河北坝上土地利用方式对农田土壤风蚀的影响

Influence of Land Use Ways on the Farmland Soil Wind Erosion in Bashang Area,Hebei,China

采用集沙仪、风速廓线仪和土壤紧实度仪对河北坝上地区多种土地利用方式的风蚀因子和输沙量进行观测。结果表明:土壤含水率与输沙量相关性最大,是影响风蚀量的关键性因子。回归拟合显示,风蚀因子与输沙量均符合三次函数方程。在各土地利用方式中,退耕地的地表粗糙度、土壤含水率和土壤硬度最大,其次为东西向莜麦留茬地、小麦留茬地、南北向莜麦留茬地,再次为油菜留茬地和弃耕地,最小为翻耕地。输沙量退耕地最小,其次为东西向莜麦留茬地、南北向莜麦留茬地、小麦留茬地,再次为油菜留茬地和弃耕地,最大为翻耕地;输沙量垂向分布随集沙高度增加呈幂函数减少。因此,适宜增加退耕地和留茬地的分布面积,减少翻耕地面积和垄向沿盛行风向分布的地块有利于降低农田土壤风蚀程度。

By sand collecting instrument, wind profilers and soil compaction meter, wind-erosion factors and sediment discharge of various land use ways were observed in Bashang area of Hebei Province. The results show that the correlation coefficient of surface soil moisture content and sediment discharge is the maxi- mum. So the surface soil moisture content is the most important influence factor on soil wind erosion a- mount. Regression fitting results between wind-erosion factors and sediment discharge show that they all conform to the cubic function equation. For surface aerodynamic roughness, soil water content and soil hard- ness, they are the maximum for rehabilitated land, followed by east-west naked oats stubble, field wheat stubble field and south-north naked oats stubble field, again followed by rapeseed stubble field and derelict land, while they are the minimum for ploughed field. Statistical results of sediment discharge of various land use ways show that it is the minimum for rehabilitated land, followed by east-west naked oats stubble field, south-north naked oats stubble field and wheat stubble field, again followed by rapeseed stubble field and derelict land, while it is the maximum for ploughed field. The amount of sediment discharge decreases with the height by the law of power functions. It is helpful to increase the area of rehabilitated land and stubble field appropriately and shorten the area of ploughed field and the farm with blocks of ridge at prevailing wind direction for the reduction of farmland soil wind-erosion.