人工降雨条件下坡耕地地表糙度的时空变异分布研究

Surface Roughness Spatiotemporal Distribution of the Slope Land under Simulated Rainfall

水蚀过程中地表糙度变化研究,特别是微地表条件下水蚀过程中地表糙度的分布及变化特征的研究是土壤侵蚀学科领域的前沿问题,目前仍处于不断的探索与发展阶段。本文试图通过对陕西省杨凌区农耕地土壤进行固定坡度和雨强下不同耕作措施的室内人工降雨试验,建立微地形条件下高精度的DEM并进行分析,探讨地表糙度在水蚀过程中的时空变异分布。结果表明:(1)人为耕作对坡面地表糙度的整体分布状态和坡面高程空间分布状况的影响显著;(2)降雨对等高耕作、人工锄耕、人工掏挖耕作措施的高程分布有一定的影响,并且高程变化量的最大值均出现在坡面的下部;(3)在降雨侵蚀的产流前后,坡面糙度的空间变化最大,而产流后糙度的空间变化趋于平稳。研究结果初步揭示了微地表条件下地表糙度的时空变异状况,并可为进一步分析不同坡度、不同雨强条件下地表糙度的综合研究奠定基础。

The evolution of surface roughness in the process of water erosion,especially under the micro-surface conditions,is becoming the hot-spot in the discipline of soil erosion,while,it is still in the stage of exploratory development. In this paper,it attempts to reveal the spatiotemporal distribution of surface roughness in the process of water erosion based on the indoor artificial rainfall experiment. The results shows that：（1） man-made slope tillage have significant effects on both overall distribution of surface roughness and spatial distribution of surface relative elevation （SRE）; （2） Rainfall can influence the distribution of SRE of contour tillage,artificial hoe and artificial dig,moreover,the maximum amount of elevation changes are in the lower slope. （3） During the rainfall erosion process,the spatial variability of surface roughness is greatest,while after the runoff the spatial variation of roughness is stabilized. The study reveals the spatial variation of surface roughness under the micro-surface conditions and may lay the foundation for a comprehensive surface roughness study of different slope,rainfall intensity in different conditions.