研究了不同氮用量对稻虾共作水稻产量与田面水水质的影响,以为稻虾共作实现精确施肥提供理论依据。试验共设5个氮肥用量处理,分别设置氮 0、60、120、180和240 kg/hm²,依次以 CK、N₆₀、N₁₂₀、N₁₈₀、N₂₄₀表示,氮肥均按基肥:分蘖肥7∶3施肥。结果表明,施肥能维持土壤较高的无机氮含量并能促进水稻干物质积累,施肥处理提高水稻产量8%~42%,其中N₁₂₀产量最高,比CK增产42%;施氮后3 d内田面水中氨态氮含量迅速增加,随着时间的推迟氨态氮随之降低,在14 d后降到最低且趋于稳定,其中施氮后5 d内各处理的氨态氮浓度差异显著,施氮越多其值越大;田面水中亚硝态氮浓度在前5 d先升高后降低再升高,其中第3 d 各施肥处理差异较显著,第7 d后其浓度处理间差异不显著;不同施氮量显著影响了田面水的pH,各处理在施肥后14 d内的pH波动在6.57~8.22之间,但14 d以后各处理差异不显著。适宜的施氮量促进水稻增产的同时也减少了田间表面水氨态氮和亚硝态氮含量,为小龙虾保持良好的生存环境,120~130 kg/hm²可以作为稻虾共作系统推荐施氮量。

To provide a theoretical basis to use appropriate nitrogen （N） amount for accurate fertilization in the rice-crayfish co-culture system, the effects of different nitrogen amounts on rice yield and surface water quality were studied. Five N application rates were set at N 0, 60, 120, 180 and 240 kg/hm² based the same ratio of basal fertilizer to tillering fertilizer （7∶3）, which was represented by CK, N₆₀, N₁₂₀, N₁₈₀ and N₂₄₀, respectively. The results showed that fertilization could maintain a higher inorganic N content in the soil and promote dry matter accumulation in rice. The fertilization treatments increased rice yield by 8%~42%, of which N₁₂₀ obtained the highest yields, which is 42% higher than CK. After nitrogen application, the ammonia N content in the surface water increased rapidly at the first 3 days and then decreased. After 14 days, it dropped to the lowest and became stable. Among them, the ammonia N concentration of different treatments within 5 days after nitrogen application was significantly different, and the value increased as the nitrogen fertilizer amount increased. The nitrite N concentration in surface water increased at first 6 days, then decreased and then increased. The difference between the fertilization treatments on the 3rd day was significant, and the difference between the treatments after the 7th day was not significant. Different nitrogen application amounts affected the pH of the surface water. The pH fluctuation of each treatment within 14 days after fertilization was between 6.57 and 8.22, but the difference between the treatments was not significant after 14 days. The appropriate amount of nitrogen application promotes the increase of rice yield, but also reduces the content of ammonia N and nitrite N in the field surface water, maintaining a good living environment for crayfish, and 120~130 kg/hm² can be used as the recommended nitrogen application rate for rice-shrimp co-cropping system.