EFFECT OF MOISTURE AND TEMPERATURE REGIMES ON AVAILABLE PHOSPHORUS INWETLAND RICE SOILS

A laboratory experiment was conducted to evaluate the effects of water and temperature regimes on availability of soil phosphorus (P). Four soil samples with variable levels of available P collected from a long -term P frequency trial were incubated under two moisture regimes, con tinuous waterlogging (CWL) and alternate wetting and drying (AWD) at 2 0 degrees C and 30 degrees C temperature for 90 days. The samples were extracted with 0.5M NaHCO3 for available P determination after incuba tion. Increase in temperature increased available P content and this i ncrease was more prominent in CWL conditions. Available P in all the s oils tested was higher under CWL than AWD conditions, however, the inc rease in available P due to CWL environment was more pronounced in soi ls with higher available P.