太湖地区稻田氮素损失特征及环境效应分析

通过氮肥减量小区试验,研究了太湖地区稻田氮素径流损失、渗漏损失、氨挥发损失以及氨挥发通量的动态变化特征,阐述了氮素损失量、水稻产量与施氮量之间的关系。结果表明：稻季氮素径流损失和氨挥发损失均随施氮量的增加不断增加,而渗漏损失与施氮量没有显著相关性。综合整个稻季,氨挥发损失以分蘖肥期最高,基肥期次之,穗肥期最低。稻季氮素总损失为13.7～59.8 kg·hm-2,占总施氮量的16.5%～22.2%,且随施氮量的增加而不断增加,其中氨挥发损失占42.2%～72.0%,径流损失占22.2%～38.4%,渗漏损失占5.8%～22.7%。稻季181 kg·hm-2的氮肥用量,较常规施氮量减少了33%的氮肥,增加了10.3%的产量,降低了48.5%的氮素损失,较好地兼顾了粮食产量和环境效应;而对于重要环境区域或高污染区域,还可以尝试更低的氮肥投入,以达到更好的环境效益。

Characteristics of N loss and environmental effect of paddy field in Taihu area

This study focused on N losses through runoff,leaching and ammonia volatilization of paddy field in Taihu Lake region;and the dynamic changes of ammonia vitalization flux have also been studied.Results showed that N losses through runoff and ammonia volatilization were increased with the increasing N applications,while N leaching losses was not significantly correlated with N inputs.Compared with other stages,the ammonia volatilization was highest at tillering stage and lowest at heading stage in summer rice season.N losses were 13.7-59.8 kg.hm-2,making up 16.5%-22.2% of total N input,from low to higher N applications in summer rice season,respectively.Ammonia volatilization losses contributed to 42.2%-72.0% of total N losses,N losses through runoff and leaching was account for 22.2%-38.4% and 5.8%-22.7% of total N losses,respectively.Compared with conventional N application,the filed with 33% N reduction（181 kg N hm-2 input） showed a 48.5% decrease in N losses,and furthermore,a 10.3% increase of yield.Therefore,for the sake of environment-friendly agriculture,N reduction was feasible in some serious pollution area.