Effects of nitrogen fertilizer application rate and transplanting density on tiller growth and grain yield of rice variety "Yongyou 6" in late season

In the late season,a field experiment was conducted with different transplanting densities(19.5×104,22.5×104,25.5×104,28.5×104,31.5×104 hills/hm2) and nitrogen fertilizer rates(180,225,270,315 kg/hm2 N) by using a super high yielding indica rice,Yongyou 6 as material.Results showed that the maximum tiller number increased with the nitrogen fertilizer rate or transplanting density increase.The panicle forming rate was first increased and then decreased with the nitrogen fertilizer rate increase,while the panicle forming rate decreased significantly with the transplanting density increase.Meanwhile,improving nitrogen fertilizer rate or improving transplanting density increased rice yield,but as over-fertilizer or density,rice yield decreased.The results also indicated that there was interaction significantly between nitrogen fertilizer application rates and transplanting densities on the yield components and grain yield of rice.In the present study,the highest yield was recorded in the treatment with 270 kg/hm2 nitrogen fertilizer and 25.5×104 hills/hm2 transplanting density.