土壤风蚀是世界许多地区面临的一个严峻环境问题。土壤风蚀特征是建立土壤风蚀预报模型、制定土壤风蚀防治措施的基础信息。综合考察了滦河源区东沟小流域地理环境特征,分析了不同风蚀强度下暗栗钙土的诊断特性。其结果表明:自然环境提供了土壤风蚀的物质条件,区域日益强化的农牧业及砍薪材活动则是土壤风蚀的触发驱动力;失去植被保护的干旱松散表土,在大风驱动下,其中的细砂和极细砂(0.01~0.10 mm)首先以跃移、悬浮方式流失,而粗砂(2~0.25 mm)则相对是非可风蚀颗粒;建立了定量刻划土壤风蚀相对强度指数,即SWEI＝粗砂含量/风蚀粒子含量。东沟小流域自然暗栗钙土表土SWEI≤2.0,轻度风蚀区表土SWEI≥ 3.0,重度风蚀区表土SWEI≥9.0;而在风积区表土SWEI≤1.5,该指标较好地反映了区域土壤风蚀强度的差异性。

Soil wind erosion is one of the most serious environmental and socio-economic problems in many semiarid ecosystems of the world. Donggou small watershed of the Luanhe River source area (41°31'36″-41°33'56″N, 116°06'06″-116°11'50″E, 1560-1960 m a.s.l.) is one of the prototype mixed pasture-agriculture-frost ecosystems in the North China, where the soil wind erosion is developing rapidly and receiving widespread attention. The properties of the soils, which are influenced by wind erosion, are very important information for the wind erosion prediction and conservation. Using the detailed ground-based investigations of the household livelihoods, land use, environmental characteristics and diagnostic soil characteristics of Donggou small watershed, this paper analyses the wind erosion properties of the Hap-Ustic Isohumisols (or dark chestnut soil) in the areas with different wind erosion intensities. The results show that: (1) During winter and spring, Donggou small watershed has very strong wind (cold wave) and little precipitation, the soil is in drying-friable state, and soil texture is sandy, these natural environmental factors have provided the material resource and kinetic energy for the wind erosion processes. For traditional farming intensity is becoming increasingly high, the livestock capacity on the grassland and demand for the fuel-wood is becoming more day-by-day. These anthropogenic factors have been the trigger driving-force for the wind erosion processes. (2) For drying-friable surface soil, which has lost the protective cover of vegetation, the fine sand (0.10-0.05 mm) and very fine sand (0.05-0.01 mm) are carried away first by suspension and saltation. But the coarse sand (2.00-0.25 mm) in the surface soil is relative nonerodible particles. (3) A quantitative index was used to estimate the wind erosion intensity in the study area, i.e. SWEI=CS/EF, where CS is the content of the coarse sand in the surface soil, EF is the content of the fine sand and very fine sand in the surface soil. In the distribution areas of the Hap-Ustic Isohumisols, the SWEI≤2.0; in the distribution areas of weakly eroded soils, the SWEI≥3.0; in the distribution areas of very strong eroded soils, the SWEI≥9.0; But in the wind deposition areas, the SWEI≤1.5.