite) 6. Guano (carbonate-hydroxylapatite) The most important types of deposits in the United States in respect to marketed production are the residual and marine phosphorites. The residual phosphorites include the Florida land pebble (30-36% P205) and Tennessee brown rock phosphates (29-35$ P205) which constitute the bulk of the rock phosphate marketed to date. These deposits were derived from phosphatic limestone formations where the more soluble carbonates have been weathered and leached out leaving the more insoluble phosphates. The Florida deposits. in addition. were subjected to marine erosion and rearrangement. The Tennessee deposits are much older than those in Florida being derived frOm rock of Ordovician age while the Florida deposits are from rock of Tertiary age (he. #3). The Idaho and Montana deposits (27-37$ P205) are marine-sedimentary in origin and chiefly of Permian age (8h). The question as to the origin of these phosphate beds. termed the Phosphoria formation. is unanswered. Recent discoveries of nodular phosphate on the sea floor of southern California. however. suggest that these beds in Idaho could have been pre- cipitated from sea waters by an increase in fluorine content of the water through volcanic activity. L, The South Carolina phosphate reserves were depleted around 1920 but the Tennessee. Florida and far western states productions more than make up what was lost from the South Carolina depletion. It has been estimated that there is enough phosphate rock in Florida alone to last the United States. at the present rate of use. for 2.000 years (97). Before the discovery of rock phosphate deposits. bones were the only known commercial source of phosphorus. Since bones supplied only a fraction of the need. the discovery of phosphate deposits was of great interest to agricultural workers. Early work. however. showed that rock phosphate was not as good a source of phosphorus as bone meal (90). The relatively inadequate supplies of bone meal. however. and the abundant and low cost supplies of rock phosphate soon resulted in rock phosphate being advocated in many areas as a main source of phosphorus for crop production. While superphosphate had been available in the United States since 1868. its use as a fertilizer was limited mainly by its cost. Superphosphate is made by mixing approximately 1100 pounds of ground rock phosphate and 900 pounds of sulfuric acid for each ton of finished 16 percent super- phosphate. These are mixed rapidly in cast-iron pans from which the mixture is poured while still in liquid form into bins where it hardens in a few minutes. After some days the superphosphate may be put through the mill and run back into the pile for further curing (38). This acidulation process converts the insoluble fluorapatite into the relatively soluble mono- and dicalcium phosphates. In 1920 the cost per pound of P205 as superphosphate was ten cents. Rock phosphate on the other hand cost only 2 cents per pound of P205. With this price differential five times as much rock phosphate as superphosphate could be applied to the land for the same price (63). With technical advances the price of superphosphate began to diminish while. conversely. increases in cost of transportation and labor increased the cost of rock phosphate. By 1909. the price of superphosphate had de- creased to 8 cents per pound of P20 . The price of rock phosphate. however. increased to nearly a cents per pound of P205. With this price differential. the quality of the phosphorus in both materials became the governing factor in its purchase. The phosphorus in superphosphate has been regarded as available to plants while the phosphorus in rock phosphate has been regarded as generally unavailable without considerable time for reaction in the soil. Since there was a quality difference in the phosphorus compounds between the two fertilizer materials the question of relative effectiveness became a prime research problem. The question of whether 1 pound of superphosphate was equivalent to 2. 3 or more pounds of rock phosphate in supplying phos- phorus for crop production needed to be answered. This research is intended. in part. to answer this question. REVIEW'OF LITERATURE FACTORS AFFECTING ROCK PHOSPHATE USE Many factors inherent in the material. in the soil. as well as time and crop govern crop response to rock phosphate. Inherent Fggtorg Fineness As would be expected the degree of fineness of rock phosphate affects its availability to plants to a certain extent. The same is true of the less soluble processed phosphates (78). Most of the rock phosphate sold for direct application to the soil is ground so that 90% or more will pass a 100 mesh sieve. Several investigators have studied the effect of fineness of rock phosphate on its availability to plants (17. 23. 26. 46. 81. 95). Their results show that in some cases finer particles than are found in the commercial product give a somewhat higher availability to plants. However. the increased availability did not seem to be great enough to justify grinding rock finer than the usual commercial product (90). Fluorine Content Investigations (39. 42) have shown that fluorine generally. is a part of the raw mineral phosphate in all deposits. In a study (6) of the response of sudangrass in the greenhouse to several raw phosphates of varying fluorine content. the natural phosphate containing the least 6 fluorine produced the highest yield. Recent work (10). however. has shown no correlation between fluorine content of rock phosphates and their availability to plants. Chemical solubility has been suggested as a better measure of availability. Source of Phosphate The composition of commercial phosphate deposits varies considerably depending on the conditions under which they were laid down (39. #2). In greenhouse experiments different sources of rock phosphate have been compared on many soils and the availability of the phosphorus in the various sources have varied considerably (2. 16). The phosphate-bound carbonate content and citric acid solubility were the two measurements that showed the highest correlation with yields of alfalfa and relative effectiveness of different sources (21). In general. foreign sources which included Tunis. Morocco and Curacao Island have been superior to all of the domestic sources except that of South Carolina. now depleted (10). ‘ The source of rock phosphate and fluorine content are apparently interrelated and the effect of the source on phosphate availability is probably due. in large part. to the inherent fluorine content character- istic for any particular source. The relatively available Curacao Island rock phosphates. for example. have low fluorine percentages (90). "Colloidal phosphate" could be considered as a rock phosphate source. It is the by-product of the phosphate mining industry whereby the phos- phate is washed into ponds and settled out from the hydraulic operations in the mining of rock phosphate. Experimental evidence comparing rock phosphate with colloidal phosphate generally shows no significant difference in the value of these materials when added in equivalent quantities (13. 15. 31. 65. 105). Colloidal phosphate may be considered finely divided rock phosphate diluted with colloidal clay material. Soil Factgzg Organic Matter It has often been suggested that decomposing organic matter exerts a solvent action on raw phosphates and increases availability. Truog (103) and Bauer (8) studied the effect of fermenting cow manure and crop residues. respectively. on the availability of rock phosphate but the results failed to prove any solvent action. It has been suggested that the beneficial effect of adding organic matter. particularly manure. with rock phosphate comes from the extra phosphorus added in the organic matter rather than from a solvent action on the rock phosphate (11. 79). Even though the solvent action of organic matter has not been proven. results continue to be reported in the literature as to the increase in the effectiveness of rock phosphate where cr0p residues were returned to the soil (68. 99) or where used with soils naturally high in organic matter content (81). In the greenhouse. each ton of green manure applied per acre produced sufficient carbonic acid to require an equivalent rate of 3000 pounds per acre of lime for neutralization. It is not likely that all of this carbonic acid would remain in the soil but it is prob- able that some of it would have opportunity to react with the slowly soluble phosphate in the soil (59). Russian workers have reported that mixtures of rock phosphate with peat or manure increases the availability of the phosphorus as indicated by the increase in amounts of water-soluble 9 phosphorus and an increase in total ash and nitrogen content of the grain of crops treated with these mixtures (#7. #8. 96). In addition. accele- rated decomposition of the organic matter is credited to the rock phos- phate addition. Soil Reaction Research has shown that liming may decrease the availability or efficiency of rock phosphate (3. 7. 23. 1+5. 69. 89. 95. 10a. 107, 117). Numerous experiments have shown that rock phosphate is of little or no value when applied to the calcareous soils of the west (37. 55, 85. 102. 109. 116). DeTurk (27) states that free calcium carbonate may retard the intake of phosphorus from rock phosphate by plants which are not "strong feeders“. It has been shown. however. that the effect of lime is less when applied well in advance of rock phosphate (1). Smith (99) in attempting to determine the cause of the differential response to rock phosphate by crops grown on two Illinois soils concluded that the surface pH had no effect on the response. At pH 6.6. however. the availability of rock phosphate was found to be actually reduced on incubation (“6). Also it has been found that adding sulphur to a soil which had been over-limed released sufficient available phosphorus from rock phosphate for satisfactory growth of oats and clover at pH 6.5 (77). Other experiments (34). using tracer techniques. showed that with rock phosphate the higher the soil pH the lower the relative amounts of fertilizer phosphorus to soil phosphorus absorbed by the plant. The practice of not lining in order to utilize rock phosphate fertilizer has been shown to be in error. Lime plus superphosphate has produced better yields of crops than rock phosphate alone (49. 81. 88). 10 Incubation Period The availability of rock phosphate on an acid Virginia soil was in- creased by applying the material well in advance of the crOp (11 months) for which it was intended (71). However. the amount of phosphorus ex- tractable on soils treated with rock phosphate in Texas showed a decreased availability with time of contact (20). This indicates that soil types vary in their inherent soil characteristics with respect to reactions with rock phosphate depending on whether the reaction is going toward release of phosphorus or towards fixation. Certainly incubation such as in composting would increase the availability of phosphorus in rock phosphate (30). Placement Little placement work has been done with rock phosphate. The liter- ature refers largely to broadcast methods or plow-down. Ohio data (81) on the banding of rock phosphate for corn and oats compared to banded superphosphate show very poor response by the crops to rock phosphate. Similar results are reported on the banding of rock phosphate for wheat in Nebraska (112). Recent research (56) indicates that the less soluble phosphates are more effective when mixed intimately with the soil. Conversely. the more soluble phosphates are more effective when banded. Further. the finer material is more effective when banded and the coarser material is more effective when intimately mixed with the soil. In the case of rock phosphate. these data would support the idea that rock phosphate is at its most effective placement when intimately mixed with the soil. The data would further substantiate the fact that superphosphate. particularly 11 the fine material. is at a decided disadvantage when mixed intimately with the soil. Crop Fggtogs The utilization of the phosphorus in rock phosphate by various plants is an important consideration in the interpretation of results. Many workers (5. 