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
864
was used b y t h e m , except t h a t a m m o n i u m hydroxide was used b y t h e m instead of potassium hydroxide. Solutions of pure potassium nitrate were first experimented with. I n each case, t h e respective flocd a t i n g agent was shaken with t h e solution a t t h e r a t e of z g. per I O O cc. of solution. Where b o t h methods were used, aliquot p a r t s of t h e same filtrate were used. T h e results given are averages of closely agreeing duplicates. TABLE I P A R T S PER k l 1 L ~ I O l uNITRATEh T I T R O G E N
Flocculating aeent Present CaCOs. . . . . . . . . . . . . . . 1 CaO.. . . . . . . . . . . . . . . . 1 CaCOa.. . . . . . . . . . . . . . 10 CaO . . . . . . . . . . . . . . . . . 10
Found Colorimetric
Found Reduction
0.97 0.40 9.0 6.6
9:94 9.66
..
T h e results show t h a t while t h e use of calcium oxide gives low results with pure nitrate solutions b y t h e colorimetric method, yet practically t h e entire a m o u n t is found b y t h e reduction method. Comparative experiments were next carried o u t on soils with high a n d low nitrate content, some with known amounts of nitrate added. I n all cases, one p a r t of soil was shaken for a half hour or less with t w o parts of water, a n d t h e flocculating agent was added a t t h e r a t e of 2 g. per I O O g. soil. T h e results given in Table I1 were all found b y t h e colorimetric method: TABLEI1 Soil No. 69
268
358
Flocculating aaent cac03 CaCOa CaO CaO CaCOs CaCOa CaO CaO CaCOs CaCOa
CaO
CaO
PARTS
PER
Added None 3.0 &'one
3.0 None 3.0 None
3.0 None
3.0 None 3.0
NITRATE NITROGEK Per cent F o u n d Recovered recovered
hfILLION
6.7 9.6 2.0 2.9 14.7 17.6 7.6 7.6 2.2 5.0 1.6 3.1
...
2.9
...
0.9
30: 0
95:O
...
idde
0:0
,..
2.8
9S:O
, . .
1.5
50:0
T h e important point brought out b y the above results is t h a t calcium oxide gives decidedly low results with soils containing a small a m o u n t of nitrate nitrogen. T h e reduction a n d t h e colorimetric methods were tried with soils which h a d been incubated 3 0 days with 0.I j o g. ammonium sulfate per Ijo g. soil. T h e extraction of t h e nitrates was carried o u t a s usual. T h e results given represent t h e amounts found in duplicate incubations a n d not duplicates on t h e same incubation. For t h e t w o methods, aliquot parts of t h e same filtrate mere used. TABLE I11 P A R T S PER
Soil h'o. C..
..........
D..
..........
Flocculating agent CaCOa CaCOs CaO CaO CaCOa CaCOa CaO CaO
MILLION
SITRATE NITROGEN
Colorimetric
152 152 135 139 145
Reduction 183
176 Lost 175
171
149
170
139
169 169
Lost
T h e above results show, in harmony with t h e experience of others, t h a t t h e colorimetric method gives somewhat lower results t h a n t h e reduction method. With t h e former method, calcium oxide produces somewhat lower results t h a n calcium car-
IO
bonate, while there is n o apparent difference b y t h e reduction method. F r o m t h e d a t a presented, one is forced t o t h e conclusion t h a t with soils low in nitrates t h e use of calcium carbonate is t o be preferred t o calcium oxide, a n d when t h e colorimetric method is t o be used t h e carbonate is always better. Carbonate in all cases yields as clear a n d as nearly colorless a solution as t h e oxide. As t o t h e reason for t h e low results b y t h e colorimetric method with calcium oxide, we are not prepared t o answer. Our results are not in harmony with those obtained b y Lipman a n d Sharp. Some difference in t h e details of t h e colorimetric method might have caused t h e discrepancy. I t is possible their use of ammonium hydroxide instead of potassium hydroxide might have made some difference. We have much more d a t a t h a n are here presented, on m a n y types of soil, a n d in practically every case t h e calcium oxide gives lower results t h a n t h e carbonate. While t h e subject is, no d o u b t , worth more complete investigation, since t h e calcium carbonate has proven entirely satisfactory, we have not seen fit t o carry t h e subject a n y further a t present. SOIL CHEMISTRY
LABORATORY
IOWA STATE COLLEGEEXPERIMENT STATION AMES. IOWA
A METHOD FOR THE DETERMINATION OF THE IMMEDIATE LIME REQUIREMENTS OF SOILS B y W. H. MACINTIRE Received July 9, 1915
9j:O
2.9
Vol. 7, No.
