Municipal solid waste compost often improved crop yield and soil fertility

What the study found: Municipal solid waste compost was generally associated with higher crop productivity and improved soil fertility in the studies reviewed. The strongest positive effects were reported at application doses above 30–40 t ha⁻¹.
Why the authors say this matters: The authors say municipal solid waste compost may address waste disposal and declining soil organic matter, and they describe it as aligning with circular economy principles as a potential alternative to mineral fertilizers.
What the researchers tested: The review analyzed 114 peer-reviewed quantitative studies from Web of Science published between 1985 and 2025. It used Latent Dirichlet Allocation, a text-analysis method for grouping themes, to examine effects on crop productivity and on soil physical, chemical, and biological properties across arable, horticultural, and orchard systems.
What worked and what didn't: Average yield increases were reported as +63.3% in arable systems, +37.3% in horticultural systems, and +23% in orchards compared with controls. Soil organic matter increased by +2.5% in field conditions and +248% in pot experiments, and benefits were especially pronounced in degraded or saline-sodic soils, where electrical conductivity fell by up to 39% and organic matter rose by up to 45%.
What to keep in mind: Most studies were short-term, with only 18% lasting more than 5 years, and many lacked detailed compost characterization. The abstract also notes concerns about variable composition, high application rates, and contaminants such as heavy metals and microplastics, and it says the review was not registered in a public protocol database.

Key points

• The review found generally positive effects of municipal solid waste compost on crop productivity and soil fertility.
• The strongest reported benefits were at application doses above 30–40 t ha⁻¹.
• Average yield gains were highest in arable systems, followed by horticultural systems and orchards.
• Soil organic matter increased in both field and pot studies, with especially large increases in pot experiments.
• Most studies were short-term, and many did not provide detailed compost characterization.