8. 14. 25. 27. 28. 36. 6“. 7h; 80. 81. 10“) have shown that plant species differ in this respect. In general. it can be said that most of the cereals are ”poor feeders". whereas buckwheat and some legumes such as sweet clover. alfalfa and red clover are "strong feeders”. It is fairly certain that satisfactory results from rock phosphate will not be obtained unless crops that are "strong feeders" are used in the ro- tation. Truog (10“) suggested that plants that require relatively high amounts of calcium are more likely to be able to utilize slightly soluble phosphates. The removing of the slightly soluble calcium from an equil- ibrium condition by plants tends to drive the reaction to completion. releasing phosphorus. Relative Effggtiveness of Rock Phosphate and Supegphggphatg Wbrk with rock phosphate at the Ohio Experiment Station. over a 35 year period. where rock phosphate was applied at a rate equal to twice as much P205 as that applied in superphosphate on an acid soil (pH 5.0) showed that rock phosphate was consistently less effective than the superphosphate (95). In a report from Alabama (31) rock phosphate ap- plied at twice the P205 rate of superphosphate resulted in half the yield increase attributable to superphosphate. Research in Arkansas (61) com- paring equal money values of rock phosphate and superphosphate, which from 1952-1955 amounted to two and a half times as much P205 as rock phosphate as in the form of superphosphate. showed crop yields similar with the two materials. In Tennessee (57).however. at these same levels of application. yields with the rock phosphate were only one third that from superphosphate. In Ohio. rock phosphate applied to corn at three times the rate of superphosphate (in lime of P205). from 1915 to 1933. was considerably less effective than the superphosphate (95). In Ken- tucky (74) three and a half to four times as much rock phosphate P205 as superphosphate P205 was needed to give equal yield. Hopkins (#1) showed that rock phosphate generally produced crop yields somewhat higher than did the superphosphate when the P205 rate was h to 1. On one field. the superphosphate was slightly better than the rock. The response of the crops to phosphorus in all cases. however. was small and actually unprofitable. Other experiments from Illinois (9) indicate that rock phosphate was roughly equivalent to superphosphate at four times the P205 rate under both lined and unlimed conditions. In 190“. at the Indiana Agricultural Experiment Station. 82 field tests were laid out where finely ground rock phosphate was compared with superphosphate at the h to 1 rate. In these tests phosphate rock showed a profit but to a much smaller degree than did superphosphate (87. 114). In a Virginia report (29) of greenhouse experiments with vegetable crOps. rock phosphate. at four times the PéOS rate as superphosphate. was in most cases less effective than the superphosphate. In Alabama (31) rock phos- phate at b times the P205 level of superphosphate did not equal the super- phosphate in cr0p yield. In Nebraska in 1950. five times as much P205 as rock phosphate did 13 not produce as great a wheat yield as did superphosphate (112). A report from Kansas (98) showed that rock phosphate applied at approximately six times the P205 rate of superphosphate resulted in similar crop yields. It is important to note here that when rock phosphate is applied at six or more times the P205 rate of superphosphate the amount of immediately available phosphorus becomes substantial. In a series of field experiments in Minnesota where rock phosphate had been applied.'at seven and ten times the rate of P205 as superphos- phate. the superphosphate was generally superior to the rock phosphate even when a much greater amount of rock phosphate was applied (93). There were a few cases in this experiment where better increases were obtained with rock phosphate and there were some instances where superphosphate was strikingly better than the rock phosphate. As little as 18 pounds of P205 as superphosphate drilled with the wheat at seeding time in Indiana. produced about the same increase as sixteen times that amount applied broadcast as rock phosphate (73). In a greenhouse experiment. reported in 195? (33). rock phosphate and superphosphate were applied at equal rates of citrate soluble phos- phorus. which amounted to twenty five times as much rock phosphate P205 as that applied as superphosphate. Oats did better on the superphosphate while alfalfa did better on rock phosphate. In Virginia (70). in 1957. on a soil which had been the most re- sponsive to rock phosphate it required 600 pounds of rock phosphate P205 to produce as much increase in corn yield as was obtained from 20 pounds applied as superphosphate. Yield increases by 35 pounds of P205 as super- phosphate on wheat required seventeen times as much P205 as the rock 14 phosphate and 56 pounds of P205 as superphosphate on red clover required eleven times as much rock phosphate. On a soil which had been least re- sponsive to rock phosphate thirty times as much P205 as rock phosphate was approximately equivalent to 20 pounds of P205 as superphosphate for wheat. On an intermediately responsive soil fifteen times as much P205 as rock phosphate was approximately equivalent to no pounds of super- phosphate P205 for alfalfa. A report on regional rock phosphate studies in Indiana (4) showed that 10 pounds of P205 as superphosphate in the row produced a yield equivalent to thirty-two and sixty-four times as much P205 as rock phos- phate broadcast. This occurred with corn. soybeans and hay. With wheat. rock phosphate did not produce significant increases in yield at any rate. while superphosphate produced a substantial increase in yield at 30 pounds of P205 applied in the row. Residual Effects The advocates of the use of rock phosphate as a fertilizing material. while conceding that superphosphate may be more soluble and more quickly available. profess that the greatest benefits of rock phosphate come in its residual effect (31. 51. 53. 5“). Data from Illinois (52)show that over a 15 year period. rock phosphate (#50 pounds P205) had a greater residual effect and produced a greater gross return in crops than a money equivalent (1935 prices) of superphosphate (160 pounds P205). In Kentucky (110) there was no decline in yield on plots treated with rock phosphate (752 pounds P205) in 16 years while with superphosphate (160 pounds P205) yields declined. A 1950 report from the U. S. S. R. (50) states that the phosphorus availability of rock phosphate continues for 15 a long period of years (25 years in experimental work). A publication from Arkansas (60). in 195“. reported the results of a greenhouse study in which 32% rock phosphate and 18% superphosphate were applied in equal amounts every four years until a total of #000 pounds had been applied over 32 years. Sodium bicarbonate extraction of phosphorus from the soil treated with rock phosphate showed over three times as much phosphorus as where superphosphate was applied. Further. the values determined by the Fried and Dean method (35) showed that the soils treated with rock phosphate had a greater availability of phosphorus than where super- phosphate was used. However. none of the craps grown. whether buck- wheat. oats. or alfalfa showed any greater growth from the applied rock phosphate than from the superphosphate. yet all gave significant yield increases. In 1957 in a report from Alabama (32) of a field experiment where various sources of phosphorus were applied. including rock phosphate and superphosphate. the residual effects of all phosphates after 20 years was in direct prOportion to the amount applied. A summary of European work (2“) on phosphate carriers states that any complete attempt to differentiate the effects of contrasted phosphates on different kinds of soils should take into account 1.. pH. 2.. base status. 3.. humus content and b.. available soil phosphorus. Swedish work on soils with pH less than 6.0 has shown that superphosphate gives the best yields in the first year but rock phosphate has a greater residual effect. On less acid or neutral soils. (pH greater than 6.0) both im- mediate and residual effects of superphosphate are greater than rock phos- phate. Rock phosphate on these soils was considered of little value. 16 In summarizing the views held in Sweden and the United Kingdom on the use Of phosphorus fertilizer the report states. "although insoluble fertilizers may give higher residual effects than superphosphate on very acid soils this fact may not be very important since such soils should be limed before they receive dressings of phosphate. It is better to improve the phos- phorus status of acid soils by liming and then using soluble phosphorus than by omitting liming in order to make use of insoluble fertilizers". Workers in Norway also consider that insoluble phosphates may have advant- ages over superphosphates on very acid soils but such soils should be limed. Unpublished data from Texas (18) shows considerably more residual effect from rock than superphosphate but a considerable superiority for frequent small applications of superphosphate. Other data (111) indicated that an annual application of superphosphate was superior to single large applications of rock phosphate in uniform and high production of forage and protein. In this respect. superphosphate has been shown to be more effective in small annual applications than when applied in a single large application (22). Frequent small applications of rock phosphate such as at 100 pounds per acre of P205 annually resulted in yields and residual effect no greater than that of the nonphosphated plots (19). In the plots receiving superphosphate. P32 absorption data indicated that there was sometimes twice as much available phosphorus as in soils which had received rock phosphate or were not phosphated. In a Virginia (72) report the availability of residual phosphorus from long time superphosphate application was four times that of rock phosphate. These data are based on annual applications of rock phosphate l7 and superphosphate at an equivalent total Pé05 basis totaling 2900 pounds of P205 over #0 years. Approximately 3/4 of the phosphorus applied over this period from either source was present in the soil as residual phos- phorus. This quantity nearly doubled the original total phosphorus con- tent of the soil. A Minnesota (12) study of the residual effects of 3300 pounds of rock phosphate and 768 pounds of superphosphate over a period of #0 years showed that 9 years after the application of the two phosphates and manure had ceased. superphosphate was much superior to rock phosphate in its ability to supply residual phosphorus. Similar results were reported in Indiana (88). Many other reports on the residual value of superphosphate have also been published (82. 9h, 101, 108, 115). In 1950. EXPERIMENTAL METHODS AND RESULTS a project was organized to study the relative effective- ness of rock and superphosphate in the north central region in which 8 member states (Michigan, Ohio, Indiana. Illinois. Minnesota. Iowa, Kansas. Nebraska) participated. This report summarizes the results of the Michi- gan experiments. Field Experiments Experimental Procedure Six treatments were utilized in the Michigan experiment: 1. 2. 3. he 5. 6. No phosphate Superphosphate at 10 pounds of P205 per acre per year Superphosphate at 20 pounds of P20 per acre per year Rock phosphate at 320 pounds of P285 per acre per 8 years Rock phosphate at 320 pounds of P205 plus superphosphate at 10 pounds of P20 per acre per year Rock phosphate aé 320 pounds of P205 plus superphosphate at 20 pounds of P205 per acre per year Treatments 1, 2, 4 and 5 were common throughout the region and 3 and 6 were optional. The phosphate treatments were applied in a manner recommended for that particular material. The superphosphate was banded at planting time for each crop and the rock phosphate broadcast in a single application (960 pounds per acre) at the beginning of the experi- ment. Research data have shown (56) that as the water solubility of the phosphorus source increases greater benefit to crop growth is afforded by band placement of the phosphorus and conversely as the water solubility decreases greater benefit occurs with intimate mixing with the soil. In the case of this experiment. therefore, where superphosphate was banded 18 19 (85% of phosphorus water soluble) and rock phosphate (no water soluble phosphorus) was mixed with the soil. both sources were compared at their optimum. The rock phosphate used in the region was from the same source. Florida. and of the same specifications. 