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Rapid Chemical Methods for the Estimation of the Capacity of the Soil to Supply Phosphoric Acid to Plants 1
Author(s) -
Fraps G. S.,
Fudge J. F.
Publication year - 1933
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1933.00021962002500030007x
Subject(s) - phosphoric acid , agricultural experiment station , citation , chemist , fair division , agriculture , mathematics , library science , chemistry , computer science , mathematical economics , archaeology , geography , organic chemistry
Methods for estimating the capacity of soils to supply phosphoric acid to crops are of considerable agricultural importance. The 0.2 N nitric acid method has been studied thoroughly in this laboratory (3, 4, 5),~ and the results compared with pot experiments with favorable results on "many of the soils of this state. Recently, the "Hi-lofosfate" method (~) and the Trt/og-LaMotte method have been proposed for use in field work for the rapid estimation of so-called available phosphoric acid in the soil. Truog (7) and Nemec, at al. (6) have proposed rapid laboratory methods.. It was considered desirable to compare these methods with respect to ease of manipulation, concordance of the results on the same samples, and the relative quantities of phosphoric acid removed from soils by each. If they remove different quantities of phosphoric acid from the same soils, the interpretation of the results must vary with the method. AS samples of soils tested by means of pot experiments were available, it was considered desirable also to compare the results by the various methods with the results of the pot experiments, as had been done with 0.2 N nitric acid method. Since previous work had shown the.o.2 N nitric acid method to be preferable to most of those tested, it deemed desirable to devise a rapid colorimetric method which would give similar results. The method of Nemec is based upon the ~% citric acid used extensively in Germany and interpretated by the standards used there. The interpretation of the Hi-lo-fosfate method is based upon field observations, but data supporting the interpretation of the Truog method and of the Truog-LaMotte met1~od have not been presented.