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T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
t h e y suffered slightly from quite uniformly distributed, b u t short-period attacks of t h e white-fly, green aphis a n d red spider. At t h e end of 81/2 months, t h e green tops were harvested, weighed, air-dried a n d reweighed. The roots also were carefully washed out from t h e soil, dried a n d weighed. T h e results in terms of t h e d r y weights secured are given in Table I . These figures show very clearly: ( I ) t h e need of t h e soil for amendment t o fit i t for clover production;
12
The results show quite clearly t h a t acidity was not t h e limiting factor for t h e growth of clover. T h e differences between pots were less t h a n in Series I . T h e averages of crop yields appear in Table I. All t h e limestone dressings did a little good, yet in b u t one case did t h e crops of t h e treated pots, though grown with t h e same care, at t h e same t i m e a n d in t h e same environment with those of Series I, approach t h e latter in yield. Since clover is a n acidityproducing crop a n d t h e requirements for its larger
-
TABLEI-DRY WEIGHTS(GRAMS)OF CROPSF R O M DIFFERENT TREATMENTS O N Two SOILS SERIES I-IN S O I L FROM FERTILIZED P L A T 32-SERIES11-IN SOIL Tops ---ROOTS---------. ----ENTIRE PLANTS-----. CROP RATIO FROM RUN-DOWN FARM
-
LIMESTONE CRUSHED
Mesh-in. Triulicates Av. Triulicates Plants died shortly after germination None 1/20 t o 1/40 0.47 0.79 0.49 0.58 1.5 2.0 0.8 1 / 4 0 t o 1/60 2.15(a)3.34 3.12 2.87 2.45(a)4.20 4.10 1/60 to 1/80 3.64 4.65 2.89(b) 3.73 5.00 4.93 3.53 1 / 8 0 t o 1/100 4.87 4.99 3.94 4.60 5.36 5.46 4.13 Finerthan 1/100 5 . 1 0 4.65 4.84 4.86 6.40 5.33 4.93 (a) Only 40 seeds germinated. ( b ) Pot leaked.
t h a t t h e fineness of t h e limestone greatly affects its value as a n amendment for many months after its application even t o a highly acid soil, t h a t is, a soil well suited t o develop toward its maximum t h e r a t e a t which calcium carbonate can act in neutralizing soil acidity. T h e improvement of t h e crop, which, for practical reasons, should be measured in this case b y t h e development of its t o p , increased with t h e fineness of subdivision, up t o t h e limits of fineness here tested. T h e r a t e of increase was n o t , however, uniform, as is better shown b y t h e crop-ratios (Table I) in which t h a t obtained with limestone finer t h a n inch is t a k e n as 100. T h e falling off in r a t e of increase in crop yield with materials finer t h a n l j g 0 inch is in line with t h e previous observation of H. Yoyokama' t h a t precipitated lime gave n o better results t h a n crushed limestone. Taking into consideration t h e cost of effecting t h e highest pulverization, a n d t h e fact t h a t stone of I / ~ O t o 1/60 inch in fineness produced only about threefifths t h e effect secured with stone finer t h a n ' / l o o inch, while stone of 1 / 6 ~ t o '/so inch caused more t h a n three-fourths of t h e effect secured from t h e finest stone, i t is judged t h a t compact limestone of high purity should be crushed t o a fineness of not less t h a n inch, t o fit it for economical use as a soil amendment. Less pure stones should, in view of t h e freight a n d handling costs a n d if sold a t prices corresponding t o their (CaO MgO) richness, not fall below this degree of fineness for a n y considerable p a r t of their weight. It is possible, however, t h a t later tests m a y establish a less rigid requirement for soft, porous rocks t h a n is here indicated for t h e compact Trenton stone. (2)
+
S E R I E S I1
For this series of experiments, a different soil, obtained from a run-down f a r m long occupied b y a succession of tenants, was used. T h e tests were carried out as were those of Series I , b u t with four pots representing each lot of limestone added. T h e lime (CaO) requirement of t h e land was 1500 lbs. a n a c r e 7 inches, t h a t is, less t h a n half t h a t of t h e soiI used in Series I . Despite t h e rundown condition of t h e soil, no fertilizer was added. 1
Vol. 7 , No.
Jour. CoZZ. Agr. I m p e r i a l Unio. T o k y o ; 2 (1909), 181-182.
Av.
