Effects of microplastic pollution on agricultural soil and crops based on a global meta‐analysis

Abstract Agricultural soil serves as a crucial reservoir for microplastics (MPs), necessitating an understanding of their global‐scale environmental impacts and potential risks that they pose to agricultural soil and crops. Little is known about the potential impact of MPs in agricultural soils, compared with MPs in aquatic sediments, especially their effects on crop traits. The purpose of our study was to explore whether different types, concentrations, sizes, and exposure time of MPs, as well as soil conditions (such as soil pH or organic matter concentration), have different effects on soil properties and crop traits. In addition, differences between soil and crop enzymes in response to MPs were compared in detail. Network analysis was used to understand the current research progress on MPs in agricultural soil. Furthermore, utilizing 63 publications and 3268 observations, a meta‐analysis was conducted to analyze the effects of MPs on soil properties and crop traits. Our result showed that China has contributed the most to MP research. Crop traits, rather than soil properties, were more sensitive to MPs, significantly increasing crop biochemical traits ( p < 0.05) and decreasing crop morphological traits ( p < 0.001). MPs significantly inhibited fruit, shoot, and root morphological traits by 13.34% ( p < 0.05), 9.7% ( p < 0.001), and 6.65% ( p < 0.001), respectively; inhibited crop physiological traits such as photosynthesis, respiration, and transpiration by 9.1% ( p < 0.001), 34.44% ( p < 0.001), and 14.74% ( p < 0.05), respectively; inhibited crop biochemical traits such as organic and inorganic metabolites， and improved enzyme activity by 11.37% ( p < 0.001), 10.07% ( p < 0.001), and 10.16% ( p < 0.001), respectively. MPs decreased soil enzyme activities of leucine aminopeptidases and sucrase by 7.22% ( p < 0.01) and 27.26% ( p < 0.001), respectively, and increased peroxidase, acid phosphatase, catalase (CAT), and urease activities by 59.21%, 7.34%, 6.86%, and 13.13%, respectively. MPs increased crop enzyme activities of CAT and malondialdehyde by 12.71% and 14.82%, respectively. Conclusively, the effect of MPs on crop traits warrants considerable attention and an urgent need to explore whether MPs cause differences between crops with regard to crop traits.