减氮对机插杂交籼稻茎秆生长及抗倒伏特性的影响

以宜香优2115和F优498为材料,设置4个不同氮肥用量处理,研究减氮对机插杂交籼稻产量和茎秆生长特性的影响,及其与抗倒伏能力的关系。结果表明,与对照（品种最高产施氮量,180 kg/hm²）相比,随着减氮量的增加,参试两个水稻品种的产量均逐渐降低,但N150处理（施氮量150 kg/hm²）的产量降低不显著,而N120处理（施氮量120 kg/hm²）和N0处理（不施氮）的产量降低显著;水稻株高和重心高度均降低,基部节间长度缩短,基部节间的秆型指数逐渐增加,节间充实度（节间干物质量、单位长度节间干物质量和单位体积节间干物质量）先增加后降低,弯曲力矩逐渐减小,折断弯矩逐渐增加,倒伏指数降低,抗倒伏能力增强。相关分析表明,倒伏指数与产量、株高、重心高度、弯曲力矩和节间长度整体上呈正相关;与节间粗度、折断弯矩、茎壁厚度、秆型指数和节间充实度整体上呈负相关。综上,适宜减氮（N150）能够同步实现机插杂交籼稻减氮稳产和高抗倒伏能力;而过量减氮（N120或N0）虽能大幅度提升抗倒伏能力,但难以实现高产或稳产。

Effects of Nitrogen Reduction on Culm Growth and Lodging Resistance of Machine-Transplanted Hybrid Indica Rice

Four different nitrogen fertilizer treatments were set to study the effects of nitrogen reduction on the yield and culm growth characteristics of machine-transplanted hybrid indica rice Yixiangyou 2115 and F You 498, and its relationship with lodging resistance. The results showed that compared with the control （nitrogen fertilizer amount 180 kg/hm²）, with the increase of nitrogen reduction, the yield of the tested rice varieties gradually decreased, but the yield of N150 treatment （nitrogen fertilizer amount 150 kg/hm²） did not decrease significantly, while the yield of N120 treatment （nitrogen fertilizer amount 120 kg/hm²） and N0 treatment （no nitrogen） decreased significantly. The plant height and the height of the center of gravity of the two rice cultivars decreased, the length of the basal internode shortened, and the culm type index of the basal internode increased, while the fullness of the basal internode （dry weight of the basal internode, dry weight of the basal internode per unit length and dry weight of the basal internode per unit volume） first increased and then decreased, the bending moment of the whole plant decreased, the bending moment at the breaking increased, which resulted in a decrease in the lodging index and strong lodging resistant. Correlation analysis showed that lodging index was positively correlated with grain yield, plant height, the height of the center of gravity, bending moment of the whole plant and the length of the basal internode; and was negatively correlated with the internode diameter, bending moment at the breaking, culm wall thickness, culm type index and fullness of the basal internode. In summary, suitable nitrogen reduction （N150） could simultaneously achieve nitrogen reduction and stable yield and high lodging resistance of machine-transplanted hybrid indica rice. However, excessive nitrogen reduction （N120 or N0） could greatly improve lodging resistance, it was difficult to achieve high or stable yield.