半干旱草原潜在土壤风力侵蚀空间格局研究

中国绝大多数的干旱半干旱地区遭受着严重的风力侵蚀。风蚀可导致土壤流失、肥力下降,最终导致土地荒漠化。半干旱草原区的荒漠化问题日益突出,由此带来的沙尘暴等灾害天气增多,给人们的生产生活带来诸多不便。从影响土壤风力侵蚀的风速、干燥度、植被盖度、地形起伏度、土壤可蚀性以及放牧压力6个方面出发,借助GIS技术,通过主成分分析研究半干旱草原区达茂旗土壤风力侵蚀的空间分布格局。结果表明:达茂旗潜在土壤风力侵蚀指数由南向北呈高—低—高趋势。达茂旗北部地区土壤风蚀主要受风速、干燥度和植被指数影响;中部地区风力侵蚀主要受地形起伏度的影响,地形起伏对风的消减作用增强,使得风力降低,加之该地区土壤可蚀性和干燥度相对较低,风力侵蚀指数低;南部土壤风力侵蚀主要受放牧压力影响,春季正是牧草返青季节,植被盖度低,且牲畜密度相对较大,放牧对草场的压力大,土壤风力侵蚀严重。风力侵蚀各影响因子的时空异质性是导致半干旱草原风力侵蚀空间异质性的主要原因。干旱草原风力侵蚀空间异质性的主要影响因素是风速、干燥度和植被指数,其次受地形和土壤可蚀性的影响,而放牧压力是半干旱草原区土壤风力侵蚀的主要人为因素之一。

Study on Spatial Pattern of Potential Wind Erosion of Soil in Semi-arid Steppe

The majority of China in the arid and semi arid regions suffered from invasion of severe erosion.Wind erosion can lead to soil loss and soil fertility decline,ultimately cause the desertification.Semi arid grassland desertification problems have become increasingly prominent,resulting in dust storms and other frequency of weather disasters,and leading to a lot of inconveniences to the production and people′s living.Based on the wind speed inducing soil wind erosion,aridity,vegetation index,relief amplitude,soil erodibility and grazing pressure,the spatial distribution pattern of soil wind erosion of semi arid grasslands in Damao County was studied by using GIS technology through principal component analysis.The results showed that the potential of wind erosion index presented high-low-high trend from south to north.In northern Damao,soil erosion was mainly affected by wind speed,aridity and vegetation index;central area of wind erosion was mainly affected by the level of relief amplitude,effect of relief amplitude on wind reduction was enhanced,the wind speed was reduced,and the change in soil erodibility and aridity was relatively low,so wind erosion index was low.Southern soil wind erosion was mainly affected by grazing pressure,spring is the season with low grass and vegetation coverage,and livestock density was relatively large,grazing on pasture pressure,soil wind erosion was very serious.Temporal and spatial heterogeneity of each factor influencing wind erosion was the main reason leading to spatial and temporal heterogeneity wind erosion in semi arid prairie.The main factors influencing spatial heterogeneity of wind erosion in semi arid steppe were wind speed,drought and vegetation index,the next factors were the relief amplitude and soil erodibility,and grazing pressure was one of the main human factors on soil wind erosion in semi arid steppe.