SOME CHEMICAL AND BIOLOGICAL CHANGES PRODUCED IN A FOX SANDY LOAM SOIL BY CERTAIN SOIL MANAGEMENT PRACTICES L. S. CARTER A THESIS PRESENTED TO THE FACULTY OF THE MICHIGAN STATE COLLEGE OF AGRICULTURE AND APPLIED SCIENCE IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY E ast Lansing 193*1 ProQuest Number: 10008276 Alt 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 10008276 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 481 06- 1346 ACKNOWLEDGMENT To D r. C. E. M i l l a r the w r it e r wishes to express h is s in c e re a p p re c ia tio n f o r ah/vice and assista n ce throughout the course o f t h is in v e s tig a tio n . - 1 - INTRODUCTION The e ff e c ts o f cro p p in g systems and f e r t i l i z e r and lim e a p p lic a tio n s on s o ils under e x p e rim e n ta l c o n d itio n s have been measured c h ie f ly in terms o f d iffe re n c e s in p la n t y ie ld s . In some o f these cases changes i n the o rg a n ic m a tte r con ten t o f the s o il have been measured by chem ical a n a ly s is , and q u ite fre q u e n tly the q u a n titie s o f a v a ila b le p la n t n u tr ie n ts in the s o i l o f tre a te d and u n tre a te d p la ts have been determ ined by methods devised f o r t h is purpose. Changes in the b io lo g ic a l c o n d itio n s o f s o ils , however, as n i t r i f y i n g power, numbers o f b a c te ria and fu n g i, carbon d io x id e p ro d u c tio n , e tc , r e s u ltin g from s o i l tre a tm e n ts have been s tu d ie d to a le s s e x te n t. In 1917» "the S o ils S e c tio n o f M ichigan S tate C olleg e p la ce d under e xp e rim e n ta l tre a tm e n t a f i e l d o f Fox sandy loam s o i l w hich had f a ll e n to such a low s ta te o f f e r t i l i t y s e v e ra l y e a rs . th a t i t had been uncropped f o r D urin g succeeding years many o f the tre a te d p la ts a t ­ ta in e d a f a i r l y h ig h s ta te o f f e r t i l i t y as measured by crop y ie ld s , as much as 50 bushels o f wheat to the acre having been grown on some p la t s . Marked d iffe re n c e s o ccu rre d , however, in the crop y ie ld s o b ta in e d from p la ts re c e iv in g d if f e r e n t tre a tm e n ts . As a m a tte r o f in t e r e s t to the men in charge o f the f i e l d and to agronom ists i n ge n e ra l, i t was con­ s id e re d im p o rta n t to know i f chem ical and b io lo g ic a l changes had taken p la ce in the s o i l o f the p la ts re c e iv in g d if f e r e n t tre a tm e n ts . T h is in v e s tig a tio n was c a r r ie d on, th e re fo re , to o b ta in in fo rm a tio n o f t h is n a tu re and to determ ine what c o r r e la tio n s m ight e x is t among the v a rio u s data c o lle c te d . - 2 - REVIEW OF LITERATURE L ite r a tu r e d e a lin g w ith the re la tio n s h ip s o f chem ical and b io lo g ic a l a c t i v i t i e s in s o i l and the crop p rodu cing power o f the s o il has been th o ro u g h ly review ed elsewhere ( 3 2 , 33) , and hence re fe re n c e w i l l be made o n ly to those papers most c lo s e ly r e la te d to the s tu d ie s p re se n te d in t h is p a p e r. RELATION BETWEEN CROP PRODUCTION AND BACTERIAL ACTIVITY IN THE SOIL Brown ( 6) demonstrated a close r e la tio n s h ip between b a c te r ia l processes as measured by n i t r i f i c a t i o n , a m m o n ific a tio n , a z o fic a tio n , and cro p p ro d u c tio n i n h is s tu d ie s o f some Iowa s o ils . R u s s e ll and A ppleyard (22) found curves f o r carbon d io x id e p ro d u c tio n , n it r a t e con­ t e n t , and numbers o f m icroorganism s in the s o i l were s im ila r enough to be c a lle d r e la te d and th a t a l l o f these fa c to rs e xe rte d an in flu e n c e on crop p ro d u c tio n . The r e s u lts o f Noyes and Connor (20) showed a d e f in it e r e la tio n s h ip between crop y ie ld s , n i t r i f i c a t i o n , and b a c te r ia l numbers in some a c id s o ils . N e lle r (18), w orking w ith lim e d and u n lim e d s o ils , found a d is t in c t c o r r e la tio n between crop p ro d u c tio n and b a c t e r ia l a c t i v i t y as measured by COg p ro d u c tio n , NO^ p ro d u c tio n , and numbers o f b a c te r ia . ” A c lo s e c o r r e la tio n e x is ts between crop p ro d u c tio n and b a c t e r ia l a c t i v i t y and b o th are e q u a lly a ffe c te d by s o il tre a tm e n t” i s a summarized statem ent o f the l i t e r a t u r e by Waksman (3 2 )* - 3 - NITRIFICATION AS A MEASURE OF SOIL FERTILITY AND THE EFFECTS OF SOIL TREATMENTS S tu d ie s o f n i t r i f i c a t i o n by Wahltman (3 0 ), Lobnis (1 7 )* K ellerm an (l^+) , and R u s s e ll (23) i n s o ils v a r io u s ly tre a te d and under d if f e r e n t e x p e rim e n ta l c o n d itio n s , re ve a le d a d e f in it e c o r r e la tio n between n i t r i f i c a t i o n and crop p ro d u c tio n . Where s o ils were c o n tim t- o u s ly cropped w ith o u t f e r t i l i z a t i o n , as re p o rte d by A lle n and Bonagzi ( i ) , n i t r i f i c a t i o n was reduced u n t i l no c o r r e la tio n between i t and crop p ro d u c tio n c o u ld be made. Harper and Boatman (12) found no in c re a s e i n n i t r i f i c a t i o n as a r e s u lt o f a p p ly in g superphosphate and m u ria te o f p o ta sh f e r t i l i z e r s to lim e d s o ils . Some re ce n t work by Ligon ( l 6) on muck s o ils d if f e r in g w id e ly in re a c tio n , showed an e x c e lle n t c o r r e la t io n between n i t r i f i c a t i o n and th e y ie ld o f spinach. The s tu d ie s o f Temple (2 5 ), Fred and G-raul ( 8) , B a rth e l, and B e ckw ith (5 )* showed th a t ammonium s u lp h a te , the most commonly used source o f n itro g e n f o r n i t r i f i c a t i o n s tu d ie s , was not s u ita b le f o r use in such s tu d ie s in a l l s o ils . H alversen ( 11) demonstrated the valu e o f ammonium su lp h a te as a source o f n i t r i f i a b l e n itro g e n f o r c e r ta in p ro d u c tiv e s o ils , b u t s ta te d th a t a c id s o ils o f humid re g io n s , low in bases, would n o t be expected to n i t r i f y th is m a te r ia l. K u lik (15) and T u rc h in (28) found a depression o f n i t r i f i c a t i o n o f urea in p o d s o