祁连山东段高寒草甸模拟放牧下的坡面土壤水蚀特征

本研究在祁连山东段高寒草甸草原采用人工模拟降雨和模拟放牧测定其坡面产流产沙过程，旨在为高寒草甸的水源涵养功能评价及以防止水土流失为前提的草地合理利用提供基础资料。结果表明：从未放牧到重度放牧径流出现的时间逐渐缩短；相较于未放牧，从轻度放牧到重度放牧的高寒草甸平均径流量分别增加150.00%，600.00%，2 200.00%，平均产沙量分别增加170.59%，535.29%，694.12%，且降雨强度对径流量的影响高于对产沙量的影响；相较于重度放牧，未放牧、轻度放牧和中度放牧3种放牧强度的平均保水效益分别为67.06%，46.04%，28.08%；固土效益分别为88.54%，70.23%，38.73%；高寒草甸的减水减沙效益与雨型具有密切关系，相关系数分别为0.967和0.961，保水效益和固土效益间有极显著的相关性，相关系数为0.995。从维持水源涵养功能的角度来说，中度以下的放牧强度是相对安全的。

Soil Erosion on Slopes of Alpine Meadow in the eastern Qilian Mountains under Simulated Grazing

The processes of runoff and sediment production on slope of alpine meadow under different simulated rainfall intensities and grazing intensities were studied in order to provide basic data for the water conservation function evaluation and soil erosion control oriented grassland utilization in the eastern Qilian Mountains. The result indicated that the time for runoff launching from non-grazing to heavy grazing gradually decreased. Compared to non-grazing,average runoff of Alpine Meadows from light to heavy grazing intensity increased by 150.00%,600.00% and 2200.00%,respectively,and the average sediment yield increased by 170.59%,535.29% and 694.12%,respectively. Moreover,the influence of rainfall intensity on runoff was higher than that of sediment yield. Compared to heavy grazing,the average water conservation efficiency of 3 grazing intensities:non-grazing,light grazing and moderate grazing were 67.06%,46.04% and 28.08% respectively,and the soil conservation efficiency were 88.54%,70.23% and 38.73%,respectively. The soil and water conservation efficiencies of alpine meadow was closely related to the rain type with acorrelation coefficient of 0.967 and 0.961,respectively. The correlation between water conservation efficiency and soil conservation efficiency was significant,and the correlation coefficient was 0.995. In terms of water conservation function maintenance,moderate or lower level grazing is safe.