氮肥类型及施用方式对节水抗旱稻田面水氮动态及产量的影响

采用大田试验,以旱优8号为试验材料,比较评价了节水灌溉条件下不同氮肥类型和施用方式对节水抗旱稻产量、经济效益、氮素吸收和田面水不同形态氮素动态变化的影响。结果表明,相同氮肥用量条件下,不同氮肥类型和施用方式的氮素吸收与产量高低无明显相关关系。在等氮量投入下,缓释肥配施无机化肥处理(SCU1)总吸氮量最高,氮收获指数(NHI)最低,造成了水稻对氮素的奢侈吸收,不利于高产群体的构建,产量相对较低;缓释肥一次性基施处理(SCU2)的NHI最高,且灌浆结实期作物生长率和比叶重较高,利于光合产物的积累,产量最高,显著高于纯化肥处理(增产18.28%);有机肥无机肥配施处理(OCN)的作物群体质量、产量和氮素吸收利用与单施无机化肥处理相比无明显差异。SCU1处理降低了基肥和分蘖肥期田面水总氮和铵态氮浓度,但增加了穗肥期的田面水氮浓度,而SCU2处理和OCN处理在3个施肥期内田面水总氮和氨态氮浓度均明显低于纯化肥处理,SCU2处理氮素浓度最低。综合成本效益分析,缓释肥一次性基施技术能够满足节水抗旱稻生长对氮素的需求,提高作物产量、经济效益和氮素利用效率,降低径流损失风险,是值得在太湖流域推广的一种施肥技术。

Effects of Nitrogen Fertilizer Type and Application Method on Surface Water Nitrogen Dy-namics and Yield of Drought-resistance Rice

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 coat-ed 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 treatment(CN). Additionally,no significant difference in crop popula-tion 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-re-sistance rice in Taihu Lake region.