T H E JO17Ravl‘dL O F I S D 1 7 S T R I d L d S D E S G I S E E R I S G C H E M I S T R Y
J u n e , 1914
TABLE 111-DETERMIKATIOS
OF
CITRlC ACID A K D NEUTRAL h-eutral ammonium citrate Acid p h o s p h a t e , . . . . . . 2 . 6 0 2.58 A v . . . . . . . . . . . . . . . . Z.5Y Acid p h o s p h a t e . ,
,
, ,
..
2.0;
2.01 .%v.. . . . . . . . . . . . . . . 1 04
Tankage.. . . . . . . .
A v , ,. . . . . . . . . . . .
6.53 6.49 6.51
IKSOLCBLEPHOSPHORtC ACID WITH .?‘/lo hMMMONIUM CITRATE (PERCENTAGES) T 10 S e u t r a l X 10 citric ammonium citric acid citrate acid 1 50 Raw bone m e a l . . . . 18.75 2 0 . 5 0 2.45 1 8 . 7 5 20.35 2.48 A v . . . . . . . . . . . . . l S , 7 5 20.42 1 .94 1.95
Complete fertilizer. AI... . . . . . . . . .
1.95
6 90 6.88 6.89
Complete fertilizer.
A v . . . . . . . .
I .64 1.60 1.62
1,5i 1.55 1.56
0.14 0.18 0 .16
0.23 0.25 0.24
N I O citric acid, therefore, is entitled t o careful consideration as a promising substitute for neutral a m m o n i u m citrate solution, as i t not only gives results substantially identical with those obtained with t h e present official reagent for determining insolub,le phosphoric acid, b u t has, moreover, a t least two imp o r t a n t advantages over a m m o n i u m citrate : I--N, I O citric acid is much more easily prepared a n d standardized t h a n neutral ammonium citrate solution. z-Extraction with X, I O citric acid is as easy a n d rapid as with hot water, t h e t i m e of filtration, particularly in bone, t a n k a g e a n d complete fertilizers. being cut down t o a very few minutes. CHEMICAL LABORATORY O F .\RMOUR 82 CO UNIOS STOCK YARDS,CHICAGO
THE EFFECT OF ENSILAGE FERMENTATION AND ANIMAL DIGESTION ON T-HE SOLUBILITY OF PHOSPHORIC ACID IN PHOSPHATE ROCK B y C. h
MOOERS
Received March 20, 1914
A recent article’ b y Forbes a n d Fritz reports some laboratory results which indicate t h a t t h e ensilage process m a y be used t o render floats soluble a n d hence available both t o animals a n d plants. With t h e object of showing t h e practical extent t o which t h e solubility of t h e rock w a s increased, t h e writer has prepared Table I from their d a t a . T h e table should be considered, however, as a t best only a close approximation, for t h e article referred t o did not furnish either t h e composition of t h e phosphate rock or other d a t a which would h a v e been of value in this connection. I n making t h e calculations of Table I , t h e writer assumed t h e floats t o contain 14 per cent of P. a n d t h a t t h e r e were used 83 parts, b y weight, of green silage corn t o I p a r t of floats. .‘lccording t o this table, 0 . 2 TABLE I--CALCLLATIO~.S BASED O N FORBES ASD Amount of d r y matter taken for basis of calculation Material Grams Green corn (whole plant) 8 3 . 0 Green c o r n . , . . . . . . . . . . 8 3 . 0 I Phosphate r o c k . , . . . . . . 1. 0 f Ensilage., . . . . . . . . . . . . . 76.7 Ensilage... . . . . . . . . . . . . 81.2 ( Phosphate r o c k . . , . , , . . 1 .0i
FRITZ
Inorganic P soluble in Total P Gram 0,lilS 0.3118 0.1718 0.3118
0 2 per cent
HC1 Gram 0 0689 0,1445 0 0851 0 1924
TABLE
Inoreanic P solible in 0.2 per cent HC1 per gram of phosphate rock Gram 0,0756
.... 0.1073
per cent HC1 dissolved j 4 . 0 per cent of t h e P of t h e floats when mixed with t h e green silage corn, b u t before passing through t h e ensilage process, a n d 7 6 . 6 j per cent after going through t h e ensilage process. This amounts, therefore, t o a n increased solubility of 3 . 1 7 pounds of P, or 7 . 2 6 pounds of P205 per I O O pounds of phosphate rock (floats). 1
THISJOURNAL, 6 (1914). 222, 223.
