THE TOXIC INFLUENCE OF FLUORINE XS FBDSPHAT2C FERTILIZERS OH THE GERMINATION OF CORN H* Hiswe M o rn A THESIS PRESENTED TO THE FACULTY" OF MICHIGAN STATE COLLEGE OF AG&ICULTURE AND APPLIED SCIENCE IN PARTIAL FULFILLMENT OF THE HBqUlEEMENTS FOR THE maws® OF DOCTOR OF PHILOSOPHY" E a s t L ansing l 9 3* ProQuest Number: 10008238 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 10008238 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 0 6 - 1346 acknow ledgement The w r ite r w ish es to e x p re s s h is a p p recia tio n to Dr. C. H. Spurway and Dr* C. S.. M illa r fo r h e lp fu l su g g estio n s X. and c r itic is m s during the p ro gress o f the work and p rep aration o f th e m anuscript. Thanks are due to oth er members o f the S o ils Department and the Experiment S ta tio n fo r th e ir k in d ly I n te r e s t and a d v ic e . 100483 - 1 - INTRODUCTION Marked re d u c tio n i n th e p e r c e n t o f g e m in a tio n o f seed s o f c u l t i v a t e d p l a n t s h a s o f te n r e s a l te d from th e a p p lic a tio n o f f e r t i l i s e r s I n c o n ta c t w ith o r n e a r th e seed* The c au se s and remedy f o r t h i s in ju r y have heen th e s u b je c t o f numerous in v e s tig a tio n s * The Commlttee on f e r t i l i s e r Placem ent o f th e N a tio n a l f e r t i l i s e r A s s o c ia tio n (7) and co­ o p e r a tin g a g r i c u l t u r a l experim ent s t a ti o n s have accom plished much to remedy t h i s o b je c tio n a b le e f f e c t by d eterm in in g s a fe and e f f e c t i v e methods o f f e r t i l i s e r a p p lic a tio n . Some e x c e lle n t work h a s a ls o been done to determ ine some o f th e causes o f t h i s f e r t i l i s e r in ju ry * I t was b e lie v e d , how ever, t h a t th e re was need f o r f u r t h e r knowledge co n cern in g t h i s m a tte r , and t h e r e f o r e , th e p re s e n te d In v e s tig a tio n was undertaken* HISTORICAL The l i t e r a t u r e i s r e p l e te w ith o b se rv a tio n s o f r e t a r d a t io n and I n h i b i t i o n o f g erm in atio n and grow th caused b y f e r t i l i s e r s and o th e r ch em ical compounds. As e a r ly a s 1733 J e th r o T u ll (lb ) n o te d t h a t "to o much n i t r e c o rro d e s a plant*1• That was ap proxim ately one hundred y e a rs b e fo re th e f i r s t shipm ent o f C h ile a n n i t r a t e from Iq u iq u e . L ate i n th e n in e te e n th c e n tu ry a n a c tiv e i n t e r e s t was tak en in the problem by f r e n c h and German in v e s tig a to rs * These e a r l y in v e s tig a tio n s were concerned c h i e f l y w ith la b o ra to ry t e s t s u s in g s o lu tio n s o f s in g le s a l t s . C la u d e l and C ro c h e te lle (3) in v e s tig a te d the e f f e c t o f SC I, ICgSO^. (BTH^gSO^, lteS03 , ammonia te d sup erp h o sp h ate, and b a s ic s l a g on th e g e rm in a tio n o f seeds* A ll o f th e s e m a te r ia ls a t th e c o n c e n tra tio n s u se d i n t h e i r experim ent ex cep t b a s ic s la g (which i s r e l a t i v e l y in s o lu b le ) , r e ta r d e d g e rm in a tio n . V incent (15)* w orking w ith wheat seeds and s e v e r a l so lu b le f e r t i l i s e r s a l t s , concluded th a t th e a b i l i t y to germ inate was d e creased w ith In c re a s e In c o n e e n tra tlo n o f th e s a l t . Much l a t e r . In 1921, Rudolphs (9 ) showed t h a t th e r e t a r d in g a c t i o n , w ith some e x c e p tio n s , co u ld he a t t r i b u t e d to an in te r f e r e n c e w ith a b s o r p tio n o f w ater by th e seed a s a r e s u l t o f th e h ig h osm otic c o n c e n tra tio n o f th e s a l t so lu tio n s * R aserous e th e r w orkers em ploying s o lu tio n s , p o t and f i e l d t e s t a have su p p o rte d th e f in d in g s o f th e s e men* L i t t l e doubt rem ains t h a t h ig h o sm o tic c o n c e n tra tio n s have a r e ta r d in g e f f e c t on germ ination* There I s , however, a n o th e r so u rce o f in ju r y to g e m in a tio n due t o to x ic s u b s ta n c e s , which cannot be a t t r i b u t e d to h ig h osm otic c o n c e n tra tio n * Sigmund ( 1 2 ) , w orking w ith peas, c o rn , and rap e s e e d s , found t h a t a 0*9 P®r s e n t s o lu tio n o f IF e n t i r e l y p re v e n te d g e rm in atio n . Bokofay (a ) found t h a t a 0*1 p e r c e n t s o lu tio n o f HaF was v e ry i n ju r i o u s to p re s s se e d lin g s and t h a t a 0*1 p e r c e n t s o lu tio n o f HF c o m p letely p re v e n te d t$S g e rm in atio n o f c r e s s , b a rle y , p e a s , f l a x , and bean se e d s. I t i s w e ll known t h a t phosphate ro c k c o n ta in s a c o n sid e ra b le q u a n tity o f flu o rin e * The a n a ly s e s by Jaco b s and Reynolds (5) and a ls o o f M arshal and co -w orkers (6) show t h a t th e f l u o r in e c o n te n t o f ro c k phosphate ra n g e s betw een t h r e e and f o u r p e r c e n t f o r most o f th e sam ples analysed* M oreover, th e f i r s t m entioned i n v e s tig a to r s showed t h a t m ost o f t h i s f lu o r in e i s c a r r i e d o v e r I n to th e p ro d u c t d u rin g th e m anufacture o f su p e rp h o sp h a te s, and th e l a t t e r w orkers found t h a t some f lu o r in e i s p re s e n t I n th e p h o sp h o ric a c id u se d f o r making tr e b le sup erp h o sp h ate. A llis o n ( 1 ) , growing c o m i n t m b l e r s , found t h a t heavy a p p lic a tio n s o f IS p e r c e n t superphosphate p re v e n te d g e m in a tio n * R ost ( S ) , i n p o t and f i e l d work, found th a t b o th 16 and U6 p e r c e n t su p erp h o sp h ates were in ju r io u s to c o m a t heavy r a t e s o f a p p lic a tio n * - 3 - H6 p e r con t superpho sphate m s toor e to x ic I n e q u iv a le n t amounts th e 16 p e r c e n t su p e rp h o sp h a te . C o n ta c t w ith th e s o i l f o r one month b e fo re p l a n t i n g l a r g e ly overcam e th e t o x i c i t y o f b o th f e r t i l i z e r s . bxpeeimehtal T o x ic ity o f S uperphosphates to G erm ination o f Com To I n v e s tig a te th e to x ic i ty o f v a rio u s f e r t i l i z e r m a t e r i a ls , a method was u se d s im ila r to t h a t u se d by b a c t e r i o l o g is ts i n t e s t i n g th e e f f ic ie n c y o f d i s i n f e c t a n t s . The organism s (c o rn seeds i n t h i s c ase) were p la c e d f o r a d e f i n i t e number o f h o u rs i n the m a te r ia l in v e s tig a te d and then p la c e d in a s u ita b le medium f o r grow th. The e f f e c t o f th e tre a tm e n t on V i a b i l i t y was th en compared w ith a c o n tr o l ru n p a r a l l e l w ith th e tr e a te d o rg an ism s. P a s t e s were made by m o iste n in g f e r t i l i z e r s w ith d i s t i l l e d w a te r. Each