T H E J 0 1. R S d L 0F I N D U S T RI A L A AV D E AVGI N E E RI N G C H E M I S T R Y
Dec., 1 9 1 j
1 . 4 j a n d t h e frozen 1.43 per cent. Turning t o t h e actual a m o u n t of acid present in a fruit, Table l ' I I I q a very marked difference is found. T h e frozen oranges shorn. a very small a m o u n t of acid present, 0.3 gram against a n average of a b o u t I g r a m for t h e sound oranges. Lemons have, of course. a much higher percentage of acid t h a n d o t h e oranges. T h e y also show a greater variation between t h e sound a n d frozen fruit t h a n t h e oranges do. T h e stored lemons which were unfrozen average 7.0 per cent acid throughout t h e experiment. r h i l e t h e frozen ones average j . 2 per cent. T h e fruit picked at different intervals averaged 6.3 per cent for nine samples of unfrozen lemons, a n d 4.6 for t h e same number of frozen samples. T h e comparison of t h e actual amounts of acid present in individual lemons shows t h e same striking differences between t h e frozen and unfrozen ones t h a t oranges do: t h e a m o u n t in t h e unfrozen lemons, showing considerable variation, ranges from 2 t o 3 grams: in t h e frozen fruit, however, i t practically disappears. S ULILI A R Y
I-The principal change caused in citrus fruits b y freezing is a n excessive loss of moisture. This is shown b y a marked lowering of specific gravity. 11-The percentages of sugar a n d acid decrease slightly b u t definitely. 111-Since t h e change in t h e composition of t h e juice is slight, its edible qualities are not impaired if i t is n o t frozen so severely as t o cause i t t o d r y up. SOUTHERN CALIFGRXIA PATHGLOCICAL LABGRATORY WHITTIER. CALIFORXIA
THE IMPORTANCE OF FINENESS OF SUBDIVISION TO THE UTILITY OF CRUSHED LIMESTONE AS A SOIL AMENDMENT By WALTERTHOMAS A N D WILLIAMFREAR Received June 25, 1915
After experiments at t h e Pennsylvania Experiment Station a n d elsewhere h a d demonstrated t h e value of calcium carbonate i n t h e form of pulverized limestone as a neutralizing agent for acid soils, m a n y questions were addressed t o t h e Station as t o t h e conditions necessary for its successful use, a n d particularly with regard t o t h e fineness t o which it should be reduced for economical results. This subject was much discussed b y t h e producers of crushed limestone who, naturally, were desirous of meeting t h e growing dem a n d for this product at t h e lowest manufacturing cost compatible with its fitness for use. Experiment Station writers differed in judgment as t o t h e importance of this quality. Agricultural literat u r e contained little t h a t bore directly upon t h e question. T h e work of Bernard' a n d Heinrich2 was n o t sufficiently broad in its scope t o afford a n answer t o a question of so great economic importance. The experiment of Voelcker3 a t Woburn was t o o indefinite t o a d d much t o our knowledge. I n none of these experiments, moreover, was t h e q u a n t i t y of limestone used proportional t o t h e acidity of t h e soil. 1
Le Calcaire.
3
Merge1 II. Mergeln, p. 29. Jour. R a y . Agric. SOC.England, 71 (1910). 349.
1041
T o afford a n answer t o t h e question, t w o series of experiments were planned in t h e early summer of 1911 b y Walter Thomas, B.S.,under t h e writer's direction, a n d conducted during t h e fall of t h a t year a n d succeeding months. The same lot of crushed limestone was used as t h e amendment in both series. T h e stone was obtained from t h e American Lime a n d Limestone Company, of Bellefonte, Pa., a n d was a good representatil-e sample of t h e compact blue stone from t h e Trenton beds of t h a t locality. T h e crushed stone was carefully sifted through sieves of 2 0 , 40, 60. 80 a n d I O O meshes t o t h e inch. T h e p a r t coarser t h a n I , ? O in. was rejected. T h e several lots of siftings t h u s obtained were separately analyzed t o ascertain if t h e y differed in composition. The fine siftings in this case contained 98.13 per cent. t h e coarser ( l , ? ~t o 1/40 in.) 95.93 per cent of calcium a n d magnesium carbonates. T h e intermediate lots increased constantly in carbonate richness i n their order from coarser t o finer. T h e average of t h e five analyses was : Acid insoluble 0 42
+
FesOs A1203 2 86
CaCOs 95.93
MgCOa Total 0 84 100 05 per cent
Kotwithstanding t h e slight differences in composition shown b y these lots of differing fineness, each was used in these experiments in quantities strictly proMgO) content. portional t o its (CaO
+
SERIES I
T h e soil used for this series represented P l a t 3 2 , of t h e General Fertilizer Series of Experiments, which h a d , every t w o years since 1881, received dressings of dissolved bone-black, muriate of potash, a n d nitrogen in t h e form of sulfate of ammonia. Owing, doubtless, t o t h e influence of t h e last-named fertilizer ingredient, this soil h a d developed a highly acid condition, a n d produced low crop yields in consequence : its supply of fertilizer constituents was not deficient. T h e acidity of this soil, as used for this series of experiment, indicated a lime (CaO) requirem e n t (Veitch) of 3 . 2 0 0 Ibs. a n acre-7 inches. T h e culture experiments were made in small, paraffined wire-baskets, of sl/z X s 3 / 4 in. size, with medium red clover as t h e crop. T h e saturation capacity of t h e soil (water-free) was 19.0 per cent, a n d moisture t o two-thirds t h a t a m o u n t was supplied a t t h e beginning of t h e experiment a n d carefully renewed, as need was shown b y frequent periodic weighings during t h e course of t h e test. T h e weighed a n d moistened soil, previously well mixed with enough of t h e limestone t o meet its lime requirement, was filled into each pot with t h e usual precautions t o secure uniform compactness. Eighty clover seeds were sown i n each pot, b u t t h e number was thinned t o fifty after t h e plants were well established. E a c h lot of limestone was represented b y three pots identically treated. During t h e first six weeks of t h e experiment, t h e plants were kept out-of-doors, with cloth shelter for nights a n d rainy days. Owing t o t h e lateness of t h e season, growth was slow. On Nov. 3rd t h e plants were removed t o a greenhouse, with a temperature of 45-60' F. Thereafter t h e y grew quite well, though
1042
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
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.
