M a y , 1916
T H E J 0 G R N A L 0 F I N D U S T RI A L A iV D E N G I AVE E RI AVG C H E M I S T R Y
425
Solutions indicated in Table V were analyzed b y 95 per cent alcohol. The occlusion of other organic acids with -precipitated pectin bodies a n d cream of different analysts on different dates with t h e results t a r t a r makes t h e use of only j o cc. of grape juice ad- given. TABLE\'-(Results in Grams per 100 cc.) visable for the determination. HALENKE A N D HARTMANN-EOFF METHOD MOSLINGER Half Completely I n case of syrups, fermentation of sugar or a separa-. ~ETERMINATION METHOD Neutralued Neutralized tion of t h e acid therefrom as t h e lead salt' is advisable. 1.96 2.52 Acidity as Tartaric.. . . . 4 . 9 2 1 .so 1.89 Total Tartaric Acid.. , . . 2 . 0 0 I t may be of interest t o mention t h a t Halenke and 0.48 0.048 Phosphoric Acid. . . , . . . . I . 9 1 1.20 1.20 1.20 Caramel b1:oslinger advise a double precipitation in t h e case 0.024 0,024 0.024 Amaranth. . . . . . . . . 5.00 5.00 5.00 Cane Sugar.. . , . . . . of grape juices. FOR ARTIFICIAL PRODUCTS COKTAINIKG F R E E PHOS-
A C I D A N D ALCOHoL-~Thile experimenting with synthetic solutions, containing tartaric acid, free phosphoric acid a n d alcohol, it was found t h a t neither the Halenke-Moslinger method nor the Hartmann and Eoff method gave satisfactory results. Further, it developed t h a t these two methods became less reliable as t h e solutions under discussion aged. This condition ivas found t o be brought about b y t h e formation of ethyl esters of tartaric acid, t h e amount of ester formed increasing with t h e time allowed for t h e reaction. This was shown b y saponifying t h e solution with a n excess of alkali before determining t h e tartaric acid, a complete recovery of the theoretical amount of acid being thereby obtained. I t was also observed t h a t in cases where much free phosphoric acid was present t h e Halenke and Moslinger method fniled t o give a n y precipitate of potassium acid t a r t r a t e whatever, notwithstanding the presence of considerable tartaric acid in t h e solution. These two points, t h e loss of tartaric acid through esterification and t h e failure of t h e Halenke-Moslinger method t o give even approximate results in presence of free phosphoric acid, were made t h e subject of investigation in 1914 by the Associate Referee on Wines of t h e Association of Official Agricultural Chemists, The heretofore unpublished work of five collaborators !vas very satisfactory and fully substantiates t h e findings recorded above. T h e behavior of alcohol a n d tartaric acid in t h e presence of other free organic acids (formation oE esters) is a well-known phenomenon and was pointed out b y Berthelot and Fleurieu in their original paper describing t h e alcohol-ether method. Esterification in p a r t may explain why very old wines, when employing t h e customary methods for determining the total tartaric acid, very often show an exceedingly small amount of this constituent. I t is very important t o know t h e extent- of esterification in artificial products containing free phosphoric acid, alcohol, and tartaric acid, since the ordinary methods may not reveal t h e tartaric acid t h a t is present even in amounts as high as 3 g. per I O O cc. of solution. I t was found t h a t by adding j cc. N NaOH in excess of neutralization t o j o cc. of t h e solution under examination, bringing t o a boil and allowing t o stand over night, a complete saponification could be obtained. The addition of t h e required amount of tartaric acid, dilution t o I O O cc. with water and t h e n proceeding as detailed for wines, yielded quantitative results for total tartaric acid.
PHORIC
C . Schmitt and C. Hiepe, 2. anal. Cham., a1 (1882), 534-41.
Alcohol. . . . .
,
...,
5.00
5.00
5.00
Table V I presents results obtained on three synthet;ic solutions, on the dates indicated. TABLE VI-RESULTS ( G . per 100 cc.) Solution Sumber I.....
HALENKE
AND DATE 1914 ~~OSLINCER 7/20 0.74 8/12 0.64 8/24 0.06 8/26 0.63 10'30 0.00
THREESYNTHBTIC SOLUTIONS AND EOFFMETHOD HARTMANN h-eutralization Preliminary Half Complete Saponification 1.88 1.90 .. 1.69 1.84 .. 1.54 1.76 1.66 1.67 2:oo 1.61 1.65 .. 1.76 ..
ON
1.68
..
