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Predicting the Dissolution of Rock Phosphates in Flooded Acid Sulfate Soils
Author(s) -
Yampracha Sukunya,
Attanandana Tasnee,
Sidibe-Diarra Aminata,
Yost Russell S.
Publication year - 2005
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/sssaj2003.0320
Subject(s) - dissolution , soil water , sorption , sulfate , chemistry , environmental chemistry , mineralogy , soil science , geology , adsorption , organic chemistry
Seven hundred sixty thousand hectares of acid sulfate soils in Central Plain of Thailand are used for rice ( Oryza sativa L.) cultivation. Insufficient nutrient P seriously limits rice growth and yield. A local rock phosphate (RP) Kanchanaburi RP (KRP), a reference RP (Gafsa from Tunisia), and a KRP containing soluble P (KRPS) were used to investigate the dissolution and availability in six acid sulfate soils under flooded conditions. The soil properties that have a major influence on RP dissolution and P sorption were investigated for developing a model and algorithms for estimating the RP requirement for rice. High KCl‐extractable aluminum (Al_KCl) and low soil pH enhanced the dissolution of KRP, Gafsa, and KRPS. The substantial calcium carbonate equivalent of the RP increased the pH of soils and limited RP dissolution. The P sorption of the soils was estimated using Bray 1 and 2 extractions. The P sorption was apparently greater than RP dissolution a few days after submergence in some acid sulfate soils, decreasing the Bray 1 level. Phosphorus extractable by Bray 2 increased with incubation time where KRP, Gafsa, and KRPS were applied. Amounts of RP predicted using an algorithm based on predicted dissolution and sorption in the various soils were similar to a local estimate of RP requirement.