Microplastic Contamination in Agricultural Soil: Sources, Distribution, Impact and Management: A Review

Abstract

Microplastic pollution of agricultural land has emerged as one of the more consequential, yet under-regulated, forms of soil contamination confronting global food systems. Plastic debris smaller than five millimetres accumulates in farmland through plastic mulching, sewage sludge and compost application, wastewater irrigation, atmospheric deposition and the breakdown of agricultural equipment, and it now appears to occur at concentrations exceeding those reported for marine surface waters. This review synthesises the current understanding of the sources, distribution, environmental fate and ecological consequences of microplastic contamination in agricultural soils, together with the emerging repertoire of management and remediation options. The available evidence indicates that microplastics alter soil structure, water retention and aggregate stability; disturb microbial community composition and nutrient cycling; impair the growth, physiology and reproduction of soil fauna; and reduce germination, biomass and yield in a range of crop species, with effects that vary strongly according to polymer type, particle shape, concentration and soil texture. Microplastics also act as vectors for co-contaminants, including pesticide residues and persistent organic pollutants, and their detection in edible plant tissue raises unresolved questions about dietary exposure and human health. Remediation approaches under investigation include biochar and mineral amendments, microbial and enzymatic bioremediation, plant growth-promoting rhizobacteria, phytoremediation and substitution with soil-biodegradable polymers, although none has yet achieved reliable field-scale performance. The review concludes that agricultural microplastic pollution requires coordinated attention from soil science, agronomy, ecotoxicology and policy, and it identifies methodological standardisation, long-term field trials and exposure-realistic toxicology as priorities for future research.