Triplicates
1.43 3.58 4.49 4.98 5.55
2.29 4.60 8.64 10.23 11.50
2.47 7.54 7.58 10.45 9.98
1.29 7.22 6.42 8.07 9.77
A v . (Last = 100) Tops Roots Entire plats 0 1.59 2.71 4.30 2.01 11.9 2.03 3.66 5.69 6.45 59.1 2.16 3.92 6.08 8.22 76.7 2.22 3.97 6.19 9.58 94,7 2.23 3.33 5.56 10.41 100.0 2.38 3,75 6.13
development should be met, it is not believed t h a t t h e results of this second series of experiments are as suitable for determining t h e question a t issue, as are those of Series I. I t m a y be added t h a t t h e results obtained in Series I are in accord with t h e results of similar experiments b y Brehmer,' Gerlachz a n d v. Feilizten.3 reported about t h e time our experiments were in progress. T h e experiments here related should be regarded as preliminary. Others of like character, b u t involving t h e use of larger pots, affording opportunity for deeper root development a n d covering a much longer period for amending action have been planned a n d are being carried out b y J . W. White, N.S., of this Section. .%GRICULTURAL
EXPERIMENT STATION
PENXSYLVANIA STATE COLLEGE STATECOLLEGE, PA.
THE LIME : MAGNESIA RATIO IN SOIL AMENDMENTS By WALTERTHOMAS AND WILLIAM FREAR
Received June 25, 1915
I n view of t h e prominence which t h e question as t o t h e influence of t h e lime-magnesia ratio upon t h e vigor of plant growth had assumed, a n d of t h e very extensive use of magnesian limes a n d limestones as soil amendments in Pennsylvania practice, a n d also of t h e lack of established relationship, in experiments elsewhere conducted, between t h e degree of acidity of t h e soil a n d t h e quantity of t h e calcareous amendment applied, i t was thought desirable t o conduct experiments upon this subject in which correlation between acidity a n d neutralizing value of t h e amendment should be secured. T h e experiment here described was planned b y Walter Thomas, B.S., under t h e writer's direction, a n d carried on a t t h e same time with t h e experiments upon t h e influence of fineness of subdivision of limestone upon its use a s a soil amendment, described in t h e preceding paper. T h e calcium a n d magnesium were added t o t h e soil in t h e form of hydroxides a n d carbonates. T h e materials used were prepared from calcite, magnesite a n d dolomite of t h e following percentage composition:. 1
2
3
llluslrivte L a n d w . Z e i f u n g , 31 (19 11). 832. D .L a n d w . Presse, 38 (1911), 409. S v e n s k a J4osskuliovfor T i d s k r . , 24 (1910). 95-98.
Dec., 1 9 1 j
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
. ..
Calcite.. . , . , , . . 0 . 1 6 Magnesite.. . . . . 0 . 4 1 Dolomite.. . . . . . 0 . 5 8
97.81 2.67 52.98
1.93 1.21 1.11
Trace 95.81 45.55
99.90 100.10 100.22
T h e hydroxides were prepared b y igniting t h e calcite a n d magnesite at low red heat in a muffle furnace until complete decomposition h a d been obtained, a n d adding t o t h e oxides t h e amounts of water necess a r y for hydration. T h e several materials, carbonates a n d hydroxides, were a t once pulverized, sifted through a Ioo-mesh sieve. a n d held in stoppered bottles. T h e soil used was t h e same as t h a t employed in Series 11, of t h e experiment described in t h e preceding paper, i. e . , it was run-down soil of 1 5 0 0 lbs. per acre-7 in. lime requirement, a n d all details of size of \?-ire baskets, methods of soil preparation, addition of amendment, planting a n d environment during growth of t h e crop (medium red clover) were t h e same as in t h a t experiment. I t m a y be added, as t o t h e soil, t h a t t h e land from which i t came lies adjacent t o t h e Pennsylvania Experiment Station farms, is of t h e same geological origin (Ordovician limestone of age earlier t h a n t h e Trenton beds) of t h e same silty loam t y p e , and probably of t h e same general composition as t o its calcium a n d magnesium. T h e surface a n d subsoil of t h e unfertilized grass lands of t h e Station f a r m contain as shown b y analyses made b y J . V. K h i t e , in t h e Station laboratory : Per cent CaO Surface . . , . . . . . . , . . . . . . . . 0.36.5 Subsoil.. . . . . . , . . . , . . , . . , , . 0.37:
Per cent M g O 0.509 0.679
These percentages represent t h e action of hot concentrated hydrocliloric acid acting for I O hours (Official Method). The proportions of these bases soluble in weaker solvents have not been determined. If all TABLEI-CLOVER Ca0:hlgO
TREAT- ratio in
--
CROPS
FROM
I
TOPS-
.