p a s te was p la c e d i n a two-pound g la s s b u t t e r d is h h aving a lo o se g la s s c o v e r. One hundred seed s o f c o rn were embedded i n each o f th e p a s te s f o r th e tim e d e sig n a te d . were u se d . Corn seeds o f uniform s iz e and h ig h g e rm in atlv e power Any seeds t h a t showed in d ic a tio n o f m echanical in ju r y o r p o o r q u a li t y were d is c a rd e d . A fte r rem aining I n th e p a s te f o r a d e f i n i t e number o f h o u rs , the seed s were removed, w e ll washed w ith d i s t i l l e d w a te r, weighed and p la c e d I n r a g d o l l s to g e m in a te . For the f l u i d tre a tm e n ts th e same p ro ce d u re was used e x ce p t t h a t 500 c c . I h r le s a e y e r f l a s k s were u sed a s con­ t a i n e r s d u rin g th e tre a tm e n t and th e se were sto p p ered w ith a b so rb e n t c o tto n . The " r a g d o l l 1* c o n s is te d o f a s t r i p o f cheese c lo t h e ig h t in ch e s wide and t h i r t y in c h e s lo n g . The hundred seeds were spread u n ifo rm ly on e ac h s t r i p and then r o l l e d up w ith th e c lo th u s in g a g la s s ro d a s an a x is to g iv e s t i f f n e s s to th e r o l l . %&ch Hr a g doll® was p la c e d i n a f iv e p i n t j a r c o n ta in in g one In c h o f d i s t i l l e d w ater so t h a t th e wick a c tio n o f th e - ch eese c l o t h m o iste n ed th e se e d s . k - The j a r s were th en connected ty means o f ru b b e r tu b in g a n d a e ra te d w ith m o ist a i r f o u r tim es d a i l y . G erm inated se ed s were removed d a ily and th e number t h a t g erm inated was re c o rd e d . As th e r e a c t i o n o f th e medium f o r p la n t grow th may in flu e n c e g e rm in a tio n , th e pH v a lu e s o f th e p a s t e s and s o lu tio n s were m easured by means o f th e q a ln hydrone e le c tr o d e . The r e s u l t s o f th e ex perim ent a re g iv en i n Table 1 . These r e s u l t s show t h a t comm ercial ammonium s u l f a t e and p o tassiu m c h lo r id e were in ju r io u s to g e rm in a tio n . The to x ic e f f e c t produced by th e two su p erp h o sp h ates was e s p e c ia lly s e v e re . Three h ours im m ersion i n th ese two m a te r ia ls was s u f f i c i e n t to reduce g e rm in a tio n s e v e n ty -fiv e p e r c e n t and th e tw elve h o u rs immersion k i l l e d p r a c t i c a l l y a l l o f th e s e e d s . S im ila r t o x i c i t y was n o t shown by monocalcium p h o sp h a te, p hosphoric a c i d , o r s u l f u r i c a c id i n th e c o n c e n tra tio n s u se d . i n w a te r. N e ith e r was i t shown by ro c k phosphate Rswever, when re e k phosphate and 0 . 1*13 j | s u l f u r i c a c id were m ixed, a p ro d u c t was o b ta in e d t h a t was h ig h ly to x ic to g e rm in atio n . S ince r e t a r d a t i o n o f g erm in atio n due to h ig h osm otic c o n c e n tra tio n o f th e medium i s r e l a t e d to th e w ater a b s o rp tio n o f th e seed th e w eight o f se e d s b e fo re and a f t e r immersion in th e f e r t i l i s e r p a s te s was re c o rd e d . p e r c e n t In c re a s e I n w eight o f th e seeds i s shown in Graph 1. I t i s The a t once a p p a re n t t h a t th e p h o sp h ates i n te r f e r e d w ith w a ter a b so rp tio n much l e s s th a n th e more so lu b le ammonium s u l f a te and potassium c h lo rid e which, in tu r n , were l e s s to x ic th a n th e p h o sp h a te s. The in te r f e r e n c e w ith w ater a b s o rp tio n , th e n , does n o t a f f o r d an e x p la n a tio n o f t h i s in ju r y . The h ig h a c i d i t y o f th e phosphates e v id e n tly d id n o t account d i r e c t l y f o r t h e i r t o x i c i t y u n d er th e c o n d itio n s o f the e x p erim en t, because th e more a c id p h o sp h o ric and s u l f u r i c a c id s d id n o t produce a s im ila r e f f e c t . T here­ f o r e , an e x p la n a tio n o f th e in ju r y must be sought elsew h ere. - 5 - Q u a lita tiv e t e s t s shewed t h a t c o n c e n tra te d s u l f u r i c a c id form ed h y d r o f lu o ric a c i d from ro o k p h o sp h a te. When th e m ix tu re was h e a te d a heavy e tc h in g was produced on a g la s s p l a t e , T h e re fo re , i t seemed d e s ir a b le to i n v e s ti g a t e f l u o r in e a s a p o s s ib le source o f in ju r y to g e m in a tio n . TOXICITY OF SOME FLUORINE COMPOUNDS TO GERMINATION OF CORN S o lu tio n s o f hydrogen f lu o r id e and sodium f lu o r id e were made con­ t a i n i n g known concent r a t io n s o f f l u o r in e . The s tr e n g th s o f th e s e s o lu tio n s were checked by t i t r a t i o n w ith 0 ,1 J thorium n i t r a t e u s in g a l i z a r i n a s a n I n d i c a t o r , a c c o rd in g to th e method o f W illa rd and W inters. The p i v a lu e s o f th e s o lu tio n s were determ ined by means o f th e quinhydrene e le c tr o d e . Four hundred c u b ic c e n tim e te rs o f each s o lu tio n were p la c e d i n s e p a r a te f i v e - p i n t J a r * . I n each o f th e s e were p la c e d two *r&g d e l l s 11 each c o n ta in in g one hundred seeds o f com * One o f th e se *feg d o l l s 1*c o n ta in e d P o la r Dent c o r n (th e same v a r ie ty used I n the p re v io u s e x p e rim e n t), the o th e r c o n ta in e d Piekefct*s Yellow Dent c o m . I n a d d itio n to th e j a r s con­ t a i n i n g th e f lu o r id e s o lu tio n s fo u r more were added to th e s e r i e s . th e s e c o n ta in e d boo c c . o f 0 . 1*13 N 0 .0 7 2 N th e t h i r d One o f the second an e q u a l volume o f bOO c c . o f 0 .0 7 2 £ p lu s one gram o f OaFg p e r 100 c c . o f s o lu tio n , w hile i n th e f o u r th j& r s o lid CaS*2 was s p rin k le d d i r e c t l y on th e seeds in th e brag dolf* and UOO c c . o f w ater was added. The j a r s were connected i n s e r i e s t y tu b in g , a e ra te d ,, e tc * , a s in. the f i r s t ex p erim e n t. I t should be n o ted t h a t t h i s egperlm ent and th e subsequent ones d i f f e r from th e f i r s t one In t h a t th e se e d s were exposed to th e re a g e n ts c o n tin u o u sly through th e w ick a c tio n o f the *rag doll*1, w hile i n th e f i r s t ex p erim en t the seed s were exposed to th e re a g e n ts only f o r a lim ite d space o f tim e . The r e s u l t s a re g iv en In Table 2 . - 6 - S e v e ra l s a l t e a t f a c t s were brought o u t by the d a ta o f the second e x p e rim e n t. Hydrogen and sodium f l u o r id e were b o th to x ic to g e rm in atio n o f c o m an d t h e i r t o x i c i t y In c re a s e d w ith c o n c e n tr a tio n . more to x ic th a n sodium f l u o r i d e . o f Boko m y ( 2 ) . Hydrogen f lu o r id e was These r e s u l t s a re in acc o