The low results obtained by the Halenke and hIoslinger method show t h e necessity of starting the precipitation b y stirring as illustrated b y the results obtained on August 24th, and October 30th. The gradual esterification of the free tartaric acid is shown by the lower results obtained a s t h e solutions aged. BUEEAUOF CHEMISTRY, ~VASHIKGTOX
THE DECOMPOSITION OF THE ORGANIC MATTER OF KELP IN THE SOIL' B y A . W, CHRISTIE Received iXovember 15, 1915
Considerable interest has been evinced of late in t h e possible use of kelp as a commercial fertilizer. Burd' has shown that probably the most practical and profitable way of utilizing kelp would consist in drying a t a low temperature and grinding. The resulting product, in addition t o the valuable potash ( I I .4 j per cent K?O in air-dried kelp ( M a c r o c y s t i s ) ) , contains all the nitrogen and organic matter. Stewart3 has shown t h a t t h e nitrogen (1.18 per cent N in airdried kelp ( M a c r o c y s t i s ) ) becomes slowly available in t h e soil. I n connection with t h e probable use of dried a n d ground kelp as a commercial fertilizer or as a filler for mixed fertilizers, it becomes of interest to learn the fate of the organic matter and whether a n y agricultural value may be assigned t o it. The extent and rate of decomposition of kelp in soil were compared with the following materials which are common sources of organic matter in t h e soil, D ~ z . , manure, straw and alfalfa. P L A N OF E X P E R I M E N T
I n each of 14 glass jars were placed 3 0 0 g. of airdried soil (fine sandy loam from a n a h e i m , California), 1 See also work of U. S. Department of Agriculture on Kelp. [EDITOR'S NOTE.] 2 "Economic Value of Pacific Coast Kelps," Bd1. 248, California Agricultural Experiment Station. a "Availability of Xitrogen in Pacific Coast Kelps," J. Agr. Research, 4, S o . 1 (1915). 21.
426
and t o each jar were added I j g. of the organic material t o be tested. The two samples of kelp used were M a c r o c y s t i s p y r i j e r a a n d :JTeqeocystis leutkea?%a, t h e varieties of greatest commercial importance on the Pacific Coast. These samples were oven-dried and finely ground and then allomed t o come t o constant moisture content by exposure t o the air a t room temperature. T h e manure, alfalfa and straw were also finely ground a n d thoroughly air-dried. Jars 11 and 1 2 , in addition t o the I j g. M a c r o c y s t i s , TT-ere inoculated with a few cc. of a solution from a jar of decomposing kelp, t o ascertain if the partial sterilization due t o oven-drying mould have a n y effect on the subsequent decomposition in the soil. A11 jars were loosely stoppered t o prevent excessive evaporation, yet allowing easy access of air, and Cere kept a t an average temperature of 30' C. for j mos. The moisture content was maintaineb. a t 18 per cent (optimum for t h e soil) by frequent additions of sterile water, accompanied by cultivation of the soil. .4t t h e end of j mos. t h e contents of each jar were removed, thoroughly air-dried and ground for analysis. A Io-g. portion from each jar was analyzed for humus and humus nitrogen, using the method of Grandeau, a s modified by Hilgard.' Table I gives the results obtained. This table shows t h a t dried and ground kelp in this experiment was decomposed t o form humus t o approxi-i TABLE I-RESULTS MATERIAL ADDED Alfalfa Straw Manure
Jars 1& 2 3 &4 5&6 7 &8 9 & 10 11 & 12 13 & 14
Neveocyslis Macrocystis
Mac. (inoc.) [Blanks]
PERCENT HEMESIN SOIL Duplicates Av. 0 . 9 8 1.08 1.03 1.14 1.24 1.19 1.08 1.11 1.10 1 . 0 3 1 . 16 1 . 10 0 . 9 6 1.03 1 . O O 0 . 9 8 1 . 0 6 1.02 0.65 0 . 6 6 0 . 6 6
GAIN 0.37 0.53 0.44 0.44 0.34 0.36
....
% S in
Humus 10.15 8.25 9.54 10.50 11.55 9.95 13.82
Hilgard, "Soils," p. 132.
PENTOSAX DECO3IPOSITIOS
Hoagland' has shown t h a t kelp contains considerable amounts of pentosans and since the other materials used are also high in pentosans. it is desirable t o s t u d y the fate of this group in t h e soil The materials were OF
S-MONTH TESTS
70 ORGANICMATTER % Pentosans Original Humified 89.00 8.81 96.50 11.49 65.50 13.98 43.60 21.00 59.60 11.85 5 9 . 6 0 12.65
..... .....