At t h e Yovember (1914)meeting of t h e Association of Official Agricultural Chemists' t h e writer gave t h e essentials of a method for t h e determination of t h e lime requirement of soils, a n d a t t h a t time s t a t e d t h a t later he would give t h e results secured from experiments' which led t o t h e adoption of t h e method. The d a t a a n d details of these investigations are t o appear i n bulletin form. T h e s t u d y was begun in t h e spring of 1 9 1 2 , a n d was based upon an investigation of t h e various factors influencing t h e determination of t h e lime requirements of soils. At t h a t time t h e laboratory methods of Veitch2 a n d Tacke3 a n d Suchting's4 modification of Tacke's procedure were t h e only ones which involved t h e use of t h e substances which are used in practice t o satisfy a soil's lime requirement. I n this country t h e method of T'eitch has been most generally accepted, in spite of the tedious manipulation a t t e n d a n t upon its use. I n our initial studies, which included extensive basket experiments, t h e Veitch method was used as a basis of t r e a t m e n t . F r o m t h e investigation of t h e factors influencing more particularly t h e Veitch method, it was hoped t o evolve a method which would bear some relation t o practice. After t h e evolution of t h e procedure given in this article, comparative studies were made with t h e Veitch, Tacke, a n d , later. t h e Hutchinson-MacLennanj methods. 1
American Fertilizey, Nov. 28, 1914. (1902), 1120. Chem. Zfg., 2 1 (1897), 174. 2. angew. Chem., 4 (1908). 151. Chemical S e w s , Eng., 1914, p 2854.
* J. A . C. S . , 24 3 4 8
OCt., 1915
7‘H E J O 1-RN A L O F I S D 1’s T RI A L A E D E X G I S E E RI -VG C H E M I S T R Y
Without wishing in a n y way t o detract from t h e priority of claim t o publication of t h e innovation of using a solution of CaC03, which priority rightfully belongs t o Hutchinson a n d MacLennan, t h e writer would s t a t e t h a t t h e method given at t h e e n d of t h i s article h a d been perfected for presentation t o t h e A . 0. A. C. before t h e appearance of their publication, which a n t e d a t e d t h e meeting of t h e Association b y several weeks. PRELIMINARY LABORATORY INVESTIGATIONS
T h e studies preliminary t o t h e evolution of t h e method included a consideration of t h e relation of soil lime requirement t o soil magnesia requirement. I t was found t h a t there exists a vast difference between lime a n d magnesia requirements of soils under laboratory t r e a t m e n t s , as well a s under contact t r e a t ments in baskets a n d in field cylinders. I t was also determined t h a t though a soil m a y be distinctly alkaline from contact with a n excess of CaC03, this condition does not preclude t h e ability of a soil t o effect extensive decomposition of M g C 0 3 . However. when soils h a d been t r e a t e d with a large excess of MgCOs above lime-requirement indications a n d h a d effected complete decomposition of t h e excess of hlgC03, t h e y t h e n effected no immediate reaction with C a C 0 3 . This was also found t o be t h e case with a n ignited soil. I t was also found t h a t t h i s propensity of a soil t o fix t h e magnesia upon evaporation of soil a n d M g C 0 3 solution was not hindered b y previous t r e a t m e n t s with sodium a n d potassium carbonates. I t t h u s appears t h a t t h e use of precipitated M g C 0 3 may satisfy a soil’s requirement for C a C 0 3 . while t h e long-continued presence of C a C 0 3 in potted soils fails t o satisfy a soil’s requirement for magnesia. This difference was found t o be d u e t o the affinity of magnesia for SiOz a n d TiOz, a s well as for acid silicates. T h e studies further led t o t h e conclusion t h a t there is a considerable difference between a soil’s immediate ability t o decompose CaC03 a n d i t s propensity t o continue t h e decomposition when soil a n d a n excess of C a C 0 3 continue in moist contact. T h a t t h i s observation is t o be found in practice is shown b y t h e analyses of t h e lime-treated plots of t h e Pennsylvania Station.’ Thirty-five per cent of t h e lime accumulated on these plots after 3 2 years of t r e a t m e n t is t o be found as silicates. I n offering t h e method, t h e differentiation is, therefore, made between immediate and continuous lime requirements of soils. I n paralleling t h e Veitchmethod procedure t h e writer endeavored t o determine t h e lime from a n excess of lime-water, which was added t o soils a n d subjected t o evaporation, a s in t h e Veitch procedure. It was t h u s intended t o determine t h e lime requirement b y difference between a d d e d . lime a n d t h e residual caustic lime. T h e procedure followed was t o evaporate soils with a n excess of lime-water, a n d t h e n t o subject t h e evaporated soil a n d t h e excess of lime t o t r e a t m e n t with carbonated water. T h e carbonated water extract was t h e n filtered a n d t i t r a t e d . It was found, however, t h a t t h e lime silicates were Tenn. Sfa. Bull. 107, 193.
865
very readily hydrolyzed, a n d t h a t t h e recovery of lime was proportional t o t h e period of extraction. Several hours’ extraction, with agitation, effected greater lime recovery t h a n was represented b y t h e a m o u n t s of t r e a t m e n t . It was t h e n decided t o use C. P. precipitated carbonate instead of lime-water in t h e evaporations, a n d t o determine original a n d residual carbonate before a n d after evaporation b y t h e estimation of COS. Examination of t h e various C. P. precipitated carbonates showed t h e necessity, however, of converting h y d r a t e impurities into carbonates before t r u e lime absorption b y soils from applied carbonate could be determined b y COY estimations. I n t h u s treating precipitated CaCOa with carbonated water there were secured s a t u r a t e d C a C 0 3 solutions. It was readily apparent t h a t t h e use of aliquots of t h e solution of CaC03 afforded numerous advantages in speed a n d accuracy over weighed charges of t h e t r e a t e d solid carbonate. Comparisons made between t h e activity of soil toward finely ground limestone a n d toward carbonate-water-treated pre-
I n ve r t ed pi pett e
CaC03 Solution
FIG. 1 -PRESSURECONTAINERFOR CaCOa SOLUTION
cipitated carbonate showed t h a t i n a given time t h e finer a n d more soluble t h e precipitated carbonate was, t h e more extensively it decomposed. This proved t r u e in controlled field t r e a t m e n t s , as well as under laboratory conditions. F u r t h e r comparisons were t h e n made between various t r e a t m e n t s of soil a n d added solution of C a C 0 3 . T h e t r e a t m e n t s included immediate evaporation. evaporation after 3 hours’ agitation, precipitation of C a C 0 3 from solution by heating on a water b a t h before adding soil, boiling for 5 minutes a n d for 3 0 minutes, a n d throwing out of solution b y subjecting soil a n d solution t o agitation with suction for various periods at room temperature. T h e results secured by immediate evaporation were t h e most uniform a n d t h e highest, a n d were almost identical with those secured b y agitating for 3 hours before evaporation. T h e
866
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
