Change of Soil Surface Roughness of Splash Erosion Process

Abstract

Soil erosion is a common global environmental problem and undermines sustainable devel‐ opment in various economies and societies. Detailed information about changes in surface roughness during the whole soil erosion process remains limited, however, due to practical difficulties in obtaining direct soil microrelief measurements (Huang, 1998) and a lack in systematic research. The Chinese Loess Plateau is one of the most severely eroded regions in the world, which has created many environmental problems along the lower reaches of the Yellow River. Despite this, however, very little erosion-based research has been conducted on the Loess Plateau. Erosion and runoff processes are influenced mainly by soil surface characteristics such as soil surface roughness, cohesion, and granular stability. Among these characteristics, soil surface roughness is a key parameter (Gomez, and Nearing, 2005; Mir‐ zaei et al., 2008), and is used to describe the variation in surface elevation across a field. The soil surface micro-topography or roughness is strongly influenced by agricultural activities, together with soil properties and climate. The term soil roughness was used to describe dis‐ turbances or irregularities in the soil surface at a scale which was generally too small to be captured by a conventional topographic map or survey. Soil surface roughness is an impor‐ tant parameter in understanding the mechanisms of soil erosion by water and wind. Many erosion related surface processes, such as depression water storage, raindrop or wind shear detachment, and sediment transport have characteristic lengths in millimeter scales. Thus, soil surface roughness resulting from small scale elements is important in understanding these processes and their spatial variation (Huang and Bradford, 1990). Soil surface rough‐ ness determines the storage of water on the soil surface and may indirectly influence its in‐ filtration capacity. The velocity of overland flow is controlled by the hydraulic resistance of the soil surface. Soil surface roughness affects the organization of the drainage pattern on