T7ITY ProQuest Number: 10008249 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest. ProQuest 10008249 Published by ProQuest LLC (2016). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code Microform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 4 8 1 06- 1346 BIOLOGICAL AS A ALAS Y d ACTIVITY 01 BOIL FERTILITY TV L0 ' i 111.-' :i Bale?" A Y r e r s A THESIS PRESENTED TO THE FAC JLTY OF HICHIGAH STATL COLLEGE OF A C R IC 7J L rF JR H ATT! A P P L I E D S C IE N C E IN PARTIAL FULFILLHOHT OF TITO PLCTTIPL: ?}\T|TC FOB THE DEGREE OF DOCTOR OF PHILOSOPHY East Lansing 13 5 6 CONTENTS PART I MANNITOL DECOMPOSITION I!T SOIL AS A MEASURE: OF CFO? RESPONSE TO FERTILIZERS ART SOIL PRODUCTIVITY Pagt ACNNOWLEDGMENT v INTRODUCTION i REVIEW OF LITERATURE _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 1 EXPERIMENTAL METHODS 7 RESULTS AND DISCUSSION Effect of Fertilizers and Lime on Carbon Dioxide Production - Effect of the Duration of the Experiment and the Amount of Fertilizer on the Production of Carbon Dioxide _ _ _ _ _ - - _ _ ~ _ ~ _ 0 10 Effect of the Hater Content of the Soil on the Production of Carbon Dioxide - 10 Effect of Different Phosphorus Carriers on the Production of Carbon Dioxide and Seed Cotton 11 Effect of Different Quantities of Superphosphate on the Production of Carbon Dioxide _ _ _ _ _ _ _ _ _ Effect of Temperature on the Production of Carbon Dioxide _ _ _ _ _ _ _ _ _ _ ig _ _ 12 Relation Between the Response of Cotton and Soil Microorganisms to Superphosphate and Their Relation to the 0.002 N Sulphuric Acid Soluble Phosphorus of the Untreated Soil Effect of Air-Truing Soils on the Microbiological Activity _ _ 13 _ _ _ Immediate Effect of AELr-Dryirg on the Production of Carbon Dioxide _ _ Effect of Prolonged Air-Drying on the Production of Carbon Dioxide Response of Soil Microorganisms to Calcium and Magnesium _ _ _ _ _ _ 13 _ 14 - 15 15 Tp1 feet of Certain Rare Elements on the Microbiological Activity of the Soil - is Effect of -Calcium Arsenate on the Production ofCarbonDioxide Effect of Iron SulobaU.eand Other Hi croo rg a n i sms Salts onArsenicToxic it:/ - 16 to _ _ Effect of Zinc, Manganese, and Copper on the Hr-od action of Carbon Dioxide 103834 iii 17 pq Relation of Crop Yields on Fertility "hot e to Carbon Dioxide Production by Soils From Ttese Plots - - - - Relation of Fertilizer cine Lime Treatment in the Field to Crop Yields and Carbon Dioxide Production _ _ _ _ _ - - _ _ _ - - _ IS - 1 8 Effect of Fertilizers ar.d Crop Rotation or the Yield of Crops and the Production of Carbon Dioxide 20 Effect of Green banures on Croo Yields and Carbon Dioxide Production - - Effect of Superphosphate on the Production of Small Grain and Carbon Dioxide - - - - - - - - - - - - - - 22 Pt Effect of Fertilizer Treatment on the Production of Sudan Grass’and Carbon Dioxide by the Ay, A p f and E Horizons of Four Soil Types SUP,DIARY BIBLIOGRAPHY - 24 - - - - - - - - - - - - - - - - - - - - - - 2 8 PART II THE EFFECT OF SOIL illCFOORGAHISMS OF SOIL PEi CTIOH IHTROFjCTION - REVIEW OF LITERATURE - SYPL.RIMELTAL Effect of Soil Hicroorganisras on the Reaction of Sand Cultures and Agar Hedia licrobiological Effects of Fertilizers on Soil Reaction I ni'.din Effect of Fertilizers on Soil Reaction _ _ _ _ _ _ Relation of Microbiological Activity to the Reaction of the Soil Where Normal Fertilizers 1Tere Applied - - - - - - - - - - - 1 - 1 - £ A ACKNOWLEDGMENT The writer wishes to express his sincere appreciation to Dr* L. M. Turk and Dr. C. E. Millar for their guidance in the research reported in this paper and in the preparation of the manuscript. Dr. 0. C. Bryan of the University of Florida, Dr. W. P. Paden of Clemson College, South Carolina, and Professor M. F. Miller of the University of Missouri supplied certain soils of known response to fertilizers. Professor Miller supplied the field data reported from Missouri. field data reported from Michigan were supplied by Professor G. M. Grantham and Professor A. G. Weidemann of Michigan State College. Professor Grantham collected part of the soil samples used in this investigation• v The PART I MANNITOL DECOMPOSITION IN SOIL AS A MEASURE OF CROP RESPONSE TO FERTILIZERS AND SOIL PRODUCTIVITY INTRODUCTION Microbiological methods used in soil investigations are based upon a relation in the requirement of crop plants and soil microorganisms for nutrients. For those elements which both crops and soil microorganisms require in large quantities, biological methods may indicate the quantities present or the response of the plants to the added elements. Crop response to fertilizers and different levels of soil fertility are measured by crop yields; soil microorganic response to fertilizers and variation in soil fertility may be determined by: 1. Numbers of soil microorganisms. 2. Rate of ammonification. 3. Rate of nitrification. 4. Rapidity of organic matter disappearance 5. Carbon dioxide production. Of these methods, the determination of carbon dioxide production Is one of the easiest. Carbon dioxide is an end-product of respiration, and as such is indicative of the activity of the organisms concerned. The object of this investigation was to determine the relation between the response of crop plants, as measured by crop yields, and the response of soil microorganisms In mannitol treated soil, as measured by carbon dioxide production, to applied nitrogen, phosphorus, potassium, calcium, magnesium, copper, zinc, manganese, and arsenic, and to soil productivity. REVIEW OF LITERATURE The production of carbon dioxide by soil microorganisms has been found to be closely related to the number of bacteria by Russell and Appleyard (39)f - z - Petersen (52), van Suchtelen (46), and Stoklasa (44). The effect of various salts on the production of carbon dioxide or the decomposition of organic matter by the soil microorganisms has been investigated by Corbet (9), Fred and Hart (13), Lenmierman and coworkers (25), Lundegardh (26), Merkle (27), Potter and Synider (34), and Remy (37). Christensen and Jensen (8) made a review of literature dealing with the use of carbon dioxide production in soil fertility investigations. Of the materials added to soils to supply microorganism energy, cellulose has probably been used more than any other. The supply of available nitrogen in the soil affects the rate of decomposition of cellulose very markedly. Carbon dioxide production is the measure generally used to indicate its decomposition. The method as it has been used requires up to twenty-four days or more and several carbon dioxide determinations are necessary.— References: Waksman and Heukelekian (49), Starkey (41), Anderson (3), Carter (6 ), Holben (18), Shunk (40), and Nicklewski (31). Holben found that 15plots receiving incomplete fertilizer treatments rank too high in carbon dioxide production to show any relation to crop yields. Several other high crop producing plots rank too far down the list in carbon dioxide evolution to credit this method as a reliable indication of soil productivity......... When soil acidity Is eliminated as a limiting factor ........ the carbon dioxide production and cellulose decomposing powers show very close agreement to crop yields”. The production of carbon dioxide in the soil from cellulose,dextrose, rye straw, alfalfa meal, dried blood, and mixed spores and mycelium of fungi was studied by Starkey (41). He found that the production of carbon dioxide from organic materials is affected by soil productivity, and that the differences In the production of carbon dioxide from the carbon contained in the soil are greater than the differences in the carbon dioxide produced by the same soils from added organic matter. - 3 - Neller (30) found a correlation between crop yield and the carbon dioxide produced from 200 gm. soil plus 0.75 gm. soybean hay. Merkle (27) added soybean hay to soil and found that nitrate of soda and basic slag increased carbon dioxide production. Ammonium phosphate, superphosphate, sulphate of potash, and raw bone had little effect, whereas muriate of potash and kainit reduced the production of carbon dioxide. Dextrose and glucose have been used In soil investigations to supply the microorganisms with energy. Konig and Hasenbaumer (22), Konig, Hasenbaumer, and Glenk (23) used carbon dioxide production from glucose in soil investigations. Waksman and Starkey (51) and Starkey (41) found that carbon dioxide production from dextrose may be used in soil fertility Investigations; the former authors (Waksman and Starkey) found that it may serve as a means of grading soils on a basis of their fertility. The quantity of nitrogen fixed by soil microorganisms has been found to be indicative of the amount of available phosphorus in a soil. Waksman and Karunaker (50), Turk (48), Stoklasa (43), Given, Kuhlman, and Kern (15) determined the nitrogen fixed in standard mannitol solutions inoculated with soil and incubated for as long as twelve weeks. Waksman and Karunaker (50) concluded that information concerning the nitrogen fixing bacteria and the available phosphorus of a soil may be obtained by the mannitol disappearance method of Christensen (7), in which 2% mannitol is added to a soil and the residual mannitol determined every five days for thirty days. Water equal to 75$ of the maximum watei^holding capacity of the soil was used. Andrews (4) found that the production of carbon dioxide in soils to which mannitol had been added furnished a basis for determining the nitrogen and the phosphorus requirement of soils for cotton. production was twenty-four hours. water-holding capacity of the soil. The time used for carbon dioxide The water used was one-third of the maximum - 4 When the work reported in this paper was started, it was arbitrarilydecided to determine the effect of fertilizer treatment on the production of carbon dioxide in mannitol treated soil and to correlate the data thus obtained with the effect of a similar treatment on the crop yield. During the course of the investigations, the following questions arose: 1. What is the effect of the soil water content on the production of carbon dioxide? Gainey (14) found 12$ water for one soil to be the water content for maximum carbon dioxide production, and that higher quantities had little effect, whereas smaller quantities reduced it. Konig, Hasenbaumer, and Glenk (23) used 50$ of the maximum water holding capacity for carbon dioxide production experiments with dextrose. Christensen (7) and Waksman and Karunaker (50) used 75$ of the maximum water-holding capacity in mannitol disappearance experiments. The optimum water content for carbon dioxide production from cellulose decomposition was found by Shunk (40) to be 50$ saturation. Van Suchtelen (46) found 75$ of the maximum water-holding capacity to be more favorable than 50$ and 90$ for the production of carbon dioxide and numbers of bacteria (dextrose was used, and the temperature was 10 to 12° C.). 