大浦镇农业非点源污染磷负荷定量研究

Loading Quantity of Phosphorus from Agricultural Non-point Source Pollution in Dapu Town

采用野外试验与实地调查相结合,利用径流方程、通用土壤流失方程和GIS平台,定量计算了太湖典型河网地区——宜兴市大浦镇农业非点源磷素潜在排放负荷和排放浓度。结果表明,大浦镇非点源磷排放磷负荷为30.1t·a-1,其中生活污水、农田排水及灌溉余水、养殖污水、垃圾流失负荷、雨水径流(非农田泥沙流失部分)分别为10.9、4.1、11.3、1.9、和1.89t·a-1,各占总量的36.1%、13.7%、37.5%、6.4%和6.3%,污水排放和养殖排放为优先控制因子;方钱、大浦和浦南3个行政村负荷量远高于其他区域;方钱、大浦、浦北和浦南4个行政村非点源磷污染平均负荷分别为21.7、17.1、10.9和8.7kg·hm-2·a-1,排放浓度分别为3.12、2.27、2.17和1.15mg·L-1,远高于其他区域,为优先控制区。

The contribution of phosphorus from rural non-point source pollution （NPS） was investigated through studying and surveying in typical river network, Dapu town, Yixing city, for identifying and ranking agricultural non-point source pollution potential and qualification of the key factors in critical areas. About 30.1 tons phosphorus per year was discharged into environment of Dapu Town, in which 10.9 tons were from people sewage loading, 1.9 tons from garbage, 11.3 tons from livestock ＆.fishery sewage, 4.1 tons from farmland （including phosphorus from paddyfield and vegetable field）, 1.89 tons from rain runoff （sediment production, except phosphorus in farmland and vegetable field）, with the contribution rates of 36.1%, 6.4%, 37.5%, 13.7% and 6.3%, respectively. The key factors were people sewage and livestock ＆.fishery sewage. More attention should be paid to Fangqian, Dapu and Punan since their phosphorus loading were highest. The critical area identified for NPS control in Dapu town were Fangqian, Dapu, Pubei and Punan for their average loss loading were 21.7,17.1,10.9 and 8.7 kg·hm^-2·a^-1, much higher than the others. The phosphorus average loss concentrations in Fangqian, Dapu and Pubei were about 3.12, 2.27 and 2.17 mg·L^-1, about 7.8, 5.7 and 5.4 times of V of surface water.