高寒地区不同土地利用方式对土壤抗风蚀能力的影响

Impacts of Different Land Use Patterns on Resistance of Soil to Wind Erosion in Alpine Area

采用风洞实验对祁连山东段天祝高寒地区天然放牧草地、退耕自然恢复草地、翻耕地、免耕留茬地和人工种植多年生草地5种土地利用方式下的原状土抗风蚀能力进行了研究。结果表明,多年生草地的临界侵蚀风速最大,免耕留茬地和天然草地次之,翻耕地和退耕自然恢复地最小;风蚀速率与风速变化成正相关,随着风速增大,风蚀速率相应增加;风蚀速率和风速变化服从幂函数变化关系。在近地表0-20cm范围内,降尘量总量依次为退耕自然恢复地>翻耕地>天然放牧草地>多年生草地>免耕留茬地;土壤抗风蚀能力表现为退耕自然恢复地>天然放牧草地>多年生草地>免耕留茬地>翻耕地。

The impacts of different land use patterns on the resistance of soil to wind erosion in Tianzhu,the alpine meadow area in the eastern part of Qilian mountains,were studied through wind tunnel experiment. Five land use patterns,including free-grazing grassland,returned farmland to naturally restored grassland,ploughed farmland,no-tillage farmland with oats stubble and sowed perennial grassland,were designed. The results indicated that the threshold wind erosion velocity for sowed perennial grassland was the biggest,the no-tillage farmland with oats stubble and free grazing grassland was next,the ploughed farmland and returned farmland to naturally restored grassland was the smallest. The rate of wind erosion positively interrelates with the wind speed. The rate of wind erosion increased with the increasing of wind velocity. A power function relationship exists between wind erosion rate and wind velocity under different land use patterns. The order of the dustfall amount of aboveground 0 to 20 cm accounted was returned farmland to naturally restored grassland〉ploughed farmland〉free grazing grassland〉sowed perennial grassland〉no-tillage farmland with oats stubble. The order of resistance of 5 patterns to wind erosion was returned farmland to naturally restored grassland〉free grazing grassland〉sowed perennial grassland〉no-tillage farmland with oats stubble〉ploughed farmland.