通过设置不同稻作模式（水稻单作、稻虾共作）和氮肥管理（不施氮、常规施氮、减氮）两因素交互试验，研究氮肥管理对稻虾共作模式水稻产量及抗倒伏特性的影响。结果表明，稻虾共作模式下常规施氮和减氮处理的水稻产量分别为7 539 kg/hm²和7 328 kg/hm²，比水稻单作模式降低29.4%~32.3%，这主要是由于试验当年水稻移栽后连续降雨导致缓苗不利所致，也与深水淹灌下水稻有效穂数、每穗粒数和千粒重下降有关。相比水稻单作，稻虾共作模式下水稻茎秆的株高、穂颈高、重心高、弯曲力矩和倒伏指数平均增加12.9%、17.9%、8.0%、20.9%和33.5%，第2节间茎壁厚、抗折力和折断弯矩平均降低38.7%、16.8%和16.6%。在稻虾共作模式中，与常规施氮处理相比，减氮处理仅减产2.9%，水稻茎秆抗折力增加13.5%、倒伏指数降低1.8%。相关分析表明，茎壁厚度与倒伏指数呈极显著负相关（p<0.01），株高和弯曲力矩与抗折力呈显著负相关（p<0.05）。稻虾共作模式可保证水稻稳产，氮肥减施有助于提高该模式下水稻抗倒伏能力，降低倒伏风险。

The effects of nitrogen management on rice yield and lodging resistance characteristics of rice in the rice-crayfish coculture were studied, by two interactive experiments of different rice cropping modes (rice monocropping, rice-crayfish coculture) and nitrogen fertilizer management (no nitrogen application, conventional nitrogen application, and nitrogen-reduction application). The results showed that, the rice yields of the conventional nitrogen application treatment and nitrogen reduction treatment under rice-crayfish coculture were 7 539 kg/hm² and 7 328 kg/hm², respectively, which were 29.4%-32.3% lower than those of the rice monocropping. It was mainly caused by the continuous rainfall after rice transplanting in the experiment year, and also related to the decrease in the number of effective panicles, grains per panicle and 1000-grain weight of rice under deep-water flooding. Compared with rice monoculture, the plant height, panicle length, the gravity center height, the bending moment and lodging index of the rice-crayfish coculture increased by 12.9%, 17.9%, 8.0%, 20.9% and 33.5% on average, the thickness of culm wall, breaking resistance, and breaking moment of the second internode decreased by 38.7%, 16.8% and 16.6% on average. In the rice-crayfish coculture mode, compared with the conventional nitrogen application treatment, the breaking resistance of the second internode of the rice stem in the nitrogen reduction treatment increased by 13.5%, and the lodging index decreased by 1.8%, rice yield reduced only 2.9%. Correlation analysis showed that the stem wall thickness was extremely significantly negatively correlated with lodging index (p<0.01), and the plant height and bending moment were significantly negatively correlated with breaking resistance (p<0.05). The rice-crayfish coculture can ensure stable rice yield, reducing application amount of nitrogen fertilizer can improve the lodging resistance under this mode and reduce the lodging risk.