Biochar and Compost Effects on Soil Physico-Chemical and Biological Properties: Implications for Remediation and Climate Mitigation

Abstract

Soil degradation driven by intensive agriculture, land-use change, and climate variability threatens global food security and ecosystem sustainability. Organic amendments such as biochar and compost are increasingly recognized as climate-smart strategies for soil restoration and sustainable agricultural production. This review evaluates the individual and combined effects of biochar and compost on soil physical, chemical, and biological properties, with emphasis on soil remediation and climate change mitigation. Published literature was synthesized to assess impacts on soil health, carbon sequestration, nutrient dynamics, greenhouse gas emissions, and contaminant remediation across diverse agroecosystems. Biochar enhances soil structure, water-holding capacity, nutrient retention, and long-term carbon stabilization because of its porous structure, large surface area, and chemical stability. Compost supplies labile organic matter, nutrients, and beneficial microorganisms, thereby improving nutrient cycling and soil fertility. Their combined application often generates synergistic benefits, including enhanced nutrient-use efficiency, microbial activity, crop productivity, and soil resilience. Co-application also mitigates methane (CH₄), nitrous oxide (N₂O), and ammonia (NH₃) emissions while increasing soil carbon sequestration. Furthermore, biochar–compost systems promote contaminant immobilization and degradation through adsorption, complexation, and microbial processes. Overall, amendment effectiveness depends on feedstock characteristics, production conditions, soil properties, climate, and application rates. Future research should prioritize long-term field studies, mechanistic investigations, and economic assessments to optimize sustainable soil management.