华北农牧交错带土地沙漠化成因与土地利用调整对策

从气候变化、土地利用等角度对华北农牧交错带典型区——内蒙古多伦县的土地沙漠化形成机制进行分析。对干湿指数、最大可能蒸散量等指标的分析表明该区域近30a来气候变化在一定程度上有利于沙化土地的恢复。1985年和2000年两期土地沙漠化、土地利用监测数据空间叠加和地统计分析表明，该区域15a来不存在明显的开荒和毁林等土地利用方式转型现象，利用方式未变化的土地占总土地的95.98%。严重沙化土地的91.39%发生在利用方式未变化的草地、耕地和未利用土地，三者沙化程度加重分别占该区所有沙化程度加重土地的55.16%、25.92%和10.31%。实地调查和遥感、统计等相关数据分析表明，耕地沙化主要是秋耕和农业大机械的应用为风蚀创造了条件，连年耕作和经济作物的种植促进了耕地退化；草地和未利用土地沙漠化主要因为载畜量过重和草原交通对草场的破坏。针对以上土地利用强度过大等造成土地沙漠化的原因提出华北农牧交错带土地利用调整策略。

Formation mechanism of land desertification and adjustment of land use in ecotone between agriculture and animal husbandry in North China

Duolun county, in central Inner Mongolia Autonomous Region, was selected as a typical region of ecotone between agriculture and animal husbandry in North China, and its' climate data, land desertification and land use data were comprehensively analyzed to find the in-depth formation mechanism of land desertification. Through analyzing the weather data of recent 30 years by linear trend method, results showed that the regional climate change made for the restoration of land desertification, and climate change was not the main reason for land desertification expansion and aggravation. Analyzing land desertification and land use observation data by means of spatial overlay and terrain statistics methods, the result showed that there was not obvious land use pattern change such as overcutting or overcultivating in the research region, and the land area without change of land use pattern accounted for 95.98% of the total land area. The aggravation of land desertification degree mainly occured in grassland and cultivatable land. The aggravation of desertification degree of these types land accounted for 55.16%, 25.92% and 10.31% of the whole, separately, and their sum accounted for 91.39% of total aggravation area of land desertification. Field survey and analyzing remote sensing, statistics etc. showed that cultivation in fall and use of agricultural machine gave rise to wind erosion of soil, and cultivation in successive years, plantation of economic crop such as sugar beet aggravated land degradation, then the heavy amount of yearly carrying livestock and traffic in grassland led to grassland degradation. Finally, according to these analysis results, land use adjustment plan was put forward.