liz e d s o ils by a d d itio n o f sulphates and e s p e c ia lly c h lo r id e . Waksman (31) s ta te s from h is s tu d ie s o f methods f o r d e te rm in in g n i t r i f i c a t i o n , th a t seve ral sources o f n itr o g e n and d if f e r e n t methods o f procedure should be employed to give a b e tte r p ic tu r e o f a s o i l f s power to n i t r i f y n itro g e n o u s m a te ria ls . - k - PRODUCTION OF CARBON DIOXIDE AS A MEASURE OF BACTERIAL ACTIVITY IN SOILS The amount o f carbon d io x id e produced by a e ro b ic b a c t e r ia l a c t i v i t y was measured by Van S uchtelen ( 29) and found to be a b e tte r in d e x o f s o il p r o d u c tiv ity th a n the number o f m icroorganism s i n a s o il. S to ckla sa and E rn e st ( 2^) found th a t th e g re a te s t amounts o f carbon d io x id e were produced in f e r t i l e , w e ll a e ra te d s o ils and th a t carbon d io x id e p ro d u c tio n p a r a lle le d n i t r i f i c a t i o n . Organic m a tte r r i c h in n itr o g e n gave a b e t t e r c o r r e la t io n between carbon d io x id e p ro d u c tio n , a m m o n ific a tio n , and n i t r i f i c a t i o n than m a te ria ls low in t h is element a c c o rd in g to Gainey (1 0 ). Carbon d io x id e e v o lu tio n from s o ils , w ith and w ith o u t o rg a n ic m a tte r a d d itio n s , may be used as a measure o f s o i l f e r t i ­ lity a c c o rd in g to Waksman (32) • CELLULOSE DECOMPOSITION IN SOILS AND ITS RELATION TO SOIL FERTILITY C h riste n se n (7) was one o f the f i r s t in v e s tig a to r s to suggest th a t c e llu lo s e decom position c o u ld be used as a measure o f s o i l p ro ­ d u c t iv it y . The work o f N ik le w s k i (19) showed th a t c e llu lo s e decom position was c o n tr o lle d c h ie f ly by the su p p ly o f a v a ila b le n itro g e n . Anderson ( 2) v e r if ie d N ik le w s k i* e (19) r e s u lts and showed the e ff e c t o f n itro g e n from d if f e r e n t sources on c e llu lo s e decom position. Some c e llu lo s e decom position s tu d ie s by Holben (13) on s o i l from the f e r t i l i t y p lo ts a t th e P enn sylvania s ta t io n le a d to the statem ent th a t t h is process i s an e x c e lle n t measure o f s o il f e r t i l i t y . The im portance o f a v a ila b le n itro g e n and phosphorus to - 5 - c e llu lo s e decom position in s o ils i s f u r t h e r s tre s s e d by Waksman (3 2 ), b u t s o i l re a c tio n i s co n sid e re d o f l i t t l e im portance in the p ro c e s s . Some re c e n t work by W hite and co-w orkers (3*0 f u r t h e r emphasizes the im portance o f n itr o g e n and a ls o demonstrates a r e la tio n s h ip between s o i l re a c tio n and c e llu lo s e de com position. experimental DESCRIPTION OP SOIL TYPES, RECORD OF SOIL TREATMENT AND CROPPING HISTORY OF PLOTS SELECTED FOR THE INVESTIGATION The Cass County Farm e xp e rim e n ta l f i e l d , near C a sso p o lis, M ic h ig a n , was p lo t t e d in 1917 as an e xp e rim e n ta l area f o r d e te rm in in g the b e s t methods o f management f o r the li g h t e r s o ils o f southw estern M ic h ig a n . F o r the purposes o f t h i s in v e s tig a tio n e ig h t p lo t s were s e le c te d from t h is f i e l d f o r study on the b a sis o f the s o i l tre a tm e n ts used and the crop y ie ld s w hich had been o b ta in e d from them. The Fox sandy loam on w hich the p lo t s are lo c a te d i s one o f th e p re d o m in a tin g s o i l type s o f southw estern M ichigan b o th in area and valu e o f i t s p ro d u c ts . I t may be de scribe d as a l i g h t brown, f r i a b l e , sandy loam s u rfa ce s o i l ly in g over a pa le y e llo w is h s o il o f s im ila r te x tu re .to a depth o f 12 to 18 in c h e s . The B h o riz o n c o n s is ts o f sand and g ra v e l cemented to g e th e r by re d d is h brown c la y and ra n g in g from 10 to 18 inch es i n th ic k n e s s . A t & depth o f 2h to 3& in c h e s , coarse sand and g ra v e l predom inate, which a ffo r d s ra p id to e x ce ssive d ra in a g e . The n a tu re o f th e B h o riz o n i s a d is tin g u is h in g c h a r a c te r is tic and g ive s to t h is s o il g re a te r r e te n tiv e powers f o r m o is tu re and p la n t n u tr ie n ts , than s im ila r s o ils in w hich t h i s h o riz o n i s not so h ig h ly developed. Under n a tu r a l c o n d itio n s , t h is s o i l is low i n content o f o rg a n ic m a tte r and p la n t n u tr ie n t elem ents, w hich would in d ic a te a g re a te r response to s u ita b le - 6 - s o i l management p r a c tic e s th a n s o ils w e ll s u p p lie d w ith o rg a n ic m a tte r and re serve sources o f p la n t n u tr ie n ts . As the Fox sandy loam is a s tro n g ly a c id s o i l , an a p p lic a tio n o f th re e to n s o f ground lim e sto n e to th e acre was made a t the b e g in n in g o f the f i e l d experim ent to a l l except the check p lo t s . F e r t i l i z e r s were a p p lie d a t the fo llo w in g ra te s p e r a c re : P otassium , 100 pounds (50$ KC1); N itro g e n , 100 pounds (NaN03) ; Phosphorus, 200 pounds ( l 6$) superphosphate); Rock phosphate, 1000 pounds; Gypsum, 86 pounds. A l l o f the f e r t i l i z e r s were a p p lie d before the crops were p la n te d w ith the e xce p tio n o f n itro g e n f o r f a l l seeded g r a in . F o rty p e r cen t o f t h is was a p p lie d in the f a l l , and s ix ty p e r cent i n the s p rin g u n t i l 1920, when the p ro p o rtio n s were changed to tw enty p e r cen t in the f a l l and e ig h ty p e r cent i n the s p rin g . P e rio d ic a p p lic a tio n s o f the f e r t i l i z e r s were made as shown in ta b le 1 , and a c c o rd in g to the amounts a lre a d y g iv e n . The cro p p in g h is to r y o f these p lo ts since they have been under e x p e rim e n ta tio n is as fo llo w s : soy beans,19171 hye, 1913; wheat, 1919; sweet c lo v e r, 1920, 1921; ry e , 1922; c o m , 1923; wheat, 192*+; sweet c lo v e r, 1925; soy beans, 1926; wheat, 1927; c o rn , 1928; o a ts , 1929; and wheat, 1930, 1931* The soy bean crop in 1926 was plowed under to supplement the o rg a n ic m a tte r d e riv e d from crop re s id u e s . p lo w in