自然降雨条件下紫色土区磷素的非点源输出规律

The Rule of Phosphorus Load with Runoff in Purple Soil by Not- point Source Way

2003年8月8日在中国科学院盐亭紫色土研究站采集动态降雨径流样并进行分析,研究了紫色土区典型土地利用方式下磷素的非点源输出规律。结果表明,在该区各形态的磷随地表径流的输出不一定随时间递减。旱地径流输出主要以颗粒吸附态磷素为主。水田在该区中因降雨引起的磷素迁移而造成的非点源污染不可忽视,其磷酸盐随径流的排放浓度在0.06mg·L-1左右波动,远超过富营养化的警戒线浓度0.02mg·L-1,溶解性磷与磷酸盐随径流迁移的浓度均达水体富营养化的警戒线。

With much more emphases having been put on cases of environment and resources recently, the studies on transfer rule for nutrient and pollutant in agricultural area between soil and water are getting more and more important. As the readily losing nutritional element, P is the studying hot in the field of environmental science. Quite a few researches on P transfer have been focused on red soil, brown soil, black soil and so on, but the studies on purple soil in south- west China are infrequent. The research was carried out in purple soil agricultural ecology system institution in Yanting to study the rule of P transfer in purple soil agricultural area. The rainfall samples were obtained every 5 min in the first 15 min, and then the time interval adjusted to 30 min in Aug 2003 when the rain continued for about 150 min and the rainfall came to 50 mm. The loading phosphorus in runoff didn't decreased with time constantly. In this area, the highest load of P- pollutants occurred in paddy field. Among all kinds of P- pollutants, the content of dissolve phosphorus and ortho- phosphrous in runoff were much beyond warning concentration for eutrophication, with the concentration of ortho- phosphrous fluctuating around 0.06 mg· L- 1. When taking measures to resolve NPSP (none point source cultivate manner pollution) in the area, we should pay attention to the load of dissolve phosphorus and ortho- phosphrous.