阴山北麓农牧交错带裸露耕地土壤风蚀物垂直分布规律

    Topsoil sediment distribution along height above bare tillage land in agro-pastoral ecotone of northern foot of Yinshan Mountain

    • 摘要: 为了解阴山北麓农牧交错带的土壤风蚀特性,采用SCC-6型集沙仪在野外自然风况下对风蚀物进行实地收集试验并对其粒度组成进行分析研究,得到了阴山北麓农牧交错带裸露耕地土壤在自然风况下风蚀物沿高度的变化规律,揭示了风蚀物沿高度的变化规律和不同跃移颗粒体的粒度组成沿高度的变化特征。并利用室内风洞研究了不同风速作用下,不同风力作用时间内,风蚀物含量沿高度的变化规律和风蚀量与风速的关系。结果表明:阴山北麓农牧交错带土壤风蚀是一种近地表的风沙运动,风蚀物跃移颗粒体主要集中在7.5~43.5 cm高度,风蚀物含量沿高度呈一递减函数,对幂函数、指数函数和对数函数均具有较好的相关性;风蚀物颗粒组成与风蚀强度和地表状况关系密切;风蚀物颗粒组成以某一粒径范围、某一高度为界随高度的变化而表现出明显的规律性;风蚀量沿高度的变化与风力作用时间有关,风蚀量随风速的增大呈指数增加。为研究该区域土壤风蚀规律及提出合理防风固沙措施奠定了基础。

       

      Abstract: Based on the field sediment collection experiment by SCC-6 sediment collector and sediment particle composition in lab experiment in order to master the characteristics of wind erosion in agro-pastoral ecotone of northern foot of Yinshan Mountain, the sediment amount distribution along height above bare tillage land in the local was obtained, which revealed the variation of sediment amount and saltation particle composition. In addition, the sediment amount distribution along height and the relation between wind speed and sediment amount was conducted under some different wind forces in 0FDY-1.2 wind tunnel. The results showed that soil wind erosion was the near-surface wind-sand activity. The sediment particle saltates mainly in 7.5-43.5 cm. Wind sediment amount decreased along height, which correlate well with power function, exponent function and logarithm function. The sediment particle composition was influenced strongly by wind erosion intensity and topsoil characteristics. However, the regularity of sediment composition was distinct in a definite paticle size in different heights. Wind erosion amount increases with wind speed exponentially, which was influenced by times that the wind does. It will lay a soild foundation for searching the rules of soil wind erosion and puting forwards some effective measures against soil losses by wind in future.

       

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