mately t h e same degree as t h e substances ordinarily employed for t h a t purpose. On a basis of equal weights of original material, the N e r e o c y s t i s is surpassed only b y straw, is equal t o manure and superior t o alfalfa. The M a c r o c y s t i s is somewhat inferior b u t nearly equal t o alfalfa. The inoculation of the Mucrocystis slightly increased its humification but not sufficiently t o cause i t to surpass a n y of the other materials. T h e variations in the percentage of nitrogen in the humus are slight and no great importance is attached t o them. Since t h e various materials used contain very different amounts of organic matter which might be humified, t h e percentage of the organic matter humified during t h e period of incubation is important. T h e per cent of organic matter in the original materials and the average Fer cent of this organic matter which humified appear in Table I. On the basis of a unit amount of organic matter, the N e r e o c y s t i s is b y far t h e best humus producer and even t h e M a c r o c y s t i s is surpassed only by the manure. T h e conditions under which this experiment was carried o u t , viz., constant moisture content of 18 per cent and constant temperature of 30' C. for j mos., would certainly be equivalent t o a considerably longer period under field conditions. Furthermore, the form and manner 1
in which these materials were added t o the soil are not t h e same as would obtain in field practice. None of t h e materials mould be finely ground, with t h e possible exception of the kelp, if it were part of a complete fertilizer. The alfalfa would ordinarily be plowed under green and the manure moist and fresh: these conditions accelerate their decomposition in t h e soil. The kelp used in this experiment,. as has already been pointed out; was heated t o a much greater temperature t h a n would be t h e case in commercial practice and hence was probably less readily decomposed. The conditions in the laboratory may favor the decomposition of one substance more t h a n another. The per cent of humus is not necessarily a definite index of the value of the organic matter in t h e soil. T h e r e f o r e , i t i s n o t desired t o convey the i m p r e s s i o n t h a t the o r g a n i c m a t t e r of k e l p is p r o v e n b y t h i s e x p e r i m e n t to be as valuable a s the othes m a t e r i a l s u s e d . The experiment does prove, however, t h a t kelp is not a n inert substance in the soil and t h a t its organic matter has some fertilizing value. Final judgment upon these points would require d a t a obtained from field experiments.
in Originals 12.18 27.7.5 11.57 6.16 7.11 7.11
.....
% PENTOSANS
RECOVERED PERCENT ORIGINAL Duplicates Av. PENTOSANSDECOMPOSED 3.17 2 . 4 7 2.82 77 4.34 6 . 8 8 5.61 80 2.45 2 . 4 9 2.47 79 77 1.46 1.64 1.55 I> 1 . 7 2 1.81 1 . 7 6 7 1.62 1 . 6 4 1.63 I ,
__
. ..
...
....
analyzed for pentosans according to the OfficiaI method,2 which is empirical and depends upon the production of furfurol from whatever source derived; hence, conclusions regarding the decomposition of pentosan materials must be based simply upon comparative data. The samples of soil and organic materials were t h e same as those previously described. After j mos. incubation t h e soils were analyzed and t h e percentages of pentosans found calculated t o t h e original weight of materials added t o the soil. Tests on untreated soil showed only very small amounts of furfurol-yielding substances, and corrections were made for the blanks. The extent of decomposition in each case is given in Table I. I t i s evident t h a t the pentosans in the different materials are all decomposed t o about t h e same extent, since in all cases between 7 5 and 80 per cent of the total amount has been decomposed regardless of t h e original source or amount. Some slight differences which are evident can be reconciled with previously established facts, e. g., it is known t h a t N e r e o c y s t i s is more easily decomposed than M a c r o cystis; inoculation slightly increased t h e decomposition of M a c r o c y s t i s . These d a t a also indicate t h a t from the standpoint of pentosan decomposition, kelp may be ranked with the other materials tested. 1
"Organic Constituents of Pacific Coast Kelps," J . Agr.
No. 1 (1915), 39. 9
Bureau of Chemistry, C. S. Dept. Agr.. Bull. 107, 54.
Res., 4.
