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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。
The conventional early rice variety Zhongjiazao 17 and the late hybrid rice variety Wuyou 308 were used as materials for the production of double cropped rice in the early stage of development, Nitrogen use efficiency of the field trials to study the effects of nitrogen application rate and number of holes per hole on the yield and nitrogen use efficiency of double-cropped rice. The results showed that the amount of nitrogen fertilizer and number of holes per hole had a significant effect on the yield and nitrogen use efficiency of double cropping rice. The highest and highest yield of N and N upland rice combinations were N12D5 and N13D4, respectively. The early rice was 8.12 t / hm ~ 2 and the late rice was 9.62 t / hm ~ 2, but the combinations with low nitrogen (N10D5, Late rice N11D4) yield was not significantly different. The rate of nitrogen uptake and utilization of rice was increased firstly and then decreased with the increase of nitrogen application rate, which increased with the increase of the number of seedlings per hole. Among them, the N uptake and utilization efficiency of early rice was the highest in N10D5, the highest in late rice was N13D4, but no significant difference with N11D4. Dry matter accumulation showed the trend of the basic and consistent production. Under the premise of not affecting the yield, increasing the number of seedlings per plant can reduce the rate of nitrogen application by 16.7% and 15.4% respectively. The utilization rate of early rice increased by 10.66% and late rice increased by 1.99%. Thus, a reasonable increase in the number of seedlings per hole and reduce the amount of nitrogen can get enough panicles per unit area to achieve high yield, but also can improve nitrogen use efficiency.