2. Should soils be air-dried before the biological tests are made? Darbishire and Russell (11) investigated the effect of partial sterilization of a soil by heating to 100° C. or by use of volatile antiseptics which were subsequently removed and found that partial sterilization increased the available N, P, and K, and also the absorption of oxygen by the soil micro­ organisms on rewetting the soil. Air-drying a soil and rewetting it has been found to increase the numbers of bacteria and/or carbon dioxide production.— References: 17, 20, 21, 55, 56, 58, and 42. Achromeiko (l), Gustafson (16), a nd Lebedjantzev (r- found that air-drying soil increased the soluble quantities si one or mora of the following: Organic matter, nitrogen, phosphorus, and other minerals. Klein (21) found no increase in soluble K, C a , and P due to a ir-dryir.g• Waksman and Starkey (55) said that protozoa and fungi are not destroyed by air-drying soils. They (55) re port the following data from Lennan (vithout reference); Influence of Desiccation of Soils on Development of Colonies of Fungi on Agar Av.No. of Colo nies Per Plate Before Desiccation Preparation Only spores pre sent in the soil 51.0 50.0 Only mycelium present in t}le soil 20.0 CO • o Fiel 5 Coil No. 1 19. C r %*( n 1J 11.6 1.0 8.3 1.1 I! Tl 11 11 11 11 ri 11 11 4 r,r o 3.0 t? 11 11 5 199.0 15.7 M 11 11 rs o 326.5 5. 6 Tkksman incr-e?’ in After Desiccation and bacterial 2 Starkey (54 ) s a i d a maters. 'Fiey that a (56) f o u n d high fungus flora, may 1* ?J 5f !'.• 1 p a r t i ' 1 s t e r i l i z e ' ' - i r i or cally e l i m : r a t e d f- u i g i . Andrews (4) found that air-drying ro 11 ircrersec ibe produc \ion 'f dioxide ly one soil and tad li d’la effoci or anot1"-v ■’ en J 1 treated r-lth mannitol. 5. of Does carbon d i o x i d e ? the lerqyf of 1 a ,a a s r f . l a . a ir ; ir-dry - er-- yer-'-ya - 6 Waksman and Starkey (55) found that increasing the length of time a soil remains in a dry state increased its production of carbon dioxide when it was rewetted. Andrews (4) found that storing one soil air-dry decreased the increase In production of carbon dioxide due to N and NP, whereas with another soil a small increase was obtained. 4. What is the effect of protozoa on the production of carbon dioxide by the soil microorganisms? Cutler (10) said that when protozoa are inoculated as cysts they will, judging from analogy in fluid cultures, probably remain as such for relatively long periods (24 - 28 hours) before excistation occurs. Cutler (10) and Telegdy- Kovats (47) found that protozoa reduce the number of bacteria. 5. Do bacteria, fungi, and Actinomyces produce equal quantities of carbon dioxide when they have consumed equal quantities of energy material? Waksman and Starkey (52) said that fungi assimilate 20 to 50%; bacteria, 1 to 50%; and Actinomyces, 15 to 30$ of the organic compounds decomposed. Buchanan and Fulmer reviewed the literature on the toxic and stimulative effects of arsenic (5-a), copper (5—b), zinc (5—c), and manganese (5-d) on micro­ organisms. The literature reviewed shows that: A. Soil productivity is related to: 1. Numbers of soil microorganisms 2. Carbon dioxide production by soils receiving a. No additional energy material b. Energy materials (1) Cellulose (2) Glucose - 7 (5) Dextrose (4) Other organic materials B. 3• Mannitol disappearance 4. Nitrogen fixation Crop response to applied nitrogen and phosphorus is related to the response of soil microorganisms to nitrogen and phosphorus when mannitol has been added to the soil. C. Carbon dioxide production by a soil is affected by: 1. Air-drying or partial sterilization 2. The length of time a soil remains air-dry 3. The water content of the soil EXPERIMENTAL METHODS Preliminary studies made during the development of the method (4) used in this investigation brought out some observations which are worthy of comment. In taking soil samples, the immediate surface of the soil was removed and the sample taken to a depth of approximately 2j inches at several places in an experimental plot or field. After air-drying, the samples were screened and thoroughly mixed, preparatory to their use in carbon dioxide production determinations after addition of mannitol and other materials, as designated. The letters in the tables presented indicate that the following quantities of fertilizers were added to 100 gm. of soil: L = 50 mgm. finely ground limestone P = 25 mgm. 20$ superphosphate K « 10 mgm. 50$ muriate of potash - 8 N = 30 mgm. nitrate of soda S = 55 mgm. 9$ basic slag R = 15 mgm. Rhum's rock phosphate The quantity of water to add was determined by Hthe feel11 of the moistened soil for the first experiments^ however, a uniform quantity was used throughout an experiment. Later the water used was based upon the maximum water-holding capacity of the soil, which was taken as that quantity of water which is retained by 100 gm. of air-dry soil in a funnel after water had been added in excess and the excess allowed to drain off. The moist soils were then put into 1000 cc. Erlenmeyer flasks and incubated for twenty-four hours, or the time specified, at laboratory temperature, or at the specified temperature. After incubation, the flasks were connected in gas trains for the collection of the carbon dioxide. The carbon dioxide was removed from the soil flasks by drawing 3600 cc. of air through the trains, and it was absorbed by ascarite. The quantity of carbon dioxide was determined by weighing the ascarite tubes before and after its absorption. RESULTS AND DISCUSSION Effect of Fertilizers and Lime on Carbon Dioxide Production The soils selected for the first experiments were Norfolk and Ochlocknee fine sandy loams. The Ochlocknee soil came from the unfertilized plots of a field on which a fertilizer analysis test had been conducted for a number of years. This soil was very deficient in potash and nitrogen was also a limiting factor in crop production. soil. Lime has never been found beneficial to crops on this Ochlocknee The Norfolk soil was taken from an area adjoining the plots of a phosphorus sources test on limed and unlimed soil. This soil was deficient in nitrogen, phosphorus, potash, and lime for the production of cotton. - 9 - Lime, muriate of potash, and superphosphate when used without nitrogen had little affect on the production of carbon dioxide (Table 1) by the soil microorganisms, whereas nitrogen trebled its production. These results indicate that lime, phosphorus,and potash were present In sufficient quantity to satisfy the needs of the soil microorganisms with the nitrogen level found in the untreated soil. Ammonium sulphate was equally as efficient as nitrate of soda for carbon dioxide production on the Norfolk soil which was deficient in lime for carbon dioxide production and crop growth. The Ochlocknee soil was not deficient in lime for biological activity and probably not for crop growth, and nitrate of soda produced 101 mgm. of carbon dioxide, whereas ammonium sulphate produced 89 mgm. On the basis of the neutralizing effect of the sodium, nitrate of soda might have been considered more efficient for carbon dioxide production on the lime deficient soil. When lime, muriate of potash, and superphosphate were applied, singly and in combinations, to the Ochlocknee soil, in addition to nitrogen, the NPL treatment was the only one that produced more carbon dioxide than nitrogen alone and the Increase was only 8 mgm. Supplying lime or superphosphate in addition to nitrogen to the Norfolk soil increased the production of carbon dioxide 38 mgm. This behavior raises the question "Was the microbiological response to superphosphate at least partially due to its calcium content?” There are no data on the effect of muriate of potash on the yield of crops on the Norfolk soil, but it was apparently deficient in potash for cotton production; muriate of potash increased the yield of seed cotton 475 pounds per acre (28) on the Ochlocknee soil. Generally muriate of potash had little effect on the production of carbon dioxide, even though these soils were deficient in potash for crop production. In order to check these results, soil was obtained fee * w m ft • W ft CD * O CO ft o o Cv2 O O • s •S f= H|P ft Cu ft -p rH • to • CD CD O O H CO • 00 0 1—1 . CO CD CO * rH O rH ft • to m C- co rH CD P CD ft rH •H O Eh CO b>£} ft l_3 P* ft p ft ft ft! ft ft P! ft! ft ft J SI bO O O ft ft P4 Eh rH P CD . a 0 . CD 00 CD • O CD bp * CD CD CO • CD CD CD • O O rH OO i—I 00 O LO to CO O O • %co o • ft •*« J? EH Is; PI S Eh -=t! ft • rH H O• to c- CO ♦ CO rH rH 00 rH to H CD CD O O ft ft s ft EH • 10 IP 0- 0 CO ft 00 ft • CO i —I ft o o PI quantities j as £ i —I *H O to of fertilizer 02 o CO • rH O rH were used o o Cvi O O CD + ft t: ft ft ft -P ft ft P O ft -p •H g ft Sh • O S P O 0 0 • CO ft O O ft ft • . g bp S 0 • 10 CO 'CJ•* O O- co • CO to rH • CO CO CD • 1-- 1 O ft O aj ft ft ft to rH cd o fan * S o •H • *rJ o rH OO rSjl CO w * -3 n O P f t rn ft M g ft ft O O . a CO * CD LQ CO • CD co CD * CO • cto • LQ C- to 1— 1 to P # O . O O ft ft Eh 0 EH CD ft H i f EH ft ft P TO 3* Table 7. Relation between the Increase in carbon dioxide production and crop yield due to phosphorus and soluble phosphorus, as determined by Truog's method, and the use of the maximum water-holding capacity and silt + clay content of the soil in the interpretation of the data. INCREASE DUE TO P SOIL TYPE P.P.M. P SILT + CLAY 8.3 70 SEED COTTON Lbs. Per Acre 385 Ruston F.S.L.