evaporation appeared t o exert negligible activities upon soil organic matter, while t h e short period of contact between soil a n d carbonated water was responsible for no apparent hydrolysis *of soil silicates. Comparative studies between t h e proposed method a n d t h e methods of Tacke a n d Hutchinson a n d MacLennan demonstrated t h a t their methods do not give t h e maximum immediate lime r e q u i r e m e n t . I n order t o eliminate t h e consideration of organic matter as being in p a r t responsible f o r t h e continued decomposition of C a C 0 8 , through its further contact with soil, red clay subsoil was used, as well as surface soil. Repetition of t h e Tacke method upon the clay which had previously been treated with CaC03 for 3 hours gave further extensive lime-requirement indications. Residual clay, freed of atmospheric COS after treatment according t o t h e Hutchinson-MacLennan procedure, gave additional a n d appreciable lime-requirement indications b y t h e ,Tacke procedure, a n d also b y t h e method given in this article, a n d b y repetition of t h e Hutchinson-MacLennan method itself. It was also found t h a t t h e indications of t h e Hutchinson-NacLennan method varied appreciably with t h e charges, a n d t h a t t h e FIG.2-cO2 GEXERATOR indications were in no may A-16 Liter Acid Reservoir B-4 Liter Generator proportional t o variations C-Broken P o t t e r y in amounts of soil used. D-Marble-Sized Limestone Lumps E-Geisler Cock Outlet for Spent Acid Repetition of the proposed F-Outlet for C o r t o Purifiers method gave no further Cock +Safety lime r e q u i r e m e n t , nor was a n y lime-requirement indication found b y t h e Tacke procedure upon t h e clay after its evaporation with a solution of C a C 0 3 . Nine soils were t h e n treated with t h e amounts of C a C 0 3 indicated b y t h e Hutchinson-RIacLennan method plus 2 drops of saturat e d lime-water t o offset a n y plus or minus analytical error, a n d t h e procedure of t h e lreitch method t h e n carried o u t . In every case t h e soils failed t o show alkalinity. T h e same soils were in like manner simultaneously treated with t h e indications of t h e proposed method, and in every case t h e Yeitch test showed alkalinity. T o t h e writer i t seemed t h a t the results of t h e other methods depending upon quantitative determinations of residual lime gave b u t a fractional p a r t of a soil’s inherent ability t o decompose C a C 0 3 under laboratory conditions, a n d t h a t i t would be well t o utilize a method which would give maximum decomposition of C a C 0 3 in t h e laboratory. T h e method here given is believed b y t h e writer t o record a definite and complete reaction between soil and CaCO8 under laboratory
Vol. 7 , NO. I O
conditions. I t s repetition a t various times gives closely concordant results, and t h e technic is such a s t o permit considerable speed when making a number of determinations. As before stated, when beginning t h e studies it was hoped t o secure results from correlative basket studies which would afford opportunity t o compare laboratory indications with field results. It appears, however, t h a t this phase of t h e subject requires somewhat extensive field work under various seasonal conditions a n d various methods of cropping through more t h a n one year. Such a n investigation would be needed t o show t h e relation of both immediate a n d continuous lime-requirement indications t o field practice. PROPOSED
METHOD
P R E P A R A T I O K O F caco3 S T O C K soLnTIox-Pass purified COZ into one or more 4-liter cylinders containing distilled water a n d about 2 0 grams of “fluffy” c. P. precipitated C a C 0 3 for 4 hours. Permit the C 0 2 t o enter with sufficient rapidity t o keep considerable of t h e carbonate in suspension. At t h e same t i m e prepare carbonated distilled water t o the amount of about one-tenth t h a t of t h e carbonate solution. Filter t h e carbonate solution through large gravity filters into t h e carbonated water. A large stock of 16 liters may be made a n d kept indefinitely without detcrminable change by use of t h e pressure-syphon bottle shown in Fig. I . Upon withdrawal of each aliquot, pressure is maintained b y blowing through the t u b e A . T h e C a C 0 3 value of the solution is determined b y first boiling a n d t h e n liberating t h e COZ of t h e precipitated carbonate. T h e v a l u e of t h e C a C 0 3 s o l u t i o n should izot be d e t e r m i n e d b y direct titration, i f the liquid ab s o 1, fl t i