g under the c ro p . The y ie ld was determ ined b e fo re O ther crops were removed; no s tra w , s to v e r, o r s im ila r m a te ria l b e in g added to the s o i l . METHOD OF TAKING SOIL SAMPLES S o il samples o f s u f f ic ie n t q u a n tity f o r a l l the la b o ra to ry s tu d ie s were taken from th e p lo ts in the f a l l o f 1931* & p! rCM o> rH S3 vr> CM cr rH Ph CM o> pH s K' CM o> rH S3 S3 w Ph S3 Ph M O Ph a S3 Ph Ph Ph § o +» § w Ph S3 Ph $3 Ph S3 S3 M & S3 I-? S3 a & a Field * Treatment 1. S S o il o CO o +C 3d o o Pi Pt CO o M CO CO a 0) ctf w a •rH o s jS S3 rH O ro <13 M •H a a #■3 era rH o 1 o r<~\ to o a a 9 h— O 1-3 P h Ph a ^ M& * CO o K3 CT\ O 1^3 o rH r^ \ he used throughout U CM CM CT iH this 03 t-H Year of to the Designated P lo ts S3 CT CM a> rH Application of F e rtiliz e rs o r<3 o> pH - 8 - To secure a re p re s e n ta tiv e com positive sample, f iv e samples were taken a t s y s te m a tic a lly lo c a te d p o in ts on each p lo t and th o ro u g h ly m ixed. Samples were taken by removing and d is c a rd in g the surface in c h o f s o il and th e n ta k in g w ith a spade the d e s ire d amount o f plowo f 6 to 8 in c h e s . s o i l to a depth A f t e r thorough m ix in g and scre enin g to remove stones and la rg e p a r t ic le s o f undecomposed o rg a n ic m a tte r, a liq u o ts were ta ke n , a i r d r ie d , and s to re d in s t e r i li z e d c o n ta in e rs . LABORATORY METHODS N itro g e n was determ ined by the method g iv e n f o r s o ils i n the O f f i c i a l and T e n ta tiv e Methods o f A n a ly s is o f the A s s o c ia tio n o f O f f i c i a l A g r ic u lt u r a l Chemists ( 2 ) . Organic m a tte r was determ ined by lo s s on i g n it io n , since the s o ils co n ta in e d no carbonates. The re a c tio n i n terms o f pH, was determ ined on a i r d ry s o il by the quinbydrone method as d e s c rib e d by Bauer (U) . A v a ila b le phosphorus i n pounds p e r acre was ob­ ta in e d by the method o f Truog ( 26) . Fred and Waksma^s (9) re d u c tio n method was used to determ ine n it r a t e n itro g e n . Numbers o f b a c te ria and fu n g i were o b ta in e d by ta k in g the average count from s ix agar p la te s o f the re s p e c tiv e media used. N i t r i f i c a t i o n and carbon d io x id e p ro d u c tio n methods are de scrib e d in the re s p e c tiv e s tu d ie s d e a lin g w ith these sub­ stan ces. RELATION BETWEEN SOIL TREATMENT, CROP PRODUCTION, SOIL REACTION, AND SOME AVAILABLE NUTRIENTS Because o f the in flu e n c e o f seasonal v a r ia tio n s on crop p ro ­ d u c tio n , w hich tend to m o dify d iffe re n c e s due to f e r t i l i z e r tre a tm e n t and - 9 - o th e r fa c to r s a f f e c t in g p r o d u c t iv it y , i t was deemed a d v is a b le to express the y ie ld s o f the d if f e r e n t p lo ts in terms o f pounds o f dry p la n t m a te r ia l produced d u rin g the e n tir e p e rio d th e y have been under e x p e rim e n ta tio n . Since the problem deals p r im a r ily w ith the chem ical and b io lo g ic a l changes w hich may have taken p la ce in the s o i l , d u rin g the p e rio d o f f i e l d tre a tm e n t and t h e i r r e la tio n to crop p ro d u c tio n , in fo rm a tio n on s o i l re a c tio n , q u a n titie s o f a v a ila b le phosphorus, t o t a l o rg a n ic m a tte r, and n itro g e n fu rn is h e s a b a s is f o r comparing s o i l changes w ith crop y ie ld s . An a n a ly s is o f the data g ive n in ta b le 2 and presented g r a p h ic a lly in fig u r e I , b rin g s o u t the fo llo w in g p o in ts . A lth o u g h the supply o f a v a ila b le phosphorus is low in a l 1 the s o ils , those re c e iv in g phosphate a p p lic a tio n s have the la r g e s t amounts. T h is i s e s p e c ia lly tru e o f s o ils 310N a^d 309. w hich were tre a te d w ith ro c k phosphate and superphosphate, re s p e c tiv e ly . Since the a v a ila b le supply o f phosphorus i s low , any d iffe re n c e due to s o il tre a tm e n t may be expected to have a marked in flu e n c e on the chem ical and b io lo g ic a l con­ d itio n s in these p lo t s . C ontent o f o rg a n ic m a tte r and t o t a l n itro g e n are c lo s e ly r e la te d f o r a l l s o ils except number 301N, w hich i s low in o rg a n ic m a tte r and r e la t i v e l y h ig h in t o t a l n itr o g e n . The r e la t i v e l y low c o n te n t o f o rg a n ic m a tte r in s o il 301^ i s doubtless due to the fa c t th a t v e ry low y ie ld s o f crops were ob ta in e d from t h is p lo t and as a r e s u lt a s m a ll amount o f crop ro o ts and stubble was l e f t in the s o i l . The h ig h co n te n t o f n itro g e n i n s o il 301^» view o f the sm all q u a n titie s o f n itro g e n -c o n ta in in g org a n ic m a te ria l l e f t in i t , th a t a n o th e r source o f n itro g e n must have e x is te d . suggests r-1 © © -P O EH © PS © •H in 0 CM PH © O to rH © -p ■a o3 rH © 1 -P a £ Crop Y ield s -P 8 8 w +» iH g A d © o i - 100 o oO V 101 121 36,200 120 100 Per ICent r-H Ph O V O CM in rH m o o m rH rH o s CM rH i 1 — a—i m VQ CM in m O GO GO CM s cn m VO m LT\ CM f ■ I— GO O o o o o m m CF\ GO r- GO rH GO o — O O CM i 1 CM rH rH m i vo m r-H a irH f VO CM i— 1 <— 1 m i— i -=t o% CM m m ol— m m 3! o o * -=f vo CM CM i 1 in i t•k 1--m CM is +3 © U © Eh Per i Cent o o rH cn o GO rH rH rH in rH • UT\ — i rH CM m s o CT\ o m a\ CM GO m t— GO CM CM CT\ V O oo m CM OG in CM o rH CM rH CT» rH rH GO rH rH VO • rH CTi in • in c\T Ph O +9 d 'd © co o o r— o i—i 27.363 rH o O rH VO o I +5 £ •H m Per Cent d So O +Fh 9 ♦H f2} o o CM § ^ Ph O Per [Pounds Pounds Per Acre i Cent iPer Acre CO ft Per Cent Organic Matter O S o il in Pounds per Acre and in Per Soiils and Crop Yields of Analyses Chemical 2, Table rH •H to *d o o • o J2! Is; rH O m rH V Oi i— rH CM rH t- in in • J=t• VO • r— • in in in in in 0 © M 3 a a CO rH O m CM o m 8f « in t- o m O m a a 8 *A GO O m o> o m O rH m 393TIOO 3±®-S NVSIHOIW In te rre la tio n s Between Soil Treatment, Crop Y ields, Soil Phosphorus, Organic M atter, and Total N itro g e n . FIG. I Reaction, and Content of A v a ila b le - 10 - Some u n p u b lish e d data on n itro g e n f i x a t i o n show