呼伦湖流域不同利用方式草场水土和氮磷流失

摘 要：为了研究不同利用方式草场水土和氮磷流失规律及原因，在呼伦湖流域选择传统放牧草场、草库伦草场、不放牧草场三种利用方式草场，用模拟降雨的方法进行了水土及氮磷随径流流失试验。结果表明：两种雨强下，传统放牧草场水土流失最严重。相同雨强下，总氮流失量：草库伦草场>传统放牧草场>不放牧草场；总磷流失量：传统放牧草场>草库伦草场>不放牧草场。同一种利用方式草场径流中总氮、总磷浓度与降雨强度关系不显著。草库伦草场可有效防止水土流失。传统放牧草场和草库伦草场的氮磷排放负荷与累积径流量之间存在线性关系，而不放牧草场的存在指数关系。该研究可为探讨呼伦湖流域草场合理利用、水环境的保护和面源污染的治理提供参考。

Soil erosion, losses of nitrogen and phosphorous under different grassland use patterns in Hulun Lake watershed

Abstract : In order to analyze the laws of Soil erosion, losses of nitrogen and phosphorous under different grassland use patterns, three use pattern grassland (traditional use grassland, enclosed grassland, no grazing grassland) of Hulun Lake watershed were chosen in this research. The experiments of soil erosion, losses of nitrogen and phosphorus with runoff production, from different use pattern grassland, were conducted through artificial rainfall simulator. The analysis have come to the following conclusions: on the condition of two different rain intensities, both of the runoff and soil erosion in traditional grazing grassland are most serious among the three use pattern grassland. Under the same rain intensity, mean amounts of total nitrogen export: enclosed grassland>traditional grazing grassland>no grazing grassland. Mean amounts of total phosphorous loss: traditional grazing grassland> enclosed grassland>no grazing grassland. It is insignificant between the amounts of the nitrogen and phosphorous losses and the rain intensities. Building more enclosed pasture can prevent soil erosion effectively. A linear relationship exists between the accumulated runoff and nitrogen, phosphorus emission load in traditional grazing grassland and enclosed pasture. However an exponential relationship is identified between them in no grazing pasture. The research could provide the theoretical evidence for the reasonable utilization of grassland in Hulun Lake watershed, the protection of water environment and the control of non-point pollution of Hulun Lake.