(?) 10.0 52 174 56.8 Orangeburg F.S.L. 35.8 7 33 27.8 Norfolk F.S.L. 17.6 49 194 23.8 Oktibbeha Clay 7.3 44 297 72.6 Sarpy F.S.L. 105.5 15 -1 61.8 Trinity Clay 94.0 7 77 65.6 8.4 16 50 66.8 Ruston F.S.L. 13.1 7 145 34.3 Yohola V.F.S.L. 85.8 14 125 63.8 Ruston F.S.L. 9.5 32 138 19.8 Rpston F.S.L. 9.4 30 238 29.3 Memphis Silt L. 4.P. 18 409 64.8 Houston Clay Denham Silt L. CARBON DIOXIDE 75. e Table 8. Correlation of some of the data in Table 7. FACTORS BEING CORRELATED Increase in crop yield due to phosphorus and increase in carbon dioxide due to phosphorus CORRELATION COEFFICIENT +.602 * .1768* Increase in carbon dioxide due to phosphorus and available phosphorus in soil -.492 ± .2102 Increase in crop yield due to phosphorus and available phosphorus in soil -.591 ± .1805 Increase in crop yield due to phosphorus and available phosphorus divided by silt -t clay content -.695 =* .1454 Increase In crop yield due to phosphorus and available phosphorus divided by maximum waterholding capacity -.652 ± .1666 -^-Standard error - 14 - rewetting have been reported many times. Many investigators report changes in the solubility of the soil nutrients— most of them being increases. In a later paper it will be shown that soil bacteria take up an excess of acidic substances over basic substances and that fungi take up an excess of basic substances over acidic substances. A general effect of bacterial growth in the soil is to increase the pH, whereas fungal growth decreases it. On this basis, when bacteria are decomposed the minerals incorporated in their bodies are returned to the soil and the pH is decreased. On the contrary, when fungi are decomposed the mineral constituents of their bodies increase the pH of the soil. The disappearance of the fungi on air-drying a soil is, therefore, in harmony with an increase in the pH and solubility of certain basic constituents, as was brought out in the literature reviewed. On air-drying and rewetting a soil, there exists a period of time when the competition from the fungi is reduced, due to their smaller numbers or decreased activity. It seems logical that the bacteria may be able to consume at least a part of the energy and other constituents of the fungi as desiccation proceeds. If this is true, the reported increases in numbers of bacteria due to air-drying and rewetting may be coincident with desiccation. The decomposition of 250 pounds of fungal mycelium containing 6% nitrogen will return fifteen pounds of nitrogen to the soil, which is equal to one-sixth of the nitrogen application used in these experiments. From this standpoint, the death and decomposition of fungi on air-drying and rewetting certain soils may increase the amount of soluble nitrogen considerably. Immediate Effect of Air-Drying on the Production of Carbon Dioxide: The carbon dioxide production data are for twenty-four hours, which is too Short a period after rewetting for fungi to be revived and be very active in the production of carbon dioxide. The carbon dioxide produced during the first twenty-four hours after air-drying a soil is, therefore, considered to - 15 be due to the activity of the bacteria. The data in Table 9 show that the production of carbon dioxide by two of the check soils was almost doubled on air-drying; and that of three of the N treated soils was very much higher; whereas fourteen of the soils showed little change in carbon dioxide production; and one showed a big decrease. The increase in carbon dioxide due to the addition of phosphorus to the Olivier soil was nearly three times as great after air-drying as before. Effect of Prolonged Air-Drying on the Production of Carbon Dioxide: The effect of air-drying soil for eight months on the biological activity is shown by the data in Table 10. The effect of fertilizers on the production of carbon dioxide in these soils was determined in November, 1955, after which the remainder of the soils were put in pots and rewetted. The rewetted soils were permitted to become air-dry during December, and they remained air-dry until the following September, when they were given similar fertilizer treatments and carbon dioxide production was determined again. 30° C. in both cases. The incubation temperature was In every case, the production of carbon dioxide by unfertilized soil was increased by prolonged air-drying. In one out of six cases, the N treated soil produced considerably more carbon dioxide after the prolonged air-drying, which Indicates a favorable change in the available phosphorus and/or calcium. In two cases, the soil receiving N produced con­ siderably less carbon dioxide after prolonged air-drying, which may have been due to a decrease in numbers of bacteria. In five cases, the increase in the production of carbon dioxide due to P was very much greater after prolonged air-drying. B.esponse of Soil Microorganisms to Calcium and Magnesium The laboratory method used below was identical with that reported above, except 500 c.c. Erlenmeyer flasks were used, the air was drawn through the train by means of a suction pump which was run for five minutes, P = PgOg equivalent to pH a cd O a cd o P Pj) TO d P3 • p a LO Hi to CO 02 P a a IS- CO o 02 02 Hi o d O o bo § & bO a • a • 02 02 -H HI Hi P o p CO cd ■ d 6 a> bO 02 tO CO • i—ICM cd P rl H1® • to IS- 02 CO IS- O ■r-t d •H rH CO OO O P CO ... 05 O O H rH CD CO •H d o -p d ... rH CO to Hi P 0 P PH CO CO CO i —| rH H P 02 60 CO a a a i— I i— I CO to to VO 02 d O CM o p 02 O a a tsa LO l— 1 CO Hi o p p 1— 1 EH CO P Q o P -p p a CO IS- CO a a a O 02 co IS- LO Hi 0 02 CO CO *s •H CD 05 Hi Hi o P a a p H O a d 0 •H > •H 02 o p CO Hi IS- o 1— 1 p to P « a O a 02 02 LO VO Hi t- P P cd 02 TO 05 a a a o rH •rf CO . •H CO d a cd to cd 40 Hi 00 a a 1 cd 02 CO 1 43 cd CO tso o cd o 05 a P -p o LO a P •H CO TO cd d d o p a CM ISa • LO TO >H P3 P d—i i O !>i cd p O <4 d o -p p 05 CO d o O {1} CD CD CO 00 ts- co O tsI— II— I __________ 05 LO LO a a a O O to CO IS- CO 02 |>* Cd CO to to 05 HI 02 Hi >-0 02 H d __________ o -p CQ d O td H* C\2 00 a a J>b TO to O a cd o 02 P 02 CO CO a a 0) d p O CO CO CO 00 05 P P C\2 05 tSa d o -p P a a 00 05 to 02 LO P P P tO a 02 00 o s P i— I o -p Ih Eh 2W P o d d TO d cd to O a CO CO a a LO 00 isCO CD HI i —I d C— CO 05 a a 02 05 HI CO IS- CO P to S •H P d o p CO d P3 S Eh « aj t— 02 02 p t^a p O S TO 02 O H to cd . a d a Eh CO CO a a OO 00 p Cd LO CO 05 P o 0 05 O U CD IS- D - d o -i—* O a a a cos CO O P 02 P type not known H P3 P I 03 S *Soil Table f>a cd p a CO 00 •H 9. Effect of air-drying the soil on the production of carbon dioxide - Mgm. carbon dioxide. Pi P W M i —I to o a 0 EH 5 cd o P IS- 02 00 cd CO CO P 02 1Sfe to Pi .p S3 • o 0 a r0 •H -p X o tXD *H *H 0 S3 fH O O rQ «H Ph cd a o o •H • P a •H 5x0 TO 53 S3 O 1 O * Ih O u TO O I o P-t to •H cd P cd S3 cd S3 o a •H *H P a CQ rH 'o •H o O Ph m Qv ha q •H S3 •H cd -P S3 •H cd g © rd •H X! o •H H3 S3 O P Ph © O o -P 0 o *£3 0 -p cm S3 O • O rH 0 pH P cd Eh o i-3 Eh t-3 IH CO <3 IH 13 O Eh 13 H i-3 0 ta£) cd Ph O -P CQ Ph 0 -P H U 0 txQ cd Ph o p to 0 Ph o Cm © 03 © cd Ph o p CQ Ph 0 P W S3 © t© © Ph O P CQ 0 Sh O Ch 0 03 to o t-3 H « CQ oo * s CO • pH LO C• CO to rH CO • oo rH • to rH rH • rH C\2 rH 0 p Cm *=3 53 ■=3 O r-3 fH O |S CO 3 IH fH fH P3 t-* *=3 t-3 O 23 O fH IH to • i— 1 to rH 0 © 5x0 cd Ph o -p CQ O P3 Eh t-3 M CQ P3 &3 M > M 1-3 O fcQ • rH * tsit rH • 00 c- 02 • 00 CO CD • st* 05 rH OO • O 03 00 • O <02 23 is; M (H is; o Eh CQ fID P3 CV2 S • LO H< ax • to 0 5x0 cd Ph O P rH • CQ 02 0 ' 02 Ph O 0091 0021 OC JO OOZi JO OD 02 009 - 19 fertility o f t h o coll. carl ':aroor: o l o n a e The jtol wczci -iUw J-1. the firot twenty-four hours wee olotted In Figure 1, and avere.ee 0rein srS strav. yields at least two sea so as sfbere ploein^ under & legume ?:r o rlso plotted in Figure 1. These yields were selected because fie unlinec, riots did not prodj.es legumes, and the turning under of the legume crops probably exaggere: ted differences between limed and unlimed plots. In general, the production of carbon do orice follows the prod act! or. of grain and straw closely, but the yields of the LFHC, LHC, and LF plots are slightly higher than the carbon dioride production indicate-, and the yields of the LX and BPCuSO^ plot^ are lav.or than tho carbon dioxide pro­ duction indicates. f .HowIn These results may be sittribated to ore or the other of the reasons: 1. The crop plants used up the added nitrogen, leading the plots which received, nitrogen no ricHw^ in nitrogen than the plots which received ro nitrogen; arc at the same time, the nitrogen may have induced r ^.renter removal of the other elements by the plants. 2. Winogradsky (-57) and Miss Ziemieka (5 8 ) found, that thee addition of nitrogen materially reduced the Asotobacter population of the soil. These plots ^ere laic out in 1917, at which time Lime oroc deed very lvrgc \rcreases ir. the crop yields, end badly ir need of lioe when. the sawples Eased upon the a l u m r,v . r - tv s 1 *me was epplH d . the plot" -'.-ere all tehee (13X1). cor ciders 1 1 or o, the crop yields obtained fu.rl~g the jc sJ' ro vert^on poors, " 1h c v :n:^ eejv'^'h ’"ith 4h:o cjwhw- d lor Ida produced, do not give o true indi cad. ion of the pro sc in! fertile';' level of xheee plots, end it 7o o uld r-oi be good: logic r e . id i; and that, d^ . id t !?*• t the treetner t *•' ■Lhi: ear-:, - ■ ; :: ]1 j ^ te to r h-vo J: to correlate c’.-'.var th e . bm 4- ’ ' .: directly. ologiccl. sc t i r biological activity expressed sr -m;.,-:, v : . d e ^'0 w e r r v ’h ; v— A ll t !•y :g u o '* t-'s.t eon the soil _.f c:s'Vs .'