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Calcium Phosphate Fertilizers: II. A Petrographic Study of Their Alteration in Soils
Author(s) -
Lehr J. R.,
Brown W. E.
Publication year - 1958
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/sssaj1958.03615995002200010009x
Subject(s) - petrography , phosphate , calcium , soil water , chemistry , apatite , hydrolysis , phosphorite , mineralogy , phosphorus , environmental chemistry , fertilizer , phosphate fertilizer , nuclear chemistry , geology , soil science , biochemistry , organic chemistry
As a supplemental study to pot‐culture tests in which six calcium phosphates were investigated, petrographic examinations were made of the fertilizer residues and surrounding soils. The materials tested were Ca(H 2 PO 4 ) 2 · H 2 O, CaHPO 4 · 2H 2 O, CaHPO 4 , Ca 4 H(PO 4 ) 3 · 3H 2 O, Ca 3 (PO 4 ) 2 , and Ca 10 (PO 4 ) 6 (OH) 2 ). The purpose was to determine the physical and chemical alterations that the materials had undergone while in a soil environment and in the presence of feeding roots. Correlations between these observations and plant response were sought. Some correlation was found between plant response and; (a) relative rates of solution or solubilities of the phosphates, and (b) chemical alterations of the phosphates. Positive evidence was found for 4 hydrolysis reactions, 2 of which confirm the postulated formation of octocalcium phosphate and apatite. Other observations lend new support to the concept of contact feeding by plant roots.