Effects of different mixture rates of coated urea and prilled urea on rice grain yield and nitrogen use efficiency

Using japonica Xiushui 110 as the tested rice cultivar, effects of different mixture rates of sulfur-polyester resin-coated urea(SPCU)and prilled urea(PU)on rice grain yield and nitrogen use efficiency（NUE）were studied in fields during 2007 and 2008. Results show that compared to the PU100% at N 210 kg/ha in conventional fertilizer application, the rice grain yields are 7644.0, 7172.5 and 7008.2 kg/ha under the single basal application of SPCU100%, SPCU70%+PU30% and SPCU50%+PU50% treatments, respectively, which are significantly increased by 17.75%, 10.49% and 7.96%, and the nitrogen use efficiencies are 27.64%, 23.24% and 18.06%, which are significantly increased by 18.73,14.33 and 9.15 percent point. These results indicate the agronomic nitrogen use efficiencies are significantly increased.