a v e ry a c tiv e n itro g e n f i x i n g f l o r a e s p e c ia lly by anaerobic organisms in s o i l 301N. I t may be concluded from t h is th a t fr e e n itro g e n f i x a t i o n was in s tru m e n ta l i n r a is in g the t o t a l n itro g e n con ten t o f t h is s o i l . The s o ils re c e iv in g com binations o f lim e , n itro g e n , and phosphorus were h ig h e r in n itro g e n and o rg a n ic m a tte r than those re c e iv in g lim e and s in g le element tre a tm e n t. Since a l l the s o ils were co m p a ra tive ly low in n itro g e n and o rg a n ic m a tte r, a d d itio n s o f these substances should have some e f f e c t on the b io lo g ic a l a c t i v i t i e s i n these s o ils as measured by n i t r i f i c a t i o n and carbon d io x id e p ro ­ d u c tio n . Due to the low b u ffe r in g c a p a c ity o f these s o ils , the re a c tio n flu c tu a te s over a co n sid e ra b le range, depending upon the m o is tu re and carbon d io x id e s u p p ly . D espite t h is tendency to v a ry , samples o f a l l the s o ils taken a t the same time o f the y e a r, should g iv e com parative re a c tio n valu es r e f le c t in g the in flu e n c e o f p lo t tre a tm e n t. Lime alone ra is e d the pH over th a t o f the u n tre a te d s o il, b u t not as much as has lim e and f e r t i l i z e r s to g e th e r. W hile the d iffe re n c e in re a c tio n between s o ils re c e iv in g lim e alone and those re c e iv in g n e ith e r lim e o r f e r t i l i z e r and between those trea.ted w ith lim e alone and lim e w ith f e r t i l i z e r s may be o f s u f f ic ie n t magnitude to in flu e n c e b io lo g ic a l and chem ical r e la tio n s h ip s , the d iffe re n c e s in re a c tio n between s o ils re ­ c e iv in g d if f e r e n t com binations o f lim e and f e r t iliz e r s a T e n o t la rg e enough to have any a p p re c ia b le e f f e c t on these processes. A l l o f the f i e l d tre a tm e n ts have in cre a se d the y ie ld o f crops over those from the u n tre a te d s o i l . Lime alone has given a ve ry marked in c re a s e , w h ile lim e w ith com binations o f n itr o g e n , phosphorus, and - 11 - potassium has g ive n the g re a te s t in c re a s e s . Com binations o f lim e and e it h e r superphosphate o r ro ck phosphate have shown the s m a lle s t in c re a s e s in crop y ie ld s over the u n tre a te d s o i l , being about the same o r s l i g h t l y g re a te r than the y ie ld s from lim e a lo n e . In t h is p a r t o f the paper, the r e la tio n s h ip between s o il tre a tm e n t, re a c tio n , crop y ie ld s , a v a ila b le phosphorus, t o t a l n itr o g e n , and o rg a n ic m a tte r has been discussed., but no attem p t has been made to c o r r e la te these fa c t o r s . These re la tio n s h ip s w i l l be discussed in p re s e n ta tio n o f d e t a il fo llo w in g /th e b io lo g ic a l in v e s tig a tio n s . NUMBERS OF BACTERIA AND FUNGI IN RELATION TO SOIL TREATMENT AND SOME AVAILABLE NUTRIENTS I f a v a ila b le n u tr ie n ts and numbers o f m icroorganism s in s o ils are r e la te d and are e q u a lly a ffe c te d by s o il tre a tm e n t as s ta te d by Waksman (32) , then a d e te rm in a tio n o f the number o f the more im p o rta n t groups o f m icroorganism s and the q u a n titie s o f a v a ila b le n u tr ie n ts should show some d e f in it e re la tio n s h ip s f o r these s o ils . The number o f fu n g i de ve lo p in g on a c id ag a r media and b a c te ria developing on Brown's a liu m in a te agar media from a i r d ry samples o f the d if f e r e n t s o ils were de term ined. The r e s u lts g ive n in ta b le 3 show the a c tu a l numbers o f organisms p re se n t and a ls o the numbers as p e r cen t based on the number fou nd i n the u n tre a te d s o i l . The re s u lts o f chem ical te s ts are expressed i n p e r cent based on the r e s u lts f o r the u n tre a te d s o il. are c o n s tru c te d from the percentage data. The curves 100 P 1 Per Cent tiD O Pi CT\ m O rH K\ S 00 00 CTv h— 00 rH 00 o r— 3 and (3 O *H P CO at ^3" CU VO O o © (6 Ph O CD pci O O O o o m o c— VO LT\ 00 00 m O «fc CTv LT\ VD rH rH © a iH w OJ o CTi * pH o 8 . r— rH cr. rH P I P3 01 rH •rl o t/1 1 a* © Pi at • o J2i © O rH O m •H m rH O m CVJ o K\ O w $ 9 9 9 In o m l— O m 00 O CT\ O m m & iH S3 — t m O i ¥: NVOIHOIW :::::::::: E - 4- m err M atter, and Available Phosphorus. Treatment, Soil Reaction, and Content ::s::::i»asK»ss to Soil ±z Organic fi-yicj-ffft in Relation i and Pungi of Total Nitrogen : Numbers of Bacteria FIG.IC 3H X V W JLN3 WXMVdHCI - 13 - Lime alo ne g r e a tly in c re a s e d the number o f b a c te ria over the number fou nd in the u n tre a te d s o i l , and lim e in com bination w ith f e r t i l i z i n g elements enhanced t h i s in c re a s e . T h is in cre ase in numbers was e s p e c ia lly marked f o r those s o ils re c e iv in g phosphorus w ith lim e o r w ith lim e and o th e r f e r t i l i z i n g elem ents. The evidence p o in ts to the im p o rta n t p a rt p la ye d by phosphorus in b a c te r ia l development i n these s o ils . A l l f i e l d tre a tm e n ts in cre a se d the number o f fu n g i de veloping on a g a r p la te s over th a t from u n tre a te d s o i l . T h is incre a se was e x ce e d in g ly g re a t f o r s o ils 308 and 309, w hich re c e iv e d lim e p lu s potassium and lim e p lu s superphosphate, re s p e c tiv e ly . A d d itio n s o f lim e a lo n e , lim e p lu s n itr o g e n , lim e p lu s ro ck phosphate, and com binations o f lim e , phosphorus, and potassium, gave o n ly sm all incre ase s in numbers o f fu n g i in the s o i l . These re s u lts in d ic a te no c o n s is te n t r e la tio n s h ip between s o i l tre a tm e n t and number o f fu n g i p re s e n t. A comparison o f b a c te r ia l numbers and a v a ila b le n u t iie n t s show some r e la tio n s h ip s , which may be c o rre la te d w ith s o i l tre a tm e n t. Phosphorus a p p lic a tio n s incre ase d numbers o f b a c te ria to a g re a te r e x te n t than any o th e r s o il tre a tm e n t. Except in case o f s o il 310N, w hich is u n u s u a lly h ig h in a v a ila b