Effect of Submergence on Changes in Soil Properties and Yield and Nutrient Uptake by Rice with Varying Nutrio-environment in Lowland Soil

Changes in available nutrient and pH in submerged rice soil were studied under field condition with varying nutrio-environment. There was decrease in availability of NH₄-N, Ca, Mg, Mn, Cu and Zn and a slight increase in available Fe due to continuous absorption by rice crop. Response to application of nitrogen only was noticed. Nutrient uptake followed the trend of dry matter production which, in turn, was influenced by rate of nitrogen application. Application of nitrogen influenced the availability of NH₄-N in soil, whereas P and K had no effect on nutrient dynamics. Changes in pH was best fitted to exponential function; NH₄-N, K, Ca, Zn and Cu to quadratic function and P, Mg, Fe, and Mn to logarithmic function.