33% PéO . 85% through a 200 mesh sieve. Four locations were chosen in Michigan three of which had an additional split treatment of liming (Kalamazoo. Genesee. Grand Traverse Counties). The cropping system on these three locations consisted of two years of alfalfa-brome hay. followed by corn and spring oats. On the fourth lo- cation (Iosco County) the cropping sequence was two years of alfalfa hay followed by corn and winter wheat. The experimental areas were divided into n fields so that each crop appeared each year. The statistical design of the Kalamazoo. Genesee and Grand Traverse experiments was a split-plot with liming being the main plot and phosphorus source the sub-plots. The sub-plot size at the Genesee location was 28 x 50 feet and at the other locations 21 x 50 feet. In the Iosco County experiments a randomized block design was used with plots 21 x 50 feet in size. The treatments at all four locations were replicated four times. Nitrogen and potash were top-dressed prior to planting each crop to insure an adequate supply of these nutrients (60 pounds of N. 60 pounds of K20 for corn. and 30 pounds N. 60 pounds K20 for the small grains). The land was fitted with minimum tillage and crops of recommended varieties were sown by conventional means. Kalamazoo County The experiments in Kalamazoo County were located on the John Campbell 20 farm. a miles north and east of the city of Kalamazoo in section 4. town- ship 2 south. range 10 west. The farming in this area of the state is largely comprised of dairying with the raising of hogs. beef cattle. poultry and sheep of importance on certain farms. The major factors influencing the farming of the area are the generally lighter soils. the relatively long growing season and the local markets of Battle Creek and Kalamazoo (“0). The growing season in this area ranges from 150 to 170 days. The last frost in the spring occurs between May 1 and 10 and the first in the fall between October 1 and 10. The elevation varies from 800 to 1000 feet above sea level with the topography ranging from level to rolling. Many of the level outwash plains are strongly pitted (40). The soils to plow depth are dominantly light colored sandy loams. light loams and loamy sands easily tilled. moderately productive and re- sponsive to manure and commercial fertilizers. They are not excessively droughty. but the lack of moisture-holding capacity. combined with the natural low fertility. is probably the greatest limiting factor in crop yields. The soils are generally acid in the surface and sub-soil layers and are low in organic matter content. Liming is usually required for satisfactory stands of alfalfa (113). The l9h7-1951 average per acre yields of field crops in Kalamazoo County were as follows: corn. 3“ bushels; oats. 37 bushels; wheat 2h bushels; hay 1.4 tons (40). The soils of the experimental area were level and very uniform. being predominantly Kalamazoo sandy loam. Approximately one quarter of the area was slightly heavier in texture and was Kalamazoo loam. Ground limestone at a rate of 1% tons per acre was applied to appro- 21 priate blocks in 1950 so that one-half of the area was limed. This liming. however. was totally inadequate for the acid conditions prevailing (pH 5.1- 5.5) and as a result this lime was virtually ineffective. (The soil re- action in 1956 of limed plots was pH 5.4-5.8). The lime requirement for the original pH level on this soil was more nearly 3% to h% tons per acre (86). 0f the six cropping years (1951-1956) at this location. three years. 1953. 195“. 1955 were characterized by late summer droughts. Two years. 1951 and 1956 had adequate precipitation but were relatively cool. Only in 1952 did the climatic factors combine to give a good cropping year. $13. The corn yields were very good in 1952. fair in 1951 and 1956 and poor in l95h and 1955. The crop in 1953 did not receive a single rain and was a complete failure. During the planting of the 1955 crop. a break-down occurred in the midst of the planting operation. The sixteen plots which did not receive superphosphate and three of the plots receiving superphosphate had been planted prior to the time the mounted planter broke loose from the tractor. The planting of the remaining twenty-nine plots was completed after repairs were made. These plots. planted after repairs. had a very poor stand (as measured in July) in relation to those planted previous to the break-down. Since yields were related to stand (r=0.760“) and stand related to some unknown difficulty the 1955 yields are not included in the corn yield summary given in Table 1. The effects of lime on corn yields were non-significant whether con- sidered yearly or as an average over the entire experiment. Since the effects of lime were not significant the yields presented in Table 1 are 22 treatment means over lime levels. Treatment means were significantly different at the 5% level in 195M. However. little importance can be attached to this result. The apparent statistical signifcance can be accounted for by the fact that corn with- out phosphate produced lower yields where limed than where unlimed and with rock phosphate produced higher yields where limed than where unlimed. This seemingly incongruous interaction was of sufficient magnitude to affect the analysis of variance and it should not be misconstrued as a phosphate response. The analysis of variance presented in Table l. for the corn data over the four years 1951. 1952. l95h and 1956 does not show significant treatment effects. A response to phosphorus by corn at this location would be expected in considering the soil tests by the Spurway ”reserve” test. as presented in Table 2. The plots which did not receive phosphate or those treated with superphosphate alone had low (<150 pounds per/acre (66)) tests for phosphorus. Corn on these plots should have exhibited a phosphate response but the plots treated with rock phosphate had high (2>50 pounds per acre) tests and little phosphate response would be ex- pected here on the basis of the tests alone. When tests of these same samples were made using the Bray adsorbed phosphorus (Pi) test. however. all tests were very high ()>35 pounds per acre) and little response to phosphorus would be expected. In this case then. the Bray P1 tests gave a better estimate of crop response to phos- phorus fertilizer. The percent phosphorus in both green tissue and grain of the 1956 crop are presented in Table 3. 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AVAILABLE SOIL PHOSPiIORUS+PRIOB TO com; PLANTING AT THE KALAMAZOO COUNTY LOCATION Pounds per Acre 1952 195a 1956 Ave. _.1reaimaniinez_aczall_ 1§ 5 Pl:— §L_ 12f 3 Pl: No phosphate fertilizer 8 16 65 27 66 18 65 10 lbs. on5(o-2o-o)per year 11 15 71 33 73 22 72 20 lbs. P205(O-20-0)per year 8 15 62 38 81 23 71 320 lbs. P205(rock)l95l 53 57 68 69 71 61 69 320 lbs. P o (rock)l951 plus 63 88 76 75 77 - 7o 76 10 lbs. P25510-20-0)per year 320 lbs. P o (rock)1951 plus 39 111 68 91 100 65 83 20 lbs. P265 O-20-0)per year L.s.n.g§g 1.1.12 is -— n. 1 1 11 10 . + S = Spurway reserve test (Extract is 0.13N HCl. l:h soil:extract ratio) P1: Bray adsorbed phosphorus test (Extract is 0.025N HGl +~0.03N NHuF. 1:7 soil:extract ratio) 25 off and composited from several representative plants in each plot when the corn tasseled. The grain analysis was made on a representative sample of the harvested yield. The plant samples were wet-ashed. taken up in 0.1N HCl and the phosphorus content determined colorimetrically using the ammonium molybdate method. Little relationship was observed between the phosphorus content of the plant samples and the phosphorus applied to the soil. However. there was more phosphorus in leaf samples from the phosphate treatments than from those without phosphate and less phosphorus in the grain where phos- phate had been applied than where without phosphate. ‘Qgtg. The dry weather which seriously affected corn yields occurred at a less critical time in respect to oat development and yields were there- fore. less drastically affected. The oat yields of 1953. when the corn crop failed. however. were rather poor. Liming increased yields signifi- cantly in 1956 but in the other 5 years did not have significant effects so the data presented in Table h are treatment means over lime levels. In the four years of significant treatment effects the annual 20 pounds per acre rate of P505 as superphosphate produced higher oat yields than did the 1951 application of 320 pounds per acre of P205 as rock phos- phate. In three of the years the 10 pound per acre of P205 as superphos- phate produced higher yields than did the rock phosphate and lower yields in one year. The average effect shows a significant yield response to all phosphates for the six.years. The only significant difference between phosphate treat- ments occurred with the significantly higher yield produced with the 20 pound rate of P205 as superphosphate than that obtained with rock phosphate. TABIE 3. TOTAL PBOSPFOEUS IN THE GREEN TISSUE AND HARVESTED GRAIN OF TEE 1956 CORN CROP. KALAEAZOO COUNTY 26 Treatmentgper gcrel Percent Phosphorus No phosphate fertilizer 10 lbs. PZOS(O-20-O)per year 20 lbs. P205(O-20-0)per year 320 lbs. P205(rock)l951 320 lbs. P O (rock)l951 plus 10 lbs. P265 0-20-0)per year 320 lbs. 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The relative effectiveness between treatments is not as clear-cut as with the oat crop because of the missing harvests. generally poor growth and only slight phosphate response. However. since the higher rate of superphosphate and the rock phosphate treatment did give measur- able yield increases some credence could be assigned to the effective- ness values for these two treatments. The increases in yield with the first year hay crop were small and yield increases per pound of P205 applied amounted to 12.2 pounds of hay with the high rate of superphosphate and 4.2 pounds with the rock phos- phate. The value for superphosphate included two years of superphosphate addition without harvestable yields (1954. 1955). If these years can be ignored as not representative of treatment the effectiveness value for superphosphate is 20.2 pounds of hay. The value for rock phosphate would not change since the material was added at the beginning of the experi- ment. Depending on how the comparison is made the relative effective- ness of superphosphate was three or five times that of rock phosphate in increasing first year hay yields. 0n second—year hay. the effectiveness value for the high rate of superphosphate is 23.0 pounds of hay per pound of P205 applied and for rock phosphate. 3.4 pounds. This indicates that the relative effective- ness of superphosphate was nearly seven times that of rock phosphate in increasing second-year alfalfa yields. The effectiveness of superphosphate in these experiments is even of greater significance when the acid re- 35 action of the soil. pH less than 6.0. is considered. Under these condi- tions rock phosphate has been considered to be more effective than super- phosphate. Genesee County The Genesee County experiments were locates on the G. Harold Leach farm 2 miles north of Davison in section 3“. township 8 north. range 8 east. This is a major dairy and cash crop area. well within the boundaries of the Detroit milk-shed. Dairying is the most important enterprise for the area and on many of the commercial farms is the sole source of income. Off-farm Opportunities are great. however. owing to the influence of metropolitan Detroit. The length of the growing season in this area is from 150 to 170 days. The last frost in the spring occurs sometimebetween.May 1 and 10 and the first in the fall between October 1 and 10. The elevation ranges from 600 to 800 feet above sea level with the general topography level to roll- ing (1+0) . The soils in this general area were derived mainly from loam glacial till. The drainage of the soils varies from well to imperfect with the latter condition generally associated with the smoother locations. The closely associated wet areas. both organic and mineral. often influence the size and shape of fields. Locally. slopes are excessively steep and may have deteriorated because of water erosion (113). The soils are deep. relatively high in fertility. and durable under cultivation except on the steeper slopes. Under a good system of manage- ment the soils can be maintained in a good state of productivity. The 36 soils are suitable for growing such staple crops as corn. wheat. oats. alfalfa. beans and sugar beets (113). The 1947 to 1951 average yields of field crOps in the county were as follows: corn. 37 bushels; oats. 41 bushels; wheat. 