rd w ith th e f in d in g s He a t t r i b u t e d th e to x ic l ty to th e passage o f f l u o r in e in to th e se e d where i t u n ite d w ith th e calcium p r e s e n t th e re to form In s o lu b le calciu m f l u o r i d e . Ha s t a t e s : #The calcium i s a n i n t e g r a l c o n s titu e n t o f many c e l l o rg a n s and p ro b ab ly o c c u rs a s calcium p r o te ln a te i n the sam e.11 M s th e o ry I s f u r t h e r su p p o rte d by h i s r e s u l t s on th e e f f e c t s o f po tassiu m o x a la te and o x a lic a c i d . B oth th e s e m a te r ia ls proved in ju r io u s in 0 .1 p e r c e n t s o lu tio n s , e s p e c i a l l y th e l a t t e r which k i l l e d th e seed s o f c r e s s . S lg su n d , a l s o , found t h a t 0 .5 and 0 .3 p a r c e n t s o lu tio n s o f t a r t a r i c a c id (a n o th e r ch em ical which form s &a In s o lu b le compound w ith calcium ) were i n ju r i o u s to wheat and k i l l e d pea and rap e se e d s . But Sigmund o b ta in e d no germ­ in a t i o n o f p e a s , w heat, and rap e when he u sed s o l i d calcium o r barium f l u o r i d e . I n th e p r e s e n t I n v e s tig a tio n , however, re p e a te d a tte m p ts to o b ta in i n ju r y to co rn by s o l i d calcium f lu o r id e in d ic a te d th a t I t had no e f f e c t on th e g e rm in atio n o f c o m . g erm in ated r e a d i l y . Seeds o f c o m com pletely embedded i n th e m oist s a l t When 0 .0 J 2 £ were e n t i r e l y d i f f e r e n t . HgSO^ was added to calcium f lu o r id e the r e s u l t s Then th e m a te r ia l became h ig h ly t o x ic , a llo w in g no g e rm in atio n to take p la c e , p ro b ab ly due to th e fo rm atio n o f hydrogen f l u o r i d e . The s tr e n g th o f the su lp h u ric a c id u se d a ls o had an e f f e c t on g e m ­ in a tio n . I n th e J a r c o n ta in in g 0.1*13 £ n o t only was th e p e r c e n t germ­ i n a t i o n red u ced b u t th e r o o ts showed sig n s o f sev ere I n ju r y , b a r e ly em erging from th e se e d , and the sh o o ts were a ls o in ju r e d b u t to a l e s s e x te n t. I n some c a s e s th e sh o o t ap p eared b e fo re th e ro o t which i s the re v e rs e o f th e n a tu r a l p ro ce ss. The s e e d lin g s soon became covered w ith mold and i t was d o u b tfu l i f th e y w eald have s u rv iv e d I f l e f t to grow. The 0 .0 7 2 £ HgSO^ tre a tm e n t prew ed t o he I n ju r io u s a le e h a t the e f f e c t wat r e l a t i v e l y much le e s se v e re . S a lte r and M cZlvalue have shown t h a t a n u t r i e n t s o lu tio n h aving a pH o f 2 .1 7 a llo w e d 26 o u t o f 30 c o m seed s to g e rm in ate . and e v e n tu a lly d ie d . The s e e d lin g s d id n o t f l o u r i s h , how ever, A s o lu tio n o f pH 2. 9 6 , on th e o th e r hand, allo w ed n e a r ly p e r f e c t g erm in atio n (29 o u t o f JO) h u t grow th was r e ta r d e d . Henee th e a c i d i t y m ust he ta k e n in to a cco u n t a s a f a c t o r a f f e c t i n g g e rm in atio n . I t should a ls o he n o te d th a t th e co rn seeds showed a marked v a r i a b i l i t y w ith r e s p e c t to t h e i r s u s c e p t i b i l i t y to f l u o r in e I n ju r y . F or exam ple, I n th e c a s e o f P i c k e t t *s p e n t In th e hydrogen f lu o r id e s o lu tio n s n in e p e r c e n t o f the seed s were a b le to germ inate i n th r e e hundred p a r t s p e r m illio n o f f lu o r in e w hereas o n ly sev en ty p e r c e n t o f th e seeds germ inated I n a s o lu tio n c o n ta in in g one hundred p a r t s p e r m illio n o f f l u o r in e . M oreover, the P o la r Bent v a r i e ty a p p e a re d to be more s u s c e p tib le to f lu o r in e in ju r y th an P i c k e t t ’ s Bent i n t h i s ex p erim en t a n d a ls o i n subsequent o n es. The q u e s tio n a ro se a s to whether the f lu o r in e had a r e ta r d in g o f f s e t on g e rm in a tio n . The w eighted mean ( d a ily p e r c e n t g e m in a tio n tim es days) i s v ery u s e f u l to e x p re ss th e tim e re q u ire d f o r g e m in a tio n and i s e a s i l y compared w ith th e g e rm in atio n means from th e o th e r tre a tm e n ts . l a s t column o f Table 2* These v a lu e s a re found I n th e The s o lu tio n s o f one hundred p a r t s p e r m illio n o f f l u o r in e a p p ea r to have h a sten e d g e m in a tio n to a s l i g h t e x te n t b u t above two hundred p a r t s p e r m illio n a r e t a r d in g a c tio n o c c u rre d . o b se rv ed i n l a t e r e x p e rim e n ts. S im ila r e f f e c t s may be - k e la tio k o r f u jo h ik e 8 - i s su p e rp h o sp h a te t o g b b m ih atig n Because f lu o r in e l a f e r t i l i s e r s seemed to Be a w a r e s o f I n ju r y to f» islB & iio n end i t sh o u ld he i n a s o lu b le f o n t i n o r d e r to he t o x i c , a a i n v e s t i ­ g a tio n o f th e amount o f s o lu b le f lu o r in e i n f e r t i l i z e r s and I t s e f f e c t on g e m in a tio n was u n d e rta k e n . P re lim in a ry work shewed t h a t th e q u a n tity o f s o lu b le f l u o r in e e x tr a c te d from superphosphate was dependent on th e q u a n tity o f w a te r u s e d and th e le n g th o f tim e o f shaking th e f e r t i l i s e r w ith th e water* There was a ls o a c o n s id e ra b le d if f e r e n c e i n th e amount o f so lu b le f lu o r in e i n d i f f e r e n t su p e rp h o sp h a te s„ T h e re fo re , th e fo llo w in g pro ced u re was fo llo w ed : two sam ples o f kk p e r c e n t superphosphate o f d i f f e r e n t o r i g in (w hich w i l l h e r e a f t e r be d e sig n a te d a s A and B ), and one sample o f 20 p e r c e n t su p er­ phosphate were o b ta in e d from sto c k s u p p lie s used a t t h i s s ta tio n * were a i r d r ie d In th e la b o ra to ry and p la c e d i n s u ita b le c o n ta in e r s , These sam ples D e fin ite q u a n t i t i e s o f th e a i r dry f e r t i l i s e r were weighed to one m illig ra m and added to *KX3 c c , o f w ater in a 550 c c . g la s s b o t t l e . These b o t t l e s were th en sto p p e re d and shaken f o r s i x hours I n a sh ak in g m achine. P re lim in a ry work had shewn th a t two h o a rs shaking was s u f f i c i e n t to a t t a i n a maximum c o n te n t o f so lu b le f lu o r id e i n th e e x t r a c t , b u t s ix h o a rs was allow ed B ar sh ak in g i n o rd e r to In s u re com plete e q u ilib riu m . b o ttle s . A f te r shaking* th e s o lu tio n s were f i l t e r e d and p la c e d i n sto p p e re d A liq u o ts o f th e s o lu tio n s were used to determ ine th e f r e e z in g p o in t d e p re s s io n by th e u s u a l Beckman therm om eter method* th e pH m in e by th e q ula~ kydrone e le c