Spatial-temporal trends of rainfall erosivity and its implication for sustainable agriculture in the Wei River Basin of China

Water and soil are important natural resources for agricultural development. Soil erosion is a worldwide problem threatening sustainable agriculture development. Rainfall is one of the major natural factors that cause soil erosion. The study of the spatial distribution and temporal trends of rainfall erosivity is practical and important for the assessment of soil erosion hazards, the planning of soil and water conservation measures, and the sustainable agriculture development. In this study, the data of daily rainfall in the Wei River Basin from 1969 to 2018 were collected, the spatial and temporal variation characteristics of rainfall and rainfall erosivity were analyzed. The results show that the regional mean annual rainfall varies from 315.0 to 807.3 mm, which shows an increasing spatial trend from northwest to southeast. The mean annual rainfall erosivity in the basin ranges from 751.4 to 2600.0 MJ.mm.hm(-2).h(-1), which has a similar pattern of spatial distribution as the rainfall. The monthly rainfall erosivity changing pattern is a single-peak type. High erosivity of rainfall was mainly observed from July to September. The peaks mostly occur in July and August. The temporal trend of annual rainfall erosivity ranges from -6.6-10.1 MJ.mm.hm(-2).h(-1) per year, the Loess Plateau and the Qinling Mountains in the southern basin show an increasing trend, and the surroundings of Xifeng, Changwu and Huanxian have the statistical significance of P < 0.05. In the midstream and downstream of the basin and the Guanzhong Plain, the rainfall erosivity shows an insignificant decreasing trend. The North Atlantic Oscillation obviously influences the rainfall erosivity in the recent two decades. The study results may helpful for the scientific management, soil erosion prevention and sustainable agricultural development of the Wei River Basin.