Nitrogen and transplanting density interactions on the rice yield and N use rate.

An experiment was carried out to study the interactive effect of increasing N fertilizer and reducing planting density on rice yield and N use rate.Two early rice varieties and two late rice varieties was used as test materials.The results showed that there was a significant influence of N level and transplanting density on the rice yield separately,but interactive effect was no significant.However,the influence of N level,transplanting density and their interactive effect on N use rate was significant.The average absorption rate of N fertilizer increased 4.2%-14.0% under the low N level in comparison with that under high N level with same planting density.The average absorption rate of N fertilizer under high transplanting density increased by 10.1%-14.6% in comparison with that under the condition of low density.The results of the trial indicated that both the rice yield and N use efficiency could be raised by properly increasing the transplanting density and decreasing the amount of nitrogen application.As a result,high yield of the rice and high N use rate can be obtained by increasing the transplanting density and decreasing the amount of nitrogen application.Take the yield and N use rate into consideration,the N fertilization rate was recommended as: N 153.1-169.4 kg/ha for the early rice with the transplanting density of 29.3×104-36.0×104 clusters/ha and N 161.5-190.1 kg/ha for the late rice with the transplanting density of 23.1×104-30.0×104 clusters/ha.