Forms of Phosphorus in Some Acidic Entisols of Subtropical Eastern India

Information about the phosphorus (P) forms in soils of Terai agro-ecological region of Cooch Behar (where P fertilizers have been applied for a long time), and their influence on the availability of P in soils is meagre. A study was undertaken to evaluate the status of different P forms in twenty five soils (0-0.15 m; acidic Entisols) collected from rice growing areas spread over the district of Cooch Behar, West Bengal, and their relationships with salient soil properties. Results reveal that total inorganic phosphorus (TIP) as the predominant form constituted 78.47% of the total phosphorus (TP) on average, and maintained equilibrium with TP and available phosphorus (AP) in these soils. Significant positive correlation of AP (Bray-1 extractable) with organic phosphorus (OP) and organic carbon (OC) content suggests reversible association between extractable P and organic matter, and further indicates non-stabilization of phosphorus-organic matter complexation in the soils (Entisols) studied.