A Systematic Review of Scientific Research on Municipal Solid Waste Compost: Impacts on Crop Productivity and Soil Fertility

Recycling Municipal Solid Waste into compost (MSWC) addresses waste disposal and soil organic matter decline. This review assesses MSWC’s agronomic effects on crop productivity and soil fertility, highlighting key findings, limitations, and research needs. We analyzed 114 peer-reviewed quantitative studies selected from Web of Science (1985–2025) using Latent Dirichlet Allocation. The review covers MSWC effects on crop productivity across arable, horticultural, and orchard systems, and its impact on soil physical, chemical, and biological properties. Studies reported consistent positive effects at doses > 30–40 t ha⁻¹. Average yield increases were highest in arable systems (+ 63.3%), followed by horticultural (+ 37.3%) and orchards (+ 23%) compared to controls. Soil organic matter increased by + 2.5% in field conditions and + 248% in pot experiments. Benefits were particularly pronounced in degraded or saline-sodic soils, where MSWC reduced electrical conductivity by up to 39% and increased organic matter by up to 45%. However, most studies were short-term (only 18% >5 years) and lacked detailed compost characterization, limiting evidence on long-term dynamics. MSWC aligns with circular economy principles as a potential alternative to mineral fertilizers. Nevertheless, challenges regarding variable composition, high application rates, and contaminants (heavy metals, microplastics) persist. Future research must prioritize long-term field studies to optimize application strategies and assess environmental safety. This review was not registered in any public protocol database.