Socioeconomic development mitigates runoff and sediment yields in a subtropical agricultural watershed in southern China

Abstract

Although the effects of biophysical factors on runoff and sediment yields have been studied extensively, the influences of anthropogenic factors, such as economic development and population growth, which might be crucial causes of soil erosion, are still unclear. To decouple the influences of biophysical and socioeconomic variables on runoff and sediment yields, observational data on runoff and sediment from 1985 to 2015 in seven hydrological stations in Gongshui Watershed, Jiangxi Province, China, and meteorological and socioeconomic statistics during the same period were collected. A structural equation model was constructed to evaluate the effects of biophysical factors and socioeconomic factors on runoff and sediment yields. The results showed that soil erosion in the Gongshui Watershed was significantly mitigated in the past 30 years and remarkable change points occurred. Both biophysical and anthropogenic factors had significant effects on soil erosion in the watershed, and the path coefficient changed dramatically with socioeconomic development. Economic development was the most important controlling factor, and the path coefficient decreased from −0.3863 in stage I (before the change point) to −0.6174 in stage II (after the change point). The promoting effect of agricultural production mainly stemmed from its expansion brought about by agricultural output, with the total effect increasing from 0.489 in stage I to 1.017 in stage II. The contradiction between socioeconomic development and soil erosion control in the Gongshui watershed was alleviated, and the gradually formatted synergy could provide continuous support for soil erosion control.

Keywords

• run off and sediment yields
• biophysical factors
• socio-economic factors
• structural equation modelling
• Gongshui watershed