o ti fl r o c e d $1re be j o l l o ut e d . T h e HC1 used in generator t o liberate C 0 2for preparation of CaCOBsolution should not exceed I :I in strength. T o insure complete removal of hydrochloric acid f r o m t h e rapid flow of gas, it is necessary t o force t h e gas through several columns of sodium carbonate solution when making large stock solutions of carbonate. A “IGpp” generator may be fitted with a 2-hole rubber stopper, a s t a n d t u b e being inserted in one hole and in t h e other a stopcock-controlled t u b e for blowing t o obtain pressure. A simple and more useful form of apparatus is t h a t of Pig. 2 . P R O C E D U R E F O R T H E D E T E R V I S A T I O X O F T H E IllMEDIATE LIME REQUIREMENT OF sons-For the average soil, t a k e Io-gram charges of soil a n d IjO cc. of C a C 0 3 solution. This volume usually represents about 0.1j o o gram of CaC03. For very heavy clays, or peaty or swamp soils, reduce t h e charge t o j g. Evaporate t o a paste in I 50-cc. porcelain evaporating dishes. Transfer paste t o a 300 cc. Erlenmeyer flask; by means of COn-free distilled water,’ delivered b y gravity from t h e reservoir. Do not have volume of transferring v a t e r t o exceed 60 t o 7 0 cc. I n unusual cases of adhesion of soil t o dish, scour with a little CaCO3-free sand. T h e tendency of the carbonate I Such water m a y be easily obtained in considerable quantities by slowly siphoning off boiling water, t h e volume of which is maintained by a gravity constant-level supply.
Oct.. 191j
T I5 E J O C R S d L O F I S D 1.S T RI A L A S D EiVGIlV E E RI iITG C R E M I S T R Y
is sometimes t o precipitate in a ring marked b y the initial level of aliquot. Determine C 0 2 b y agitation a n d aspiration for 30 minutes. a t room temperature, with 4 inches vacuum, using j cc. concentrated HaPo4 t o effect liberation of gas.’ Hydrochloric acid may be used instead of H3P04, if proper precautions be taken for collection of volatile acid. T h e gravimetric method of absorption is decidedly preferable unless t h e analyst is thoroughly conversant with t h e technic of the liquid absorption and double titration procedure. Xlthough absolute theoretical recovery of COn cannot be secured in large amounts b y t h e volumetric absorption, a t room temperature, the factor is apparently uniform. However, t h e differential COS values in the small charges used in t h e method may be very accurately determined a t ordinary temperatures if proper precautions be observed.* I n this laboratory we have secured very satisfactory results, even on large amounts of C o n , b y the procedure of precipitating t h e alkali carbonate formed in t h e a b sorbent solution with a constant maximum amount of BaC12, and making t o joo cc. volume with COa-free distilled water. An aliquot of z j o cc. of the clear supernatant caustic liquid is t h e n titrated directly with standard acid, using phenolphthalein as a n indicator. From the determined strength of t h e absorbent is then deducted the blank obtained in t h e same manner upon the original solution. Ten cc. of approximately N / z S a O H , diluted t o j o cc. with C02-free water, is sufficient t o absorb the liberated COS. If the double titration procedure be followed, t h e number of cc. of X / z o acid used in t h e methyl orange titration of t h e blank, minus t h a t of t h e determined residual, will give, in terms of 1 V v / 2 0 acid. the CaCO:, decomposed b y the soil. This number, multiplied b y o . o o j g. and divided by t h e charge and multiplied b y I O O will give t h e per cent of lime requirement in terms of carbonate of lime. If t h e barium chloride precipitation procedure be followed the difference lietween cc. of titration of one-half of original absorbent solution after its treatment with BaClz and t h a t of z j o cc. aliquot after absorbing CO? multiplied b y t h e C a C 0 3 value of titration-acid and divided b y charge will give C a C 0 3 requirement. The