基于GIS的南四湖沿岸农业面源氮磷负荷估算研究

Estimation of Nitrogen and Phosphorus Loading of Agricultural Non-point Sources along Nansi Lake Based on GIS

以济宁市沿南四湖县区乡镇为主要研究区,根据降雨径流和土壤侵蚀量,运用遥感(RS)影像和地理信息系统(GIS),确定土壤通用流失方程(USLE)各参数,运用USLE对南四湖沿岸氮磷流失模数进行定量估算,为南四湖沿岸农业氮磷流失的消减与控制提供科学依据。结果表明:USLE模型计算的氮磷流失量主要集中在湖西区域,以喻屯镇、王鲁镇和唐口镇的流失量居于前列,最高的喻屯镇氮、磷流失量分别达439.9t/a和271t/a;湖东区域,石桥镇、马坡镇、欢城镇和韩庄镇的氮磷流失量居于前列,最高的石桥镇氮和磷流失分别为174t/a和120.6t/a。农田实际调查的氮和磷的流失量与模型计算值趋势较一致,两者呈极显著线性正相关(p<0.01)。氮的模型计算流失量略低于实际调查流失量,而磷的模型计算流失量远远高于实际调查流失量。主要是因为南四湖沿岸农田氮的流失是氮的主要流失形式,远高于畜禽养殖和生活排污的氮流失。而磷的流失主要来自畜禽养殖,其次才是农田流失磷。

In this paper, the counties and towns in Ji＇ning City along the Nansi I.ake shore were selected as tile main study area. The factors of Universal Soil Loss Equation （USLE） were determined by runoff and soil srosion, remote sensing （RS） and geographic information systems （GIS）. The loss; of nitrogen and phosphorus was calculated by USLE. The objective of this study was to provicle a sciautihe basis fordecrcasing and controlling loss of nitrogen and phosphorn〈 from agricultunal couces.flhe resuits indicated that be mose loss of nitrogen and phosphorus from the Yuttn Tuwn, Wanglu Town aud Tangkou Toy Town tocating in west coast of Nansi Lake. The maximum value of loss of nitrogen and phosphorus was from Yutun Town and wa,- 439.9 t/a and 271 t/a, respectively. The most loss of nitrogen and phosphorus from theShiqiao Town, Ma po Town, Huancheng Town and Hanzhuang Town !ocating in east coast of Nansi Lake. The maximum value of loss of nitrogen and phosphorus was from Shiqiao Town and 174 t/a and 120.6 t/a, respectively. The losses of nitrogen and phosphorus by field survey and USLE were more consistent and both showed a significant linear correlation （p〈0.01）. The loss of nitrogen calculated by USLE was lower than it by field survey while the loss of phosphorus by estimated by USLE was higher. The reason was that loss of nitrogen was mainly from farm soil erosion along Nanshi Lake, while the loss of phosphorus was mainly from livestock and poultry breeding and secondly from farm soil erosion.