26 bushels: hay. 1.5 tons per acre (40). The soils of the experimental area were not very uniform but were characteristic for this area of the state. Approximately four-fifths of the experimental area was divided evenly between the two soil types Blount loam and Metea sandy loan and the remainder of the area was comp prised of Morley loam and Pewamo silt loam. The surface was nearly level with a few plots located on gently sloping land. This small area of sloping land was moderately eroded (Class 2) while the bulk of the area was not eroded or slightly eroded (Classes 0. l) (100). In 1950 1% tons per acre of ground limestone was applied to appropri- ate blocks so that one-half of the area was limed. With an original pH of 5.9 to 6.1 the lime requirement for these soils was 2% to 3% tons per acre (86). As a result of under-liming the acid condition was corrected only to pH 6.1 to 6.5. Of the eight cropping years (195C-l957) at this location. four years. 1953. 1954. 1955 and 1957 were characterized by late sumer droughts. In the case of these experiments. however. the effect of dry weather was not as drastic as in Kalamazoo County because of the better water relation- ships of these soils. In 1952 the climate was warm with sufficient rain- fall to produce good yields. The other years had adequate rainfall but were relatively cool. Corn. The corn yields were very good in 1952. poor in 1951 and 1957 and above average during the other years. The effects of the lime on corn yields were not significant whether considered yearly or as an average. 37 Since liming was not significant the yields presented in Table 9 are treatment means over lime levels. Treatment means were significantly different at the 5% level in 195“ and 1956. The higher rate of superphosphate and the combination of the two materials produced significantly higher yields than that obtained without phosphate. These differences carried through into the average for the eight years. The mean yield, produced by the low rate of super- phosphate. was higher than that of the rock phosphate though not signifi- cantly. six out of the eight years. The average yield obtained with the rock phosphate. however. over the eight years. was lower than that pro- duced without phosphate. The net increase in yields of corn produced by phosphate fertilization. the total amount of phosphate applied and the effectiveness values over the eight year period are given in Table 10. The rock phosphate treat- ments had a net deficit in the increased yield value which can be assumed zero response. As a result the relative effectiveness of superphosphate to rock phosphate is infinite. The soil tests for phosphorus on samples taken prior to corn plant- ing are given in Table 11. As in the Spurway tests in Kalamazoo County the plots treated with rock phosphate all gave "high" soil tests for phos- phorus and all other plots gave "low” tests. Since yields from plots with rock phosphate alone averaged less than those from the plots with no phos- phate. this test is misleading. The Spurway ”reserve" extractant apparently removes phosphorus from the rock phosphate which plants cannot remove. The Bray adsorbed phosphorus test on the other hand. shows low-medium tests for all treatments and a need for considerable amounts of phosphorus. 38 N0.0¢ cam Anvaouhm games mes R axwxa .m.: «0.0 mm.m: mm H x a 0®0.~ nn.mHH n A x a 000m.0 mm.omm m hevmpcmsvmoue 0H.m0H. 0N Aevwouua .0.:.Nn.H oo.me 0 H x A .05 00.~ No. 000 .0 30023 ..~0.0HH 00.000.00 0 000000000 .0.: 00.H 0H.mm~ 0N movaodeom 000 .038. amp» :0: oamocm :00: Eooooau Ho cowvmaumb no mooumon condom "ooomaum>.uo mathmcw :.N .m.c cam. .04: o.n .m.: an.m um.q .m.: NHm>oH Wwv.o.m.a m.nm 0.0: 0.m© 0.0n H.on w.m¢ 0.Hm m.0~ H.03 nsHQ oanAxoohv own .mnH own saga 00000.00-0 0000 .000 00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0:00 0000000000 0 0 .000 000 0.00 0.00 0.00 0000 0.00 0.00 0.00 0.00 0.00 00000000000000 .000 000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 use» aoaA0.00-000000 .000 00 0.00 00.00 .0.00 0.00 0.00 0.00 0.00 0.00 0.00 0000 00000.00-000000 .000 ca 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 amusaesa.a .saaamoaa oz >< H H H H H N H H H H Acumm ummwmcofipmoue .oho< woo nHonnsm ZOHB<0QH EDOO mummzmo NE. 9.0 Zmoo ho SE .0 Ema; 39 TABLE 10. NET INCREASE IN YIELD OF CORN IN 8 YEERS PRODUCED BY PHOSPHATE F ERTILIZATION AT THE GENESEE COUNTY IDCATION Pbunds Bushels Effectiveness P20 Increase Value Treamggflpe: ggggl Aggligd in Yield Eta/lg P305 10 lbs. P205(0-20-0)per year 80 9.0 0.11 20 lbs. P205(0-20-0)per year 160 1.1.2 0.26 320 lbs. P205(rock)1950 320 -3.5 -0.01 320 lbs. P o (rock)1950 plus #00 28.7 0.07 10 lbs. P285 O-20-O)per year 320 lbs. P O (rock)l950 plus 480 33.5 0.07 20 lbs. P255{0—20—0)per year TABLE 11. GENESEE COUNTY LOCATION Pounds per Acre AVAILABLE SOIL mosmoausfinxon TO cow PLANTING AT THE #0 1953 1951‘L 1955 1956 1957 Ave. Tre ent re 8 P1 8 P S P S S P S P No phosphate fertilizer 1h 19 4 15 9 16 18 16 14 15 11 16 10 lbs. P205(O-20-0)per year 10 18 7 17 10 17 20 17 10 14 12 17 20 lbs. P205(O-20-0)per year 13 19 9 19 12 18 38 20 12 16 18 18 320 lbs. P205(rock)l950 65 19 57 17 1.2 18 58 18 no 14 1+7 17 320 lbs. P 0 (rock)l950 plus 81 21 59 18 36 18 61 19 46 17 54 19 10 lbs. Pé85QO-20-O)per year 320 lbs. P 0 (rock)1950 plus 88 21 67 19 51 21 51 19 50 18 55 19 20 lbs. P255io-20-0)per year L.s_.p.j5$ level) --n.s. 18 2 8 2 23 0.3.30 2 8 1 + S = Spurway reserve test (Extract is 0.13N HCl. 1:“ soil:extract ratio) P1: Bray adsorbed phosphorus test (Extract is 0.025N H01 + 0.03N NHAF, 1:7 soil:extract ratio) 41 As was true in the case of the Kalamazoo eXperiment. the Bray test gave the best prediction as to crop response to phosphorus in this test also. The phosphorus analyses of the plant tissue are presented in Table 12. There were no significant differences, between phosphate treatments or liming on phosphorus content. in either the leaf samples taken at tas— seling time or the grain. ‘Qatg. Oat yields were generally above average for the area except in 1955 when yields were poor and in 1957 when the plots were drowned out by spring rains. In 1953. when the corn crap failed at the Kalamazoo location and the oat crop was poor. the Genesee location had the best oat crop of the experiment. The oat yield data and analysis of variance summary are pre— sented in Table 13. ldmdng did not have a significant effect on oat yields nor were there significant lime interactions so the data in Table 13 are treatment means over lime levels. In four years. 1952. 1953. 195“. 1955 as in the final analysis. treat- ment means were significantly different at the l$ level and in one year. 1951 at the 5% level. During the five years of significant treatment effects the plots treated with rock phosphate did not exhibit significant yield increases. Superphosphate consistently produced greater yields than the rock and no phosphate treatments. Only in one year. 1956. did rock phosphate produce a greater yield. though not significant, than the lowest rate of superphosphate. The effects of the combination of the two materials was not greater than that attributable to superphosphate alone. The net increase in yield of oats produced by phosphate fertilization. the total amount of phosphate applied and the effectiveness values between treatments over the seven year period are presented in Table 14. The lower 1+2 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 4.230..” mu“ .Q.m.q ill 0000 00000.00uo 0000 .000 00 0000 0000000000 000 .000 000 0000 00000.00-0 0 00 .000 00 0000 0000000000 0 0 .000 000 000000000v0000 .000 000 .300 0008.00-80000 .000 00 0000 00000-00-0v0000 .000 00 0000000000 000000000 oz .o>< 0.an oan nmmH msaonmmosm poooaom 202.403 H.558 550 Man. .0 .0 05 0.0.0. 84 2.000 no 2320 Egg 9: mammHH Eu m5 2H mamommmozm 4.0808 .NH @348 “3 00.0n Q00 Apvpouum .0.0 00.0 00.00 on 0 x 0.x 0 .n.: 00.0 0m.00 on M x a .o.: 00.0 00.00 0 0 x a ..00.00 00.000 0 0000000500000 00.000 00 00000900 .05 00.0 00.00 0 H x .0 .n.: 00.0 00.000 0 00v0200 ..00.00 00.000.0 0 00000000 .u.c 00.0 00.000 00 00000000o0 000 00009 pump :0: 000900 000: 2600000 «0 co0vw0uw> 00 0000009 000500 "oocm0uw> no 000000c< .uqmuuuuqmqm 040 0.0. 0.00«:, 0.0 ”0.0 .0.0 ~0m>o0 000.0.0.0 uil 00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0000 0000000000 0 0 .000 000 0000 00000.00uow0w00 .000 00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0000 0000000000 0 0 .000 000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 00000000000000 .000 000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 00o0 00000-00-000o00 .000 00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0000 uo000.00-000ofim .mp0 00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0000000000 000000000 oz 40Mm:uIawmmuIII00m0IIuIum“m0wxInIn0m0InInumnmmuunnumwmwnnllumwmm 1~muquummqmqmanummH||. 0004 000 00onusm 202.033 goo mama—Ho BE. .30 90.40 000 QHM .00 00m< on 0an 00.H 00.0 05.H 0:.H 50.0 00.H ~0.H 50.0 00.H 00.H 55.0 n:.~ mm.H «0.0 Hm.H you mmww :mmH new and nn0H 0:5 and ~n0a 28.9503 37500 mmmmzmo mm... ed §0g1<5<5< mam» 9mm“: mo SMH» .oa mqm mo monumen ooudom "oocmau0> mo namhflmc< sa.0 HNso 00.0 .e.: mmaolmm.0 0000 H_.0....0.._.m~..0 Nlmsolmné Nausea. 03.0.0.4! 00.H 00.0 00.H 50.H 00.H 50.0 on.H :N.N 0H.H mo.N 00.H 0H.N mm.d 0H.N HN.H 00.H w:.a 00.H md.a MH.N ®N.H 00.H 0H.H N0.N nm.a 0m.H 0H.H m0.N 30.0 dw.H . on.H 00.H N0.H mm.H nH.H dw.H Cu .ess 500a mesa l' 0H.H 0n.m H0.H 00.H 04.0 00.H 00.H 00.0 5m.H 0m.H 0:.N m0.H Nm.H 00.H :0.H 50.H 00.H 00.H N a 000a sn0a euo¢ wen mace was 00.0 mm.~ 00.H no.0 mafia e 0-00-0 a . 0H om 000aaxooa0 0 a .una 00 we.» poaaouowno n ma .una 0a H0.m 00.0 00.H 00.0 000HAaoeav 0 m .00H 000 0H.~ 00.0 00.H H0.~ 000aaxeesvnoem .ena 000 00.0 ea.~ 0H.H 00.0 uses uoeao.0~-0vn0mm .00H 00 0:.N w®.H mm.o no.m amok hommonomucvnomm .mDH 0H 00.H H0.H 00.H 00.0 pesaaasuee manganese oz ucw Awwma mmmuvem9u00uan 000a ~00H ZOHH no nooumoo condom ooswanm>_mo namhflmo< o.“ 0&1 66.4 .39“ 303-00-0w0w00 .pr 00 0.00 0.00 0.00 0.00 0.00 0.00 33 000038: 0 a .30 000 to» 320.000 0 0m .an 00 0.00 0.00 0.00 0.00 0.00 0.00 340 000208.: 0 a .2: 000 0.00 3.00 0.00 ~.wm 0.0m dun Humixoowvnomm .23 can 0.0m m.u~ 0.20 0.5m «.0m n.0n use.A woaAouomnov0dmm .mna cm in 0.00 0.00 «.00 0.00 0.3 as” 0&A900é0000 .2: S 0.00 0.00 0.2 0.00 0.00 0.00 0333.30 320820 oz 1410.?4 32 $2 an Auk”. havfiqgmflhh e0ma 0000 0000 20He_mo mammamcs w.m ~.o s.m .e.: elm. ,amas m.w 0.4: H.0m a.am 0.5: w.ms w.mm m.ms n.sm mead anmafixooav o.m .mna omm sees audfiouo~-o nwma .hea oH m.ms s.o~ e.nm m.ma s.es e.sm m.eb N.wm beau HanAsoouv o a .ena own H.5m e.o~ e.m~ m.ss n.sm H.wm o.sn ~.em HanAsooavnomm .aba own s.~s H.mm n.om s.~n H.Ha b.6m 3.36 s.mn use» aoaAouomuOVmofim .upH om m.as 6.0m m.sn o.Hm e.mm H.sm o.me ".mm sacs uaeaouomuovnomm .hsa 0H o.mn 3.:m o.NN 0.