48 7
I n t h e proportions used by Forbes a n d Fritz, a I O O t o n silo would require goo pounds of floats, a q u a n t i t y which, even with full allowance for t h e increased solubility, would a m o u n t t o a moderate application for only t w o acres. Not t o mention t h e x-ery narrow margin of profit which this indicates, t w o questions arise a t this point: ( I ) SYould there be any cletrimental effect on t h e feeding value of ensilage treated with floats? ( 2 ) K h a t would be t h e effect of t h e process of animal digestion on t h e solubility of t h e floats? T o answer t h e first question satisfactorily would require m a n y more d a t a t h a n t h e a u t h o r has a t hand, b u t Table II gives t h e results of some feeding experiments made a t t h e Tennessee Agricultural 1Sxperiment Station i n 1909. I n these experiments a b o u t 2 pounds of finely ground phosphate rock were mixed tvith TABLE 11-FEEDINGT E S T OF ENSILAGE TRBATED WITH
F L O A T S AS C O M -
UNTREATED ENSILAGE T h e “ t r e a t e d ” ensilage was prepared b y mixing a b o u t 2 lbs. of finely ground phosphate rock with 100 lbs. of chopped corn (whole plant) a t time silo was filled. Feed per d a y U’eieht Of Cottonseed Ensilage Date animal Ensilage meal uneaten Lb3. Lhs. (19091 Animal Lbs. Lbs. Ensilage containing floats 7 Cow h o 30 Feb. 2 Si5 5 C o n S o . 30 Feb. 3 . . 2 18 Cow h-0. 30 Feb. 4 ... 16 2 Cow No 30 Feb. 5 ... 2 14 Cow X o . 30 Feb. 6 830 2 10 Blue heifer Feb. 2 480 1 21,? Blue heifer Eeb. 3 ... 1 4 Blue heifer Feb. 4 ... 1 1 Feb. 5 ... Blue heifer 1 i Feb. 6 463 Blue heifer 1 41, t Ensilage without floats Feb. 2 Cow No. 10 1000 441/2 2 0 Feb. 3 Cow Avo. 10 ... 45 2 0 ... Cow A-o. 10 45 2 0 Feb. 4 Feb. 5 Cow No. 10 45 2 0 Feb. 6 C o w No. 10 990 22 ’,:?(a) 7 0 Feb. 2 F a w n heifer 460 25 1 0 ... Feb. 3 Fawn heifer 28 1 0 Feb. 4 Fawn heifer ,, , 28 1 0 Feb. 5 F a w n heifer ,, . 25 1 I Feb. 6 F a w n heifer 480 121/12(u) 1 21/? ( a ) Morning feed only. NOTE-Both groups were fed plain ensilage a n d meal for two days previous , t o beginning of record, each animal eating t h e amounts given f o r F e b . 2 without waste for t h a t period. P A R E D WITH
-
--
every I O O pounds of t h e corn a t t h e time t h a t t h e silo was filled. T h e results show plainly t h a t in this case t o o much rock was present, for t h e animals soon refused t o e a t more t h a n a small p a r t of t h e treated ensilage, although i t s odor a n d appearance indicated excellent material. I n connection with t h e ,feeding experiment, some d a t a were obtained bearing on t h e second question, i n regard t o t h e availability of t h e P2Oj of t h e phosp h a t e rock when voided b y t h e animals. Samples of dung were saved from each animal, and Table I11 gives t h e per cent of t o t a l P205 in each sample when calculated t o a moisture-free basis. Assuming t h a t TABLEI I I - T o r A L
