Microplastics are increasingly present in soil, posing significant threats to soil carbon pools and plant performance. Microplastics can alter soil physicochemical properties, such as bulk density, porosity, and pH, which in turn affect microbial habitats and plant growth. They can mimic soil carbon storage, influencing soil organic matter (SOM) turnover through priming effects, and alter the distribution of soil carbon in particulate and mineral-associated organic matter. Microplastics also influence dissolved organic matter (DOM) by increasing its aromaticity, molecular weight, and humification degree. These changes may be due to microplastic-derived DOM and interactions with microbial degradation processes. Microplastics create distinct ecological niches for microbial growth and contribute to necromass formation. Conventional microplastics reduce microbial necromass carbon contribution to the stable soil carbon pool, while bio-microplastics may increase it. Microplastics affect plant performance through internal and external factors, influencing seed germination, vegetative and reproductive growth, and inducing ecotoxicity and genotoxicity. Future research should focus on understanding the impact of microplastics on microbial necromass accumulation and carbon storage in mineral-associated fractions, as well as rhizosphere dynamics. Microplastics can decrease soil bulk density, alter soil porosity and aggregates, and affect soil pH and fertility. They can influence SOM composition and mineralization, with some studies showing increased DOM content after microplastic addition. Microplastics may also affect microbial community structure, enzyme activity, and the degradation of microplastics by microbes. Microplastics can serve as a carbon source for microbes, influencing microbial necromass accumulation and soil carbon pools. The effects of microplastics on plant performance include reduced seed germination, altered vegetative and reproductive growth, and potential toxicity. Overall, microplastics have complex and multifaceted effects on soil ecosystems, requiring further research to fully understand their impacts.Microplastics are increasingly present in soil, posing significant threats to soil carbon pools and plant performance. Microplastics can alter soil physicochemical properties, such as bulk density, porosity, and pH, which in turn affect microbial habitats and plant growth. They can mimic soil carbon storage, influencing soil organic matter (SOM) turnover through priming effects, and alter the distribution of soil carbon in particulate and mineral-associated organic matter. Microplastics also influence dissolved organic matter (DOM) by increasing its aromaticity, molecular weight, and humification degree. These changes may be due to microplastic-derived DOM and interactions with microbial degradation processes. Microplastics create distinct ecological niches for microbial growth and contribute to necromass formation. Conventional microplastics reduce microbial necromass carbon contribution to the stable soil carbon pool, while bio-microplastics may increase it. Microplastics affect plant performance through internal and external factors, influencing seed germination, vegetative and reproductive growth, and inducing ecotoxicity and genotoxicity. Future research should focus on understanding the impact of microplastics on microbial necromass accumulation and carbon storage in mineral-associated fractions, as well as rhizosphere dynamics. Microplastics can decrease soil bulk density, alter soil porosity and aggregates, and affect soil pH and fertility. They can influence SOM composition and mineralization, with some studies showing increased DOM content after microplastic addition. Microplastics may also affect microbial community structure, enzyme activity, and the degradation of microplastics by microbes. Microplastics can serve as a carbon source for microbes, influencing microbial necromass accumulation and soil carbon pools. The effects of microplastics on plant performance include reduced seed germination, altered vegetative and reproductive growth, and potential toxicity. Overall, microplastics have complex and multifaceted effects on soil ecosystems, requiring further research to fully understand their impacts.