Assessing the role of cover crops in enhancing soil carbon sequestration: Experimental evidence from umariyapan block, Dheemarkheda District, Katni, Madhya Pradesh

Abstract:

Background: Soil organic carbon (SOC) is a critical indicator of soil fertility and climate resilience, particularly in semi‑arid agro‑ecosystems. Cover crops have emerged as a sustainable practice to enhance SOC and improve soil quality.

Objectives: This study evaluated the impact of leguminous (cowpea) and non‑leguminous (mustard) cover crops compared with fallow control plots on soil organic carbon (SOC), soil physical properties, and microbial biomass carbon (MBC) in semi‑arid regions of Madhya Pradesh, India.

Methods: Field experiments compared cowpea and mustard cover crops with a fallow control. Researchers measured SOC content, soil moisture, bulk density, and microbial activity to assess cover crops' contribution to soil improvement.

Results: Cover crops significantly improved soil properties compared with the fallow control. SOC increased marginally in fallow plots (0.32 → 0.33%, +0.01%), while cowpea showed the greatest improvement (0.31 → 0.41%, +0.10%), followed by mustard (0.32 → 0.37%, +0.05%). Soil moisture retention was greatest under cowpea (15.8 ± 0.6%) and moderate under mustard (14.2 ± 0.4%) compared to the control (12.4 ± 0.5%). Bulk density decreased slightly in cover‑cropped plots, with cowpea (1.46 ± 0.02 g/cm³) and mustard (1.48 ± 0.02 g/cm³) performing better than the fallow (1.52 ± 0.03 g/cm³). Microbial biomass carbon increased significantly, rising from 145 ± 10 mg/kg in the control to 210 ± 12 mg/kg in cowpea and 185 ± 11 mg/kg in mustard plots, reflecting the beneficial influence of cover crops on microbial activity.

Conclusion: Cover crops, particularly legumes, effectively enhance SOC and soil quality in semi‑arid regions. Adoption of cover crops can support climate‑resilient agriculture, improve soil fertility, and promote sustainable farming practices. Policy interventions and farmer training programs are recommended to encourage wider adoption in semi‑arid India.