PHOSPHORICACID (P?Oj) IN D U N G FROM A N I M A I . ~ USED I N FEEDING EXPERIMENT Results on moisture-free basis Per cent
PZOS
Animal Cow No. 10 Cow No. 30 Fawn heifer Blue heifer
Cottonseed Cottonseed Cottonseed Cottonseed
Kind of meal a n d meal and meal a n d meal a n d
feed in dung unphosphated’ensilage 1 . l i phosphated eksilage 5.95 unphosphated ensilage 1 . 7 8 phosphated ensilage 9,34
with t h e same kind of feed t h e dung from the cows would be of similar composition, a n d t h a t in like manner t h e dung from t h e heifers would be com-
488
T H E J O L; R,lr..i L O F ILVD U S T RI -4L A-VD ENGILVEERILVGC H E M I S T R Y
parable, t h e a m o u n t s of phosphate rock in t h e d u n g of cow K O . 30 a n d of t h e blue heifer were calculated from t h e analyses given in Table 111. Table IT gives t h e quantities of t h e various materials t a k e n , t h e a m o u n t of o I per cent citric acid used as a solvent, a n d t h e percentages of P 2 0 5 found. T h e finely ground phosphate used throughout contained 3 2 . c per cent of P?Oj. T h e citric acid solution mas shaken u p in contact with t h e material for t w o d a y s a n d filtered, a n d t h e PZOS in t h e filtrate determined. F r o m these determinations t h e calculation was made t h a t t h e combined action of t h e ensilage process a n d t h e process of animal digestion resulted i n a n increase of 0 . 9 3 pound of PzOj per I O O pounds of t h e rock in t h e case of t h e cow a n d 1.17 pounds in t h e case of t h e TABLEIV-PHOSPHORIC ACID
SOLUBLEIN CITRIC ACID
(P20,)
CENT
1000 Cc. OF 0 1 PER
All percentages are calculated on a uniform basis of moisture-free a n d phosphate-free manure, z e , t h e plain manure from the unphosphated feed (15 0 grams) IS taken as t h e basis of comparison Quantity used for analysis P205 (Water-free basis) found Grams Per cent Material D u n g from cow No. 10 (unphosphated ensilage) 15.0 0.76 Dung from cow No. 10. . . . . . . . . . . . . . . . . . . . . . . . 15.0 Phosphate rock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 7 137 O ’ 88 D u n g from cow N o . 30 (phosphated ensilage).. . 17.7137 1.05 D u n g from fawn heifer (unphosphated ensilage) 15 . O I .38 D u n g from fawn heifer.. . . . . . . . . . . . . . . . . . . . . . 15 . O Phosphate rock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.9256 .4i D u n g from blue heifer (phosphated ensilage). . . . . 19.9256 1.86 NoTEs-~--A water solution of manure is normally alkaline and hence much of t h e “ a v a i l a b l e ” PzOj is in a precipitated form. Only a slightly acid solution is necessary in order t o get a marked increase in soluble P 2 0 ~ ’-If manure be treated with a 0.1 per cent citric acid solution in the proportions used, t h e solution is a p t t o become alkaline in t h e course of a few days, due t o t h e production of NHI b y bacteria; hence long standing must be avoided.