tr o d e and th e so lu b le f lu o r in e c o n te n t by tb s m ethod p roposed by W illa rd and W in ters. A ll th e s e d e te rm in a tio n s were made in d u p lic a te . J a r s con­ t a i n i n g " r a g d e l l s 11 were s e t up a s b e fo re and 200 c c . o f s o lu tio n were added to each. The g e rm in atio n t e s t was ru n s i m ila r to and c o n c u rre n tly w ith t h a t o f th e p o re f lu o r in e compounds so t h a t c o n d itio n s o f te m p e ra tu re , e t c . were the same f b r b o th e x p e rim e n ts. Tbfele 3 g iv e s th e r e s u l t s o f th e t e s t s . A g lan ce a t Tablo 3 1® s u f f i c i e n t to show t h a t superphosphate 3 was m ere to x ic th en th e 20 p e r c e n t superphosphaie which I n tu r n was more to x ic th an superp hosphate A. The in ju r y to g erm in atio n produced by tb s s o lu tio n s txo& 20 p e r c e n t superphosphate in c re a s e d w ith an in c re a s e In c o n c e n tra tio n o f s o lu b le f l u o r i d e . B. The same h o ld s tr u e f o r superphosphate A and supe rphoepbat® B u t, a s m ight be e x p e c te d , th e a c i d it y and osm otic concent r a t i o n a ls o i n ­ c re a s e d w ith in c re a s in g amounts o f f e r t i l i s e r . In f a c t , the q u e s tio n m ight be r a i s e d w hether o r n o t th e t o x i c i t y was e n t i r e l y doe to th e se l a s t named f a c t o r s . To answ er t h i s q u e s tio n one tre a tm e n t was s e le c te d in which th e m in e s o f th e se f a c t o r s were the l e a s t . I n th e case o f superphosphate B one gram o f f e r t i l i s e r p e r 100 c c . o f w a ter gay© a f r e e z in g p o in t d e p re ssio n o f o n ly .19°C which c o r re sp o n d s to a n osm otic m in e o f 2*2$ atm ospheres* S h ire (11) o b ta in e d a s good g e rm in a tio n in s o lu tio n s o f S.G atm ospheres a s he d id w ith the c o n tr o l c u l t u r e s . The a u th o r found In f u r t h e r woxk w ith C, P . ammonium s u l f a te and p o tassiu m c h lo r id e s o lu tio n s t h a t c o rn se ed s co u ld germ inate a t much h ig h e r osm otic c o n c e n tr a tio n s . P e r f e c t g e rm in atio n was o b ta in e d in s o lu tio n s o f ammonium s u l f a t e h a rin g a f r e e z in g p o in t d e p re s s io n a s felgh a s l.btyHJ. P e r potassium c h lo r id e th e l i m i t m s s t i l l h ig h e r , b e in g l.g ^ N J. The pH o f th e superphosphate s o lu tio n under d is c u s s io n happens to c o in c ld c w ith t h a t o f th e s o lu tio n u se d by S a l t e r and McIXwalne on co rn i n which th e y o b ta in e d so r e d a c tio n i n germ ination* Also th e s l i g h t l y g r e a t e r a c i d i t y o f th e f o u r gram s o lu tio n o f superphosphat e A d id n o t produce such t o x i c i t y . The f lu o r in e c o n te n t o f th e s o lu tio n from superphosphate B was Ijjb p a r t s p e r m illio n . The p e r c e n t g erm in atio n urns ap proxim ately th e same a s t h a t In 100 p o r ts p e r m il l i o n o f f lu o r in e a s hydrogen f lu o r id e (T able 2 ) . I t must be t r u e . 20 th e r e f o r e , t h a t th e t o x i c i t y o f th e f lu o r in e i n th e superphosphate i s m o d ified V o th e r f a c t o r s . A com parison o f the s o lu tio n o f superphosphate B h a rin g is o grams o f f e r t i l i s e r p e r 100 cc • w ith t h a t o f 20 p e r c e n t superphosphate h a rin g f o u r grams p e r 100 c c . o f w a te r shows t h a t the osm otic v a lu e s and a c i d i t y a re p r a c t i ­ c a l l y th e same, and t h a t t o x i c i t y to g erm in atio n v a r i e s d i r e c t l y w ith th e f l u ­ o r in e c o n te n t* l e c h o f th e s e s o lu tio n s * however, was l e s s to x ic th a n c o rre sp o n d in g s o lu tio n s o f hydrogen flu o r id e * I n th e th re e m entioned c a se s th e pH o f th e s o lu ­ t i o n was h ig h e r th a n t h a t o f th e c o rre sp o n d in g hydrogen f lu o r id e s o lu tio n s * The s o lu tio n o f 20 p e r c e n t superphosphate c o n ta in in g 12 grams o f f e r t i l i s e r p e r 100 c c , c o n ta in e d 200 p a r t s p e r m illio n o f f lu o r in e and i t s a c i d i t y I s p r a c t i c a l l y th e same a s th e hydrogen f lu o r id e s o lu tio n o f t h a t stre n g th * The in ju r y to g e rm in a tio n i n t h i s e ase I s s l i g h t l y g r e a t e r th an t h a t o f th e hydrogen f lu o r id e so lu tio n * I t a p p e a rs , th e n , t h a t th e t o x ic ity I s fa v o re d by h ig h a c id ity * T h is c o n c lu sio n i s f u r t h e r su p p o rted by th e f a c t t h a t hydrogen f lu o r id e proved mere to x ic th a n sodium f lu o r id e * Had superphosphate A been o m itte d from the experim ent th e e x p la n a tio n o f T able 3 and some l a t e r experim ents would have been g r e a tly s im p lifie d f o r I t s i n j u r y to g e rm in atio n I s much le s s th a n would be expected from i t s so lu b le f l u o r in e eon te n t* There w ere, however* th re e m ajor d iffe r e n c e s betw een t h i s f e r t i l i z e r and th e o th e r two f e r t i l i z e r s . The a c i d i t y was l e s s and the s o lu b le f l u o r in e was l e s s f o r a g iv e n w eight o f a v a ila b le PgO^ than In th e c ase o f th e o t h e r two f e r t i l i s e r s * Superphosphate A a ls o c o n ta in e d a sm all amount o f co p p er a s shown by q u a li t a t iv e a n a ly s is o f the m a te ria l* i n th e o th e r two f e r t i l i z e r s . Bo tra c e o f copper was found There I s need o f f u r t h e r I n v e s tig a tio n to d e te r ­ m ine th e e x a c t cause f o r th e low er t o x i c i t y o f superpho spha t e a* The tim e re q u ire d f o r g erm in atio n i n th e v a rio u s s o lu tio n s I s g iven i n th e l a s t column o f Table 3* In c re a s in g amounts o f f e r t i l i z e r cau sed g r e a t e r \ - r e t a r d a t i o n o f g e rm in a tio n . 