“: m.mm o.mm o.Hm n.sm aoawflaeuom caanmond oz thquuw, sued unmallllnnmduuuldmmah .mwms, wmma, awash muaemsmmmqammammmwmlu ZOH9*35 lbs. phosphorus per acre). The response of the corn to the applied phosphate is in accord with the soil tests since there was a significant increase in yield with the low rate of superphos- phate but a non-significant increase beyond this with the higher rate of superphosphate. In the Genesee County experiments with generally low-medium Bray tests for phosphorus the corn showed significant yield differences be- tWeen rates of superphosphate. In the Kalamazoo County experiments. on the other hand with very high Bray tests for phosphorus. averaging around 25 pounds per acre greater than in the Grand Traverse County experiments. W .0w\sp .3 30a.» .0345 mm 30.2“ Hwfihm .0034“ NOH m gnome.» magnum HmEE .0m\o.m +3 m 950mm.” hmgsdm .33 3:05 0H $830.33 maosdmofi 033390230 opoz .33 v5.8 .mamnomofinodom mowm pH OH 6054 .>H woman 90305 m 0.83m .053 o: .momnemofi xoom .HHH 3mg , . . . ... -A ....m 6de mm 33% Hmfih .0m\£ mm m atone .33."st 5&3 an ode?» Hgb .8}: mm m 030mm.“ hwEQm .285 m 9.53 Batman .32 .853 .HH 9:5 .33 852: n 23m .mpmfiwofi o: 623 .H 8.5 . HVV...q....\...... ._. 203433 E00 Egg 5246 WE. HR 550 71 Acapmu pomuvxmuadom “HH .mzmz zmo.o + Hum znwo.o ma pomupxmv ummv mayoanonu umpuomnm hwum "an Aoaumu pomuvxmuafiom and .Hom zma.o ma pomuvxmv vmwv w>ummmu hwaudam u m + : m 1m 1S 2 8 6&1. «H : om Admwmdwufldé .89” ummS..o~..o nowm .mfl om mm mm Hg mm mm an 0: mo um mm mafia anmafixoouv 0mm .mna can pack uoaaouom-ownowm .mpfl 0H m: me :n mm an no 3: mm on we ”can anmaflxoouv 0mm .mnH own :: ow w: on an an m: mm an «A HanAxoouvnonm .npfl own 0: mm m: Hm ow mm 3: mm an :a amok umaAo-om-ovnon .mpH ow m: mm a: “H mm o: «a ma om NH “mom “mafio.omucvnon .mna 0H mm ma 0: ea m: mm on ma on NH uoaaadapmm mpmgqnona oz mm m an mwu. an m an m fin m 1~ouom gomqmmmmmmmmwun. .m>< mama wmma mmma :mma uuo< uma mncsom MBZDQQ mmmm>4 .mN mqmde 72 the corn exhibited no phosphate response. The Bray "adsorbed phosphorus" (P1) test. therefore in all cases. gave a better estimate of the response of corn to phosphate than did the Spurway ”reserve" test. The phosphorus analyses of the plant tissue are presented in Table 30. The treatment means were not significantly different nor was the effect of liming significant on phosphorus content in either the leaf samples or in the grain. Qélé- Oat yields were generally average for this area of the state with the exception of 1957 when yields were well above average. Liming did not have a significant effect on oat yields nor were there significant lime interactions. The oat yield data presented in Table 31. therefore. are treatment means over lime levels. In 1952. 1953 and 1955 treatment means were significantly different at the 5 percent level with rock phosphate producing a significant yield increase only in 1955. In 1954 as in the average over the six years, treat- ment means were significantly different at the 1 percent level. The re- sults of 1954 further correspond to those of the six year average in that the superphosphate treatments produced significantly greater yields than either the rock phosphate or the no phosphate. The plots with rock phos- phate averaged higher yields than those without phosphate but were not statistically significant. The combination of the two materials did not produce greater yields than that attributable to superphosphate alone. The net increase in yield of oats produced by phosphate fertilization, the total amount of phosphate applied and the effectiveness values between treatments over the six year period are presented in Table 32. The low rate of superphosphate applied at a total of 60 pounds of P205, over this 73 .Illdem 5.: 1.3.» .954 amen a88.0~..0w00~m .2: on 03.0 08.0 N000 000.0 000.0 3N0 30.0 030 $020380 0~m .2: own to» $03.80 000m .an 0H 93.0 03.0 003.0 09.0 93.0 3N0 mmmé 030 $3383 own .03” 0mm 0.3.0 03.0 000.0 20.0 03.0 93.0 08.0 Hmmflxoobnomm .05 0mm 09.0 2.0.0 P00 30.0 «8.0 03.0 000.0 to» a88-0~..800~0 .2: on 0.3.0 3N0 32.0 03.0 03.0 30.0 mmmd he» a880~u0000~m an: 0H 09.0 80.0 «00.0 08.0 £30 .800 baud awaits.“ 320020 oz ulllddjw «o o a mob. .95 shad onma mam." 330005 #:3qu name 94 zmoo mo 259mm Ewe/.5: 92¢ mbmee Emu at. 2H mbmozmmomm 44.806 ”83.0.63 H.558 mméa 92g . on mama. 74 0©.NN OQH AnvuOhhm .m.: 00.0 00.HN 0N H w w x 0. 000.H “0.0: mm w_w a .06 8.0 H06 0 .H x .H. 000:.HH Hm.0wm n Ahvnvcoeumoha 0m.m: 0H Amvaoanm .05 mwé main m. M x A .n.: ma.: 00.00H H AAVuEdq :09an 0~.NOH.0H m 30.80» .0.: 00.H 00.0: 0H umpmoHHdom bwm Havoa $3 :0. 230» 5...: 80080 No 0030200 00 nooawon ooaeom «oocwaumb no 0H00H0c< 0!..H. N 0 N JHflm 0.0. 1| mén 0.3 mean min 0. on him m.m~ 2:0 $020303 0N0 .2: 0N0 .800 808.80%on .2: 0H H00 0.H0 0:0 Nan 0&0 0.0N 0:0 2:0 $22020 0N0 .a: 0N0 0. 00 H00 0.Nn 0.:N 0.00 0.0H N.0N 302.3200on .2: 0N0 0.00 0.00 040 0.00 H.Hm N.0N 0.00 .300 308.8000on .2: 0N 0.00 0.8 0.0: 0.00 0.00 0.NN 0.0N .300 303.8000on .2: 0H 0.00 0.00 0.3 H.0N 0.00. 0.8 0.0N 8539.30 320800 oz 4 H 23. .30 ”#225 N H H H H 8 a0 0 oh. 20:38 05500 09545. 0038 ME. .2 2.3 00 Sm: .H0 0403. TABLE 32. NET INCREASE IN YIELD OF OATS IN 6 YEARS PRODUCED BY PHOSPHATE FERTILIZATION AT THE GRAND‘TRAVERSE COUNTY LOCATION 75 T e r 10 lbs. P205(0-20-0)per year 20 lbs. P205(0-20-O)per year 320 lbs. P205(rock)1951 320 lbs. P 0 (rock)1951 plus 10 lbs. Pé65TO-20-0)per year 320 lbs. P O (rock)l951 plus 20 lbs. P285?0-20-0)per year — Pounds P50 Bushels Increase Effectiveness values A 1 ed in Yiel Bushels l P 0 Re i 60 120 320 380 15.1 30.6 9.14 3u.2 32-5 0.25 8 0.26 9 0.03 l 0.09 3 0.07 2 76 period, increased oat yields by 15.1 bushels per acre or 0.25 bushels per pounds of P20 . The 320 pounds of 2205 as rock phosphate increased yields by 9.4 bushels per acre or 0.03 bushels per pound of P205. Superphosphate at the low rate of application, therefore, was 8 times as effective in increasing yields as the rock phosphate. At the high rate of superphos- phate. with a total application of 120 pounds of Péos per acre. the net increase in.yield of oats was 30.6 bushels per acre. or 0.26 bushels per pound of P205 applied. Relative to the rock phosphate the high rate of superphosphate was 9 times as effective in increasing oat yields. The treatments combining the two materials had greater effect than rock phosphate alone but considerably less than superphosphate alone. The treatment of the low rate of superphosphate plus the rock phosphate pro- duced a net yield increase twice that of superphosphate alone. This re- sult is of greater magnitude than a simple additive effect of both ma- terials. It.might be concluded that there was a stimulative effect in the use of the two materials tOgether. However. this effect has not been noted in the other trials nor is it known to have been reported in the litera- ture. In all likelihood this result is entirely within the minge of ex- perimental error. Representative samples of the 1955. 1956 and 1957 oat craps were cut from the plots at time of heading and total phosphorus determined. These data are presented in Table 33 as treatment means over lime levels. Liming did not have a significant effect on phosphorus content nor were there significant lime interactions. Treatment means were not significantly different although the average over the three years shows all phosphate TABLE 33. TOTAL PHOSPHORUS IN THE OATS SAMPLE!) AT HEADING TIME AT THE GRAND TRAVERSE COUNTY IOCATION 77 Percent Phosphorus ngatmentflpgr gore) _::;955 _l2§§______l957 ‘ggg:_, No phosphate fertilizer 0.212 0.318 0.236 0.255 10 lbs. P205(0-20-0)per year 0.230 0.361 0.209 0.267 20 lbs. P205(0-20-0)per year 0.230 0.369 0.216 0.272 320 lbs. P205(rock)l951 0.216 0.353 0.210 0.261 320 lbs. P 0 (rock)l951 plus 0.278 0.387 0.225 0.297 10 lbs. P205TO-20-0)per year 320 lbs. P20 (rock)l951 plus 0.200 0.362 0.238 0.267 20 lbs. P203 0-20-0)per year L.S.D. l e n s n s s . 78 treated oats with higher phosphorus content than those without phosphate. ‘flgz. The yearly hay yields would be considered well above average for the area since these yields consisted of only the first cuttings. The second year hay field. after the first cuttings were removed. were field cultivated to control quack grass for the following corn crop. The first and second year hay yields are presented in Tables 34 and 37. The yearly effects of liming on first year hay were not significant. However, the average effect of lime over the six:year period was significant statisti- cally at the 1 percent level. Practically. it was of little consequence. since this average yearly increase in yield. due to lime, amounted to only 0.16 tons per acre. 'With the effect of lime being of such small magnitude and since there were no significant lime interactions, the best method of analysing phosphate treatment differences is from treatment means over lime levels. The yield data in Table 30 is presented in this manner. The treatment means were significantly different at the 5 percent level in 1953 and 1957 and at the 1 percent level in 195“. During these years the rock phosphate treatment did not significantly increase yields. The high rate of superphosphate. however. significantly increased yields in 1954 and 1957 and was significantly higher in yield produced in 1953 than the rock phosphate treatment. In 1950. all plots receiving super- phosphate had significant increases in yield. The treatment means over the six year period were significantly different at the 1 percent level. Only the high rate of superphosphate. however. and the combination treatments significantly increased yields. The yields produced by the low rate of superphosphate and the rock phos- mma.o 00H Anvhcanu .e.: mm.H 0mm.o mm A x H x H ..00.N 0Hn.o mm 0.2 a .m.: 00.0 30H.0 n A x 9 ..00.0 23: 0 50025.80 NHN.0 ma Anymoahu 3.: 00.H 0H0.0 H 302.3 nemm.m 00.H n Aaveamow .000.na n:.mm QM moanedflnom .n.: ®:.H 3am.0 kwN Hmaoa 0009 ch. 0:050» :00: sovoouh Ho coavsaum>.mo 0002009 condom "ooceaum>.uo ndthmc< H0.H 00.H 00.0 00.0 0:.N 00.0 00.0 0204 use mace 2:0 R0228: 0N0 .2: 0N0 .300 2.08-8.3. 0%: .2: 0H 0N.H 0N.H N00 00.0 00.H n0.N 00.0 2:0 $020.80 0 0 .2: 0N0 0H.H 0N.H H00 H00 .3: 00.H 00.0 $022090 noNa .2: 0N0 00.H 00.H N00 00.0 00.H 00.0 00.0 .0...» 2.08.0380on .2: 0N 0H.H 0H.H 00.0 00.0 00.H $.N 00.0 .800 0&A90No0000N0 .2: 0H 00.H 0N.H 00.0 00.0 1:.H 00.N 00.0 0.53.80 3200000 oz Illa: 00:441.: 9% ZOHB4ma 924mm was 84 mzommwdsaduq< m mo manhdmc< AUflINIIebo leHWre: 1031 N300 on.“ [Maw “aegemeg ||||l 00.H 00.H 00.0 00.N 0N.m asH0 302225 0 0 .2: 0N0 a...» 03:90NuownmN0 .2: 0H 00.H 9A N06 H0.H «NA mane Hmmflxooav o m .3." 0mm 00.H .34 00.0 00.H 0H.0 H00H202000N0 .2: 0N0 00.H 00.H H00 HH.N N20 .2.» .&A0-0N-0000Na .2: 0N 00.H 00.H 00.0 00.H 00.0 .800 0&A0-0N-0000N0 .2: 0H nn.H 0~.A 40.0 Nn.A mm.~ wouAAHvuou ovenmnosa oz 1.3. 000% 0004? 00mm 000.” 