May, 1916
T H E JOC'RIVAL O F 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
427
for action of acid on organic matter being applied. Nor is i t usually found possible t o recover by t h e Dried a n d ground kelp decomposes in t h e soil under double titration method all the carbon dioxide from laboratory conditions, increasing t h e humus content samples of pure carbonates. t o a n extent comparable with alfalfa, manure a n d As t h e result of work done in this laboratory, a n d straw. Of t h e pentosans present, 7 5 t o 80 per cent having for its object t h e improvement of t h e Marr was decomposed in all t h e materials. method a n d a t t h e same time t h e retention of its Acknowledgment is made t o Professor D. R. essential feature, which is decomposition of soil carHoagland, a t whose suggestion t h e above work was bonates b y dilute acid a t reduced pressure and temperformed. perature, involving t h e least possible a t t a c k upon AGRICCLTURAL EXPERIMEKT STATION soil organic matter which is compatible with complete U N I V E R S I T Y OF C A L I F O R N I A , BERKELEY decomposition of carbonates a n d complete evolution of t h e gaseous carbon dioxide i n t h e minimum ESTIMATION OF CARBON DIOXIDE AS BARIUM CARperiod of time, it has been found possible t o do away BONATE APPLIED TO THE MARR METHOD with t h e objectionable double titration. This is acFOR DETERMINATION OF CARBONcomplished b y .effecting t h e absorption of t h e carATES IN SOIL bon dioxide evolved Erom t h e sample in barium hyB y C. J. SCHOLLENBERGER Received December 27, 1915 droxide solution contained in a Meyer bulb tube. Closely following t h e publication by l l a r r l of a T h e precipitated barium carbonate is filtered off method for soil carbonates, a modification embodying a n d determined as described b y Cain.' The method its essential features, which are evolution of carbon is essentially t h e same as t h a t recommended for dioxide b y boiling with dilute acid under reduced adoption as a tentative method b y t h e Referee on pressure a n d absorption of t h e evolved carbon dioxide Soils of t h e dssociation of Official Agricultural Chemin a solution of sodium hydroxide, t h e carbonate therein ists in 1 9 1 5 . E . Truog2 has described a method for t h e deterbeing subsequently estimated b y t h e well-known double titration method of Brown a n d Escombe,* mination of carbon dioxide b y absorption in a measwas extensively studied in this laboratory a n d a form ured excess of barium hydroxide solution and t i t r a of apparatus adapted t o it subsequently described tion of t h e excess of barium hydroxide, using phenolby E. W. Gaither.3 phthalein as indicator. ,4 trial was made of this Extended experience with this method, both in method also, b u t effecting t h e ab.sorption in a hleyer el-ery-day use on routine samples a n d with t h e special bulb t u b e , which seemed t o be better adapted t o t h e samples furnished by t h e Referee on Soils for t h e Asso- purpose in this instance t h a n did t h e ingenious bead ciation of Official Agricultural Chemists' work in 1 9 1 4 tower described b y Truog. The results were satisa n d 1 9 1 5 , has served t o establish t h e fact t h a t t h e factory when t h e acid used for t h e titration was decomposition of soil a t a moderate temperature standardized b y t h e use of a sample of known cari~zvacuo b y dilute hydrochloric acid is undoubtedly bonate content, as pointed out b y brad^.^ If t h e t h e most accurate of all procedures so far proposed theoretical strength of t h e acid had been employed for this determination, as it reduces t o a minimum in making t h e calculations, a considerable minus t h e activity of acid o n organic material. When t h e error might have been introduced. T h e method offers soil is treated with acid in t h e cold there will be for important advantages over t h e double titration prosome samples, depending on t h e nature of t h e carbon- cedure, a n d will probably give better results in t h e ates present, a n incomplete decomposition of carbonate. hands of operators not thoroughly familiar with t h e If t h e soil be boiled a t atmospheric pressure with acid latter method, b u t it must not be forgotten t h a t it there will be a n excessive action on t h e organic matter is subject t o t h e same great source of error, viz., t h e with consequent liberation of carbon dioxide not de- presence oE substances supposedly neutral t o phenolrived from carbonates, necessitating a blank de- phthalein, b u t through hydrolysis, alkaline t o t h a t termination on a n extracted sample a n d t h e applica- indicator-sodium bicarbonate in t h e one case a n d tion of a correction for carbon from organic sources barium carbonate in t h e other. which involves considerable uncertainty. For t h e reasons enumerated above, it is evident There is, however, a source of error in t h e Marr t h a t absorption in barium hydroxide solution a n d method if t h e double titration procedure is used for titration of t h e residual hydroxide offers only a slight determining t h e evolved carbon dioxide. This is advantage over t h e older scheme of absorption i n indicated b y t h e fact t h a t t h e results b y t h e Marr sodium hydroxide a n d double titration on t h e score method, although showing excellent agreement with of accuracy of results, although it does offer some adthose obtained b y boiling with stronger acid, t h e vantages in t h e points of speed and convenience. proper correction being applied a n d t h e double t i t r a - By careful standardization of t h e method, it would tion procedure used in each case, do not show such dpubtless give satisfactory results for routine work. good agreement when compared with results obtained The filtration method proposed b y Cain is not subby boiling a t atmospheric pressure and measuring ject t o t h e above sources of error, a n d should give t h e carbon dioxide gas, t h e correspondiflg correction SUMMARY
1 2
3
Jour. Agr. Sczence, [2] 3, 155 Phzl. Trans. ( B ) , 193 (1900), 289. THE JOURNAL, 4 (1912). 611.
1 Technologzcal Paper 33, Bureau of Standards, also THISJ O C R N A L , 6 (1914). 465. * THISJOCRNAL, 7 (1915), 1045. 3 Ibid.. 6 (1914), 843.
