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Calcium Phosphate Fertilizers: IV. The Relation Between Solubility in Soils and Availability Coefficients of Dicalcium and Fused Tricalcium Phosphates
Author(s) -
Bouldin D. R.,
Sample E. C.
Publication year - 1959
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/sssaj1959.03615995002300040016x
Subject(s) - phosphate , soil water , granule (geology) , chemistry , calcium , anhydrous , solubility , phosphorite , mineralogy , environmental chemistry , soil science , materials science , environmental science , organic chemistry , composite material
The availability coefficient indexes per unit of P of 2 granule sizes of fused tricalcium phosphate (FTP), anhydrous dicalcium phosphate (DCPA), and dicalcium phosphate dihydrate (DCPD) were measured with 3 soils in greenhouse experiments. Availability coefficient indexes increased as granule size was reduced. Per unit of geometric surface area, availability coefficient indexes increased in the order FTP < DCPA < DCPD for all 3 soils. The composition of solutions after 2 weeks' reaction between 1 g. soil and 1 g. of phosphate in 40 ml. of water was measured. The product of the concentration of P in these solutions and geometric surface area of the respective fertilizers explained 86% of the variation in availability coefficient indexes of the 6 fertilizers in the 3 soils.