Spatial distribution characteristics of sediment connectivity and soil erosion in small watershed in brown soil hilly region of low mountains in western Liaoning Province, China.

Abstract

Understanding the spatial distribution characteristics of soil erosion and sediment connectivity is important for formulating integrated watershed management measures. Based on the InVEST sediment delivery ratio model, we used the connectivity index and soil loss model to measure the spatial distribution characteristics of sediment connectivity and soil erosion in Erdaoling watershed of brown soil hilly region of low mountains in western Liaoning. By exploring slope, aspect and land use characteristics under different sediment connectivity levels and soil erosion levels, we analyzed the relationships among topography, land use, sediment connectivity, and soil erosion. The results showed that the average sediment connectivity in the watershed was -3.79, and that the average soil erosion was 614 t·km2·a-1. High connectivity was mainly found in sloping farmland, while low connectivity was mainly found in forest and grassland. The soil erosion intensity of 93.3% of the watershed area was below moderate, with only 1.1% of the area being above extremely strong. The higher the sediment connectivity level, the higher the proportion of the area <5° slope, while the area proportion of the rest slope was relatively stable. The proportion of cultivated land area increased, while the proportion of forest and grassland land area decreased. The area proportion on negative slope decreased, while that on positive slope increased. With increasing soil erosion intensity, the area proportion of slope <8° increased and the area proportion of the rest slope was relatively stable. The proportion of forest and grassland area decreased, while the proportion of other land use area increased. The proportion of slope area on positive slope increased, while that on negative slope decreased. Land use was a key factor influencing the spatial response relationship between soil erosion and sediment connectivity in this watershed.