Effect of Nitrogen Applied before Transplanting on Tillering and Nitrogen Utilization in Rice

Abstract

Nitrogen(N)before transplanting,applied in seedling-bed and carried to the paddy field with seedlings is proposed in this paper.The effect of this method on tillering,N accumulation,N fertilizer utilization efficiency(NUE),and grain yield were investigated in a field experiment with a japonica cultivar Ningjing 2.The results indicated that,on the condition of equal basic and tillering N fertilizer,the tillers number in the treatment of nitrogen fertilizer applied before transplanting(N-100%)was 300 thousand ha-1 higher than that in treatment of no N fertilizer applied before transplanting(CK).At the critical stage of productive tiller,the tillers rate with leaf age 3 in N-100% treatment was remarkably higher than that in CK.Compared with CK,the rate of effective tillers,number of effective panicles,N accumulation,NUE,and grain yield of N-100% treatment were markedly in-creased.But the application of N was only 5.55 kg ha-1 more than that of CK.In N-75% treatment the application of N was 32.4 kg ha-1 lower than that in CK,while N accumulation and NUE were higher than those in CK.Compared with CK,N application of N-50% treatment was too lower,therefore it had negative effect on accelerating tiller's development.As a result NUE and grain yield of N-50% treatment were observably lower than that of CK.The results suggested that proper N fertilizer applied before transplanting had positive effect on accelerating tiller's development,and enhancing rate of effective tillers.Moreover,application of N fertilizer before transplanting could reduce the quantity of basic and tillering N fertilizer,speed absorption and utilization of N fertilizer,and increase N accumulation and NUE in rice.