le phosphorus, a d i s t i n c t r e la tio n s h ip was found between the supply o f a v a ila b le phosphorus and numbers o f b a c te r ia . Since a l l com binations o f lim e and f e r t i l i z e r tre atm e nt had equal e f f e c t on s o i l r e a c tio n and since these same com binations in cre a se d the numbers o f b a c te ria u n e q u a lly , l i t t l e i f any c o r r e la tio n e x is ts between numbers o f b a c te ria and s o i l re a c tio n f o r these s o ils . Organic m a tte r co n te n t -1 4 - c o r r e la te s w e ll w ith the number o f b a c te r ia , except f o r s o ils 309 and 310N, w hich are c o m p a ra tiv e ly low in o rg a n ic m a tte r and h ig h in numbers o f b a c te r ia . T o ta l n itro g e n con ten t shows the same c o r r e la t io n w ith numbers o f b a c te r ia as does o rg a n ic m a tte r except in the case o f s o i l 301N, w hich i s r e la t iv e ly h ig h e r in t o t a l n itro g e n , but con taine d the s m a lle s t number o f b a c te ria . Numbers o f fu n g i showed l i t t l e r e la t io n to s o il tre a tm e n t a lth o u g h the o th e r fa c to r s discussed d id , so i t i s e v id e n t th a t l i t t l e o r no c o r r e la t io n c o u ld be made between numbers o f fu n g i, o rg a n ic m a tte r, t o t a l n itr o g e n , a v a ila b le phosphorus, s o il re a c tio n , o r numbers o f b a c te r ia . NITRIFICATION OF NITROGENOUS MATERIALS IN SOILS AND ITS RELATION TO OTHER SOIL PROCESSES N i t r i f i c a t i o n in s o ils , as a measure o f c e r ta in b io lo g ic a l and chem ical r e la tio n s h ip s , has been used w ith v a ry in g degrees o f success f o r many y e a rs . I t i s con sidered by some in v e s tig a to r s as a tru e measure o f s o i l p r o d u c tiv ity since the c o n d itio n s most fa v o ra b le f o r the n i t r i f y i n g process are q u ite s im ila r to those f o r p la n t g ro w th . I f t h is be tru e o r p a r t ly so, a study o f n i t r i f i c a t i o n in these s o ils should give some in fo rm a tio n o f value in d e te rm in in g the changes ta k in g p la ce i n s o ils due to s o il tre a tm e n t. S in c e th e b e g in n in g o f n i t r i f i c a t i o n s t u d i e s i n s o i l s , d i f f e r e n t methods o f p r o ced u re and d i f f e r e n t m a t e r i a l s f o r n i t r i f i c a t i o n have b e e n u s e d . Many o f t h e s e m ethods were m o d i f i c a t i o n s o f e x i s t i n g the S o Pt o by One of 43 rH 43 00 r— rH id Pi LT\ hrH CT\ VO id a CM CM rH rH O r*— 43 TO rH $ 00 rH K\ K"\ 8 iH VD h" rH S ' CM -=f IT \ CM CM 00 CM CM O I^N O O rH jdr 00 i" - 00 p^ 1 —1 -=f -=!■ rH O PO CM O O iH CM J" O LO 0 -M- j=3r CT\ r^\ rH rH O 1^rH O O rH ur\ CT\ • rH rH -=1" • O rH 00 CM tH rH • 00 -=t• Jh s 00, O • CM [*— O • VO O ir \ • r— LTv 00 • p— r*• 00 • ct-n 00 0 • CM ON rH • rH CT\ 0 00 CM CM 00 -xt r<~•N CM O r— 0 0 O VD rH CM s 8 & 0 - methods changed to f i t 16 - the c o n d itio n s o f the p a r t ic u la r in v e s tig a tio n . In re c e n t years an e f f o r t has been made to use o n ly the most g e n e ra lly accepted methods, so th a t re s u lts may have a more u n ifo rm in t e r p r e t a t io n and a w id e r use. It is e vid e n t th a t a b e tte r p ic tu r e o f the n i t r i f y i n g c a p a c ity o f a s o i l may be o b ta in e d by u s in g a standard method o f procedure a and s e v e ra l m a te ria ls c o n ta in in g th e n i t r i f i a b l e n itro g e n . The most commonly used method i s to add the n itro g e n o u s m a te ria l to 100 grams o f s o i l in tu m b le rs, make up to optimum m o is tu re , in cu b a te f o r tw enty e ig h t days, and determ ine the q u a n tity o f n it r a t e s form ed. From a survey o f the more re cent l i t e r a t u r e on t h is s u b je c t, i t i s e v id e n t th a t a l l n itro g e n o u s m a te ria ls are not e q u a lly n i t r i f i e d and th a t the n itro g e n in some m a te ria ls may be n i t r i f i e d r a p id ly under one set o f s o i l c o n d itio n s but ve ry s lo w ly under o th e rs . To determ ine the most s u ita b le m a te ria ls f o r n i t r i f i c a t i o n s tu d ie s in the s o ils , a group o f o rg a n ic and in o rg a n ic s a lts o f ammonium and urea were s e le c te d f o r a p r e lim in a ry t r i a l on one o f the s o ils used in th is in v e s tig a tio n . The m a te ria ls were added in s u f f ic ie n t q u a n titie s to give f i f t y m illig ra m s o f n itr o g e n pe r one-hundred grams o f a i r d ry s o i l . No a tte m p t was made to determ ine the most s u ita b le q u a n tity o f n itro g e n , because se ve ra l in v e s tig a to r s have shown th a t t h i r t y to f i f t y m illig ra m s o f n itro g e n p e r one-hundred grams o f s o il i s w e ll s u ite d f o r n i t r i f i c a t i o n s tu d ie s . A s u f f ic ie n t number o f s o il samples were prepared to p e rm it o f d e te rm in in g n it r a t e p ro d u c tio n a t weekly in t e r v a ls . The data are g ive n i n ta b le 6 in m illig ra m s p e r one hundred grams o f s o i l and a lso in pe r cent based on n it r a t e p ro d u c tio n in th e u n tre a te d s o i l . The fo rm e r data were Comparative Rate of N itr ific a tio n of Soil .Ammonium Salts in r>ne *-p *1. vme 01 « Soils >■■■■■■■ 3£)3n® tbD 3J.VJ.S N^filHOIW Nitrogen, Urea, and Several F IG . 