Soil Organic Carbon Storage under Different Agronomic Management Practices: A Review
Soil organic carbon (SOC) is a central component of soil health and a major terrestrial carbon reservoir that influences nutrient cycling, soil structure, water retention, biological activity and crop productivity. Indian agricultural soils have experienced SOC depletion because of intensive cropping, conventional tillage, residue burning and inadequate organic input return, with average SOC levels in many croplands reported at 0.3–0.5%, below the approximate 0.75% level considered important for sustaining productivity in many tropical agro-ecosystems. This review synthesises the manuscript evidence on the effects of agronomic management practices on SOC storage, stabilisation and persistence across Indian farming systems. Conservation tillage, zero tillage and minimum tillage reduce soil disturbance and support carbon retention, with reported SOC stock gains ranging from 0.15 to 0.80 Mg C ha⁻¹ yr⁻¹ depending on practice and region. Diversified crop rotations, particularly those involving legumes, improve root carbon inputs, residue quality and biological nitrogen inputs, while cover crops and green manures add biomass and enhance aggregate-associated carbon. Organic amendments such as farmyard manure, vermicompost, compost, poultry manure, press mud and biochar increase SOC by 15–60% under the rates reported in the manuscript, with biochar showing comparatively high stability. Residue retention, integrated nutrient management, agroforestry and conservation agriculture further contribute to SOC accumulation by increasing organic inputs and improving aggregate protection. However, SOC responses vary substantially with soil texture, climate, cropping intensity, management duration and socio-economic constraints. The review highlights that region-specific combinations of carbon-positive practices, supported by monitoring, extension services and policy incentives, are required to improve soil fertility and strengthen climate-resilient agricultural systems in India.