•'+ w l f h . - fsrtillt*- aao. & B Q C-CD tO LO cq P P 00 H1 sit 05 rH Cxi Ph e O 3 oo 3 •H CXi a O CD CO CD LO CD O sjt 05 to w 3 o oo o CD E- tO si< LO LO to a) tH rQ sit fH o rH 3 TO fH O O Cxi IQ (H 0 T3 0 rH 0 a 0 x LO rH Ht • ■ X rH *H 05 CD 0 05 ^ I—I LO E-t CQ -p O rH O to Cxi CXi to CD to to oo rH to 05 02. CQ E-t -aj O 0 X P O LO LO LO Cxi LO o Cxi C xi cxi t- S sJt ( to 0 -P 3 tuD •H to to LO to 05 CXi CO CD *vjt sit 05 CXi sit £ to CO o CQ 0 a .3 0 -P P <+H 05 co 05 rH LO 05 sft • H* sit 05 oo I —f CD LO lO to to OO CO O CD rH Cxi C xi C-- i —1 rH to sjt LO CXi rH sit to LO O Cxi 05 o « C D 05 LO LO 00 to o s*t CXi LO LO sf to to CXi Cxi LO 05 OO to 00 oo LO CD 3 o •rH P O 3 HD O 3 £° © S TO 3 sit CXi 05 LO Cxi LO C O rH Sft LO Cxi to si* ^ft • LO i —! to rH T O 3 O 0 Oh* o • a O- <—I 0 rH P 3 E-t o 3 bQ CO <+H •h rH 3 3 3 0 3 3 3 Cxi co O •H 3 -.Cm r^j I— IP 0 CO 3 O •H 0 •H fH rH P 3 3 X OP r© CO LO CXi Department CQ •H P O p a E-t ?? E-t ■=3 pci EH O O Cxi p o m n © P 0 § 3 P o P sit P 3 0 3 3 3 E-t O (-3 Ph •xr 3 +3 Cxi 0 P 3 3 0 P P 3 3 P O 3 O P to Ph 05 O O rH X P 3 0 a p tH Cxi to H 05 O P 3 0 0 3 P 3 Ph CXi Cxi to Cxi g o 3 •H to pH 05 1 C O o 05 >H 0 P 0 3 3 -R 3 rH 3 3 s*t CXi 05 Cxi 0 O P 0 3 3 3 3 O to to rH 05 i —I O P 0 3 3 3 0 3 P 3 3 3 0 0 0 05 o p 0 O rH S 05 I —t 1 0 rH !•§: rH i— ! 3 3 TO 3 3 3 3 3 O oo rH o O LO *H !>> to to to 3 P 0 P-, Pi 3 3 0 £3 3 0 t 3 0 0 0 3 05 3 O 0 Ph S a p CL, +5 t>> r5^ i—I Ph •H rH 0 rH O r3 0 •r\>Cj 3 rH 3 P o 3 •H 0 3 •H P 0 3 0 3 •rH © WP 3 Cm to O P 3 3 0 o {>> O rH rH P P i— I 3 3 0 3 X cr* t£ 0 bO 3 •H to O O 0 TO bo I •*x to (H to i —1i —1 rH 3 O 3 P 3 O P P 3 05 0 3 ■=i"^5 05 TO 0 sjt 0 r3 u * £3 3 O 3 rH 3 I Ja to £5 3 LO to CD 3 to Soils to fH •n 0 •H 0 O h fH 0 3 O 3 rO CQ © P ay the '— 3 P 3 3 3 0 3 3 O P 0 p 3 O 0 o a •H 3 X 00 to of the University 05 i—! LO Cxi supplied 04 O •H fH T3 0 0 0 3 csJ O o P rH 3 3 -P fH O rH o •H Table SO. Production of carbon dioxide in the laboratory by the A-^, Ag, and B horizons of several soil types, which had grown two crops of sudan grass in the greenhouse* and the greenhouse yields.* GREENHOUSE TREATMENT CROP H E L D 1 st 2nd Gm. CARBON DIOXIDE Gm. CROP YIELD 1st | 2nd Mgm. Gm. Gm. AX HORIZON CARBON DIOXIDE Mgm. CROP YIELD 1st [ 2nd Gm. Gm. CARBON DIOXIDE Mgm. B HORIZON Ag HORIZON BELLEFONTAINE SANDY LOAM Ck NK NP KP NPK 5.00 2.55 6.65 7.54 9.05 2.16 2.51 5.02 5.15 5.46 25.7 26.5 (47.1** 55.2 40.5 59.4 0.69 1.19 2.71 2.72 3.75 0.75 1.45 1.02 0.79 1.02 0.85 0.88 3.23 2.50 3.74 1.64 1.20 0.80 0.85 1.66 9.5 6.7 8.4 6.3 7.8 ,27.7** l19.0 16.5 16.9 2.59 1.60 11.4 2.55 3.66 ,12.7** ^21.2 15.7 2.70 5.65 2.06 10.8 2.48 (19.8** 11. 9 1.64 13.9 2.31 (10.4** H 6.1 8.1 8.0 8.5 6.9 7.7 0.24 0.19 4.20 0.75 3.94 0.54 0.26 1.72 5.63 2.52 15.1 9.2 10.6 8.8 8.4 5.2 (1 .1** '•6.9 8.0 2.7 10.5 8.0 9.9 8.4 9.5 CONOVER LOAM Ck 5.29 6.15 46.0 2.35 2.11 NK NP 6.19 5.51 10.00 7.57 41.9 70.0 2.76 3.16 4.53 3.16 KP 10.40 7.82 51.4 4.24 2.57 NPK 10.74 10.01 51.5 4.71 3.58 HILLSDALE SANDY LOAM Ck NK NP KP NPK 9.48 12.68 12.96 14.28 14.61 6.87 8.49 6.64 6.86 7.10 56.7 55.4 54.7 29.5 54.1 0.16 0.25 0.25 1.44 2.61 0.79 0.28 1.12 0.66 1.30 M IAMI L 0AM Ck NK NP KP 2.58 1-85 5.12 2.58 14.29 9.79 4.55 5.82 NPK 15.16 5.05 16.5 12.7 29.3 (27.5** H8 . 7 ,27.2** <21.1 1.84 0.22 4.74 4.40 1.25 0.57 8.3 5.2 3.62 0.78 1.55 1.06 2.51 1.64 14.5 10.4 5.96 4.78 1.80 1.10 6.85 1.70 10.2 7.15 2.23 6.8 *The yields of Sudan grass were taken from Ellis* thesis (12). **The carbon dioxide produced by soil from duplicate plots did not check closely. - 24 - horizons of four soil types on which the nutrient deficiencies had been determined in the greenhouse by Ellis (12) are reported in Table 20. He grew two crops of Sudan grass on the A^, Ag, and B horizons of Conover loam, Hillsdale sandy loam, Beliefontaine sandy loam, and Miami loam in the greenhouse. By means of labo­ ratory tests, he maintained the phosphorus, potassium, and nitrogen at the same levels. Six months after Ellis had harvested the second crop of Sudan grass, these soils were sampled for carbon dioxide production studies. The state of fertility of the soils as they were used in the laboratory was more nearly like their fertility during the growth of the second crop than that existing when the first crop was grown. Both the greenhouse and the field data are reported in Table 20. "Data for the first crop show that the addition of a complete fertilizer to the Ag and B horizons of all soil types studied, except the Hillsdale, resulted in a yield in excess of that obtained from the unfertilized A^ h o r i z o n .......... The data for the second crop show that the untreated horizon gave a greater yield in all cases than that of any treatment of the Ag and B horizons". The carbon dioxide produced during the twenty-four hour period is considered an index of the numbers of microorganisms involved and the micro­ biological activity of the soil at this time. The production of carbon dioxide by the A! horizon of all four soil types was usually several times as large as the production of carbon dioxide by the Ag and B horizons. In certain cases, the NK treatment reduced the production of carbon dioxid_e. In a few cases, the NP treatment increased the production of carbon dioxide. SUMMARY The effect of fertilizer treatment on the production of carbon dioxide by mannitol treated soils was studied, and the data were correlated with crop yields. A. The data show that: Nitrogen alone, and lime, superphosphate, and basic slag in combinations - 25 with nitrogen increased the production of carbon dioxide by mannitol treated soils. Potash did not increase the production of carbon dioxide by the micro­ organisms of soils which were deficient in potash for cotton production. B. A twenty-four hour period of incubation brought out the greatest differences in carbon dioxide production due to soil treatment. The effects of the treat­ ment on carbon dioxide production were more evident with the larger than with the smaller amounts of fertilizers. C. The increases in carbon dioxide production due to the addition of superphosphate were greatest with a water content of 21% of the maximum water—holding capacity, whereas more carbon dioxide was produced when water equal to 50% of the maximum water—holding capacity was used. D. The phosphorus carriers which produced the largest increases in seed cotton on both limed and unlimed soil produced the largest increases in carbon dioxide produced by the soil microorganisms. E. The soil microorganisms used PgOg efficiently when supplied in quantities equal to one-half the quantity of nitrogen supplied. F. Increasing the temperature from about 27° to 50° and 55° C. increased the production of carbon dioxide, but the increases due to the fertilizer treat­ ments were practically identical at all temperatures. G. There was a fair correlation between the increase in crop yield and carbon dioxide production due to phosphorus treatment, and a fair negative correlation between the phosphorus and the 0.002 N H gS04 soluble phosphorus (Truog Ts method)• Clay soils require a higher soluble phosphorus content than do sandy soils to supply the needs of cotton for phosphorus. Air-drying increased the production of carbon dioxide on rewetting, by some soils, but it usually did not have a great effect except with prolonged airdrying. One soil showed a decrease in carbon dioxide production due to prolonged air-drying. On soils which were deficient in calcium for crop growth and microbiological activity, the substitution of magnesium for part of the added calcium increased the production of carbon dioxide in two cases out of three. The effect of certain elements seldom applied to soils on the production of carbon dioxide by the soil microorganisms: 1. Calcium arsenate had no effect on carbon dioxide production when used in large or small amounts, but intermediate quantities reduced it. 2. Contrary to the results obtained with crops, superphosphate did not intensify arsenic toxicity to soil microorganisms, nor did iron sulphate and other salts alleviate the harmful effects of arsenic, as measured by carbon dioxide production. 3. Zinc, manganese, and copper did not increase the production of carbon dioxide by soils known to be deficient In these elements for certain crops. The relation of crop yields on fertility plots to carbon dioxide production by soils from these plots in the laboratory: 1. There was a close relation between the carbon dioxide produced by soil from the plots of a Fox sandy loam experimental field and the average yield of grain and straw two or more years after the plowing under of a legume crop. The carbon dioxide produced by the nitrogen treated plots was not as high as the yields indicate it would have been, which may be explained on the basis that the added nitrogen was largely used up by the plants before the samples were taken. There was a relation between the production of carbon dioxide and the crop yields by a Putnam silt loam from Missouri. The experimental field contained rotations, as well as different fertilizer treatments. The cultural practices with the different crops probably influenced carbon dioxide produced very materially. Green manure tops plowed under increased the yield of grain insignificantly over where they were removed. The carbon dioxide produced by the soil in the laboratory was signifi­ cantly less where the tops were plowed under when nitrogen alone was applied. The addition of superphosphate in addi­ tion to nitrogen brought the production of carbon dioxide to the same level. The superphosphate added in 500 pounds per acre of 3-48-10 in the field was sufficient to supply the needs of the micro­ organisms in the laboratory. Fertilizer treatment at a rather high level did not increase the production of carbon dioxide by the Ag and B horizons of four soil types to that of the no-treatment A-^ horizon. - 28 BIBLIOGRAPHY 1. Achromeiko, A* 1928. The Influence of Pulverizing and Drying of Soils on Their Productivity. Chem. Abs. 22:4699 2. Aghnides E. 1926. Influence of Manures and Microorganisms on H Ion Concentration in the Soil. Int. Review of the Science and Practice of Agriculture. 