Effect of organic sources on nitrogen availability in flooded rice soils

Abstract

A study was conducted during the rabi season of 1982 to study the changes of N in the lateritic rice soil as well as in the rice plant as influenced by flooding in the presence of various organic and inorganic sources of nitrogen. The results revealed that daincha treated plots were able to liberate more nitrogen in the soil as well as in the solution than farm yard manure or azolla treated or urea alone treated plots. In general the NH4-N content in the soil showed a progressive decrease from tillering to harvest (11.13 - 1.99 ppm). The chemical kinetics of NOj-N, hydrolysable-N, non-hydrolysable N, organic carbon and total N were not influenced by the various treatments. Urea applied alone or in combination with daincha was found better for increased N uptake by the rice plant.