403030.013 oao< use econ. ll ll 203003 2.2000 enema; 02500 E .2 880045050 mi» 08000 00 080:» 3.2.00 0.0.50 .00 .303 8“ Significant yield differences due to treatment were achieved only in 195“ when the high rate of superphosphate. alone and in combination with rock phosphate, produced a significant yield increase. The yield increase of the combination treatment was no greater than that of the superphos- phate alone and. therefore. could be credited to only the superphosphate portion of the combination treatment. In considering the average over the four years. the high rate of superphosphate and the two combination treatments prOduced statistically significant yield increases. The yields from the combination treatments. however. were not significantly greater than the respective superphosphate treatment and the benefit in yield of these treatments can be attributed to the superphosphate alone. The net increase in yield and the effectiveness values for the second year hay are given in Table 38. Since the 1956 crop was not har- vested. the superphosphate applied during this year was not included in these data. Generally. the superphosphate was just as effective on the second year hay as on the first year hay. as measured by the pounds of hay produced per poundiof P205 applied. However. relative to the rock phosphate. it was less effective. producing only a 15 times greater yield than the rock. This value is less than that achieved on the first year hay by virtue of the rock phosphate being twice as effective on the second year hay crop. The phosphorus analyses of the 1957 hay crop are given in Table 36. The rock phosphate and combination treatments produced a higher average phosphorus content than superphosphate and no phosphate. A re- verse effect to that observed in the first year hay crap. These differences. however. were not statistically significant. TABLE 38. THE NET INCREASE IN YIELD OF SECOND YEAR HAY IN FOUR YEARS PRODUCED BY PHOSPHATE FERTILIZATION AT THE GRAND TRAVERSE COUNTY LOCATION 85 Trea nt er acre A 1 ed 10 lbs. P205(O-20-0)per year 20 lbs. P205(0-20-C)per year 320 lbs. P205(rock)1951 320 lbs. P’O (rock)195l plus 10 lbs. P§83%0-20-0)per year 320 lbs. P20 (rock)l951 plus 20 lbs. egos 0-20-0)per year Pounds P'O NO 80 320 360 #00 Thus Increase in Yiel P 0-59 1.22 0.38 0.87 1-37 Effectiveness Values 29 30 2 4 1b P O R 15 15 tiv Greenhouse Experiments Fried and Dean (35) have hypothesized that the radiochemical analyses of plants grown on soils receiving applications of fertilizer containing P32 can be utilized in calculating the phosphorus supply of the original soil. They have assumed that a plant presented with two sources of phos- phorus. that is. soil phosphorus and fertilizer phosphorus. will absorb the phosphorus in direct proportion to the amount available from each source. Experimentally. their hypothesis consists of the application of a standard amount of P32 tagged fertilizer to different soils result- ing in this phosphorus being absorbed in an inverse relation to that avail- able in each soil. The more phosphorus available in the soil the less P32 tagged fertilizer phosphorus in the plant. This relationship is ex- pressed in the following manner: Agree-r) y where A = the amount of soil phosphorus supply. B 8 the amount of the fertilizer phosphorus supply. y 8 fraction of the phosphorus in the plant derived from the fertilizer. This A value has been accepted by agronomists as a method of deter- mining phosphorus availability of soils. It is not clear. however. how the time factor of previous applications to the soils of phosphorus ma- terials affects the A value. It is apparently assumed that all previous additions of phosphorus to the soil are soil phosphorus as opposed to that of the immediately applied testing applications of P32 tagged material. The A value then. is in fact. a measure of the average availability of all sources of phosphorus contained in the soil. which in most cases. is 87 residual fertilizer. If the A value is a measure of residual fertilizer it could be used in evaluating the effectiveness of rock phosphate in crop growth. This present experiment was devised to utilize this method of soil phosphorus evaluation. Experimental Procedure The experiment was divided into two sections by differences in previous soil treatments. The first part consisted of two soils which had applications of rock phosphate just prior to the experiment. The second part consisted of soil taken from the Kalamazoo and Genesee County field experiments in 1953. In both cases 2 gallons (9000 grams of air-dry soil), was completely mixed with 0.580 grams of radioactive treble (“8.5% Pé05)superphosphate which added 12“ milligrams of phosphorus tagged with P32 to each pot. Based on an acre of soil to plow depth weighing 2.000.000 pounds this was equivalent to 128 pounds of treble superphosphate per acre. The soil was then placed in 2 gallon pots and planted to Yorkwin wheat and mammoth clover. The wheat was harvested six weeks after planting. oven-dried and weighed. The samples were ground in a‘Wiley-mill and 2 gram samples pelleted for radioactive analyses. Six weeks later the clover was har- vested and treated in a like manner. The standard sample to which the unknown plant samples were compared was made up from the tagged fertilizer material. The following procedure was used: 1.0231 grams of the tagged fertilizer was dissolved in 500 cc of distilled water. then a 10 cc aliquot was mixed into 10 grams of ground 88 alfalfa. the alfalfa oven-dried and then pelleted in 2 gram portions. The 2 gram pellets were checked for uniformity to guarantee a homogeneous standard. Each standard contained. therefore: lgggglzgfifl x 10 cc x §6£§; x .085 P205 = 1.985 ”Em P205 The activity of this amount of standard P205 was compared to that of the plant samples. Since the activity of the samples was in direct proportion to the amount of fertilizer phosphorus contained. the amount of fertilizer phosphorus in the plant was readily determined. Availability of New Application of Rock Phosphate Twenty four 2 gallon glazed clay pots were filled with air-dried and screened Oshtemo loamy sand and an equal number with a Miami loam. Three months prior to planting. line was added to twelve pots of each soil. Precipitated Ca003 at an equivalent rate of one-half ten per acre was added to the Oshtemo and at one ten per acre to the Miami. All soils were watered with distilled water and kept moist for two months. when they were allowed to dry. At this time. one month prior to planting. eight pots-of each soil. four limed and four unlimed. were thoroughly mixed with an equivalent rate of 1000 pounds per acre of rock phosphate. All other pots were Just mixed to assure that the only variable at this time was the added rock phosphate. The soils were again watered and kept moist until planting time when they were allowed to dry. At the time of planting. another eight pots of each soil. four limed and four unlimed. were mixed with the equivalent rate of 1000 pounds per acre of rock phosphate. In addition. the radioactive treble superphosphate 89 was mixed into all pots. as previously described. Therefore. there were four pots or replicates each. of Miami and Oshtemo. in a limed and unlimed condition. with the following treatments: 1. No rock phosphate 2. 1000 pounds per acre of rock phosphate applied at time of planting 3. 1000 pounds per acre of rock phosphate applied one month ahead of planting. These pots were arranged on the greenhouse benches in a randomized block design. The liming only slightly affected the pH of the Oshtemo raising it from pH 5.3 to pH 5.5. The pH of the Miami of less acidity originally. was more greatly affected. from pH 6.0 to pH 6.5. Spurway "reserve" soil tests for phosphorus on the original soil showed medium phosphorus (45 pounds per acre) in the Oshtemo and low phosphorus (13 pounds per acre) in the Miami. The potassium levels in both soils amounted to 1&0 pounds of potassium per acre. The yield of the winter wheat. the plant analyses. and the A values derived are given in Table 39. Little significant difference was noted between the phosphate treatments. However. differences due to soil were highly significant. except in yield per pot. which were not significantly different. The Miami loam gave significantly lower A values than the Oshtemo loamy sand and significantly higher values in plant phosphorus. The lower content of available soil phosphorus in the Miami as compared to the Oshtemo was also indicated in the Spurway "reserve" test. The yield of the second crop. clover. the plant analyses and the A values derived are presented in Table #0. The same highly significant differences between soil types were observed as in the case of the wheat. 90 TABLE 39. THE YIELD OF GREENHOUSE GROWN WHEAT. PERCENT PFOSPHORUS III THE PLANT AND A VALUES OF THE SOILS Plant P205 Yield Total Percen A Value Soil Treatment Gr/Pot Pergent fromfw2 g_§gm/Pot No phosphate 9.3 0.230 5#.l 112 Miami 1000 lbs. rock phos- 9.3 0.216 51.h 95 phate/ac at planting 1000 lbs. rock phos- 9.9 0.2hl 58.0 96 phate/ac 1 me. before No phosphate 9.0 0.167 21.4 #64 Oshtemo 1000 lbs. rock phos- 10.8 0.1“9 20.8 “87 phate/ac at planting 1000 lbs. rock phos- 9.2 0.161 20.3 u99 phate/ac 1 mo. before L.S.D. with soilsgfii level) n.s. n.s. ng§.. n.§._ TABLE 40 . THE YIELD OF GREENHOUSE GROWN MAMMOTH CLOVER . PERCENT PHOSPHORUS IN THE PLANT AND A VALUES OF THE SOILS. 91 Plant P 0 Yield Total Percen A Value Soil Treatment GrlPot Percent from P 2 figEZPot No phosphate 9.7 0.370 30.7 282 Miami 1000 lbs. rock phos- 9.7 0.1m 31.4 307 phate/ac at planting 1000 lbs. rock phos- 9.3 0.376 30.4 29h phate/ac 1 me. before No phosphate 5.0 0.763 18.5 622 Oshtemo 1000 lbs. rock phos- 5.h 0.7h5 12.7 86“ phate/ac at planting 1000 lbs. rock phos- 5.b 0.871 13.2 833 phate/ac 1 mo. before L.S.D. within soils level n s. n.s. n.g, lgfi 92 but in addition the yield differences were also significant at the 1 per- cent level. with lower yields observed on the Oshtemo. The effects of the phosphate treatments in increasing the A value on the Miami loam were not significant. However. the rock phosphate did increase the A values significantly with the Oshtemo loamy sand. Yield increases were also associated with this increased A value but were well within the realm experimental error. Residual Effect of Treatments on Soils from the Field Plots After the corn was harvested in 1953 from the Kalamazoo and Grand Traverse County field experiments. prOportionate amounts of the plow layer were taken from each plot and composited by treatment. This soil was air-dried. screened (h mesh) and placed in 2 gallon pots. four repli- cates per treatment. At the time of planting the radioactive treble superphosphate was mixed into all pots. as previously mentioned. The experimental design employed was similar to that utilized in the field. Kalamazoo Coun I- The yield of wheat. plant analyses and A values de- rived are presented in Table #1. These data are given as treatment means over lime levels. The only treatment significantly increasing yields was the combi- nation treatment of rock phosphate plus the low rate of superphosphate. In respect to the phosphorus content of the plant this treatment produced a lower phosphorus percentage than the treatment without phosphate al- though to a non-significant degree. The rock phosphate treatment and the rock phosphate plus the high rate of superphosphate significantly in- creased the phosphorus content. 93 TABLE bl. THE YIELD OF GREENHOUSE GROWN WHEAT. PERCENT PHOSPHORUS IN THE PLANT AND A VALUES OF THE SOILS FROM NE KALAMAZOO COUNTY LOCATION Total Plant P205 Residual P20 Yield Total Percegg A Value Treatmentfper_pcre) Applied Gr/Pot Per ent omP Po No phosphate fertilizer . 0 6.2 0.593 00.4 166 10 lbs. Fé05(0-20-0)per year 30 5.7 0.658 37.5 210 20 lbs. P205(0-20-0)per year 60 6.0 0.706 35.6 229 320 lbs. P205(rock)1951 320 5.8 0.719 36.3 226 320 lbe. P o (rock)l95l plus 350 7.2 0.511 39.1 201 10 lbs..P255 O-20-0)per year 320 lbs. P 0 (rock)1951 plus 380 5.4 0.793 30.2 2A8 20 lbs. Pzaséo-Zo-O)”r year M--- _ _va's°D° (5g Level-L 79.8 0.120 591 Jig 90 Wheat grown on the soil from the field plots without phoaphate utilized the greatest percentage of tagged fertilizer phosphorus. indicating less available phosphorus in this soil. This was borne out by the A values. This soil had a significantly lower A value than where treated with rock phOSphate. the high rate of superphosphate and the combination of the two. The soil treated with the low rate of superphosphate alone or with rock phosphate exhibited higher A values than the soil without phosphate but ‘was not statistically significant. The observations presented for wheat are also given for the following mammoth clover crap in Table #2. The clover being one crop considered a "strong feeder” on less available forms of phosphorus produced higher yields on the soils containing the rock phosphate. However. only the soils with rock phosphate alone produced a statistically significant increase in yield. The phosphorus content of the plant material was not significantly affected by treatment. however. the lowest amount of tagged fertilizer phosphorus was observed in plants grown on the soils treated with rock phosphate. The A values for these soils was considerable higher than where rock phosphate was not used but these values were within experimental error. The fact that the A values of the soils were higher for the clover than for the wheat was a probable result of two effects. First. the amount of radioactive phosphorus was reduced for the clever crOp by that removed in the wheat. This would result in the residual or A.va1ue phosphorus being in greater proportion to the P'32 for the clover. Secondly. and probably more important. the clover utilized more insoluble forms of 95 TABLE 42. THE YIELD OF GREENHOUSE GROWN MAI'R'ZOTH CLOVER. PERCENT PHOSPHORUS IN THE PLANT AND A VAUUES OF THE SOILS FROM THE KALAMAZOO COUNTY LOCATION 9 .r’. .