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A COMPARISON OF THE POLYCARBOXYLIC ACIDS EXTRACTED BY WATER FROM AN AGRICULTURAL TOP SOIL WITH THOSE EXTRACTED BY ALKALI
Author(s) -
LINEHAN D. J.
Publication year - 1977
Publication title -
journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 0022-4588
DOI - 10.1111/j.1365-2389.1977.tb02244.x
Subject(s) - chemistry , fulvic acid , humic acid , fractionation , organic matter , alkali metal , soil water , environmental chemistry , elemental analysis , organic chemistry , soil science , fertilizer , environmental science
Summary Humic and fulvic acids were isolated from an agricultural soil by conventional means. The same soil was extracted with water and the organic matter freed of inorganic and low molecular weight substances. The usual chemical differences between humic acid and fulvic acid were confirmed and the water extract was shown to resemble fulvic acid quite closely. Further fractionation of the fulvic acid and water extract showed that the elemental composition, carboxyl and acidic hydroxyl contents, molecular weights, and infrared spectra of the purified polycarboxylic acids were virtually identical. Both promoted the same growth response in cultured isolated tomato roots. It is suggested that the qualitative similarity of fulvic acid to the polycarboxylic acid extracted by water justifies the use of the more easily isolated fulvic acid in physiological experiments on the direct effects on plants of soil organic matter.