The factors affecting microplastic pollution in farmland soil for different agricultural uses: A case study of China

Abstract

Microplastics (MPs) accumulation in agricultural soil seriously affects soil quality and grain production, and endangers ecological environment and human safety. The factors contributing to the MPs accumulation in various agricultural land-use soils remain unclear. In this study, a meta-analysis was conducted to analyze the influence of meteorological factors. Furthermore, the accumulation process of MPs pollution in different agricultural land-use soils in China was explored. The conclusions are as follows: (1) The MPs abundance varied from 23 to 41,741 n/kg in Chinese agricultural soil. Especially, the moderate and severe pollution (≥4,000 n/kg) were found in the Yunnan-Kweichow Plateau. (2) The order of MPs abundance in soil was as follows: vegetable > orchard > food crops. Compared to non-mulching, MPs abundance in mulching food crops, vegetable, and orchard soil was approximately 1.4-fold, 11.4-fold, and 1.1-fold, respectively. (3) In orchard and food-crop soils, MPs abundance was negatively associated with rain and wind speed, but positively correlated with altitude and temperature. Whereas MPs abundance in vegetable soil was significantly positively affected with temperature, altitude, sunshine hours, wind speed, and rainfall. (4) The MPs pollution accumulation in soil was mainly dominated by mulching agricultural measures under different agricultural land-use. Meteorological factors have an indirect impact by affecting MPs fragmentation and migration. The results provide theoretical support for soil pollution control, agricultural production safety, and watershed management.