每穴苗数和施氮量对双季机插稻产量及氮肥利用效率的影响

以常规早稻品种中嘉早17和杂交晚稻品种五优308为材料,针对双季机插稻生产中存在的前期发不起、中期控不住、后期穗小苗弱影响双季机插稻产量及氮肥利用效率的问题,通过大田试验研究施氮量和每穴苗数对双季机插稻产量及氮肥利用效率的影响。结果表明,氮肥用量和每穴苗数对双季机插稻产量及氮肥利用效率有显著影响。机插早晚稻均以中氮高苗组合（早稻N12D5,晚稻N13D4）产量最高,早稻为8.12t/hm ²,晚稻为9.62t/hm ²,但与低氮高苗组合(早稻N10D5,晚稻N11D4)产量差异不显著。氮肥吸收利用率早晚稻均随施氮量的增加呈先上升后下降的趋势,随每穴苗数的增加而升高。其中早稻氮素吸收利用率以N10D5处理最高,晚稻虽以N13D4处理最高,但与N11D4处理间差异不显著。干物质积累量所表现出的趋势基本和产量一致。在不影响产量的前提下,适当增加单株苗数,可使早稻比当前习惯施氮量减少16.7%,晚稻可减少15.4%。早稻氮素利用率提高10.66%,晚稻提升1.99%。由此可见,合理地增加每穴苗数和降低施氮量既可以获得足够的单位面积有效穗数实现高产,又可以提高氮素利用效率。

Effects of Nitrogen Application and Transplanting Seedlings Number Per Hole on the Grain Yield and Nitrogen Use Efficiency of Double-Rice by Machine Plug

Zhongjiazao 17 as the early rice, Wuyou 308 as the late rice were tested in this study.In view of the problems of present machine early planting, middle control, the late weak spikes,in order to determine effects of nitrogen application and transplanting seedlings number per hole on double-rice systems, an experiment was carried out to study the yield, yield components and nitrogen use efficiency of double-rice by machine plug.The results showed that both the nitrogen application rate and transplanting density had significant effects on yield. At the nitrogen plus high density rate the grain yield was maximized, being 8.12t/hm ² in early rice and 9.62t/hm ² in late rice,while the difference was not significantly been compared with low nitrogen plus high density rate. Nitrogen use efficiency decreased at the lower planting density, but increased first and then dropped with the increase of nitrogen application rate. At the low nitrogen plus high density rate the early rice nitrogen use efficiency was maximized, and at nitrogen plus high density the late rice nitrogen use efficiency was maximized.Dry matter accumulation exhibited trends of consistent with the yield.By appropriately increasing the seedlings number per hole, the early rice nitrogen fertilizer could reduce 16.7% application rate than the current diet, and the late rice decreased 15.4%. Nitrogen utilization increased by 10.66% of early rice, 1.99% of late rice. As a result, a reasonable reduction of nitrogen fertilizer and increase of transplanting seedlings number per hole,could indeed significantly increase the effective panicle number per unit area, and nitrogen use efficiency was improved.