TRANSFORMATION OF LABILE-P IN 2 ALKALINE SOILS AMENDED WITH SESBANIA-ACULEATA AT 2 MOISTURE REGIMES

Labile organic and inorganic P in an alkaline sandy loam and loamy san d (Typic Ustochrepts) amended with dried Sesbania aculeata and incubat ed for periods ranging from 10 to 100 days was investigated. A signifi cant decrease in soil labile organic P occurred with a simultaneous in crease in the labile or dissolved inorganic P soluble in 0.5M NaHCO3. The decrease in labile organic P is explained by its rapid mineralizat ion to inorganic P. Dissolved organic P, therefore, makes a significan t contribution towards the P nutrition of crops, a factor relevant to soil management.