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Phosphate Solubility in Relation to Cations and pH: Magnesium
Author(s) -
Perkins Alfred T.
Publication year - 1948
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1948.036159950012000c0041x
Subject(s) - chemist , citation , chemistry , relation (database) , solubility , order (exchange) , library science , computer science , organic chemistry , database , finance , economics
E effect of pH and cation on phosphate solubiliJ. ty and availability is of great importance. Many publications have appeared on this general subject dealing with it either directly or indirectly. The effect of magnesium on phosphate solubility and availability has been studied for many years and recently the role of magnesium has been studied intensely. A recent issue of Soil Science has been devoted entirely to magnesium and soils. The present paper includes data showing the effect of some cations commonly found in soils on phosphate solubility in the presence of kaolin. The work was outlined to give information on the role magnesium plays in phosphate solubility with the purpose of helping evaluate the use of dolomitic limestone in place of calcitic limestone on acid soils deficient in phosphate, and on the role that magnesium might play in rendering the phosphate of rock phosphate available. Among the many publications dealing with phosphate solubility may be listed that of Gaarder (3) who showed that phosphate in the presence of iron or aluminum is almost completely insoluble at an acidity of pH 3.0, but that as the solutions become more basic the solubility of the phosphate increases. This and similar data have led to the general statement on precipitation of phosphate that iron and aluminum are active.below pH 5.5, that calcium, is dominant at pH 6.5, and that magnesium enters the picture at pH 7.5 (2).