Effects of Nitrogen Fertilizer Type and Application Method on Surface Water Nitrogen Dynamics and Yield of Drought-resistance Rice
HOU Pengfu;XUE Lixiang;FAN Lihui;ZHAO Jiangning;XUE Lihong;YANG Linzhang;YU Yingliang;FENG Yanfang;HE Shiying;Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences;College of Agronomy,Nanjing Agricultural University;
Field experiment was carried out to study the influence of different nitrogen(N) fertilizer type and application method on rice yield, N uptake, profit and the surface water N dynamics with Hanyou 8(water-saving and drought-resistance rice)as material.The results showed that there was no significant correlation between N uptake and yield under different N type and application method with the same N application rate(200 kg/hm2). Compared with pure chemical N treatment(CN), SCU1 treatment(70% of N was sulfur coated urea applied at basal, and 30% as common urea applied as panicle fertilizer) had the highest plant N uptake but the lowest N harvest index(NHI), which caused a relative low yield due to the N luxuary uptake. SCU2 treatment(all N was sulfur coated urea applied at basal) had the highest NHI, maximum specific leaf weight and crop growth rate at grain filling stage, therefore the yield was highest and significantly higher than pure chemical N treatmen(tCN). Additionally,no significant difference in crop population indices,yield and nitrogen uptake was found between OCN(20% N as organic fertilizer applied at basal) and CN treatments.Compared with CN treatment, SCU1 decreased the surface water N concentration at basal and tillering fertilizer stage, but increased that at panicle fertilizer stage. While SCU2 and OCN decreased the surface water N concentration at all three fertilizer stages with the lowest value for SCU2. Based on cost-benefit analysis, SCU2 could increase N use efficiency, yield and economic income, reduce the N runoff loss risk. Thus, it could be an economic, high-yielding and environment-friendly measure for water-saving and drought-resistance rice in Taihu Lake region.