以水稻单作模式为对照，研究了长期稻虾共作模式对不同施氮量下直播水稻产量及氮肥利用效率的影响，以期明确2种模式下的最佳施氮量。结果表明，相对于水稻单作模式，长期稻虾共作模式水稻产量增加16.3%，且主要是通过增加有效穗数来实现的；长期稻虾共作模式的氮肥偏生产力、氮肥农学效率以及氮肥表观利用率分别提高了15.3%、7.6%和22.7%；采用线性+平台模型确定在长期稻虾共作模式和水稻单作模式下直播水稻氮肥合理用量分别为102.4 kg/hm²和139.6 kg/hm²，长期稻虾共作模式的直播水稻合理施氮量较水稻单作模式降低了26.6%。由此可见，长期稻虾共作模式能够大幅增加水稻产量，提高氮肥利用效率。

The effects of long-term integrated rice-crayfish model(CR) on the yield and nitrogen use efficiency of direct seeding rice under different nitrogen application rates were studied with monoculture mode of rice(MR) as control,and the best nitrogen application rates were determined under the two modes.The results showed that compared with MR model,the rice yield of CR model increased by 16.3%,which was mainly achieved by increasing the effective spike number.The partial productivity of nitrogen fertilizer,agronomic efficiency of nitrogen fertilizer and the apparent use efficiency of nitrogen increased by 15.3%,
7.6% and 22.7% under CR model compared with those under MR models respectively.The rational nitrogen fertilizer amounts for the direct-seeding rice determined by linear+platform model were 102.4 kg/ha and 139.6 kg/ha under CR and MR models respectively.The nitrogen fertilizer amount of the direct-seeding rice under CR model decreased by 26.6% compared with that under MR model.Therefore,the longterm CR model could significantly increase rice yield,reduce the application rate of nitrogen fertilizer and improve the use efficiency of nitrogen fertilizer.