11 - The degree o f r e t a r d a t i o n was n o t w holly c o n tr o lle d by o sm o tic c o n c e n tr a tio n , h a t was a f f e c t e d by o th e r f a c t o r s a s w e ll. Ho doubt th e f l u o r in e c o n te n t p la y e d some p a r t i n r e ta r d in g g e rm in atio n , HEBBCTIOB 07 TOXICITT OF SUPERPHOSPHATES BY THE PARTIAL REMOVAL OF FLU0RIHE A lthough th e r e s u l t s o f th e fo re g o in g experim ents in d ic a te d t h a t so lu b le f l u o r in e was re s p o n s ib le f o r th e t o x i c i t y o f th e I n v e s tig a te d superp h o sp h ates to th e g e m in a tio n o f c o rn , a n e x a c t i n t e r p r e t a t i o n o f th e r e s u l t s was co m p licated by th e in flu e n c e o f o th e r f a c t o r s which may have had some e f f e c t on g e rm in atio n . An a tte m p t was made, t h e r e f o r e , to remove th e so lu b le f lu o r in e from th e su p er­ p h o sp h ate by a method which would cause the l e a s t p o s s ib le a l t e r a t i o n o f the p h y s ic a l and chem ical p r o p e r tie s o f th e superpho spha te u se d . F or t h i s p u rp o se th e v o l a t i l i z a t i o n method seemed b e s t a d a p te d because i t d id n o t re q u ire th e a d d itio n o f any fo reig n , su b sta n c e except w a ter an d , f o r t u n a t e l y , th e f l u o r in e d i s t i l l e d o v e r a t a low tem p eratu re (120°C) which removed o nly a tra c e o f ph o sp h o ric and s u lf u l’l e a c i d . T w enty-four grams o f superphosphate B was a c c u r a te ly weighed in to a hOO c c , E hrlenm syer f l a s k and p la c e d in a c o n s ta n t tem perature oven a t 135°C^ 2 ° . The sto p p e re d f l a s k was connected to a w a ter-co o le d condenser on th e o u ts id e o f th e oven by means o f g la s s tu b in g . The superphosphate was a l t e r n a t e l y w etted and d r ie d by the a d d itio n , through a c a p i ll a r y tu b e , o f approxim ately 10 c c , p o r tio n s o f d i s t i l l e d w a ter fo llo w ed by s e v e ra l hours o f d ry in g a t 135°**, d i s t i l l a t e was re c e iv e d in a s u ita b le c o n ta in e r . The B aring e ig h t days o f a l t e r n a t e w e ttin g and d ry in g 223 c c , o f d i s t i l l a t e was o b ta in e d . The h a rd cake o f su p er­ p h o sp h ate form ed by t h i s procedure ad h ered to the f l a s k so s tro n g ly t h a t removal was n o t a tte m p te d , b a t th e f l a s k a s w e ll a s i t s c o n te n ts was broken up i n a m o r ta r , p la c e d i n a 550 c c . b o t t l e , b00 c c . o f d i s t i l l e d w ater added, shaken f o r s i x h o u r s , an d th e n f i l t e r e d . The p h y s ic a l appearance o f th e f e r t i l i z e r a f t e r - 12 - ■h airin g d id n o t seem to ho d i f f e r e n t th a n th a t o f th e o r i g in a l su p e rp h o sp h ate. The f i l t r a t e and th e d i s t i l l a t e from th e superphosphate s e r e a n a ly se d and u se d f o r g e rm in a tio n t e s t s a s i n th e p re c e d in g experim ent • T able shoes t h a t a l l o f th e so lu b le f lu o r in e mas n o t restored from th e su p erp h osphate by t h i s m ethod, h u t I t was g r e a t ly reduced In q u a n tity . The r e d u c tio n i n so lu b le f l u o r in e c o n te n t was accompanied by a d e c re a se i n th e t o x i c i t y o f th e su p erp h o sp h ate. The d i s t i l l a t e from th e sup erp h o sp h ate, on th e o th e r h an d , was h ig h ly to x ic to g e rm in atio n . T h is t o x i c i t y , no d o u b t, was due to th e h ig h c o n c e n tra tio n o f f l u o r in e which must h a re been i n com bination a s f c y d r o - f lu o s ilic ic a c id because o f th e method u se d f o r s e p a ra tio n . The osm otic c o n c e n tr a tio n o f th e d i s t i l l a t e was much too sm all to hare a n a p p re c ia b le e f f e c t on g e rm in a tio n , and i t h a s been shown i n Table 2 t h a t .072 £ EfeSOty hawing a pH o f 1 .^ 3 * e s mot a s to x ic a s t h i s d i s t i l l a t e which had a pH o f 1 .8 9 . Hence, th e t o x i c i t y m ost have been due d h le f ly to the so lu b le f lu o r in e p r e s e n t. HFEBCT OF SOUM S011S OH TOXICITY OF FEHTILIZER SOLUTIONS TO G&MIHATXOH 0? COBH R e s u lts o b ta in e d w ith s o lu tio n c u ltu r e s a re o fte n q u ite d i f f e r e n t from th o se o b ta in e d I f th e s o lu tio n i s added to th e s o i l . The s e l l u s u a lly red u c es th e t o x i c i t y o f s o lu tio n s and may com pletely overcome I t . An experim ent ru n to d eterm in e i f t h i s were tr u e w ith f lu o r in e i n f e r t i l i s e r s . was I f the s o lu tio n fend been added to th e s o i l th e p o s s i b i l i t y o f d eterm in in g th e e f f e c t o f th e s o i l on s o lu b le f lu o r in e would haws been e lim in a te d due to la c k o f s u i t a b l e methods f o r e x t r a c t i n g th e s o i l s o lu tio n . T h erefo re an in te rm e d ia te method was chosen. S o lu tio n s o f superphosphate 3 were made a s the s o lu tio n s given i n T ab le 3 e x c e p t t h a t 50 grams o f s o i l (even dry b a s is ) were added f o r each 100 c c . o f w a te r u s e d . The p ro ce d u re f o r sh ak in g , a n a l y s i s , and g erm in atio n was th e - taoft a s b t f o r e , 13 - The g e rm in atio n t e s t a ra n c o n c u rre n tly w ith th o se o f th e a f o r e ­ m entioned e o la ti o n s . The r e s u l t s a re g iv en i n Table 5« The a d d itio n o f s o i l to th e s o lu tio n s caused a masked re d u c tio n i n th e s o lu b le f l u o r in e c o n te n t and in th e a c i d i t y . T his e f f e c t was accompanied by a g r e a t change in th e t o x i c i t y o f th e f e r t i l i z e r . More th a n tw elve tim es a s much su p erp h o sp h ate B w ith s o i l added was r e q u ire d to produce the same degree o f t o x i c i t y o b ta in e d when one gram o f superpho sp h ate 2 was used w ith o u t s e l l (T able 3) • The r e d u c tio n i n f lu o r in e c o n te n t, no d o u b t, i s due to the fo rm a tio n o f in s o lu b le calciu m f l u o r id e w hich a c c o rd in g to Table 2 i s n o t to x ic to g e m in a tio n o f c o m . Brooks to n loam was more e f f e c t i v e th an Miami s i l t loam I n re d u c in g th e s o lu b le f l u o r id e c o n te n t o f th e s o lu tio n . g r e a t l y changed. The osm otic valu e o f th e s o lu tio n s was n o t The r e ta r d in g e f f e c t o f th e s o lu tio n s i s shewn i n th e l a s t column o f T able 3* S ix grams o f superphosphate 2 p lu s s o i l ap p eared to h a s te n g e m i n a t i o n , b u t the more c o n c e n tra te d s o lu tio n s showed a r e t a r d in g in flu e n c e on th e g e rm in a tio n . RELATION 07 FERTILIZER PLACEMENT TO GERMINATION OF CORN I I POT EXPERIMENTS Having determ ined th a t s o i l was e f f e c tiv e in overcoming th e t o x ic i ty o f th e su p erphosphates to com * experim ents were ru n in the greenhouse to i n v e s t i ­ g a te th e t o x i c i t y o f th e f e r t i l i z e r s when p la c e d in th e s o i l w ith th e se ed . Two- g a llo n g la z e d j a r s were u s e d , c o n ta in in g s o i l made up to d e f i n i te m o istu re con­ t e n t s u s in g ?000 grams o f a i r - d r y s o i l In th e case o f B rookston loam and 3000 g r ams in th e ease o f Miami and Pox s o i l s . TIbb r a t e o f a p p lic a tio n o f f e r t i l i z e r was based upon a h i l l a p p lic a tio n I n a c i r c l e th r e e In ch es i n diam eter w ith the c o m p la n te d i n check rows th re e pmA o n e - h a lf f e e t a p a r t . By t h i s method o n ly 1/250 o f th e t o t a l a r e a i s c o v ered . - 11* - B ence, a n a p p li c a t io n o f 25 pounds p e r a c re i n th e h i l l e q u a ls 2$ t i n e s 250 o r €230 pounds p e r a c re b ro a d c a s t f o r th e a r e a co v ered . 