4 (N.S.) 294-306 3. Anderson, J. A. 1926. The Influence of Available Nitrogen on the Fermentation of Cellulose in the Soil. Soil Science 21: 115-126 4. Andrews, W. B. 1935. Carbon Dioxide Production by Mannite-treated Soils as a Means of Determining Crop Response to Fertilizers. Soil Science 39: 47-57 5. Buchanan, R. E. and Fulmer, E. I. 1930. Physiology and Biochemistry of Bacteria. Vol. II. a 376-379, b 405-409, c 413-414, d 412-413 6. Carter, L. S. 7. Christensen, H. R. 1923. Influence of Soil Condition on Bacterial Life and Changes in Soil Substances: II Ability of a Soil to Break Down Mannite. Soil Science 15: 329-560 8. Christensen, H. R. and Jensen, H. L. 1926. Bacteriological Methods for the Investigation of Soil Fertility: Carbon Dioxide Production. Int. Review of the Science and Practice of Agriculture. 4 (N.S.) 782 9. Corbet, A. S. 1951. A Bacteriological Study of the Decomposition of Organic Matter and Its Bearing on the Question of Manuring. Jour. Rubber Research Instute of Maylaya 3: 5-27 10. Cutler, D. W. 1923. The Action of Protozoa on Bacteria When Inoculated Into Sterile Soil. Ann. Applied Biol. 10: 137-141 11. 12. 13. Darbishire, F. W. Ellis, N. K. Fred, E. 1955. Some Chemical and Biological Changes Produced in a Fox Sandy Loam by Certain Soil Management Practices. Soil Science 40: 223-236 and Russell, E. J. 1907. Oxidation in Soils and Its Relation to Productiveness: II The Influence of Partial Sterilization. Jour. Agr. Sci. 2: 305-526 1935. Nutrient Deficiency in the A^, Ag, and B Horizons of Some Common Michigan Soil Types. A thesis presented to the faculty of Michigan State College. B. andHart, E. B. 1915. The Comparative Effect of Phosphates and Sulphates on Soil Bacteria. Wis. Agr. Exp. Sta. Res. Bui. 3535-66 - 29 - 14* Gainey, P. L. 1919, Parallel Formation of COg, Ammonia, and Nitrates in Soil. Soil Science 7: 293-311 15. Given, G. C., Kuhlman, G. J. and Kern, C. A. 1917. Velocity of Nonsymbiotic Nitrogen Fixation in Soils of the General Fertilizer Plots. Pa. Agr. Exp. Sta. Ann. Report for 1916-17: 405-409 16. Gustafson, A* F. 1922. The Effect of Drying Soils on the Water-soluble Constituents. Soil Science 15: 173-213 17. Heinze, B. 1920. VI. Bakteniologische Versuche. Landw. Jahr. 55: 139-184 18. Holben, F. J. 1932. Soil Respiration in Relation to Plot Yields. Penn. State Agr. College Tech. Bui. 275: 26-28 19. Jenny, Hans, and 20. Khalil, F. 1929. The Effect of Drying on the Microbiological Processes in Soils. Centrbl. Bakt. II, 79: 93-107 21. Klein, M. A. 1915. Studies on the Drying of Soils. Soc. Agron. 7: 49-77 22. Konig, J. and Hasenbaumer, J. 1920. Die Bedeutung nuer Bodenforschungen fur die Landwertschoft. Landw. Jahrb. 55: 185-252 23. Konig, J., Hasenbaumer, J., and Glenk, K. 1923. Uber die Anwendung der Dialyse und die Bestimmung der Oxydationskraft fur die Beurteilung des Bodens. Landw. Vers. Sta. 79-80: 491-534 24. Lebed jant zev, A.N. 25. Lemmerman, 0., Aso, K., Fisher, H., and Fresenius, L. 1911. Untersuchungen uber die Zersetzung der Kohlenstoff-Verbindungen Verscbiedener Organischer Substangen im Boden, Speziell unter dem Einfluss von Kalk. Landw. Jahr. 41: 217 26. Lundergardh, Henrik. 1927. Carbon Dioxide Evolution of Soil and Crop Growth. Soil Science 23: 417-450 27. Merkle, F* G« Shade, E. R. 1934. The Potassium-lime Amer. Soc. Agron. Jour. 26: 161-170 Problem in Soils. Jour. Amer. 1924. Drying the Soil as One of the Natural Factors in Maintaining Soil Fertility. Soil Science 18: 419-447 1918. The Decomposition of Organic Matter in Soils. Jour. Amer. Soc. Agron. 10: 281-302 1931. Commercial Fertilizers for Cotton Production 1925-1931 Mississippi Agr. Exp. Sta. Bui. 289 28. 29. Neller, J. R. 1920. The Oxidizing Power of Soil from Limed and Unlimed Plots and Its Relation to Other Factors. Soil Science 10: 29-39 30. Neller, J. R. 1918. Studies on the Correlation Between the Production of C0g and the Accumulation of Ammonia by Soil Organisms. Soil Science 5: 225-241 - 50 - >1 . Uicklovicki, B. Peter 1012. Bodcnfcakter1ologis che Biobucktur r>r- v Zur Beurteilung von £x.er., Cantrbl. i .-209-217 ; i o fV 4- ++T TO t ' '- .Idun; 1870. Uber den Sin flues des kernels auf die vor Eohlensaars und Salpsterssure in Acker bod er>. r\ie Landw. Versuch. 15: 155. Review taken from reference -15 35. Pierre, "h IT. and Browning, G. 1085. The Temporary Inj urious Elf act of Lining Acid Soils and Its Relation to the Phosphate Nutrition of Plants. Jour. Amer. Soc. Agran, 27 : 742-759 34. Potter, P. S. and Synider, p. 8 . 191S. Carbon Pi oxide 7 t o C u c j-ion in Soils and Carbon and Nitrogen Changes in Soils Variously Treated Iowa Agr. Exp. Sta. Res. Bui. 39, 1916. 35. Prescott, J. A. 1920. A Note on the Sheraqui Soils of Egypt. A Study in Partial Sterilization. Jour. Agr. Sci. 10: 177-181 36. Pahn, 0. 1908. Bakteriologische Untersuchung uber das Trochnes des Bocens. Central. Baht. Abt. 2 20: 5 3-61 37. Ferny, Th. 1926. Pie Einwerkung Zimehmenden Kelt: gehaltes auf die Lebersaucserungen der bodenbevohrender iileinlebcvclt• Read in Biol. Abs. 8564 1929 38. Ritter, G. 1912-1915. Das Trochnes der Erden. Abt. 2 33: 116-145 39. ■ox: Centrbl. Baht. The Atnosober , E. J. and Appleyerd, A. 191? Cosipo c m on ano. Causer cu Va.x'.i.f•tior 1-48 >11 * 1+ J our. Aar. 8 ci . 7: Shunt:, I . V . 1929. Microbiological Activities in the Soil of an Upland Bog in Eastern IT. C. Soil Science 27: 285-505 Etarxey, P. L» 1924. Some Observations or the Becompositior of Organic he + te- ir roil£.B Soil Science 17: 293-314 42. Steenkaup, J. L. 1928. The Effect of Dehydration of Soils Upon Their Colloidal Constituents: 1 Soil Science 28: 165-182 43. Stoklasa, J. 1912. Ueikoder Zur Biocbenischer. Unte-rsuchung de, ITcrcbuch cer Bioclieniischen Arbeit sue t^oder von E. A.bd er h a 1 d e n 5: 84 3 - 9 G 9 4/ Stoklsea, J. *1 m'* r>4'ef'oGs f 02’ the Eel .922. Eloche: Fertility of Soil. Chen. Abs. 18-17? 45. ~toklc.cn, J. end 46. ersui:^ cer nerenstaT ^grepvan Snch-Uf-cr, I7'. P. H. 1919. Uber die Ae r obi nt i scL en Rakterier. in Bods:: dun ch. die Kohlercwire :roduktior . Centrbl. Rah-:. 2 Abt. 28: 45-89 40. 'ocers. ioi. of the p. 1905. Uber den Unsprung, die her.ge und die Bedeutung des Kohlensaure in Eocer.. Cenlrbl. BskJ:., /!. <7I <-T —rI7i•r-.p r-. ite . JT l -- . v -> E r n e s 4-, - 51 47. Telegdy-Kovats, L. de* 1932* The Growth and Respiration of Bacteria in Sand Cultures in the Presence and Absence of Protozoa. Ann. Appl. Biol* 19 (l): 65-86. Read in Biol Abs. 25231 1932 48* Turk, L. M. 49* Waksman, S* A. and Heukelekian, 0* 1924. Microbiological Analysis of Soil as an Index of Soil Fertility: VIII Decomposition of Cellulose. Soil Science 17: 275-291 50. Waksman, S.A. and 1935* Studies of Nitrogen Fixation in Some Blichigan Soils. Michigan Tech. Bui. 143 Karunakar, P. D. 1924. Microbiological Analysis of Soil as an Index of Soil Fertility: IX Nitrogen Fixation and Mannite Decomposition. Soil Science 17: 379-393 51. Waksman, S. A. and Starkey, R. L. 1924. Microbiological Analysis of Soil as an Index of Soil Fertility: VII Carbon Dioxide Evolution. Soil Science 17: 141-161 52. Waksman, S. A. and Starkey, R. L. 1951. The Soil and the Microbe, p. 94. John Wiley & Sons Inc., New York 53. 54. Ibd. p. 68 Waksman, S. A. and Starkey, R. L. 1923. Partial Sterilization of Soil Microbiological Activities and Soil Fertility: 1 Soil Science 16: 137-156 55. Ibd: II. 246-268 56. Ibd:III. 343-357 57. Winogradsky, S. 1935. The Method inSoilMicrobiology as Illustrated by Studies on Azotobacter and theNitrifying Organisms. Soil Science 40: 59—76 58. Ziemieka, Jadwiga 1932. The Azotobacter Test of Soil Fertility Applied to the Classical Fields at Rothamsted. Jour. Agr. Sci. 22: 797-810 PART II THE EFFECT OF SOIL HICROORCAEIS'TS OH SOIL REACTION INTRODUCTION The T,reactiorj of soils’1 has justifiably received considerable attention during recent years. Emphasis has been placed 03: concentration of hydrogen Ions. the means of determining the Changes in reaction over short or long periods of time have been recorded as facts and, in most cases, the reasons for the charges have not concerned the investigators. The object of this paper is to pre­ sent data on the effects of microorganisms on the reaction of the soil. REVIEW OF LITERATURE Andrews (l) reviewed several papers on the effect of air-drying soils on certain chemical changes, and determined the effect of air-drying on the microbiological activity of the soil. The conclusion was reached that the changes produced on air-drying a soil are directly due to changes in the soil flora. The fungal mycelium disappears during desiccation; and between the time of desiccation and shortly after rewetting, the bacteria, increases in number In many ca.se. Certain investigators have reported increases in Ca, hig, P 2 O 5 , etc. on air-drying, whereas others- have reported no increases. Evidently, a large part of the fungus mycelium is available for bacterial consumption during slow drying or immediately after revetting the soil. Feher (f) and Nehring (4 one 5) have recently reported that the pH of the soil of id e has been found to be as much as two units lore]'’ c nr i p year than during certain of the warmer months. the colder months Nehring (4) gave a general summery of the seasons 1 chf nges in oil which he quoted from Feher, D. In "Tiss. Arc-o.lv. f. Landw., A, 9, 171 (1932), as follows: ”Auch der regelmessig bebau+e Ackerbober sovie die Wier-enboden zeig.en i n allgemeinen das gleiche Verhalten wie der Faldboden und der unberuhrter Bra cine. Da aberletzbere der ausglei chentier. M r hung C es schutzei den V.'aldM o s -m r c e c i s t l e r so iCOiiiiner. bei ihr die Klimasch v.'c.r-kur.geis be sorb era d e n t l H run Ausdruch and m i olgedessen Leigt sie aucb gevrolinlich grog sere Veraderungen In der' Bodenazic.il Das gleiche gilt aucii fur den Ackerboden.” vie die Baidboden. The data pres tinted by bake mar (7a) corcerir ng the numbers of be cleric and fungi at different seasons of the year should be cor sibered in c o n n e d ion with the seasonal changes in pH reported above. The numbers' of fungi are nuclt higher ir. the Tain ter and. early sprint, than in tve s m u e r und fell, 'terrvr with v a r h t i o u s the opposite Is true for bae+eiww . Turk and hillsr (S) found that where organic matter m s and combined with 'nitrogen, the pH also decreased inthe untreated used alone pH decreased over a period of tv opears. soil. The The pH at the end of twelve months usually much higher than at the end of eight or sixteen months. was A further check of the data revealed that the water content of the soil was usually lover at the end of the twelfth month than vhen any other determinetion ~sa .us.de. content probably resulted in the removal of the fungal mycelium. Tv e lo" rai, e r The change in the fungal flora may have influenced the chs-nge. in the £ oil r a c t i n . Clevenger and 7’illis (2) attributed increases in pH where cottonseed meal and urea 7 0 :-a added to .oil In combine ti 0 ^ M t h dolomiiic lire stone to the accuisulatior of ammonia; but '’hei e sulphate of ammonia was adc.ct , the m e n esse jr cy W£L£: Qp about the same magnitude and no exp la nation was offered. dolo.