上海郊区稻田氮素流失研究

通过测坑和大田小区试验，研究了上海郊区稻田氮素排水流失和渗漏流失的特征、相关因素和流失负荷。结果表明，稻田综合排水TN为6.55mg／L，流失负荷为16．68kg／hm^2，以铵态氮为主，稻田氮素的排水流失负荷为16．68kg／hm^2。稻田渗漏水氮浓度与前茬作物有关，草莓和蔬菜高，麦茬低，TN为5．73mg／L，渗漏负荷为22．92kg／hm^2，其中硝态氮占50％左右。稻田氮素总流失负荷占稻季化肥用量的13．23％。测坑和大田试验都证明，施用有机肥可较多地减少稻田氮素流失量。

Nitrogen losses in paddy fields in Shanghai suburbs

With leaching-pond and paddy field plot scale experiments, the characters, relevant factors and loads of nitrogen losses via drainage and leakage from paddy fields were studied in Shanghai suburbs. It is found that the total N (mainly as ammonium-N) in the drainage water is 6.55 mg/L,The results showed that the loads of drainage and leakage loss of nitrogen from rice fields were 16.68 kg/hm2 and 22.96 kg/hm2 respectively, and total of them was about 13.23% of the whole usage loads of chemical nitrogen fertilizer in paddy fields, which is somewhat dependent on the plants developed in the fields of study. Both of the leaching-pond and paddy field plot scale experiments proved that the amounts of nitrogen losses could be reduced greatly when organic fertilizer was used to replace chemical nitrogen fertilizer in paddy fields.