25 lb s ./a c r e l a M i l Z 6 ,2 3 0 l b s ./ a c r e b ro a d c a s t 50 lb s ./a c r e l a b i l l - 12,500 l b s . / a c r e b ro a d c a s t 100 lb s ./a c r e In M i l - 25,000 l b s ./ a c r e b ro a d c a s t 200 lb s ./a c r e In M i l s 50,000 I b s ./ a c r e b ro a d c a st boo Ib s ./a c r e la M i l - 100,000 l b s ./ a c r e b ro a d c a st Tbs f e r t i l i s e r was a p p lie d with, la rg e s a l t s h a k e rs , c o v erin g the e n t i r e c ro s s s e c tio n o f th e s o i l a t th e b ro a d c a st r a t e s n o te d . j a r a t a d e p th o f two and o n e -h a lf in c h e s . f i f t y seed s were p la n te d p e r The j a r s were made up to w eight e v e ry o th e r day by a d d in g w ater to th e low er s o i l th ro u g h a g la s s tube p la c e d th ro u g h th e c e n te r o f th e s o i l colusai. An experim ent was conducted to determ ine what e f f e c t p la c in g th e embryo a g a in s t th e f e r t i l i s e r would have upon g erm in atio n a s compared to th e same tre a tm e n t w ith th e endosperm tow ard the f e r t i l i s e r . Com was p la n te d on Miami s i l t loam a t te n p e r c e n t m o istu re c o n te n t, u s in g 20 p e r c e n t superphosphate i n e o n ta e t w ith th e M ed . The placem ents and r e s u l t s a r e g iv en i n T able 6 . S ince th e w ater was added to th e low er p a r t o f th e s o i l c o it u s th e movement o f m o istu re In th e s o i l was predom inantly upward a s I t would be i n th e f i e l d I f no r a in s o c c u rre d d a rin g th e tim e f o r g e m in a tio n . Under th e s e c o n d itio n s th e f e r t i l i z e r below th e se ed was in ju r io u s to g e m in a tio n o f c o m r e g a r d le s s o f w hether th e f e r t i l i s e r was I n c o n ta c t w ith th e embryo o r th e e n d o sp em . The f e r t i l i s e r above th e seed produced g r e a te r in ju r y when th e embryo came i n c o n ta c t w ith th e f e r t i l i z e r than when the endospem d id . days a f t e r th e seed was p la n te d . P l a t e 1 shows th e s e j a r s tw elv e S im ila r r e s u l t s w ith re g a rd to f a c in g o f th e embryo o f th e c o m k e rn e l tow ard o r away ftem th e f e r t i l i z e r were o b ta in e d by C oe, u s in g Aomo-Phos i n c o n ta c t w ith th e seed . The experim ent in d ic a t e s t h a t when - 15 th e d i f f u s i o n o f th e f e r t i l i z e r ta k e s p la e e in a d i r e c ti o n a s s y from the seed a few m illim e te r s s e p a r a tio n o f seed and f e r t i l i z e r may make a p ro found d i f ­ f e r e n c e i n th e p e r c e n t g e rm in atio n f o r when th e f e r t i l i z e r was above th e seed i n c o n ta c t w ith th e endosperm g erm in atio n was much b e t t e r than when th e embryo was exposed to th e f e r t i l i z e r . imPLUEKCX 07 SOIL MOISTURE 01 TOXICITY 07 FERTILIZERS TO GERMINATION OF COM Truog and h is co-w orkers ( 13) found t h a t th e in ju r y to g e rm in atio n o f c o m c a u se d by a com plete f e r t i l i z e r v a rie d In v e rs e ly w ith th e m o istu re con­ t e n t o f th e s o i l . An ex perim ent was conducted to determ ine i f th e same were t r e e f o r su p e rp h o sp h a te s. m o istu re c o n te n t. th e eatbxgre. J a r s o f Miami s i l t loam were made up to d e f i n i te The f e r t i l i z e r was a p p lie d b e n e a th the seed in c o n ta c t w ith S upeiphosphates A an d B and 20 p e r c e n t superphosphate were in c lu d e d I n t h i s e x p e rim e n t• The amount o f f e r t i l i s e r u se d in th e case o f th e more con­ c e n tr a te d c a r r i e r s was i n c h t h a t an e q u iv a le n t amount o f a v a ila b le PgO^ was u se d i n a l l th re e s e t s o f p o t s . b e fo re . C a te rin g was accom pli shed i n th e same manner a s B a lly c o u n ts were made o f th e number o f p l a n t s em erging from th e s o i l and from th e s e th e w eighted M a n f o r tim e o f emergence was c a lc u la te d * Table 7 c o n ta in s th e se r e s u l t s . The d a ta show t h a t g e rm in atio n was b o th r e ta r d e d and red u ced by a d e c re a se i n s o i l m o istu re c o n te n t. S im ila r r e s u l t s were o b ta in e d by u s in g B reek- s to n loam a t 20 p e r c e n t and 15 p e r c e n t s o i l m o istu re c o n te n t. Bus to th e n a tu r e o f th e experim ent r e l i a b l e chem ical a n a ly s is o f th e s o lu tio n coming in c o n ta c t w ith the seed was im p o ssib le b u t from th e la b o r a to r y r e s u l t s c e r t a i n s u p p o s itio n s seem j u s t i f i e d . The low er m o istu re c o n te n t o f th e s o i l p ro b ab ly r e s u l t e d I n a h ig h e r c o n c e n tra tio n o f so lu b le m a te r ia l in c lu d in g f lu o r in e a t th e s u r f a c e o f th e se e d . A lso , no d o u b t, th e re was a slow er r a t e o f r e a e tld n betw een f e r t i l i z e r and s o i l a t th e low er m o istu re c o n te n t than a t th e h ig h e r one - 16 f o r d i f f u s i o n l a tb s s o i l was p ro b ab ly slo w e r. Tbs com bination o f th e two c o n d itio n s named sh o u ld have fa v o re d a h ig h e r so lu b le f lu o r in e c o n te n t a s w e ll a s a h ig h e r osm otic c o n c e n tra tio n in th e d ry e r s o i l r e s u l t i n g i n r e t a r d a t io n and i n h i b i t i o n o f grow th. EFFECT 07 MIXING SUPERPHOSPHATES WITH SOILS TS. BISECT CONTACT WITH SEED OH GERMINATION An experim ent was s e t up to determ ine th e e f f e c t on g e rm in atio n o f m ix in g th e su perphosphates w ith the s o i l a s compared to the placem ent o f th e same i n d i r e c t c o n ta c t w ith th e se e d . The j a r s f o r th e d i r e c t c o n ta c t t r e a t ­ m ents were made up a s b e fo re p la c in g th e f e r t i l i z e r below th e se e d i n c o n ta c t w ith th e embryo. I n th e j a r s where m in in g o f f e r t i l i z e r w ith th e s o i l was d e s ir e d , one k ilo g ra m o f a i r - d r y s o i l was m ixed w ith the f e r t i l i z e r , b ro u g h t to th e d e s ir e d M i s Imre c o n te n t, and p la c e d i n a la y e r o v e r u n tr e a te d m o is t s o il. I n t h i s la y e r th e c o rn k e rn e ls were p la n te d . The la y e r o f f e r t i l i s e d s o i l was a p p ro x im ate ly one in c h th ic k an d was eev ered by a la y e r o f u n f e r t i l i s e d s o il. T hree s o i l s were u se d —B rookston loam a t 20 p e r c e n t m o istu re c o n te n t, Miami s i l t