Effect of optimal and suboptimal nutrient management on nutrient changes, yield and nutrient uptake by rice in submerged soil

Field experiment was carried out to study the effect of optimal and suboptimal dose of nutrient management on nutrient changes in soil, yield of and nutrient uptake by transplanted rice. The pH of the soil increased up to 40 days after transplanting whereas Eh decreased (−100 to -170 mV). Salinity and soil available NH4-N and K decreased continuously with the increase in period of soil submergence. Availability of Ca, Mg, Fe, Mn, Zn and Cu in soil decreased up to 30 days after transplanting, increased up to 40 days followed by a decrease thereafter with the increase in rate of N application. In general, pH of soil solution increased up to 40 days, then decreased up to 50 days, followed thereafter by an increase of soil submergence, whereas salinity and nutrient concentration in soil solution decreased with the progress of crop growth and period of soil submergence. Fertilizer application resulted in comparatively more decrease in Eh over control and N application influenced the magnitude of availability of nutrients in soil and dynamics of salinity. though the pattern of changes were almost the same irrespective of treatments. There was significant increase in grain yield when N was applied in combination with P and K. Nutrient uptake increased with the increase in fertilizer application and also with the progress of crop growth.