Study on role of controlled release fertilizer in increasing the efficiency of nitrogen utilization and rice yield

Field experiment was conducted in paddy soil to determine the relationship between N release from controlled release fertilizer and N uptake by rice plants N release rate of controlled release fertilizer was higher during the early growing period of rice, but gradually decreased with time The cumulative N release reached about 80% of the total N content of fertilizer at around 70 day after application or when cumulative air temperature had reached about 2000℃ Nitrogen uptake from the fertilizer followed a cubic curve Therefore, the fertilizer can meet the N requirements of two line system late hybrid rice throughout the whole growing period There were lower N concentrations of the water and hardly any algae observed in the plots where controlled release fertilizer applied Higher urea N and ammonium N concentration of the water in the paddy field after urea applied indicates the greater N losses from NH3 volatilization and denitrification As high as 72.3% in late rice of fertilizer N were recovered by the rice plant at harvest (grain+straw) with the 70 day type controlled release fertilizer Controlled release fertilizer increased efficiency of nitrogen use and minimized environmental pollution