-itic supplements, the changes Ir pH vere smell. unaXjyls inec M a r g e s hithout They also reported other in oh. n. •. _r t saJ tj m.> ■.'t.-<_ Iffact Reaction of f a i l M e n .vp-garis/m or o f Ca.rd C u l t u r e s a n d A g a r 1’ e M d i e The production of carter dioxide by soil suspensions ir o ruhriert solutions cortairirm maunl+ol v-. r ir vestigated. c u j w l M Into The method was identic, vritx that reported bp Andrews (l), except £!-H nutrients we: & added A o sand • nutrient solutions used and the data obte ir.ed are i e lortec. in Table 1. ratio of calcium to magnesia.:.' was aucv supei Lo?- to its - o ..w.y-e s M u , TM Tee 4:1 5:5, 2:?, 1:4, rut . l o s unc. no calcium in the production of carbon dioxide by the soil uic.roorgs rn ’s. The procvicbior of carton 6ioxide "hove was rether lor,.-, end J;fo pH of the nutrient solutions was Ion. The affect of Ireieasily the quantity of calcium and magnesium on the production of carbon dioxide was -ext determined. The calcium to magnesium ratio vras maintained at 4:1* as shorn in Table 2 with the date obtained. The solv.itions were added The Ca (OB)c> r n added in solution and evaporated to dryness before tie other nutrients weie added. calcium was added to produce a pH range of 5.37 to 7.68. Sufficient Increasing the quantity of calcium and magnesium increased the production of car b or dioxide from f .3 mg si. at the original -u of 5.37 to 71 nig-i. vrhere tlie original pH was 7.68. During this part of the experiment, it was accidentally discovered that the pH of or.e of the nutrient solutions ir.cre* sed. during the period of incubation. The nutrient solutions s e n then set up again and inoculated, and the pH data were obtained as reported Ir Table 2 (The original pH vslues, as discussed above, rerc taken fro i this part of the experiment). The pH of +he sard cultures varied from 5.37 to 7.63 at the beginning of the experiment; after seventeen days, they varied from 6.75 to 7.78. The changes produced were gradual and reasonably uni for:.1 ., which indicates that they were coincident with the growth and development of the soil flora which 'vs inoculated into the cultures. The ext re me difference ir pH rh JM betr . r i p of the tes t v as 4.51 units; ty-. p h e . e difference seventeen days later vac 1.15 pH units. The nitrogen used ir. 4'v,is experiment vac Titrate nitrogen, and Jfe rewovol of ar excess of ni +re ’e M + r y p r over b e would have Increased the pH of the solution. base: it Is C D v e c h t M t h In order for the soil micro- Table 1. Effect of the Calcium : Magnesium ratio of a nutrient solution on the production of carbon dioxide by inoculated sand cultures.* C.C. USED FOR EACH CULTURE Ca:Mg RATIO MGM. COg .1 N %po4 .1 N KgCOg .1 N H 2S04 HgO 0.00 2.50 0.63 0.63 3.75 2.00 0.50 2.50 0.63 0.63 3.75 4:1 60.5 3 1.50 1.00 2.50 0.63 0.63 3.75 3:2 25 •2 4 1.00 1.50 2.50 0.63 0.63 3.75 2:3 29.7 5 0.50 2.00 2.50 0.63 0.63 3.75 1:4 13.5 6 0.00 2.50 2.50 0.63 0.63 3.75 NO. .1 N Ca(N05 )2 .1 N Mg(N0g)g 1 2.50 2 72 Hours 31.4 23.2 *Used 100 gm. of washed sand plus 0.5 gm. mannitol and in addition given treatment indicated in table. t1—1 to rH CO CO ts IN *aj O Cl o rH rQ *H u O cd to O P P o O -p d o o © •H ft P ft cd O © ft pO d ■© © © O ft a Ci ft Oh © TD c © d d ft cd -p rH ft © d © o I h d a -p d •H CO © ft Q cd Eh LO • CO o to to • t— co o 00 CO • tN CD C• tN IN H • CO cd to • io LO • c- o o • oo CO • t- o • oo O co co o ft to CO LO CO o LO • IN c- in * CO • tr­ CO • CO LO o> • LO o LO LO • to CO to • CO o ft LO • to rH tto • O to 02 © O C o d o d cd • ft c• t- CD CO • c- CD • ft * CO cd • CO 02 O • IN LO to o • IN- CO • t- 00 02 » CO CO o> • CO CO 02 • C— IN C• D— LO IN o CD CO p • t- 00 CO • c- 00 co c- d •H CD LO CD • CO • CO © i—1 ft cd ft c — © p CO * c- •H ft d *H o p o rH • CO in • CO • c- • IN d © a p cd © d P d •H t© co • 02 o • o 1—1 s C3 00 ^ • CD 02 • LO LO o « O CO to a i —1 IN d o •H P •H s ft ft cd o 02 ft LO tN ft ft1 o ftCO to CO • to LO c- LO IN to to to CO • CO • • LO C— • to LO to LO IN • to to CO • CO CO • to CO a in • d •H ft d d o ft 00 IN • IN P a w Pi ft ft © © rd ft -P © rH CD CD • C- • 02 d tut) d cd cti f t 02 00 LO • t— o d O •H o O o © i—I d a© cd o •H d ft rQ © o t© © c< -p f t o O «H o © M Ci ft O o ft *H •H PsQ ft a rH LO • in - LO m cd 02 02 • N- • 1 M Eh to t• CO * C2 ft ft to Oh o £3 rH O Eh PI CD o f t o <1 Eft * 0 2 M ft ^ O rH P-t • to ft ft o ft to o Ip rH f t c © ft • f ft CO to S to CO • o o LO • 02 o • o O o o o to CO « o to co • o to CO • CO CO • o to CO • o o o LO • 02 o LO • o LO * 02 o o LO • 02 02 o LO c• O o o o 1 —1 o o • 02 LO IN • rH o LO • • LO • p LO 02 o o o • LO • 02 02 o o O LO • p o o o • o 02 • o • o • o co ft to o rH f t *cd 02 O --- -----• cd o p •H a t»0 id• O © d rH P-! ft d cd © ft LO • 1 —1 • © ci "to cd £ ft o ft 02 s t fft cd i—1 o O • o to • CO o t• to co rH to • CO o • o LO t• CO co a t© o o ft © « o ft rH 02 CO © LO co ft * _ 4 - organisms to increase the pIT oh the culture from consumed considerably more acids than bases. Z .57 to 6*73, they must heve The culture with an original pH of 6.10 had nearly enough bases present to neutralize the acids, yet the grov-th of microorganisms increased the pH. The other four cultures had sufficient bases present to more than neutralize the acids and the growth of the microorganisms increased the pH. It follows that if the soil microorganisms involved in these cultures consumed a greater cpuantity of acids than of bases, the return of the assimilated acids and bases through the decomposition of the microorganism to the culture would dec 2-ea.se the pH to the original value. In a later experiment, fungi reduced the pH of a dextrose agar medium from 4.90 to 3.00, whereas bacteria increased the pH of a m a m i t o l agar medium from 6.31 to 6.99 in eight days. was 5.59. The pH of the fungal mycelium This ^ffect of fungi and bacteria on the pH of agar media is apparently in agreement with the base and acid content of bacteria and fungi, as reported by Waksman (7b). The combined affect ofbacteria and fungi on reaction of a soil will, therefore, dependupon the changes equilibrium between the bacteria and the fungi. the which occur in the The effect of the Actinomyces on the reaction of the soil has not received any attention. Microbiological Effects of Fertilizers on Soil Reaction The data obtained above indicate that the ’’Immediate effects of fertilization on soil reaction”, reported by Clevenger and Willis (f) and reviewed above, may have been due to the effect of the fertilizers on the microbiological activity of the soils treated with- the respective fertilizers, and that their unexplained changes in soil reaction might be accounted for. Therefore, an experiment was set up to determine the relation between microbiolorical activity and soil reaction. Clevenger and Willis 1 experiment - 5 was duplicated in part. . Fertilizer was applied at the rate of 16,000 pounds of 3-8-6 per acre to 1,000 gm. iDortions Qf Fox sandy loam soil. The sources of nitrogen were ammonium sulphate, nitrate of soda, and cottonseed meal. The fertilizers were applied in duplicate, alone, and with calcium carbonate equivalent to the nitrogen. The soil and the fertilizers were mixed and water equal to one-third of the maximum water-holding capacity of the soil was added. The soil was then put into 3000 c.c. Erlenmeyer flasks and maintained at room temperature. The carbon dioxide produced, the nitrate, and the ammonia nitrogen, and the pH were determined on the dates indicated in Table 3 and Figures 1 and 2. The pH was determined by the quinhydrone electrode method; the carbon dioxide was absorbed in ascarite; the nitrate and ammonia nitrogen were removed from the soil with dilute HC1 (5 c.c. of concentrated HC1 per liter) and determined by the usual distillation method. The carbon dioxide was removed from the flasks and then the soil was thoroughly mixed and samples were taken for the pH and the nitrogen determinations. was added on the thirty-first day. Two gm. of mannitol per 100 gm. of soil The experiment was set up November 18, 1935. The data are reported in Table 3 and Figures 1 and 2. Immediate Effect of the Fertilizers on the Soil Reaction: Clevenger and Willis (2) found that "in all cases on mixing the fertilizers with the soil a drop in the pH of the soil ranging from 0.6 to 1.0 unit took place immediately", which was attributed to the superphosphate and muriate of potash. In this experiment (Table 4) the pH of the original soil was 4.88. addition of the 0-8-6 fertilizer reduced it to 4.28. 