small and nearly constant atmosphere blank of t h e apparatus is included in t h a t of t h e added C a C 0 3 and absorbent solution. This eliminates t h e necessity of rinsing t h e apparatus before each determination in order t o remove a n y acid residual from the preceding determinations. This, together with t h e elimination of necessity for sweeping t h e apparatus free of atmospheric COS prior t o each analysis, greatly facilit a t e s speed when making a large number of determinations. In very accurate work t h e slight action of t h e acid u p o n t h e soil organic matter in t h e cold should be recorded. T h e blank would t h e n be run simultaneously upon t h e aggregate of a charge of t h e original soil equivalent t o t h a t used in t h e evaporation, t h e Description of apparatus and detailed directions for manipulation of this determination werr given in Tennessee Station Bullelin 100 and in THIS J O U R N A L 7 (1915), 227. 2 See Lincoln a n d Walton. “El. Quant. Chem..” p. 64. 1
867
boiled C a C 0 3 solution, the apparatus atmosphere, a n d the absorbent solution, if t h e volumetric absorbent method were used. If t h e apparatus above specified for determination of residual carbonates a t room temperature be not available, residual carbonates may be determined b y bringing t h e soil and acid t o boiling and continuing t h e boiling for otie minute, with passage of purified air during boiling and for 3 0 minutes subsequently. B blank should then be run upon the acid soil in the same manner and correction made therefor. The boiling necessitates great care in order to prevent moisture being carried through the sulfuric acid into t h e soda lime tubes. Camp absorption towers will be found to be very efficient in t h e drying of the evolved gas. DEPARTMENT OF CHEMISTRY A N D AGROXOMY EXPERIMENT STATION AGRICULTURAL UNIVERSITYOF TENNESSEE. KNOXVILLE
O N THE COMPOSITION OF THE SEEDS OF MARTYNIA LOUISIANA’ By E. H. S. BAILEYA N D W. S. LONG
Received June 9, 1915
Our attention was first called t o t h e possible industrial value of this plant b y Mr. J. A. Puntennay, of Granada, Colo., a locality just across the KansasColorado, line. He estimates t h a t under ordinary conditions of t h a t climate the plant will yield 2 0 bushels of cleaned seed per acre, a n d under more favorable conditions this amount may be much increased. The plant, which is found growing in waste places, escaped from gardens, from Maine t o Georgia, and which occurs wild from Indiana west and southwest through LTtah, Texas and New Mexico, is a coarse, diffusively branched, glandular, pubescent and viscid, strongly scented shrub. It is commonly known as utzicorn or Deoil’s C l a m . I t has opposite, ultimate, long-petioled leaves, and large, violet-purple, whitish or mottled flowers in short terminal racemes. The seed-pod when inverted has the shape of a n elephant’s t r u n k , hence t h e name Eleflhant’s Trunk, often applied t o t h e plant. When d r y t h e pod splits in t h e center and two horns or projections appear. T h e Martynia grows abundantly as a weed in a climate t h a t is so d r y t h a t few other plants will flourishj because i t has a t a p root t h a t penetrates the soil t o a great depth. The herb is very drought-resistant, and will mature its seed in localities where the moisture is not even sufficient t o produce Mexican beans. With abundant moisture the yield is much increased. The seeds, of which as many as seventy are often found in a pod, are surrounded b y a husk, and Ti-hen this is removed, a comparatively soft, nearly white kernel remains. This is easily crushed, even when dry, and its oily character is apparent t o the touch. The seed has the following percentage composition: E t h e r extract (Fat) 60.63
Protein
(h-X 6.25) 24 4 1
Starch 4.55
Crude fiber 3.05
LIoisture 2.91
Ash 3.80
1 Presented a t t h e 5Lst Meeting of the American Chemical Society, New Orleans, March 31 t o April 3 , 1915.
