都市农业区域暴雨径流磷素输出特征研究——以上海市新场镇果园村为例

Characteristics of Non-point Source Phosphorus Transport in Urban Agricultural Area Under Rainstorm——A Case Study of Xinchang Town,Shanghai

为了进一步阐明果园区小流域典型降雨磷素随径流的输出规律,并为果园区域化肥减量化提供一定的科学依据。于2009年7-8月对上海市南汇区新场镇具有代表性的都市农业区降雨径流过程进行连续监测,同步监测径流过程中总磷、磷酸盐和颗粒态磷的非点源输出过程与负荷。研究表明:3次暴雨过程的降雨量和径流量变化趋势大致相同。总磷(TP)和颗粒态磷(PP)浓度的变化趋势表现出随流量变化的特征,总磷和颗粒态磷浓度随降雨径流上升趋势极为显著,随后趋于稳定,磷输出峰值均发生在径流峰值之前。3次暴雨事件中,颗粒态磷输出的平均值分别为6.38mg/L、7.65mg/L和4.12mg/L,其对应的TP平均值分别为7.88mg/L、8.92mg/L和5.36mg/L,PP输出占TP的比例是76.9%～85.5%,颗粒态磷素流失量显著高于溶解态磷素。降雨强度对磷素的流失负荷影响显著,当降雨量为149.5mm的最强降雨时TP的输出负荷为108kg/hm2,占总输出负荷的65.69%。

For detailed elucidation of the typical mechanism of phosphorus with runoff in a small watershed of orchard when rainfall occurs,and supplying enough scientific foundations to decrease the application rates of fertilizers,this study was carried out from July to August in 2009for consecutive investigation of runoff processes,and simultaneously monitoring the non-point output process and loads of total phosphorus（TP）,phosphate and particle-phosphorus（PP）,in Xinchang Town,where was a typical municipal farming zone of Nanhui District in Shanghai.The results indicated that the change trends of runoffs and rainfalls were approximately consistent in three storming processes.Meanwhile the concentrations of TP and PP changed with the varieties of runoff,and especially an increasing trend was observed significantly when runoff increased,after that,it stabilized without varieties.The greatest values of phosphorus losses all appeared before the occurrence of runoff peak values.In the three storming events,the average values of PP losses were 6.38mg/L,7.65mg/L,4.12mg/L,respectively,with the average values of TP were 7.88mg/L,8.92 mg/L and 5.36mg/L,respectively,which accounted for 76.9%～85.5%of TP losses,thus the amount of PP losses was higher than dissolved phosphorus losses.In addition,the effect of rainfall intensity（RI）on phosphorus losses load was significant,which showed the TP loss load was 108 kg/hm2 accounting for 65.69%of TP losses,when RI was the greatest（149.5mm）.