- Total Plant P 0 Residual P20 Yield Total Percen A Value 2,Irsaiaaaiiasz_asre) App :9 erfot Peasant from.£.2 Re: No phosphate fertilizer 0 4.3 0.525 29.0 305 10 lbs. P205(0-20-C)per year 30 0.5 0.577 28.4 322 20 lbs. P205(0-20-0)per year 60 4.0 0.566 29.8 305 320 lbs. P205(rock)l95l 320 6.0 0.528 26.2 359 320 lbs. P O (rock)l951 plus 350 4.8 0.554 25.1 390 10 lbs. PQU5LO-20-O)per year 320 lbs. P 0 (rock)l951 plus 380 4.9 0.574 26.5 384 20 lbs. P285?0-20-0)per year L'S‘D‘Sii level) 4.2 n_g_30 n05; n.s. 96 of phosphorus than wheat and would. therefore. show a greater quantity of available phosphorus. This fact is evidenced by the higher A values of the soils treated with rock phosphate with clever as compared to those without rock phosphate and the small differences in A values between these soils when wheat was grown. Genesge County. The yield of wheat. plant analyses and A values derived are presented in Table 43. These data are given as treatment means over lime levels. Less consistency is noted in these data than with the Kalamazoo County soils. Yields of crops produced by the rock phosphate and the low rate of superphosphate were significantly greater than from the soils with- out phosphate. Yet the yield from these materials combined was signifi- cantly lower than from the soils without phosphate. A greater amount of tagged fertilizer phosphorus was utilized by the wheat in these experiments when compared to the soil from the Kalamazoo County experiments. This would indicate a lower available phosphorus content in the Genesee County soils. This conclusion is corroborated by the soil tests (P1) of the field experiments which show considerably more available phosphorus in the Kalamazoo County soils. The A values are accordingly lower in the Genesee County soils. with little difference between treatments. although the low rate of superphosphate resulted in a significantly lower A value than in the soil without phosphate. The mammoth clover data. given in Table 44. are summarized as treat- ment means over lime levels. These data. as with the wheat. are of little significance. In relation to the soil without phosphate the phosphate treatments did not significantly affect phosphorus content nor the A value. As with the Kalamazoo County soils the clever gave higher A values than the Wheat 0 TABLE 43. THE YIELD OF GREENHOUSE GROWN WHEAT. PERCENT FHOSPHORUS IN THE PLANT AND A VALUES OF THE SOILS FROM THE GENESEE COUNTY LOCATION Residual P20 Yield Total Percen A Value Tregtment‘pgr ggrgz Applied Gr/Pot Pergent from P 2 MzmlPot No phosphate fertilizer 0 9.3 0.570 46.5 153 10 lbs. P20§(0-20-C)per year no 10.9 0.521 53. 5 111 20 lbs. P205(0-20-0)per year 80 9.4 0.552 #8.? 135 320 1b.. P205(rock)l950 320 11.6 0.510 50.3 126 320 lbs. P 0 (rock)l950 plus 360 7.9 0.592 h3.2 171 10 lbs. P283?0-20-0)per year 320 lbs. P 0 (rock)1950 plus boo 8.6 0.58? 1.5.6 152 20 lbs. P285?O-20-0)per year L.S.D. level 1.0 n.s. 116.5 35 TABLE #4. THE YIELD OF GREENHOUSE GROWN MANHOTH CLOVER. PERCENT PHOSPHORUS IN THE PLANT AND A VALUES OF THE SOILS FROM THE GENESEE COUNTY IOCATION 98 Total C'Plant P 0 Residual P20 Yield Total Percen A Value Treatment r ere) Applied GrZPot Peggeg; from P 2 figQZPot No phosphate fertilizer 0 8.0 0.h43 34.0 250 10 lbs. Pé05(0-20-0)per year #0 7.1 0.077 36.2 226 20 lbs. P205(O-20-0)per year BC 7.5 0.378 39.8 202 320 lbs. P205(rock)l950 320 8.9 0.393 37.0 225 320 lbs. P 0 (rock)l950 plus 360 6.9 0.096 31.8 279 10 lbs. PZSSIO-20-0)per year .320 lbs. P 0 (rock)l950 plus “00 7.9 0.075 32.2 268 L.S.D level L133; 0.075 305- 53 SUMMARY AND CONCLUSIONS The results of the four field experiments are summarized in Table #5. These data are given as the relative effectiveness of superphosphate over rock phosphate. The A values. also determined. did not give as com- zalete a comparison. These effectiveness values presented in Table #5 are averages of those of both rates of superphosphate which were given earlier. It is felt that the differences in effectiveness between these rates is well within experimental error. The only observations with a wide difference between rates are those of the wheat crop from Iosco County and the first year hay from Grand Traverse County. The other ten observations ranged only a few units apart. Since these relative effectiveness values are derived from the net increase in yield and the total P205 application over the duration of each experiment they are actually the average effectiveness over the time period of the investigation. As such. these values are of greater importance in evaluating the effectiveness of rock phosphate than differences in average yield or comparisons of one years effects which have been the usual methods listed in the literature. The corn crOps did not give yield responses to the applied rock phos- phate. In estimating the value of rock phosphate in a cr0p rotation. there- fore. the corn crop must be considered as non benefiting. The oat crop did give small increases in yield from the applied rock phosphate. however. superphosphate ranged from 6 to 26 times more effective. Generally. superphosphate averaged 15 times greater in ef- fectiveness than the rock phosphate in increasing yield of oats. 99 100 TABLE 05. THE RELATIVE EFFECTIVENESS 0F SUPERPHOSPHATE 0m ROCK PHOSPHATE PER POUND or APPLIED P20 5 Small First Second ‘ngatign P1 te§t Corn: grgin Year Hay, Year Hay Kalamazoo v.high n.r.p.+ 6 5 7 Genesee low n.r.r. 20 6 2.5 Iosco medium n.r.p. 26 ll 8 Grand Traverse high n.r.r. 9 27 15 Average 15 12 8 + n.r.p. = no response to phosphate n.r.r. a no response to rock phosphate 101 The first year hay crops exhibited a similar superiority of super- phosphate to rock phosphate. The range of effectiveness of superphosphate was 5 to 27 times greater in increasing yields. As an average superphos- phate was 12 times more effective than rock phosphate per pound of Pé05 applied. The second year hay showed a greater response to rock phosphate than the previous crops. However. the effectiveness of superphosphate was still 2.5 to 15 times greater. These values averaged 8 times greater over the four experiments. Hflth the best average effectiveness of rock phosphate at one-eighth that of superphosphate. rock phosphate does not belong in the fertilization program of rotation crops on the farms of Michigan. 0n the basis of super- phosphate priced at $50.00 a ton. or 12.5 cents per pound of P205. rock phosphate would have to sell at 1.6 cents per pound or $10.56 a ton. at the most. to be an equivalent buy. 'Nith an average effectiveness of one- twelfth that of superphosphate as a fertilizer for small grains and first and second year hay. rock phosphate would have to sell at 1 cent per pound or $6.60 a ton to be equivalent. 1. 2. 3. 10. ll. 13. 102 LITERATURE CITED Ames. J. W. and K. Kitsuta. Availability of rock phosphate as in- dicated by phosphorus assimilation by plants. Jour. Amer. Soc. Agron. 2h:103-122. 1932. Armiger. w. H. and M; Fried. The plant availability of various sources of phosphate rock. Proc. Soil Sci. Soc. Amer. 21(2):183-188. 1957. Bachtell. M. A. and G. W} Volk. Rock phosphate results inferior to those of superphosphate. Ohio Agr. Exp. Sta. Farm and Home Res. Bull. 271:59-60. 1951. Barber. Stanley A. Report on regional rock phosphate evaluation in Indiana. Purdue Agr. Exp. Sta. Agron. Dept. Mimeo. AY no. 81. June. 191+7o Bartholomew. R. D. The unavailability of phosphorus in rock phosphate to some southern crops. Journ. Amer. Soc. Agron. 20:913-920. 1928. . Fluorine. its effect on plant growth and its re- lation to the availability to plants of phosphorus in phosphate rock. Soil Sci. 40:203-217. 1935. . Availability of phosphate rocks in soils of vary- ing acidity. Jour. Amer. Soc. Agron. 29:293-298. 1937. Bauer. F. C. The relation of organic matter and feeding power of plants to the utilization of rock phosphate. Soil Sci. 12:12-h1.1921. . A. L. Lang. C. J. Badger. L. B. Miller. C. H. Farnham. P. E. Johnson. L. T. Marriott and M; H. Nelson. Effects of soil treatment on soil productivity. Illinois Agr. Exp. Sta. Bull. 516. 1945. Bennett. 0. L.. L. E. Ensminger and R. W. Pearson. The availability of phosphorus in various sources of rock phosphate as shown by green- house studies. Proc. Soil Sci. Soc. Amer. 21(5):521-524. 1957. Bray. R. H. Phosphorus availability and crop response. Proc. Soil Sci. SOC. mere 11:215-221. 1937. Bridgford. Ray 0. and C. 0. Rest. Comparative value of rock phosphate and superphosphate as fertilizers. Submitted for publication. Minn. Agr. Exp. Sta. 1958. Brown. B. E. and A. Hawkins. A comparison of colloidal phosphate. rock phosphate and superphosphate as sources of P in potato fertilizer in Aroostock County. Maine. Am. Fertilizer 100(8): 5-7. 19119. 14. 15. 16. 103 and K. D. Jacob. Greenhouse and field tests com- paring colloidal phosphate. phosphate rock and superphosphate as sources of phosphorus for various crop plants. Am. Fertilizer 101(13) :7‘10 0 19M. . J. A. Chucks. A. Hawkins and J. E. Campbell. Field comparisons of colloidal phosphate. rock phosphate and superphosphate as sources of phosphorus in potato fertilizers. Am. Potato Jour. 21 3 241-2149 0 19M 0 and K. D. Jacob. Greenhouse pot culture tests on rock hosphates as sources of phosphorus for plants. Am. Fertilizer 102(1 :11-12. 19%. 17 Burlison. W} L. Availability of mineral phosphates for plant nutrition. 18. 19. 20. 21. 22. 23. 2h. 25. Jour. Agr. Res. 6(13):h85-514. 1916. Caldwell. A. G.. F. 1» Fisher and R. H. weihing. The effect of lime and phosphate on the yield of pasture at three Texas stations. Unpublished data. Texas Agr. Exp. Sta. Project 573. 1955. . A Hustrulid and F. L. Hammers. Residual availability in the soil of various sources of phosphate as measured by plant absorption of P32 and by soil test. Proc. Soil Sci. Soc. Amer. 20 (1) :25‘28 e 1956. . Hugo Velasco and Curtiss L. Godfrey. Effect of time. soil type and source of phosphorus on the extractability of applied phosphorus. Abstract of paper presented to the Agron. Sec.. South. Agr. Werkers. February 5. 1957. Caro. J. H. and W: 1“ Hill. Characteristics and fertilizer value of phosphate rock from different fields. Jour. Agr. Food Chem. h:68b- 687. 1956. Cheaney. R. L.. Ralph M. Heihing and R. Norton Ford. The effect of various rates and frequencies of application of rock and super- phosphate on the yield and composition of fora e on a Lake Charles clay loam soil. Proc. Soil Sci. Soc. Amer. 20 l):66-68. 1956. Conner. S. C. and J. E. Adams. Availability of Tennessee raw rock phosphate in relation to fineness and other factors. Jour. Amer. Soc. Agron. 18:1103-1107. 1926. Cooke. George W} The agricultural value of phosphate fertilizers which economize in the use of sulfuric acid. European Prod. Agency. Org. European Ebon. Coop. Project No. 162. Dean. L. A. and M. Fried. Chap. II. Soil-plant relationships in the phosphorus nutrition of plants. Pierre. W; H. and A. G. Norman. Editors. Soil and Fertilizer Phosphorus. Academic Press Inc.. New York. 1953. 492 pp. 26. 27. 28. 29. 10h “Mk. E. E. 39th Am. Rep. 111111013 Agr. up. st.. p. 230 19260 . The problem of phosphate fertilizers. Illinois Agr. Exp. Sta. Bull. 1:81}. 1942. Dickman. S. R. and E. E. DeTurk. Response of’young corn plants to inorganic phosphate differing in solubility:1. The effect of phosphorus absorption from rock phosphate on the composition and dry weight of corn at three periods. Proc. Soil Sci. Soc. Amer. 5:213-219. 19h0. Dunton. E. M. Jr. A study of the effectiveness of four phosphorus carriers on increasing soluble soil phosphorus and on crop growth with a virgin Sassafras sandy loam. Virginia Truck Exp. Sta. Project Report No. (Soils 1h-B. 1953). 30 Dymond. G. C. The increase of available phosphate in rock phosphate 31. 32. 33- 3“. 35- 36. 37. 38. 39. by composting. Proc. Ann. Cong. S. African Sugar Tech. Assoc. 25: 8A-85. 1951.Seen in abstract only. Chem. Abst. h6:3l97:. 1952. Ensminger. L. E. Response of crops to various phosphate fertilizers. Alabama Agr. Exp. Sta. Bull. 270. 1950. and R. W. P'earsogé Residual effect of various phos- phates as measured by yields. P uptake and extractable phosphorus. Proc. 5011 Sc1. 50c. Aware 21(1):80-8’4. 