作　　者： ; ; ; ; ;

机构地区： 西北农林科技大学资源环境学院

出　　处： 《中国农业科学》 2014年第12期2365-2373,共9页

摘　　要： 【目的】探讨微尺度下(2 cm×2 cm)地表糙度在侵蚀过程中的空间异质性规律,为进一步理解和定量化描述地表糙度与土壤侵蚀的相互耦合关系奠定基础,并为黄土高原坡耕地水土流失的治理提供一定的理论依据。【方法】以黄土高原不同耕作措施条件下(4种常见的农业耕作措施:人工锄耕、人工掏挖、等高耕作、直线坡(对照)的坡耕地为研究对象,通过室内人工模拟降雨实验,利用激光扫描仪获取地表糙度数据,运用地统计学和分形维数方法对地表糙度的空间分布特征及变异性进行研究。【结果】基本统计特征分析表明,黄土坡耕地地表糙度在整体上的分布较均匀,具有较弱的空间变异特征。半方差函数分析表明,黄土坡耕地地表糙度均表现出中等以上的空间自相关性,其空间自相关尺度范围为2.02—3.82 m。由空间结构特征引起的异质性占总异质性的比例较大。分形维数分析表明,黄土坡耕地地表糙度具有良好的分形性质,其分形维数介于1.59和1.91之间;随坡度的增大,各坡面地表糙度的空间分布趋向复杂,空间异质性增强;人工锄耕、人工掏挖、等高耕作坡面的空间异质性在小尺度范围内依次增强,具有良好的水土保持作用。【结论】造成地表糙度空间异质性差异的主要原因是由人为耕作和坡度所形成的空间结构特征。地表糙度的空间配置格局在小尺度范围上由人为耕作和坡度、在大尺度范围上由降雨及其侵蚀过程所控制。该研究结果可为进一步理解地表糙度与侵蚀的相互耦合关系奠定基础,并为黄土坡耕地的水土流失防治提供一定的科学依据。 【Objective】The objective of this paper is to reveal the spatial heterogeneity of surface roughness of 4 typical loess tilled slopes during different erosive stages under a micro-scale（2 cm×2 cm） condition.【Method】When slopes with 4 different gradients and tillage measures were prepared（artificial backhoe, artificial digging, contour tillage and straight cultivated slope（check）, an erosive rainfall with a rainfall intensity of 60 mm/h was carried out. Soil surface roughness relative elevation data points were taken by a laser scanner and analyzed with both the semivariogram function and fractal dimension models.【Result】The result of classical statistical analysis showed that the loess tillage slope surface roughness has a weak spatial variability. The result of the semivariogram analysis indicated that the loess tilled slope surface roughness had a higher spatial autocorrelation, their spatial autocorrelation scale of surface roughness ranged from 2.02 m to 3.82 m. The spatial heterogeneity caused by the spatial structure characteristic accounted for the greater proportion of the total heterogeneity. The fractal dimension analysis showed that the surface roughness had good fractal features, and it ranged from 1.59 to 1.91. With the increase of gradient, the spatial distribution of slope surface roughness tended to complex, its spatial heterogeneity was stronger. The spatial heterogeneities of the artificial backhoe（AB）, artificial digging（AD） and contour tillage（CT） increase in turn within the scope of the small scale, and had a good effect on soil and water conservation. 【Conclusion】The main reason for the differences of the spatial heterogeneity of surface roughness is the spatial structural characteristics formed by the integrated interaction of human farming and slope and the artificial cultivation. The space configuration pattern of surface roughness is mainly controlled by slope gradient factor in a smaller scale range, and by the rainfall with its erosion process in a

关 键 词： 黄土高原 坡耕地 地表糙度 空间异质性 半变异函数 分形维数

领　　域： [农业科学] [农业科学]