3 Studied rjtywaHj.VM do j.N3Mj.uvdaa - 17 - used f o r c o n s tru c tio n o f fig u r e I I I . Some decided d iffe re n c e s are shown in the ra te a t w h ich t h is s o i l n i t r i f i e d these m a te ria ls . More n it r a t e s were produced from a l l th e s a lts except ammonium c h lo r id e , than from th e s o il* s own sup ply o f n itr o g e n . Ammonium sulp hate was a ls o a po or source o f n i t r i f i a h l e n itr o g e n . T h is decrease in n i t r i f i c a t i o n w ith the a d d itio n o f ammonium c h lo rid e and the r e la t iv e ly slow n i t r i f i c a t i o n o f ammonium sulphate i s i n agreement w ith the r e s u lts o f K u lik (15) aud T u rch in (28) on s im ila r s o ils . Urea was the most r a p id ly n i t r i f i e d o f the m a te ria ls used, fo llo w e d c lo s e ly by the o rg a n ic s a lts o f ammonium. Diammonium phosphate was n o t n i t r i f i e d r a p id ly d u rin g the f i r s t week, but a t the end o f it tw en ty days/was w e ll n i t r i f i e d . Prom these r e s u lts i t i s e v id e n t th a t ammonium c h lo rid e and s u lp h a te would n o t be as s u ita b le f o r n i t r i f i c a t i o n s tu d ie s on these s o ils as some o f th e o th e r s a lt s . To study n i t r i f i c a t i o n in these soils, u re a , ammonium o x a la te , c it r a t e , a c e ta te o r phosphate cou ld be used as s u f f ic ie n t q u a n titie s o f n it r a t e s were produced from them to p e rm it o f comparisons o f the e ffe c ts o f f e r t i l i z e r tre a tm e n ts . Por the n e x t stu d y, urea and diammonium phosphate were s e le c te d , because the form er c o n s is te n tly produced the g re a te s t amounts o f n it r a t e s and because the l a t t e r produced s u f f ic ie n t q u a n titie s o f n it r a t e s f o r the purposes o f the study and in a d d itio n the phosphate fa c to r was e lim in a te d f o r a l l p l o t tre a tm e n ts . To. these were added ground a l f a l f a and cottonse ed meal in o rd e r to have a g re a te r v a r ie ty o f m a te ria ls since i t i s main­ ta in e d ( 31) th a t a b e tte r p ic tu r e o f n i t r i f i c a t i o n in s o ils can be o b ta in e d by u s in g se ve ra l m a te ria ls and more than one method o f procedure. The m a te ria ls were added to one hundred grams o f a i r d rie d s o il in quan- ^OJ 3• 00 ft o ITv r^\ • o rH 00 0\• OJ rH IT \ OJ • rH rH LTk 1— • rH rH CTs lT\ • rH rH 00 OJ « cr. Vt O m o LT\ • OJ B &b o or-t OJ cr» • 00 • 5 s • CX\ +> •H CD +3 <6 ft +» •H A lf a lf a (Treatment to Field in Relation O O 00 OJ I M aterials >> s £ tx *t(X from D ifferent to * -=r ^J* O • LTv 8 o• o LT\ VD * VjO i s production +> CD cU <0 Ta”ble 5* Ultrate EH a O © (D ft Ei a •H & M a a a a ir \ 0~- 00 O r-o CPk a M rH •H O CO • o & & rH O r^\ CO rH O r*-\ OJ o l*-\ o o r^> o o rH rD * Nitrate s Production tin Relation to Field g 3©3-QoO 3±V±S NV^IHOIW Treatment t- L.m-:a±xh Materials of S o ils m from D ifferent FIG. 4 XVIAI dO XN3MXUVe(3a 1 - title s 19 - to g iv e f i f t y m illig ra m s o f n itro g e n f o r urea and diammonium phosphate and o n e ^ h a lf o f one p e r cen t o f the o rg a n ic p la n t m a te ria ls * The u s u a l s o il tu m b le r method was fo llo w e d throughout the study o f n itr if ic a tio n . N it r a t e p ro d u c tio n in m illig ra m s from the fo u r a p p lie d m a te ria ls i s g ive n in ta b le 5 and in fig u r e IY . I t i s e v id e n t from th e data th a t f i e l d tre a tm e n t has changed the a b i l i t y o f these s o ils to n i t r i f y c e r ta in n itro g e n o u s m a te r ia ls . phosphorus, and potassium i n s o i l 3^5 The com bination o f lim e , re s u lte d in the g re a te s t n i t r i f i c a t i o n power, fo llo w e d c lo s e ly by lim e , phosphorus, n itr o g e n , and potassium i n s o il 302. Lime p lu s superphosphate, lim e p lu s po tas­ sium, and lim e p lu s n itro g e n produced in the o rd e r given g re a te r eg Pi S O of Nitrogenous M aterials n it r if ic a t io n 6. r -to ! Ph Pi © O Pi a Oh CO fi o © 01 ta © Pi & Table Pi © Ctfi O Pi 43 tH }2l 1—1 •H o U1 O © 4 * 1 £> •H J2S S © © p +* *H d P .3 H-5 O Pi g to Pi © a 1 .§ Pi n * ID Pi •xi © © W rH pi CD O © +» a +» o o. rH rH CO CM o o o A Pi 01 o © VI rH ctf Vi Ph © ,_| O rH ir\ rH 3 rO cO r-t •H O Pi ■3 J 1 pH •H o 03 •h tfi Oh © Ph E4 • o tSi © PJ O £3 pSi rH O f'-N § Hi 1 g S a S 03 r—1 O o CM LCV O l^ i I'— O fOv to ov o o & O rH r<"\ ViSHJLVMI I o p C O 4* 6 0) 6 p flj © fn EH •CJ L::;q±!:r_'+r^ * fH (0 •H iffiSS P=l P Pi © u 0) «H •H w w -4 i ! L',;-'J®° rJ o ft •H t> © n iH fH *5 Ph ta i rH •H 0 CO Pi ■H (0 © «n rp i ri-i—fi dimcuiq iiiiiH I &j±S 6 i fH © P P ai S o p C O •d a 1 fn O 2 a © © t*o > <0 to o fH P 1 O d o •H W-iT*i ^ V f 4 - - j 4 —I s o3 P p o •H o p cC o •H fn P •H i§ s g EH PI © p PI o o o a o •H P jrjijqrbj^L- rLdiLnz we: -,J-*— ti 3031100 BJ^LS NV9IHDIW " : :•’-.•■>Ja *■) fl3 rH o CO j§ Ph p - 21 fig u r e V on a percentage b a s is * W ith the e xc e p tio n o f s o i l 310U w hich i s h ig h in a v a ila b le phosphorus and r e la t iv e ly low in n i t r i f y i n g c a p a c ity f o r u re a and cottonseed m eal, th e re i s a close c o r r e la tio n between a v a ila b le phosphorus and n it r a t e p ro d u c tio n from these m a te ria ls f o r a l l s o ils s tu d ie d . N i t r i f i c a t i o n o f a l f a l f a meal c o r re la te s n ic e ly w ith a v a ila b le phosphorus, except f o r s o ils 309 and 3^0 * w hich are h ig h i n t h is element and r e la t i v e l y low in n it r a t e p ro d u c tio n from t h i s m a te r ia l. N itr a t e p ro d u c tio n from diammonium phosphate shows l i t t l e c o r r e la t io n w ith a v a ila b le phosphorus. O rganic m a tte r con ten t and n it r a t e p ro d u c tio n from cottonseed meal and urea show a c le a r c o r r e la tio n , w h ile n it r a t e p ro d u c tio n from a l f a l f a and diammonium phosphate shows le s s r e la tio n s h ip . T o ta l n itro g e n shows a s im ila r r e la t io n to n it r a t e p ro d u c tio n from the d if f e r e n t m a te ria ls as o rg a n ic m a tte r c o n te n t. CARBON DIOXIDE PRODUCTION PROM CELLULOSE IN RELATION TO SOIL TREATMENT B io lo g ic a l processes i n s o ils r e s u lt in g i n the lib e r a t io n o f carbon d io x id e from o rg a n ic m a te ria ls have been s tu d ie d e x te n s iv e ly f o r many y e a rs . I t has been claim ed by some in v e s tig a to rs th a t a measure o f t h is process fu rn is h e s a b e tte r in d e x o f b io lo g ic a l a c t i v i t y i n s o ils than any o th e r method y e t devised. In t h is study we are concerned c h ie f ly w ith the e f f e c t o f f i e l d tre a tm e n t on chemical and b io lo g ic a l r e la t io n ­ ship s i n se ve ra l s o ils . A measure o f carbon d io x id e p ro d u c tio n from s o il the decomposable m a te ria l in these s o ils may show changes r e la te d to s o i l tre a tm e n t, i f changes o f measurable magnitude have taken p la c e . © 1 o u PH cd ifl U Pi o •H Q Pi -=JCM rH IsCM rH PdrH rH to rH rH j? -=1* rH VO CT\ CM VO o VO LTV LT3 to LC3 rH e \ to CT\ o> CO . ic\ K'* to VO CM VO to CM VO CM O o rH IsCM 1—t VO VD rH rH O'* rH to rH O K-\ rH VO VO rH VO rH CM to to CM CM O O O CM rH CT\ <—! VO VO CM rH 110 o 100 Per Cent rH o o rH rH rH rH rH VO CM rH rH 3 IT \ CT\ rH vjD VO O O rH to r— rH CT> CM hO O', CD CO 4* O rH r“1 o rH M rH CD O cd o CD CO o CMrH rH 0 Q rH Cti rH O CD O + Per Cent to O LT\ CM jp Is- • a a CM !