Research advances in nutrient runoff on sloping land in watersheds

摘要

High nitrate and phosphorus concentrations in runoff resulting from sloping lands (especially agricultural sloping lands) have direct consequences on the aquatic environment through eutrophication of surface water. This paper details the transfer mechanism of nutrients in soil on sloping lands influenced by natural and artificial factors. Results showed that the rainfall intensity had a small influence on nutrient concentrations in runoff, but a significant influence on the runoff flow on sloping lands. The slope length influenced the nutrient loss by soil erosion on areas that receive rainfall. The slope gradient influenced the nutrient loss by runoff flux and velocity on sloping land. As the slope gradient decreased, the nutrient loss decreased because of the increase in infiltration. The soil texture, porosity, and water content influenced the motion of soil water and the transfer and form of nutrients in soil, through oxidation and deoxidation. Vegetative coverage influenced the infiltration coefficient of rainwater into subsurface soil, and thus influenced the runoff flow velocity. Therefore, different sloping lands need to be managed in different ways. To better carry out best management practices in watersheds, a new management based on sloping lands needs to be further studied, including changing fertilization quantity, improving fertilization technology, adjusting vegetation coverage, and studying cultivation systems on different sloping lands within a watershed.