loam a t 15 p e r c e n t m o istu re c o n te n t , and Tex sandy loam a t 12 p e r c e n t m o is tu re c o n te n t. The m o istu re c o n te n t was ap p ro x im ately o n e -h a lf o f th e m o is tu re h o ld in g c a p a c ity . The r e s u l t s o f th e experim ent a re re c o rd e d i n T able 3. By pj x l a g th e f e r t i l i z e r w ith th e s o i l th e t o x ic i ty o f th e f e r t i l i z e r was a lm o st com pletely overcome ex cep t i n th e ease o f th e h e a v ie s t a p p lic a tio n o f th e 4b p e r c e n t su perphosphates on Fox sandy loam. More th a n s ix te e n tim es a s much f e r t i l i z e r c o u ld he a p p lie d w ith o u t re d u c tio n i n g e rm in atio n by m ixing w ith th e s o i l th an when th e f e r t i l i z e r was u se d in d i r e c t c o n ta c t w ith th e se ed . When th e su p erp h o sp h ates were in d i r e c t c o n ta c t w ith the seed th e r e a c tio n betw een s o i l and f e r t i l i z e r was n o t com plete enough to overcome i t s t o x i c i t y . - 17 I t was supposed t h a t th e s e l l type s i g h t p la y an Im p o rtan t p a r t i n th e a b i l i t y to o v e rs e a s t o x i c i t y . E xcept f o r th e h e a v ie s t a p p lic a tio n on Pox eandy l e a s , th e r e s u l t s a r e r a t h e r unco n v in cin g . The d i r e c t c o n ta c t r e s u l t s i n d i c a t e t h a t r e a c tio n betw een s o i l and f e r t i l i s e r was n e t s u f f i c i e n t to p r e dace s i g n i f i c a n t d if f e r e n c e s w hereas th e r e a c tio n betw een th e mixed s o i l and f e r t i l i s e r was g r e a t enough to overcome t o x i c i t y i n th e m a jo rity o f th e c a s e s . The lo w er t o x i c i t y to g e m in a tio n o f superphosphate A i s a g a in b rought o u t i n th e d i r e c t c o n ta c t tre a tm e n ts o f T able S . The d iffe re n c e betw een th e t o x i c i t y o f superpho sp h a te 3 and 20 p e r c o s t superphosphate, how ever, was dimin­ is h e d a s compared to the t o x i c i t y produced a s shown i n Table 3 . T h is can be a c c o u n te d f o r by th e f a c t t h a t a g r e a te r w eight o f d ry f e r t i l i s e r was u se d i n th e c a s e o f 20 p e r c e n t superpho sp h ate w hich m ust have reduced th e m o istu re c o n te n t i n th e im m ediate v i c i n i t y o f th e seed . In c re a s e d r e t a r d a t i o n o f emergence o f c o rn o c c u rre d w ith in c re a s in g am ounts o f f e r t i l i s e r . The se e d i n s o i l mixed w ith f e r t i l i z e r came up 1 .3 days e a r l i e r a s an av erag e th an when th e same r a t e o f a p p lic a tio n was a p p lie d i n d i r e c t c o n ta c t w ith th e se e d . T032GITT OF FERTILIZERS TO GERMINATION OF COBH IN FIELD EXPERIMENTS The f i n a l experim ent w ith r e s p e c t to t o x i c i t y o f superpho sp h ate s was conducted i n th e f i e l d . \ The f e r t i l i z e r was a p p lie d in th e M i l i n a c i r c l e th r e e in c h e s i n d iam ete r and the seeds p la n te d in d i r e c t c o n ta c t w ith th e f e r t i ­ l i z e r , u s in g amounts o f th e 44 p e r c e n t f e r t i l i z e r s e q u iv a le n t i n to th e amounts a p p lie d i n the 20 p e r c e n t superphosphate a p p li c a t io n s . c o n te n t For e a c h tre a tm e n t te n h i l l s were p la n te d w ith f i v e k e rn e ls o f c o m p e r b i l l . Sample o f s o i l were tak en a t th e time o f p la n tin g on which m o istu re c o n te n t and pH 18 ***• d e te rm in e d . p la n tin g . Emergence c o u n ts were made a t 12 and 21 days from d a te o f Tbs f i n a l emergence i s g iv en In f a b l e 9 . The r e s u l t s o f tbe greenhouse t e s t s a r e confirm ed by th e f i e l d t e s t s . T here was a marked d if f e r e n c e produced by f a c in g th e embryo tow ard o r away from th e f e r t i l i s e r , The low m o istu re c o n te n t p ro b a b ly a cc o u n ts f o r th e low er p e r c e n t g e rm in a tio n on H ills d a le sandy loam. Superphosphate A p ro v ed l e s s to x ic th an superphosphate B o r 20 p e r c e n t to g e rm in a tio n . how ever, was much h ig h e r ex p e rim e n t. The p e r c e n t g e rm in a tio n , i n th e f i e l d experim ent th a n i t was i n th e greenhouse T h is may be due, i n p a r t , to th e f a c t t h a t o n ly a c i r c u l a r a r e a t h r e e la c h e s i n d ia m e te r was cov ered w ith f e r t i l i s e r whereas in th e j a r s i n th e greenhouse th e e n t i r e c r o s s s e c tio n o f th e j a r was co v ered . The p l a n t s t h a t grew showed a marked tendency to send th e r o o ts th ro u g h the s e l l beyond th e f e r t i l i z e r r a t t ie r th a n through th e f e r t i l i z e r . F a r th e r com parison o f p e r c e n t g e rm in a tio n betw een th e greenhouse and f i e l d t e s t s s c a rc e ly seems j u s t i f i e d b ecau se d i f f e r e n t s o i l s were u sed h a v in g d i f f e r e n t m o istu re c o n te n ts and th e c lim a tic environm ent was e n t i r e l y d i f f e r e n t . SXJffiL&M I n t h i s I n v e s tig a tio n ( 1) la b o r a to ry , greenhouse, and f i e l d experim ent have shewn t h a t th e superphosphates in v e s tig a te d were capable o f e x e r tin g a to x ic in f lu e n c e on th e g e rm in atio n o f c o rn due to t h e i r c o n te n t o f so lu b le f lu o r in e s ( 2 ) th e s o i l s u se d in th e experim ent were e f f e c tiv e i n re d u c in g o r overcom ing th e t o x i c i t y p ro v id e d t h a t s u f f i c i e n t r e a c tio n took p la c e between th e s e l l and th e f e r t i l i z e r * These two f a c t s f u r n is h a s a t is f a c to r y e x p la n a tio n o f ( 3 ) th e h ig h t o x i c i t y o f superpho sp h a te s when p la c e d in d i r e c t c o n ta c t w ith th e se e d an d a ls o (H) th e re d u c tio n o f t h i s t o x ic i ty when th e superphosp h ates were m ixed w ith the s o i l . (9 ) Com was found to be q u ite v a r ia b le i n I t s su s­ c e p t i b i l i t y to f lu o r in e in ju r y , ( 6 ) The f a c in g o f th e embiyo o f th e seed tow ard \ % - 19 Hie su p erp h o sp h ate r e s u l t e d i n g r e a t e r r e d a c tio n i n g e rm in atio n o f c o n tb an when th e p o s i t io n o f th e k e rn e l mas r e v e rs e d , p ro v id e d th a t th e f e r t i l i s e r d i f f u s e d away from th e s e e d , ( 7) There warn c o n sid e ra b le d if f e r e n c e In th e amount o f i n ju r y produced by th e t i m e superphoaph& tes i n v e s tig a te d , F u r th e r r e s e a r c h i s needed to d eterm ine th e e f f e c t s o f n itr o g e n and p o ta s h c a r r i e r s on th e s o lu b le f l u o r in e c o n te n t and t o x i c i t y o f th e superphosphates i n m ix tu re s o f th e s e f e r t i l i s e r s * BBS'BEBHCSS 1, A l l is o n , P . X, 1918. S tu d ie s w ith ammonium p h o sp h ate. S o il S e t, 9s 2. Bokon a y , Th. 1913* Uber den E in f lu s s v e rs e h le d e n e r S ubstansen a n f d ie Xelnrang d e r P flansensam en. Bioeheiaiecbe Z e i t s e h r l f t . $Qi 1 - US, 3 * C lau d e l and C r o e h e te lle . 