*■% rH CM CM LT\ rH rH Iscr> pd" 1— VD i—1 rH LTv rH 3 IsO CM R rH CO r^1—1 • CO i r^> KN to rH rH i—1 rH LTv rH r*~\ rH rH CM CM VO rH CM O O rH K't i—1 i—1 Is- if VD cr\ J- 1— i—1 -=J- CM CM O tJ r*“\ to CO Per Cent CL, CD •H CM 111 CMrH S3 O 0) vo K\ rH 121 •H Per Cent & ,3 0 D ifferent CM CM -Z j- rH rH rH • CO a rH rH CD ai w CD CO O r^J rH rH CD CD ft O Per Cent •H CO 1 rH i—i rH o CM IT \ rH LO» rH rH tr\ rH i—1 VO O CM CO CM CM rH IsrH rH IsrH to LTx rH CM CM rH O i—1 « o S3 CD & o S3 5 O K-\ O Lime CD U EC F ie ld Treatment Pi +§» S oil with Cellulose Per Cent Average Tor All Treatments to S o il added in Relation Chemicals + CD CO -=1* o O rH , Pi •H o 1 R rH S 1\j from Production Carbon Dioxide 01 & CD 7» ro p O rH S ■ —1 3 r3 o © 10 pi Table CD 4- co O to l a s-3 3 CO rH O K') K-\ CM O lo O ro r— o i*"\ to o M S3 K'S a g? 03 O < --i O K\ r*~\ used in carbon t r« iSs. ,0a4- Apparatus dioxide evolution f Fig. VI. s tu d ie s . OJ - 23 The 'usual method o f s tu d y in g carbon d io x id e p ro d u c tio n in s o ils i s to add an o rg a n ic m a te r ia l and c o lle c t the carbon d io x id e e vo lve d by a b s o rp tio n in an a lk a lin e s o lu tio n . D iffe r e n t o rg a n ic m a te ria ls have been used as a source o f energy f o r m icroorganism s in carbon d io x id e p ro d u c tio n s tu d ie s w ith v a ry in g degrees o f success. t h i s study c e llu lo s e was used as the source o f energy, because i t In con­ ta in s carbon, oxygen, and hydrogen, w ith o u t any m in e ra l elem ents, and because o th e r in v e s tig a tio n s have proved i t s valu e in s tu d ie s o f t h is k in d . I t has f u r t h e r been shown th a t c e r ta in elem ents, namely n itro g e n and phosphorus, in flu e n c e the ra te o f CO2 p ro d u c tio n from c e llu lo s e and s in c e the s o ils under study are a l l low i n these elements b u t show d iffe re n c e s due to f e r t i l i z e r tre a tm e n t, i t was deemed a d v is a b le to make some d e te rm in a tio n s in w hich phosphorus o r n itro g e n was added w ith c e llu lo s e to the s o ils . For a d d itio n a l com parisons, potassium and c a lciu m i n the form o f c h lo rid e s were added w ith c e llu lo s e to some c u ltu r e s . In s te a d o f u s in g an a lk a lin e s o lu tio n f o r a b sorb ing the carbon d io x id e , as i s u s u a lly done, a s o lid commercial p ro d u c t known as n a s c a rite " was used. S u ita b le apparatus was assembled as shown in fig u r e V I, to make the necessary d e te rm in a tio n s o f carbon d io x id e p ro d u c tio n . T h is method i s s im ila r to the one found e n t ir e ly s a tis fa c to r y f o r t h is k in d o f study by T urk ( 27) . In fig u r e V I, l e t t e r s A, B, and C re p re s e n t c o n ce n tra te d sodium h yd ro xid e , s u lp h u ric a c id , and soda lim e , r e s p e c tiv e ly , f o r p u r if i c a t i o n o f the incom ing a i r . D i s d i s t i l l e d w ater f o r m o is te n in g the a i r to p re ve n t excessive d ry in g o f the s o ils , E i s a $00 c c . E rlenm eyer f la s k c o n ta in in g the tre a te d s o i l ; F i s c o n ce n tra te d s u lp h u ric a c id f o r the removal o f w ater v a p o r; G c o n ta in s phosphorus p e n to xid e dO ANaWXUVdHd ca P o •rl > u Ph CD •rH O CO p •H Q > ca o CD o s u o $ *H « o p o fi as o «H O P o •H +> O £ o J-t Ph JS m +» o $a A ca JJ-J-U rH as aS CD h o eh ,H S 'd J ) (D •H P» p CD !h Cg it O te ff t= £ CD S> tH CD O P © P rH •H «*0 P -H *> -H © «H O P M ijeSjn 3 £ > 3 ljjf c > 3 3 X V JL S N V g f lH O IW 1 CD pej - 2k - f o r f u r t h e r d e s s ic a tio n o f the a i r ; H c o n ta in s the R ascarite« f o r a b s o rb in g the COg produced; and I c o n ta in s co n ce n tra te d sodium hydroxide to p re v e n t back flo w o f carbon d io x id e from the s u c tio n pump J . Suf­ f i c i e n t a i r was drawn th ro u g h th e system by s u c tio n from the w ate r pump to draw a l l the carbon d io x id e produced in the s o i l in to the ,,a s c a r ite ,, tu b e , where i t was absorbed f o r w e ig h in g . R e s u lts o f carbon d io x id e p ro d u c tio n d e te rm in a tio n s i n m i l l i ­ grams p e r hundred grams o f s o il and in p e r cent based on r e s u lts from the u n tre a te d s o i l are g ive n in ta b le 7* A comparison between the amounts o f carbon d io x id e produced from c e llu lo s e in these s o ils w ith a d d itio n s o f chem icals i s shown g r a p h ic a lly in fig u r e V II i n m illig ra m s o f COg p e r 100 grams o f s o i l , produced in 2^ days. The a d d itio n o f n it r a t e n itro g e n gave a much g re a te r p ro d u c tio n o f carbon d io x id e from c e llu lo s e in a l l s o ils than any o f the o th e r tre a tm e n ts . These r e s u lts s u b s ta n tia te co n c lu s io n s c ite d in the li t e r a t u r e th a t n itr o g e n p la y s a very im p o rta n t p a rt in c e llu lo s e decom position as measured by COg p ro d u c tio n . Th^bear out the statem ent made in an e a r lie r p a r t o f t h is paper th a t these s o ils being extre m e ly low in t o t a l n itro g e n would be expected to respond to a p p lic a tio n s o f t h is elem ent. A d d itio n s o f a v a ila b le phosphorus increased the p ro d u c tio n o f carbon d io x id e from c e llu lo s e much more than d id a d d itio n s o f calcium o r potassium c h lo r id e . • T h is s tim u la tio n o f carbon d io x id e p ro d u c tio n from c e llu lo s e by phosphorus a d d itio n s fo llo w s from the f a c t th a t these s o ils are r e la t iv e ly low in t h is element and th a t a v a ila b le phosphorus sup ply has been shown to in flu e n c e the ra te o f c e llu lo s e decom position as measured by