1
1
heifer. T h e increase in soluble P20j was, therefore, very small. On t h e assumption t h a t all of t h e phosphoric acid was voided in t h e dung, these results, t a k e n into consideration with those of Forbes a n d Fritz, indicate a reversion of t h e P205 made soluble b y t h e ensilage. S U 11 M A R Y
I-From calculations based on work reported b y Forbes a n d Fritz, 2 2 . 6 5 per cent of t h e total phosphoric acid of phosphate rock (floats) was rendered soluble i n 0 . 2 per cent HC1 through t h e ensilage process, I p a r t of rock being used t o 2 5 0 p a r t s of green silage corn. a-Feeding experiments b y t h e a u t h o r proved t h a t when 2 pounds of finely ground phosphate rock were mixed with I O O pounds of green silage corn at t i m e of filling of t h e silo, t h e resultant ensilage, though excellent in odor a n d appearance, was not suitable t o be fed in ordinary a m o u n t s , t h e animals soon refusing to eat it. 3-The solubility in 0 . I per cent citric acid of t h e P206 of t h e phosphate rock in t h e dung of t h e animals fed phosphated ensilage mas increased only 3 . 28 per cent of t h e t o t a l PZOj as a n average of tn-o trials. 4-Based on t h e assumption t h a t all of t h e phosphoric acid was voided in t h e dung, t h e d a t a a t h a n d indicate t h a t a reversion of t h e soluble P205took place during t h e process of animal digestion. S-The general conclusion is indicated t h a t t h e silo does not offer a practical means of making t h e P205 of phosphate rock available for plant use. AGRICULTURAL EXPERIMENT STATIOX UNIVERSITY OF TENWESSEE KNOXVILLE
.
Vol. 6, KO. 6
THE THEORETICAL BASIS FOR THE PROPORTIONS OF LIME AND SULFUR USED IN THE COMMERCIAL PREPARATION OF THE LIME-SULFUR SPRAY By HER31.4N
V. TARTAR
Received March 11, 1914
Various formulas (i. e . , proportions of lime, sulfur a n d water) have been recommended for use in t h e preparation of t h e commercial lime-sulfur spray. I n t h e early literature on this subject, t h e proportions of lime ( C a O ) a n d sulfur v a r y within wide limits; t h e more recent work’ shows t h e proper ratio of lime t o sulfur t o be approximately I : Z . There are, however, some differences still existing among t h e recommendations made in this connection b y t h e different agricultural experiment stations. It is well known, too, t h a t various factors such as concentration a n d length of time of boiling, have a n influence on t h e a m o u n t s of lime a n d sulfur required. E v e n t h e length of time of cooling, following t h e boiling period, modifies t h e composition of t h e solution a n d consequently t h e requirements of raw material. For example, in one of t h e experiments a t our local station plant where 108 gallons of material were prepared. a sample t a k e n a n d immediately cooled just a t t h e close of t h e cooking period h a d a gravity of 33O, while one t a k e n after t h e solution h a d cooled i n t h e t a n k for 1 2 hours, h a d only a 30’ strength. This decrease in gravity was due, no doubt, t o t h e decomposition of calcium thiosulfate in t h e hot solution. Similar experiments, in which t h e entire solution was cooled immediately after boiling, showed n o decrease in gravity upon standing. Because of these numerous factors which influence t h e composition of t h e spray, t h e formulas given by different investigators have been worked o u t largely b y t h e “cut a n d t r y ” method. Different a m o u n t s of lime, sulfur a n d water have been cooked for various lengths of t i m e a n d from t h e analyses made of t h e resulting solutions a n d sediment (sulfite), t h e formulas have been derived. B u t little, if a n y , attention has been given t o t h e exact chemical’reactions which occur. T o all familiar with this subject, i t is very evident t h a t a n y formula used in making lime-sulfur m u s t necessarily be based on t h e reactions taking place. Investigations carried out in this laboratory2 have shown t h a t these reactions are represented by t h e following equations:
--
(I) 3Ca(OH)? ( 2 ) Cas4 S (3) C a S 2 0 3 +
+
+ ICS
zCaS4
+ CaS203 + 3 H 2 0
Cas6 CaS03
+S
There is also some oxidation of t h e polysulfides when t h e material is exposed t o t h e air b u t this is so slight, under ordinary conditions of commercial preparation, where large, tall cooking v a t s are used, t h a t i t need n o t be considered here. T h e knowledge of t h e exact n a t u r e of these chemical reactions affords a theoretical basis for determining t h e proportions of lime a n d sulfur required in t h e preparation of a given sample of lime1 Cordley, unpublished results of this station: Stewart, Penn. Agr. Exp. Sta., Bul2. 99; Van Slyke, N. Y . Agr. Exp. S t a . (Geneva), Bull. 329. 2 Jour. Amer. Chem. SOC.,27 (1914). 495.