1896, In flu e n c e de q pelques su b sta n c e s employees comme e n g r a ls s u r l a g e m in a tio n , Ann, a g ro a , t XXII p , 131* 4, C oe, Dana G. 1923* #AsHnD-phos»i I t s e f f e c t upon seed g e m in a tio n and p la n t growth, 9 . J . Agr. Exp. s t a . S u l, 375* 5* J a c o b , 9* B ., and R eynolds, P . S, 1928* The f lu o r in e c o n te n t o f phosphate ro c k , J o u r . A ssoc. O ff. A gr. Cbem. 11; 237 - ^ 0 . 6. M a rs h a ll, H, L . e t a l , 1933* F actors a f f e c t in g the phosphoric a c ld -p h o sphate reck r e a c tio n . Jour. Ind. and Eng. Ohem. 25: 1253* 7* s p o r t s o f Committee on F e r t il i s e r Placement o f n a tio n a l F e r t il i s e r Assoc­ i a t io n , Washington, P. C, 1925 - 1933* 8. R ost, G. 0 . 1930, E ffe c ts o f superphosphates upon the g e m in a tio n o f c o m . J o u r . Amor. Soc. Agron, 22; H9S - 507- 9, Rudolphs, W. 1921* E ff e c t o f s a l t so lu tio n s having d e fin ite osm otic con­ c e n t r a t i o n v a lu e s upon a b s o rp tio n by se ed s. S o il S e t. 11: 277-293* 1 0 , S a l t e r , R. I t , , and M c llv a in e , W. G. 1920. E f f e c t o f s o lu tio n r e a c tio n on g e m in a tio n and growth. Jour, Agr. Res. 19: 73-96* 11, S h ir e , J . W. 1 9 l£ , se e d s. E ffe c t o f s a l t concentration on the g e m in a tio n o f H, J . Agr. Easp, S ta , Asm, Rpt. **55-^57. 12. Sigmund, %a. IS 96. Tiber d ie Binwirkxmg chemischer Agemtlen a u f die Keimong. Landw. V e rsu e h s-S ta tlo n e a XLVII: 1 - 53. 1 3 . Wrung, B. e t a l , 1925- F e r t i l i s e r ejqoeriments. R es. B o l. 65. l b . T a ll, J e th r o , 1733. 15. V in cen t, B&rse Boeing Husbandly. Wisconsin Agr, B^>. S ta . London, 1898. Absorption dee d is so lu tio n s n u tr itiv e s par l e grain do b i s , Ann. dee Sc agronoa 2 s e r l e k a n n ie t I I , 1 6 . W illard , H. H. and W inter, 0 . B. 1933* Volumetric method fo r d e tem in a tio n o f f lu o r in e . Jour. Ind. and Eng. Chem. Anal, Bd. 5: 7* t e i +)a£0lt 2k RELATION OF FERTILIZER PLACEMENT TO GERMINATION OP CORN PLATE I 20$ superphosphate on Miami s l i t loam a t te n p e r c e n t mole to re c o n te n t. F e r t i l i s e r was p la c e d above th e se ed . C — No f e r t i l i s e r 1 12,500 l b e /a c r e 2 — 12,500 l b s / a c r e — 2J f000 l b s / a c r e «*» 25*000 lb s/A c re in in in in c o n ta c t c o n ta c t c o n ta c t c o n ta c t w ith w ith w ith w ith endospem embiy© endosperm embryo Table 1 P e r Cent G e m in a tio n o f Com a f t e r Immersion in F e r t i l i z e r M a te ria ls atm en t lim b e r o f h o a rs immerse A : Concent r a t io n pH o f : L { 3 i 6 ; z h :9 6 : o f Medium Medium: •» : r m iSSiW 898U51t — j S ubstance 1 %0 ( d is tille d ) 2 (5 %>2 S0^ (com1X) • • * 3 KC1 5 P a s te t » : (com* 1) • k 5 «■ P2O5 : « 2 . 1f t « 1 .5 6 • * Ca (HgPO^)p C. P . 7 HjPOl* $ Beck phosphate & % 0 3 10 %SQ1| Beck phosphate & -1^2 L s* 5 i 1 .6 1 0 .1 & is CC* * i 93s®5 *S • i Superph© sphat* 20# PgO^ Superphosphate 3 %.23 5 e 6*90 : # 2 .>*S I 0.11*3 £ :5 gsu/lOQ ee* ( a ) Average o f 10 de te m in a tI o n s o f 100 seeds e ach S ta n d a rd d e v ia tio n a 1 .1 2 ^ i i i 65 * 27 1 * 0 S i i 2^ t 9 0 :0 : 0 — s91 *« * 2 .bo 0 0 100 I 5*1 61 : * 2 2 .0 0 • * t i « ft« ! « S « • • SaP « i 200 ft 1 5*5? 300 1 5 .a boo * e *: « i ft : fftt fftt I • i s .1*3 a, SgSOi^ . o p i B^SO* • * * * ftft % .072 £ H^SO* tk lit g erm in atio n 12,500 Ibs/A He tre a tm e n t f e r t i l i s e r below seed i n c o n ta c t w ith f e r t i l i s e r below seed in c o n ta c t w ith f e r t i l i s e r above seed i n c o n ta c t w ith f e r t i l i s e r above seed In c o n ta c t w ith *• e embryo : *f endosperm; •I embryo : s endosperm: 25,000 lb s/A 9* e 100 18 ♦ft s : 0 lh 12 Ik 10 82 1*2 fa b le 7 In flu e n c e o f S o il M oisture on T o x ic ity o f F e r t i l i z e r s to G erm ination o f C era F e rtilis e r — : : Days f o r i _. . * g em in atio n i y n — M : 1 5 5 1Mil ; 10)6 Mil :153t eoiltlC? • o i l m o istu re JL m o istu re saoieturezm o i s to r e * 9* e e e e Superpho spbate 20J& 6,250 l%s/A i SO a 12,500 t e * 50 12 2, 8*1 ; 58 1* * * 96 : 5 .0 0 ftft ft• ftft 5.6 7 .0 i S.6 S 10.0 9 .7 e ------------- : ftft e ft 4 •• 9 ,6 ft e • 96 4 • e e # #. a » t e ♦ 1 : *♦ : 1 2 • * Superphosphate A 100 • • I 25,000 f : i i 6 .3 : : 7 .2 f a b le & E f f e c t o f M ixing F e r t i l i z e r w ith S o liz on the T o x ic ity o f F e r t i l i z e r * to the g e rm in a tio n o f Cora £ g e m in : B ate o f 2 $ gem in s a p p li c a t io n : B rookston loam t Miami s i l t lean} c o n tr a c t : mined ; 5 I b a /A c r * s V i 11 n -------- - 1 n niLif ................ r ............ : T , , v .m ^ . r - . t*...........................* * e • s i s 98 3 100 s s — — : 100 : 98 * 3 3 J ! j 3 3 : 2 3 80 3 — 3 2 6 ,2 5 0 * 90 : 3 1 t s **€ : 98 2 1 2 . 5©0 ! 90 : 98 • • i 3 % 98 12 3 98 0 : 2 5 ,0 0 0 2 ; » F e rtiliz e r ' - ■■ ------- - - 1 III 111 Cbeek 20^ IL . * UM A t 50 ,00 0 $ r 100,000 im t s 2 ,« 4 l t i 5.682 : 0 100 0 : 100 : — : J 9n « *- J$ i t m 9 6 : \ — j & 1 — S 100 100 100 100 100 Off 100 I 92 4 R 7 — t 98 j : 3 t 1 100 s s 98 1 98 e a j • e • i* g e m i n Fox e m i r loam mixed smixed lim ed sn o t lim e d — : ; 100 98 98 L3 52 I 100 16 1 1 , 5 6 4 : 100 100 98 1 0 0 100 100 8 6 a • » 22,727 t t 4 5 , 4 5 4 0 100 ; 1 100 — ~ ! 2 ,8 4 1 7^ s - 5.682 I 56 11,364 i 6 ; 3 • ♦ pH o f M i l 9* I 100 44 8 98 Adf y o 18 8 96 * 0 2 2 .F 7 45.454 — — 1 — e 0 9« s 1 100 100 98 98 J 98 j 100 s 98 • * • 1 : e s 6 — f : : — 1 1 ! i i i t ; 5 44* B O 9% — : 1 7.13 i — • • * 92 2 0 GM 5 .1 0 • • 5 .1 8 fa b le S T o x lttity o f I t s l i U t t T s to G erm ination o f Com i n F ie ld Saqperioenis Obo* so . t B ate o f 3F e r t i ilz e irt a p p li e s t i on: above * 0 e e e we endaaneim : -e 3 e 3 Ckwfc e 38 e » : i e : SO?! 86 : 50 lb s/A 3 *• s : 63 1 100 3 : ! • 3 60 : 200 3 «• : • e• 96 : 4 4 ^ i * 50 * 3$ i * ■ 100 t e bS t - 200 •e 1 f•t m ft « : 44#B s 0 5© 08 e . . * 1 2 3 b 5 s 7 8 9 . : j ■■100 • e • j • • m : bellow seed s f# e s it m a s 32 ■r i ** i 4fkt : 38 below weed A• we embryo « 3 3 ftft 0^ 5* ft ft 20 14 ft • 8 0 ft ft 53 ftft •' ftft 26 2% fftt 24 S4 %k ft ft• ftft ftft € ftft M 88 3* 6 * 10 I S o i l ty p e S o li m oletere - 2 0 0 t H ills d a le loam H ills d a le loam & ui 7 .8 6 21.1 7 .81 0 H ills d a le sandy loam 1 0 .4 7 .8 4