0-8-6 Increased the pH slightly. The Nitrogen In addition to the The addition of lime Increased the pH of the soil from 4.88 to 6.58; the addition of the 0-8-6 to the limed soil reduced the pH from 6.58 to 5.98. Nitrogen in addition to the 0-8-6 and lime reduced the pH from 6.58 to 6.48, 6.46, and 6.31, respectively, for ammonium sulphate, nitrate LO to co LO i— i on the production of carbon o H CV2 i-0 0 line anb 02 t- CO C - CO co to CD E>- — i 1 cn ECd i 1 oo to r-l (H Cd of co 02 CLO i— ) rH CO to LO j0 LO SH rH 6 * r i Cd • so or H 1 ! • i— ISO « C02 £-! U1 CC to Pi b 00 Co H tr r-l '“i o (X —1 1 i H■ i —i r e-o PH O 0 s=? o H 02 00 i— ! hi « rH H •i-i •i—! C-l ro o CO 1— 1 0 .c >-0 O O, O o E-t H A o CD to * rH r H 00 O * * j? t L. • o 02 H Eh f— I 00 • H o 00 1—1 Hi H CO ISO ■ o 0 2 to •-< ca 02 CO c: 1 1— 1 (H : 1 H i LO O CO LO b O 1 C2 c\i i— 1 02 CO C— 02 — CO H ts1 to o Si t o rp of fertilizers e> O • H •t~i m 05 to • 00 cst to • CHi to • i—) to to . Hi CM CM • CM O rH • 00 to o • o rH K 43 Or 3 0 p-r 3 The immediate soil reaction 1 1 00 to 0 oo to • to 00 o> • CO CT> * to o o H • c- CO . CO H* • CO 00 Hi • CO LO CO * 05 O • co co rH Hi • E- Ch o tSJ •H rH •H -P 0 3 o 0 3 0 3 0 Cm Ph CO S3 OO »H o 1 1 o p cd 3 to o o M t-3 Eh 0 CM ^—x H § v-- / o o 3 rH •V O O rH rH o o • to o CO • CM LO O o • to CD • CM . o CO LO 00 H * • 1— 1 o M to o o rH m tSJ •H rH •H P o •H 0 CO O rH 0 3 ft P 3 0 P •H O o o ■ o CO 3 •H 3 0 O tu o HI *k CO i—i P • O P P 3 0 P 3 0 H P3 i> a p 0 0 3 *H p 3 Cd 0 cHi r CO CM m to 0 0 43 •H P •H P P 3 0 0 O P cd P 3 0 0 > •H 3 cd / —* * 3 r— 1 O •H 0 0 *0 0 3 0 *=3 0 0 3 rH -P rH rH W O No 30 mannltol present Ammonia present nitrogen SULPHATE OP SOIL AMMONIUM Mannltol Nitrate nitrogen^ Nitrate nitro NITROGEN PER 100 GRAMS pH- AND AMMONIA NITRATE OF SODA nitrogen MILLIGRAMS OP NITRATE NITROGEN Ammonia COTTON SEED MEAL 20 -Ammonia nitrogen 10 Nitrate nitrogen- 11 Figure- lo Ch- r0e^ j.n pTT, a.naonLu and nitrate nitrogen of a M foil the odd ifion of tvn-aonLura sulphate, nitrate of soda, and cottonseed >neal in r o m a l 30 No mannltol preeent Ammonia Mannltol . present nitrogen *4 H co AMMONIUM SULPHATE 10 o Nitrate nitrogen Ni trate ni t ro gen- o NITRATE OF SODA Ammonia COTTON SEED nitrogenr>. MEAL o 20 co Ammonia nitrogen Nitrate nitrogen- 10 J T'J - 6 of soda, and cottonseed meal. Relation of Microbiological Activity to the Reaction of the Soil Where Normal Fertilizers were Applied; Before ms.nnitol was added (Figure l), the pH of the soil increased 0.4, 0.5, and 1.1 units where the source of nitrogen was sulphate of ammonia, nitrate of soda, and cottonseed meal, respectively. The pH values obtained on the fifth day were nearly a maximum for all three sources of nitrogen. reached. At this time, the maximum production of carbon dioxide had also been From the fifth to the thirty-first day, the rate of production of carbon dioxide was on the decline and only small increases in pH took place. The pH increased from 4.50 to 4.85 from the first to the fifth day where sulphate of ammonia was applied. During this time, the ammonia nitrogen decreased slightly and the nitrate nitrogen increased slightly, whereas the ammonia nitrogen increased and the nitrate nitrogen decreased from the fifth to the thirty-first day and the pH increased only from 4.85 to 4.88. These changes were brought about through the soil microorganisms taking out an excess of acids over bases without consideration of the nitrogen. The decreases in the ammonia and increases in nitrate nitrogen while the pH was increasing from 4.50 to 4.85 in the absence of the soil flora would have decreased the pH. The decreases in the nitrate nitrogen where nitrate of soda was applied were much greater than the changes in ammonia nitrogen where sulphate of ammonia was applied, and the pH increased about the same in both cases. The production of carbon dioxide was significantly less where nitrate of soda was applied than where sulphate of ammonia was applied. Since the removal of ammonia nitrogen, on a chemical basis, from the sulphate of ammonia would decrease the pH, and an increase was obtained, and the removal of nitrate nitrogen from the nitrate of soda would have increased the pH, and the pH was increased about the same in both cases by the fifth day even though there had been as much nitrate nitrogen from the nitrate of soda as ammonia from the sulphate of ammonia taken up by - 7 - microorganisms, combined with the fact that less carbon dioxide was given off where nitrate of soda was applied, indicates that the microbiological flora was different in the two cases. These data indicate that bacteria predominated where sulphate of ammonia was applied and that fungi predominated where nitrate of soda was applied - on the basis that bacteria consume more acids than bases and that fungi consume more bases than acids (See data above). Coincident with the increase of 6.6 (8.6 - 2.0) mgm. of ammonia nitrogen and at least 1.7 (5.1 - 1.4) mgm. of nitrate nitrogen per 100 gm. of soil from the first to the fifth day where cottonseed meal was applied the pH increased from 4.54 to 5.41. If it is assumed that nitrate nitrogen and ammonia nitrogen are equally effective in changing the reaction of the soil, 4.9 (6.6 - 1.7) mgm. of ammonia nitrogen was responsible for changing the pH of the soil from 4.54 to 5.41. From the fifth to the thirty-first day, the ammonia nitrogen increased 6.5 mgm. more than the nitrate nitrogen, and the pH increased from 5.41 to 5.59. The decrease in hydrogen ion concentration coincident with the formation of the excess of 4.9 mgm. of ammonia nitrogen was twenty times as great as the subsequent decrease with the appearance of the 6.5 mgm. more of ammonia nitrogen than of nitrate nitrogen. During the time the 4.9 mgm. of ammonia was accumulating, the microorganisms were very active, as indicated by the carbon dioxide produced (Table 3); whereas during the time the 6.5 mgm. was accumulating, the carbon dioxide produced was very much less, which indicates that the activity of the soil microorganisms had a greater effect on the pH of the soil than the small amounts of ammonia. When mannltol was added on the thirty-first day, there was approximately as much nitrogen present in the form of ammonia and nitrate nitrogen where ammonium sulphate and nitrate of soda were added to the soils, respectively, as was added by them. By the thirty-fifth day, the pH where sulphate of - 8 ammonia and cottonseed meal were applied had gone down, whereas it had gone up where nitrate of soda was applied. The ammonia and nitrate nitrogen had practically all been removed from the ammonium sulphate treated soil by the thirty-fifth day, and the pH decreased from 4.88 on the thirty—first day to 3.69. The data in Table 4 show that the pH of the soil receiving the 0-8—6 fertilizer and the H^SO^ equivalent to the sulphate of ammonia had a pH of 3.31. If the pH changes were determined by the ammonia nitrogen present, as concluded by Clevenger and Willis, the pH of the ammonium sulphate treated soil would have dropped to 5.31 on removal of the ammonia and nitrate nitrogen. The concentration of hydrogen ions at pH 3.31 is two and one-half times that at pH 3.69* The soil microorganisms prevented the pH from reaching the low level it should have reached on the basis of the removal of the nitrogen. This action of microorganisms is in harmony with the effect of bacteria noted above on the pH of the media, and it indicates that the bacteria predominated over the fungi in that apparently the acids were absorbed in greater quantity than the bases, which prevented the pH from dropping to 3.31. From the thirty-fifth to the forty-second day the pH increased from 3.69 to 4.30 coincident with the removal of 1 mgm. nitrate nitrogen and 0.6 mgm. of ammonia nitrogen, which leaves a negligible removal of nitrate nitrogen.to increase the pH from 3.69 to 4.50. The increase in pH from 3.69 to 4.30 took place with a negligible change in ammonia and nitrate nitrogen, and at the same time the production of carbon dioxide was very high. The pH change may be accounted for on the basis of the bacteria increasing relative to the fungi, which, in the absence of available soil nitrogen,would necessitate a destruction of the fungi. to derive nitrogen from fungi?" "Are bacteria able Waksman (7c) said that "when the amount of available nitrogen is low - - - - - a part of the synthesized protoplasm of the microorganisms will be decomposed, liberating some of the nitrogen which is imrnedint eiy ago in us simile, ted - - - -.» The pH at the beginning of tlie expert ''eut m s was 4.30. 4.50; tha+ at ’’.he end At the beginning of the eo oeriment, there were ^80 pounds uj x ere of ammonia nitrogen pro cent; at fixe ere, there n.- t. negligible am aunt of eolutl nitrogen. The difference in pH at the end of the experiment and that (3.53) when the 0-3-6 and KpSCp equivalent to the ammonium sulphate vac applied .nay he attributed to th.e removal of an excess of xci.es over bases, d5_sr-oga r c ing: the nitrogen. On this basis, the ciicroorgar■isms reduced the hydrogen ion con­ centre t ion more than tventy-four- times as much as the removal of 4 30 pounds of a monia nitrogen by the soil liars reduced it. The affect of the organic acic decomposition products of mannitol on the pH of the soil is not to be overlooked• feezesses in pH ir soil and. in culture solutions heve often been attributed, to ike increi.ce of organic decomposition products, end subsequent increases i r pH to their cecomposit Ion. If the decrease in pH from 4.38 to 5.69 was considered to be due to the effect of organic acids and the removal of the ammonia nitrogen, end the increase (with r.o accumulation in ammonis nitrogen) in pH from 3.69 to 4 .30 7/as due to the decomposition of the organic acids, then It is concluded that the soil micioorganisms consumed muc 1 larger quantities of mineral acids than of bases than would be necessary to proc nee this action with the organic acids playing only ur insignificant role in the changes in p H • then mannitol was added to the nitrate of soda soil, from 4.31 nitrate on the thirty-first day to 5.91 on the thirty-sixth and ammonia nitnoger. were almost completely remove cl. T-Per 0-8-6 and Ha^CO^ sere a d d e d therefore, to t^e soil wos C.?Q. e pH increased day when the The pi obt': ived The soil microorganisms, ?revonted. the pH from increasing to the point calculated on the ha a is of com ale to jure, 1 of the rilr' h and ammonia r h r y f T . In c o b e / f t a tv e sul-.hfte of '■"’ i •t:. date, these d: 1z Indicate t ;.t the H m g l prodonin ated over - 10 - the bacteria, which is brought out again in the decreases in pH which folloi c-.c.j hut on the last date, the pH indicates that the bacteria were increasing relative to the