w’EIGHTS
c
Av. dressings Determinations 1 : 1 2.10(a)2.26 2.00 1.87(b)2.06 4.26 2 : 1 1.90 2.15 2.12 2.30 2.12 4.00 3 : 1 2.69 1 . 8 0 ( a ) 2 . 3 3 2.94 2.44 4.20 2.21 2.47 2.22 3.46 1.70 2.50 Ca(OH)* \ 1 : 1 and - 2 : 1 1.85(c)2.70 2.35 2.15 2.74 3.56 3.26 2.90 2.73 2.75 1.96 2.18 Mg(OHh / 3 : I Dolomite 1 : 1 1.54 2.18 2.20 1.91 1.96 2.68 Untreated . . . . 1.84 1.52 1.39 1 . 5 2 1.57 2 . 7 2 ( a ) Coating cracked. ( b ) 42 seeds germinated. (6) Coating MENTS
During t h e period of growth t h e only point of distinct difference between t h e crops from high magnesian a n d high calcium treatments, respectively, was a retarding, b y three or four days, of t h e germination of t h e clover seed where magnesian amendments were used. At t h e conclusion of eight a n d one-half months, t h e clover tops were cut, weighed, air-dried a n d re-weighed, a n d t h e roots were washed o u t , dried and weighed. T h e root systems in all t h e pots containing amendments were more fibrous a n d shon-ed better development of tubercles t h a n those grown in t h e untreated soil. T h e air-dry crop weights from t h e several treatments were as given in Table I. These results, like those of Series I1 in t h e preceding paper, indicate t h a t acidity was not t h e limiting factor for clover growth on this soil. The yield from t h e carbonate treatment 168 : 40 was only half of t h a t obtained from t h e corresponding fine limestone on t h e soil of Plat 3 2 . Severtheless. all t h e treatments Tyere attended by some crop increase. T h e C a O : 11gO ratios represented do not include, a t this time, ‘any case in which t h e magnesia added exceeds t h e amount of lime added. These ratios r e r e chosen t o represent those found in numerous lime products on t h e market, rather t h a n t h e possible extremes for such experiments. I t is t r u e t h a t t h e 101~- magnesian dressings mere attended by somewhat higher yields t h a n those with t h e narrowest CaO : 11gO ratio; b u t t h e yields from individual pots m-ere overlapping in marked degree, a n d t h e differences between averages for t h e treatments not large. Moreover, t h e yield with l;/lo~ mesh very low magnesian limestone, from crop grown on t h e same soil
DIFFERENTTREATMENTS,
AIR-DRY CROP
AND
(GRAMS)
ROOTS-Determinations 4.23 3.18 4.06 3.65 4.20 3.55 4 . 0 0 4.05 4 . 2 1 3 . 0 6 3.49 3 . 2 0 3.26 4.03 3.26 4.20 4.13 4.00 2.77 2.56 2.60 2.82 2.66 2 . 6 7 cracked; leaked.
t h e C 0 2 present be reported as combined with CaO, t h e C a C 0 3 represents only I S per cent of t h a t base soluble under t h e conditions above stated. T h e CaO : MgO ratio in t h e acid-soluble materials is for t h e surface soil, I : 1.37; for t h e subsoil, I : 1.80. If, therefore, t h e ratios of these bases soluble in strong acid were a satisfactory criterion of t h e balance between these bases in t h e nutrient supply gained b y plants from this soil, we should expect, from t h e findings of Loew a n d his pupils, a distinct disadvantage t o t h e crop from t h e application of amendments increasing t h e proportion of magnesia ai-ailable t o t h e crops, a n d possibly also from such as very greatly raise t h e proportion of calcium t o magnesium. T h e amendments mere added t o t h e soil in amounts requisite for neutralizing its acidity, a n d in such mutual proportions as t o secure in t h e amendments t h e CaO : h l g O ratios s t a t e d below. E a c h t r e a t m e n t was represented b y four pots.
I043
LIME:
RATIOSIK .