19570 Finn. B. J.. R. 1“ Cook and C. M. Harrison. Comparison of rock phos- phate to superphosphate for cats and alfalfa on three podsolized soils of eastern Canada. Jour. Amer. Soc. Agron. 49:465-“68. 1957. Fried. M. and Arnold J. MacKenzie. Rock phosphate studies with neutron irradiated rock phosphate. Proc. Soil Sci. Soc. Amer. 1h:226-231. 1949. and L. A. Dean. A concept concerning the measurement of avail- able soil nutrients. Soil Sci. 73:263-271. 1952. . The feeding power of plants for phosphates. Proc. Soil Sci. Soc. Amer. 1700:357-359. 1953. Green. J. Phosphate investigations in Mentana. Montana Agr. Exp. Sta. Bull. 356. 1938. Gustafson. A. F. Handbook of Fertilizers. hth edition. Orange Judd Pub. Co.. Inc.. New York. l9h9. 172 pp. Hendricks. S. 8.. Wk L. Hill. K. D. Jacob and M. E. Jefferson. Struc- tural characteristics of apatite-like substances and composition of phosphate rock as determined from microscopical and X-rey diffraction examinations. Ind. Eng. Chem. 23:1“13-1418. 1931. Hill. Elton. B and Russell 0. Mawby. Types of farming in Michigan. Mich. Agr. Exp. Sta. Spec. Bull. 206(2nd Rev.). 1950. 41. 1+2. 43. 52. 53- 5“. 105 Hopkins. C. G. Phosphates and honesty. Illinois Agr. Exp. Sta. Ciro . 186 . 1916 . Jacob. K. D..'W. L. Hill. H. In Marshall and D. S. Reynolds. The composition and distribution of phosphate rock with special refer- ence to the United Stated. U.S.D.A. Tech. Bull. 36“. 1933. . Chap V. Phosphate resources and processing facilities. Jacob. K. D..Editor. Fertilizer Technology and Resources. Academic Press. Inc. New York. 1953. 45“ pp. Jones. Randa11.J. and Howard T. Rogers. New fertilizers and fertilizer practices. Norman. A. 6.. Editor. Advances in Agronomy. I. Aca- demic Press Inc. New York. 1999. #39 pp. Jones, U. S. Availability of phosphorus in rock phosphate as influ- enced by potassium and nitrogen salts. lime and organic matter. Jour. Amer. Soc. Agron. 10:765-770. 19%. Joos. L. L. and C. A. Black. Availability of phosphate rock as af- fected by particle size and contact with bentonite and soil of different pH values. Proc. Soil Sci. Soc. Amer. 15:69-75. 1950. Karovkin. M. A. Increasing the effectiveness of rock phosphate under the influence of sod culture. Sovet. Agron. 10(9):83-84. 1952. Seen in abstract only. Chem. Abst. h7:5059 b. 1953. . Utilization of rock phosphate flour for organe- mineral composts. Sovet. Agron. 10(12):57-60. 1952. Seen in abstract only. Chem. Abst. “7:50590. 1953. Kentucky. University of. Summary of results of experiments at western Kentucky Substation. 1927-1949. Kentucky Agr. Exp. Sta. 1950. Koshel'kov. P. N. The neutralizing capacity of ground rock phosphate. Pochvovedenie(U.S.S.R.) 1950:688-697. Seen in abstract only. Chem. Abate “5 319392 a 0 1951. Lang. A. L. First things first in soil fertility. Better crops with Plant Food Mag. Nov. 1945. . The use of rock phosphate in Illinois. Proc. Soil Sci. Soc. Fla. 10:147-67. 1950. . Rock phosphate for direct application. A natural in soil conservation work plans. Jour. Soil‘whter Cons. Jan. 1953. . Rock phosphate. Farm Quart. Spring 1953. 55- 56. 57- 58. 59. 61. 62. 63. 6h. 65. 66. 67. 106 Larson. H. W. E. and G. 0. Baker. A preliminary report on the rela- tive value of various phosphate fertilizers for southern Idaho soil conditions. Idaho Ext. Bull. 120. 1939. Lawton. Kirk. C. G. Apostolakis. R. L. Cook and W. L. Hill. Influ- ence of particle size. water solubility and placement of fertilizer on the nutrient value of phosphorus in mixed fertilizers. Soil Sci. 82:065-476. 1956. Long. 0. H. Rock phosphate or superphosphate? Tenn. Agr. Expt. Sta. Res. Report 1955. McKelvey. V. E.. J. B. Cathcart. Z. S. Altschuler. R. W. Swanson and Katherine L. Buck. Chap. XI. Domestic phosphate deposits. Pierre. W. H. and A. 0. Norman. Editors. Soil and Fertilizer Phos- phorus. Academic Press Inc.. New York. 1953. 1492 pp. McLean. E. 0.. D. A. Brown and C. A. Hawkins. Comparative evaluation studies on rock and superphosphate. Arkansas Agr. Exp. Sta. Bull. 528. Nov. 1952. . and J. E. Hoelscher. Factors affecting yields and up- take of phosphorus by different crops:I. Previous applications to the soil of rock phosphate and superphosphate. Soil Sci. 78(6) “53 -462 s 195“ s . Field evaluation studies of rock and superphosphate. Arkansas Agr. EXp. Sta. Mimeo. Series. No. 41. Feb. 1956. . Factors affecting yields and uptake of phosphorus by different craps: II. Rock phosphate and superphosphate. separate and in combination under extended cropping. Soil Sci. 82(3): 181- 192. 1956. Mehring. A. L.. 'J. Richard Adams and K. D. Jacob. Statistics on fer- tilizer and liming materials in the United States. U.S.D.A.. A.R.s. Stat. Bull. 191. 1957. Merrill. L. H. Ability of different plants to get phosphoric acid from crude phosphates. Maine Agr. Exp. Sta. 7th Ann. Report 1891. Michigan State University. Colloidal phosphate. Soil Sci. Dept. Mich. Ext. Mimeo. March. 1956. Michigan State University. Fertilizer recommendations for Michigan Crops. Soil Sci. Dept. Mich. kt. Bull. 159(revised).1957. Miller. Edwin C. Plant Physiology. 2nd Edition. McGraw Hill Book Co.. Inc. New York. 1938. Minnesota. University of. Phosphate facts. Minn. Ext. Ser.. Minn. Agr. Exp. Sta. Misc. Paper No. 741. 69. 70. 71. 72. 73- 7“. 75- 76. 7?. 78. 79. 80. 81. 82. 83. 107 Mooers. C. A. The comparative values of different phosphates. Tenn. Agr. he Sta. 81111. “ls 19290 Moschler. W. W. Experiments with rock phosphate fertilizers in Vir- ginia. Virginia Agr. Exp. Sta. Res. Report No. 9. July 1957. and George R. Jones. Applying rock phosphate prior to seeding increases availability. Written communication 1958. . R. D. Krebs and S. S. Obenshain. Availability of residual phosphorus from long time rock phosphate and superphos- phate applications to Groseclose silt loam. Proc. Soil Sci. Soc. Amer. 21(3):293-295. 1957. Mulvery. R. R. Sources of phosphate for field crOps grown on Crosby silt loam soil. Purdue Agr. Exp. Sta. Numeo. AY No. 81. June. 19h7. Murkdck. J. T. and Wk A. Seay. The availability to greenhouse crops of rock phosphate phosphorus and calcium in superphosphate-rock phos- phate mixtures. Proc. Soil Sci. Soc. Amer. 19(2):199-203. 1955. Natural Phosphorus Research.Wbrk Group. Summary of phosphorus research in the United States relating to soils and fertilizers. U.S.D.S. Bur. Plant Ind.. Soils and Agr. Engin. Beltsville. Maryland. 1950. National Plant Food Institute. Our land and its care. Washington. D.C. 1956. Neller. J.R. Effect of Sulfur and gypsum additions on availability of rock phosphate phosphorus in Leon fine sandy. Soil Sci. 82(2 : 129-134. 1956. and F. D. Bartlett. Effect of particle size on avail- ability and mobility of fused tricalcium phosphate and rock phos- phate compared with other phosphates in contrasting soil types. Proc. Soil Sci. Soc. Amer. 21(2):189-l92. 1957. Noll. C.T. and C. J. Irvin. Field tests of phosphate fertilizers. Penn. Agr. m. Sta. Bull. “'23. 1.9qu Odland. T. E. and T. R. Cox. Field experiments with phosphate fer- tilizers. RhOde ISland Agr. EXP. Sta. Bull. 281. 1.9qu Ohio State University. Handbook of Ohio experiments in agronomy. Ohio Agr. Exp. Sta. Book Series B-3. Nov. 195?. Olsen. Sterling R. Chap. IV. Inorganic phosphorus in alkaline and calcareous soils. Pierre. W. H. and A. G. Norman. Editors. Soil and Fertilizer Phosphorus. Academic Press Inc.. New York. 1953. 492 pp. Pierre, W. H. Phosphorus deficiency and soil fertility. Soils and Men. U.S.D.A. Yearbook of Agriculture 1938. ‘Washington. D. C. 1232 pp. 8h. 86. 87. 88. 89. 91. 92. 93. 9’4- 95- 96. 97. 98. 108 PirSson. ‘Iouis and Adolph Knopf. Rocks and Rock Minerals. 3rd edition. John Wiley and Sons. Inc. New York. 1956. 349 pp. Pittman. D. W. and D. W. Thorne. Fertilizers for Utah soils. Utah Agr. Exp. Sta. Circ. 116. 1941. Porter. J. A.. P. J. Rood and E. D. Longnecker. Lime and its use. Mich. Ext. Bull. 31h. 1955. Purdue University. Results of phosphate comparisons. Purdue Agr. Exp. Sta. Mimeo. AY 9 (rev.)April. 1951. Purdue University. Progress report on field plot comparisons of phosphate materials in Indiana. Purdue Agr. Earp. Sta. Mimeo. AY 8. EarCh 19520 Roberts. George. J. F. Freeman and E. J. Kinney. Soil management Experiments. Univ. Kentucky Bull. 397. 1939. Rogers. H. T., R. W. Pearson and L. E. Ensminger. Chap.VII. Compara- tive efficiency of various phosphate fertilizers. Pierre. W. H. and A. G. Norman. Editors. Soil and Fertilizer Phosphorus. Academic Press Inc. New York. 1953. l+92 pp. Roosevelt. F. D. Message to Congress. May 20. 1938. Rorty. James. Phosphorus: bottleneck of the Worlds hunger. Harper's Magazine. 1158(Nov.):1+72-1-|80. 19’46. Rest. C. 0. and Paul M. Burson. Comparative trials with rock phosphate and superphosphate in Minnesota. Minn. Agr. Ext. Div. Soil Series No. 18. January 191W. Russel. E. W. Soil Conditions and Plant Growth. 8th edition. Long- mans. Green and Co. London. New York. Toronto. 1950. Salter. Robt. M. and E.E. Barnes. The efficiency of soil and fer- tilizer phosphorus as affected by soil reaction. Ohio Agr. Exp. Sta. Bu11.553. 1935s Samoilov. I. I. Increasing the effectiveness of rock phosphate flour. Koklady Vsesoyuz. Akad. Sel'skokhoz. nauk im. V. I. Lenina 17 ('4): 3-10. 1952. Seen in abstract only. Chem. Abst. “72h539a. 1953. Sauchelli. Vincent. Manuel in Phosphates in Agriculture. (revised Edition). Davison Chem. Corp. Baltimore. Maryland. 1951. Smith. F. W.. F. E. Davison and V. H. Peterson. Soil fertility in- vestigations at Columbus experiment field. l92h-5U. Kansas Agr. Exp. Sta. Bull. 372. July. 1955. 99. 100. 101. 102. 103. 104. 105. 106. 107. 108. 109. 110. 111. 112. 113. 109 Smith. R. S. The differential response of two soil associations to rock phosphate. Jour. Amer. Soc. Agron. 42(10):415-497. 1950. Soil Survey Staff. Soil Survey Manuel. U.S.D.A. Handbook No. 18. Washington. D.C. August. 1951. 503 pp. Stanberry. C. 0. The behavior of phosphorus in an alkaline irriga- ted soil in Washington. Proc. Soil Sci. Soc. Amer. 13: 205-212.1948. Toevs. John L. and G. Orien Baker. Progress report of phosphate and other fertilizer investigations at the Aberdeen Branch Station. Idaho Agr. Exp. Sta. Bull. 230. 1939. Truog. E. Factors influencing the availability of rock ph05phate. ‘Wisc. Agr. Exp. Sta. Bull. 20. 1912. . The utilization of phosphates by agricultural crops. in- cluding a new theory regarding the feeding power of plants. 'Wisc. Agr. Exp. Sta. M1. “10 1929s . Value of so-called colloidal phosphate or soft phosphate containing colloidal clay. Univ. of Wise. Soils Dept. Mimeo.. May 10. 1947. Van Rise. C. R. Preservation of the phosphates and the conservation of the soil. Amer. Acad. Polit. Soc. Sci. Ann. 33(3):215-226. 1909. Volk. Garth W2 Availability of rock and other phosphate fertilizers as influenced by lime and form of nitrogen fertilizer. Jour. Amer. Soc. Agron. 36:46-56. 19““. . Response to residual phosphorus of cotton in con- tinuous culture. Jour. Amer. Soc. Agron. 37:330-340. 1945. Volkerding. 0.0. and T.E. Stoa. Is rock phosphate a good fertilizer for North Dakota? North Dakota Agr. Exp. Sta. Bimonthly Bull. 10 (1) 313-170 19u7s Weeks. M. E. and H. F. Miller. The residual effects of phosphates used on long time field experiments. Proc. Soil Sci. Soc. Amer. 13:102-107. 1948. 'Weihing. Ralph M.. A. G. Caldwell and J. F. Fudge. in pasture production on a Bernard clay loam. (in press). Phosphate sources Jour. Amer. Soc.Agron. Weldon . M. D s fertilizer. 1958. Rock phosphate and colloidal phosphate for use as Univ. of Nebraska. Agron. Dept.. Ext. Ser. form letter. Whiteside. E. P.. I. F. Schneider and R. 1“ Cook. MiChs Agr. Ens Stas SpBCs Bull. “02. 1956s Soils of Michigan. 114. 115. 116. 117. 110 ‘Wiancko. A. T. and S. D. Conner. Acid phosphate vs. raw rock phos- phate as fertilizer. Indiana Agr. Exp. Sta. Bull. 187. 1916. Williams. E. G. Phosphate fixation and availability. Jour. Sci. Food Agr. 8:244-248. 1950. Willis. W. P.1Jr. and F. M. Harrington. Phosphate investigations in antana. Montana Agr. Exp. Sta. MI. 369- 1939. Wisconsin. University of. Solubility of rock phosphate at different pH levels or in soils of varying reaction. Soil Sci. Dept. Ext. Mimeo. Jan. 24. 1951. 34065.3 ESE QSQLY M'CIIWWINHWIWIWW HWWVIWIW IIWIWIWES 3 1293 03062 0227