Premium
The Fixation of Phosphates by Soil Colloids 1
Author(s) -
Scarseth G. D.,
Tidmore J. W.
Publication year - 1934
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/agronj1934.00021962002600020007x
Subject(s) - chemist , citation , library science , chemistry , mathematics , computer science , organic chemistry
It is well known that soluble phosphates in ferti]izers become relatively insoluble when mixed with soils and that only small quantities are lost in drainage waters. Most soils are deficient in available phosphorus even though the total supply of native phosphorus may be high. Many soils which have received annual phosphatic fertilization for several years show the need for further applications of phosphate in order to produce satisfactory crops. Such facts, established by the results of many investigators (i, 3, 6, 8, 9, ~o, ~, ~6, ~9, 20, 2~, ~4, 3o)~, show that softs possess vast capacities for fixing phosphates. Mattson (~4) showed that the phosphate ion was absorbed to a considerable extent by a number of. soil colloids. He noted that most absorption occurred where the silica-sesquioxide ratio was the smallest, these ratios varying from 0.55 to 3.8~. Roszmann (2~) reported that absorption of phosphorus by sodium and calcium soil colloids was greatest at pH values between 3.0 and 3-5. Teakle (2S) has shown that different Hand OH-ion concentrations in soil solutions greatly affect the solubility of various kinds of phosphates. It is apparent from the work of these investigators and others that different soils may vary greatly in their phosphate-fixing behavior and that the acidity of the soil, particularly the degree of calcium saturation, is of great significance in the fixation of phosphates, Although the nature and extent of phosphate fixation is not thoroughly understood, it is generally accepted that the colloidal fraction of the soil is the principal seat of the fixation. It is the purpose of this paper to present some characteristics of the phosphate-fixing properties of soil colloids extracted from soils which were derived from non-phosphatic materials in a subtropical climate. The object of this investigation was to study the effect of the chemical composition, as expressed by the silica-sesquioxide ratio, and the effect of the degree of calcium.saturation of the colloids on the fixation of PO~ from some of the common sources of phosphates.