不同氮肥种类对稻虾共作水稻生长和田面水水质的影响

稻虾共作模式具有较高的综合效益，近年在全国发展迅速。为稻虾共作选择适宜氮肥种类，既能保证田面水水质，又能保证水稻氮素供应而促进水稻生长，对稻虾共生系统的清洁生产至关重要。设置3种施肥处理（CF，基施复混肥并追施尿素；CRF，缓释复混肥作基肥一次性施用；OF，基施有机无机复混肥并追施尿素），并以不施氮肥为对照（CK），研究不同施肥处理对水稻分蘖期之前田面水水质及全生育期水稻生长的影响。结果表明，与CF和OF处理相比，CRF处理降低稻虾田田面水氨氮及亚硝态氮的效果最好，有利于小龙虾回田生长；施肥处理提高了土壤无机氮含量，促进了水稻干物质累积；CRF处理水稻的有效穗数、产量、氮肥农学效率和氮肥偏生产效率显著高于其他处理，与CF和OF处理相比，产量分别提高14.26%和12.84%，氮肥农学效率分别提高64.86%和54.65%，氮肥偏生产效率分别提高15.00%和13.60%。此外，CRF处理还节约了追肥所需的劳动力。综上，从田面水水质、水稻生长及氮肥利用效率等因素考虑，在稻虾共作中采用缓释复混肥一次性基施的施肥方式是较佳选择，有利于该模式的可持续发展。

Effects of Different Nitrogen Fertilizers on Rice Growth and Field Water Quality in Rice-crayfish Integrated System

The rice-crayfish integrated model has high comprehensive benefits and is developing rapidly in China. Choosing suitable nitrogen （N） fertilizer for rice-crayfish integrated system can not only ensure the water quality of the field surface, but also ensure the nitrogen supply of rice to promote rice growth, which is very important for the cleaner production of the rice-crayfish integrated system. Three fertilization treatments （CF, basal application of compound fertilizer and topdressing of urea; CRF, one-time application of slow-release compound fertilizer as basal fertilizer; OF, basal application of organic-inorganic compound fertilizer and topdressing of urea） were set up in this experiment, and the no nitrogen fertilizer was used as the control （CK） to study the effects of different fertilization treatments on the water quality of the field water before the tillering stage and the growth of rice in the whole growth period. The results showed that compared with CF and OF treatments, CRF treatment had the best effect on reducing the ammonia nitrogen concentration and nitrite nitrogen concentration in the field water, which was beneficial to the growth of crayfish. Fertilization could increase soil inorganic nitrogen content and promote rice dry matter accumulation. The number of effective panicles, yield, nitrogen fertilizer agronomic efficiency（ANUE） and nitrogen partial production efficiency （PEPN） of rice treated with CRF were significantly high than those of treated with treatments. Compared with CF and OF treatments, the grain yield of CRF treatment increased by 14.26% and 12.84%, the ANUE increased by 64.86% and 54.65%, and the PEPN increased by 15.00% and 13.60%, respectively. In addition, CRF treatment also saved the labor. In conclusion, considering the factors such as field surface water quality, rice growth and nitrogen utilization efficiency, the one-time basal application of slow-release compound fertilizer is a better choice in rice-crayfish integrated model, which is conducive to the sustainable development of this model.