lungi. Does the presence of sodium in a soil relatively low in bases favor fungal activity over bacterial activity? When mannite was added to the cottonseed meal soil, the pH decreased from 5.59 on the thirty—first day to 4.55 on the thirty-fourth day, at which time the nitrate and ammonia nitrogen had been almost completely removed. The pH increased from 4.55 to 5.09 with little change in nitrate and ammonia nitrogen, and the increase was probably due to an increase in the bacteria, or a decrease in the fungi or both. This indicates that the bacteria, may obtain nitrogen at the expense of the fungi. The production of carbon dioxide was much greater where cottonseed meal was applied than where ammonium sulphate and nitrate of soda were applied. Hone carbon dioxide was produced where ammonium sulphate was applied than where nitrate of soda was applied. The nitrate of soda soil produced much less carbon dioxide than the sulphate of a monia soil at the beginning of the experiment and immediately after putting on the mannltol. Relation of Microbiological Activity to the Reaction of the Soil There Normal Fertilizers Plus Lime Were Applied: The quantity of lime added was equivalent to the nitrogen; the same quantity of lime was added where nitrate of soda, and cottonseed meal were applied as where sulphate of ammonia was applied. Without mannltol, the pH of the ammonium sulphate and the nitrate of soda treated soil increased slightly at first, followed by small decreases. There were small changes in the ammonia and nitrate nitrogen, but there was no apparent relation between them and the pH changes. H e r e cottonseed meal was used, the pH increased from 6.31 to 6.77 on the fourth day, with no change in content of ammonia nitrogen and. probably a slight increase in nitrate nitrogen content. It toolc 28 mgm. ammonia nitrogen to change the pH of the soil from 6.40 to 6.99 (Table 4). The soil microorganisms reduced the hydrogen ion con- - 11 - centra 4 ion .00000055 moles per liter, whore a;. the 53 mg.,!. (4 ^ 8 ^ o i m h of rutro 0 er: reduced it only .000000506 moles pci liter. per a ere) These data indicate that the soil flora had consumed acids equivalent to 44 3 pounds per : ere of ammonia nitrogen. H e n uannitol was added to the ammonium sulphate soil, the- pH decree cod from G.06 to 4.73 in three days, at which time practically till of the ammonia, and nitrate nitrogen had been removed; hut coincident wit 11 decrease in the G:mnonia nitrogen, the pH increased again to £.51, which indicates that changes in the flora took place, thus leaving bases available to increase the pH. This voulc take place with the increase of the bacteria at the expense of the fungi. The pH of 4.79 is lower than that, 4.36, obtained from the addition of the 0 -8-6 and H^SO^ equivalent to the aomoniuji sulphate. Then munnitol was added to the sodium nitraie soil, the pH increased from 3.35 to 7.55 when about all of the ammonia and nitrate nitrogen had beer, removed, and it increased to 7.45 a.nd decreased to 7.19, which indicate: that changes in the soil flora, were taking place. The pH obtained when N&gCOg instead of nitrate of soda, was put on the soil was 7.10. Their mannltol was added to the coil orseed seal treated soil, the pH increased from 6.15 to 6.56 on removal of about all of the nitrate and ammonia, nitrogen. The pH continued to increa.se and decrease wiJh little change in soluble nitrogen. The data in Table 3 show the t usually sulphate of amionig vac more efficient for carbon dioxide production than was socium nitrate; cottonseed meal was more efficient tliai• either, except wuere siar.ni tol rw a accec. DISCUfSIHH The data scot soil reaction. that >i1 mteroorge.r The fiinL.i decres.sec the w isms exeitec a marked effect on 4ke of a necnim, v o o-w s e bacteria. - 12 increased it. The change in the pH of the medium due to the growth of the bacteria and the fungi is considered to be due to the absorption of more acids than bases by the bacteria and more bases than acids by the fungi, which is in harmony with the chemical composition of fungi and bacteria reported by Waksman in his book "Principles of Soil Microbiology". If the bacteria increase the pH by an absorption of an excess of acids over bases and the fungi decrease it by an absorption of an excess of bases over acids, a decrease in the bacterial popu­ lation will have the same effect on the pH as an increase in the fungal population, and a decrease in the fungal population will have the same effect as an increase in the bacterial population, due to the reentrance of the absorbed constituents into the soil solution. The effect of the soil population on the pH of the soil depends upon the microbial equilibrium which exists at any one time. It is logical to assume that organisms other than bacteria and fungi played a part in the reaction changes which took place. Upon complete removal of the nitrogen, in several instances, the resulting pH was very much different from the pH obtained on addition of all of the fertilizing constituents except nitrogen, which indicates that there was an excess absorption of acids or bases. Changes in the pH took place which were significant without changes in the soluble nitrogen content; these changes apparently were brought about by a shift in the equilibrium between the bacteria and fungi. These data, therefore, indicate that the bacteria are able to derive nitrogen and probably other products from fungi, and under certain conditions fungi may increase at the expense of bacteria. There is an indication that the sodium from the nitrate of soda is more favorable for the development of fungi than for bacteria. The ammonia and nitrate nitrogen play a part in the reaction of the soil, but the part played by the soluble nitrogen is probably secondary to the removal of an excess of acids or bases by the soil microorganisms. It would be possible to imagine a condition in which the increase or decrease in soluble nitrogen would - 15 - determine the pH changes. This condition could exist when the e qui librium between the fungi and bacteria was such that they would remove or add to the soil solution equivalent hydroxol and hydrogen ion producing substances. Under field conditions, decreases in pH obtained when organic matter is turned under is probably cue to the predominance of fungi in the decomposition of the added material rather than to the production of organic acids. Certain date', presented in this paper show that if the organic acids did play an important part, much more of the mineral acids would need to have been taken up to produce the results obtained. SUMMARY The following data presented in this paper show that soil microorganisms influenced the pH of the soil: A. Soil microorganisms increased the pH of a sand culture from 5.57 to 6.75; the pH of other cultures was also increased. B. Fungi decreased the pH of dextrose agar medium from 4.20 to 5.00; the pH of the fungal mycelium was 5.59. C. Bacteria increased the pH of a rnannitol agar medium from 6*51 to 6.19. B. The oH of soil changed significantly with insignificant changes in ammonia and nitrate nitrogen. E. kith changes in nitrate and ammonia nitrogen was applied than where greater where nitrate of soda ammonium sulphate was applied, the ;jH increased in both cases about the same amount. F. The soil microorganisms prevented the pH of the soil where ammonium sulphate was applied from dropping below 5.69, whereas the pH of the soil receiving Hr,SO. equivalent to the ammonium sulphate was 3.cl. #7 hr - 14 ~ C t. The pH (see F above) Increased from S.69 to 4.60 without a c V r ^ e In ■' ’. •: . on'•• and nitrate nitrogen. H. The results under F and G were obtained immediately after applying uannit-ol. If organic acids should be considered a.s playing a significant role in reducing the pH, the data. (F and G) would have to be explained on the basis of a much greater absorption of acids than if they are considered to play an insignificant part. I. The pH where nitrate of soda was applied on the high as was calculated on the basis unlimed, soil did not go as of complete removal of the nitrate nitrogen, whereas on the limed soil it went higher. J. Dhere cottonseed meal was added to soil, increases in pH took place with s m a l l increases In ammonia nitrogen, which were much greater than those which took place through the addition of the nitrogen as ammonium carbonate. IC. The pH changes which took place on the unlimed soil without mannitol were much greater- where cottonseed meal was applied than w h e r e either nitrate of soda or sulphate of ammonia were applied. The literature which was reviewed in this paper shows the following, which ooint In the same direction a.s The da ta re porteds A. The pH of a soil may vary as much as two units from winter to summer. B. The funri in the soil may be higher In winter tnac in summer (relshive to bacteria), whereas the reverse is true for bacteria* C. Drying soils may Increase their pH. D. Drvinw a soil tends to decrease the quantity of fungal mycelium. - If, - EIBLIOGPAPHY 1. Andrews, E. 1955. Mar-nitol reco^position os a rieo sure of Cro ) Response to Fertilizers and Boil 'Productivity. ?r] I of tiiis Thesis. Clevenger, C. B. anc P'illis, i,. G. 1955. Iairiediate Effects of Upon Soil Benetton. Jour. Auer. Soe. Ayr or . 'v.*v+■iior 9:7:35/5-396 Feher, E. 1955. Einige Berner’a m g e n uber die Schvankunger Cer PeaktionsverbrItnisse in Bocer. Zeit. fur Pflanzenernahrung, Bungling and Boderfcunde. A 57:512-314 4. Behring, K. 1955. Uber cfli.« chrankungen der Reaktiorsverhaltnisse fur Pflanzenernahrung, Lungung und i/i Bocer. Zei' Boderdmnde. A 40:157-141 5. Nehring, 1954. Uber die Schrankungen der feaktionsverholtnisse i.i Bocer. Zeit. fur Pflanzenernahrung, rungung und Eodenkunde. A 56:957-270 6. Turk, tj. P. and llillsr, C* E. 1956. The Effect of Blfferont Plant Materials * Line, end Fertilizers or tie Accuraulatn on of Soil Organic Matter. In Press, Jour. Auer. Soc. Agron. 7. Paksman. 1952. Principles of Soil Microbiology. Wilkins Company a. pp. 2 8-51, end 42 b. o. 567 o. 591 The Williams and