C02 p ro d u c tio n . LVH3HJ.VM JO J.N3MXUVd3d Alone and from t# sssse S85SSSSSSS 5S8S 1 of Carbon Dioxide from Cellulose s ::s!!ss:»8s»9«sasss^ £ ¥= r n - i- m mmW 303"tS?0 3.LVJ.S NV9IHOIW m Effect of Previous Soil Treatment Cellulose plus Various Chemicals of Production ■ iiiiin n i - 25 - A d d itio n s o f calcium and potassium c h lo rid e s in c re a s e d to a lim it e d extend the p ro d u c tio n o f carbon d io x id e from c e llu lo s e over th a t from the s o ils re c e iv in g c e llu lo s e a lo n e . Potassium c h lo rid e seemed to be more e f f e c t iv e i n t h is re sp e ct than calcium c h lo rid e . T h is would in d ic a te a more im p o rta n t p a r t p la y e d by potassium in t h is process than c a lciu m as the q u a n titie s o f c h lo rid e s added in b o th cases were e q u a l. When the r e s u lts o f carbon d io x id e p ro d u c tio n from c e llu lo s e w ith c e r ta in chem icals added i s c a lc u la te d in p e r cent based on the u n tre a te d s o il as shown in ta b le 7 and fig u r e V I I I , the e f f e c t o f s o il tre a tm e n t on t h i s process may be dem onstrated. The r e s u lts show a marked in cre a se in th e s o il* s a b i l i t y to produce COg from c e llu lo s e f o r a l l f e r t i l i z e r tre a tm e n ts as compared to the u n tre a te d s o i l . Lime alone in c re a s e d the p ro d u c tio n o f COg from c e llu lo s e o ve r the u n tre a te d s o i l , b u t n o t to the e x te n t th & t com binations o f lim e , n itro g e n , phosphorus, and potassium d id . The p ro d u c tio n o f COg from c e llu lo s e was g re a te s t in s o il 305, w hich had re c e iv e d lim e , potassium , and phosphorus i n the f i e l d . S o il 302 fo llo w e d 305 i n COg p ro d u c tio n from c e llu lo s e a lo n e , w h ile com binations o f lim e p lu s n itr o g e n , lim e p lu s potassium , and lim e p lu s phosphorus were l i t t l e i f any b e tte r than lim e alone i n in c re a s in g the p ro d u c tio n o f COg from c e llu lo s e in these s o ils . Carbon d io x id e p ro d u c tio n from c e llu lo s e w ith a d d itio n s o f ca lciu m c h lo rid e and o f potassium c h lo rid e s was g re a te s t i n s o ils 305, r e c e iv in g lim e , po tassium , and phosphorus, fo llo w e d by s o ils 307, re ­ c e iv in g lim e and n itro g e n i n the f i e l d tre a tm e n ts . A l l o f the f i e l d tre a tm e n ts in cre a se d COg p ro d u c tio n from c e llu lo s e w ith a d d itio n s o f CVI rH rH i—1 rH O O rH O rH i—1 CO r<-\ rH a rH O O rH i—1 rH rH VO OJ rH O O rH to r— O O rH I to CT\ CO to VO OJ ■ —i rH KV rH CT\ KV i—1 i— rH VD S CVI r<~\ rH rH CVJ rH rH i—1 rH O KV rH -dCVI rH r— OJ i—i -drH rH CO rH rH i—1 CTN to CO LTV CO ro CO rv o- 1*— 0J VO VO rH rH CTV rH KV to rH CVI I— i—1 CVI LTV rH j=3r O O rH VO rH CO 1—1 rH r— rH <3 rH H ir\ -d" 8 rH O O rH » rH 1— K> rH a ■ —i LT\ rH rH rH rH 81 T o ta l N itro g e n O O rH — r*-\ O rH o S3 rH is A v a ila b le Phosphorus -d" CT\ . . . Based . Nitrogen ! 1 O O rH Phosphorus and Total to B o * © 5b © H J © d B © to *■ O to Available S(D s© Ssi o d 0 •H +» 1 ta -=t o o •S . ® 4* © o •a o £ d o -p d < o o u © CL, d •H 4> © 1 3 QJrH CO © £3 O fH CM in Relation <-« *3 rH M rH © O o rH rQ . S o 4 © W r& J ^ O © to o rH O ra tJ i—1 © o © vi +> 8 © A +3 d o F ie ld Treatment Chemical rH •rH O CO 100 *3 8 H* U ---- and B io lo g ic a l 3 CD o rH NO - 31 GREENHOUSE STUDIES To determ ine f u r t h e r the e f f e c t o f s o i l tre a tm e n t on chem ical co m p o sitio n and b io lo g ic a l processes in the s o i l , crops o f sweet c lo v e r, ry e , and soy beans were grown on the s o ils in p o t c u ltu re s in the greenhouse. The crops were cu t a f t e r a 12-weeks growth p e rio d , a i r d r ie d , and w eigh ts determ ined. The harveste d m a te ria l was then ground and re tu rn e d to a p o r tio n o f the s o i l on w hich i t grew f o r carbon d io x id e p ro d u c tio n stu d y. I t was the o b je c t o f t h is study to determ ine i f s o il d iffe re n c e s found in the p re vio u s work on these s o ils cou ld be measured by cro p y ie ld s in the greenhouse and i f carbon d io x id e p ro d u c tio n when the crops grown were re tu rn e d to the s o ils was comparable to r e s u lts from p re v io u s carbon d io x id e p ro d u c tio n s tu d ie s . D u p lic a te tw o -g a llo n p o ts o f the d if f e r e n t s o ils were used. The m o is tu re co n te n t was m a in ta in e d by w eighing the p o ts a t fre q u e n t in t e r v a ls and b r in g in g up to w eight w ith d i s t i l l e d w a te r. The crop y ie ld s i n grams and in per cent based on the y ie ld from the u n tre a te d s o i l are g ive n in ta b le 10. The data in p e r cent are a ls o presented g ra p h ic a lly i n fig u r e X l The r e s u lts show th a t s o i l 302, tre a te d in the f i e l d w ith lim e , n itr o g e n , phosphorus, and potassium , produced the la rg e s t y ie ld s o f a l l th re e crops and th a t s o il 30^* tre a te d i n the f i e l d w ith lim e , potassium , and phosphorus ranked second i n y ie ld o f p la n t m a te ria ls . These r e s u lts are i n acco rd w ith those o b ta in e d under f i e l d c o n d itio n s * F ie ld tre a tm e n ts o f lim e p lu s n itr o g e n , and o f lim e p lu s potassium , gave a p p ro x im a te ly the same y ie ld s o f legume p la n t m a te ria l as lim e a lo n e , but the y ie ld s were n o t so la rg e as f o r s o ils 302, 305» and those re c e iv in g lim e w ith phos­ p h o ru s. The s o i l re c e iv in g lim e alone tre a tm e n t gave la r g e r y ie ld s o f a l l Studies Expressed as Grown o f Greenhouse Pot from Crop Yields 10* Table © 5p fH © > << 6 o Jh i O 03 W P H R © © Pi r o •d © © © PP © r> Ph •H »d R © % R CQ CD •H EC & 3 © R ffl cb fH _R R 1 fn P R © O fH © Ph R © O fH © Ph rn Pi R © o fH © Ph O O rH r^\ ro CM CO C\| KN r^vo CM LO St CM CO KN CM r— IT\ CM VO CO CM O O LO ir \ lf \ h- O r— CM VO CO ir \ CO VO VO VO sir rH • VO ITS ir•\ OS 1"— st 3 r*• -R- CT» 1"• St S t© st i— I rH rH rH rH rH rH rH rH rH rH rH p P R © O +3 p fH © > rH rH m m CD (D CD CO rH i—i CO rH O GO rH o LO. rH VO CO rH OJ tO H rH OJ rH rH i—1 rH CO