Impact of watershed management on soil organic carbon stock: Insights from Hiware bazar and Daithane semi-arid landscapes, Maharashtra

Abstract

Soil organic carbon stock (SOCS) is a vital indicator of soil fertility, ecosystem functioning, and long-term carbon sequestration potential. This study evaluated the spatial and vertical variability of SOCS in two semi-arid watersheds of Maharashtra with contrasting management histories: Hiware Bazar (treated with soil and water conservation measures) and Daithane Gunjal (untreated). A total of 176 georeferenced samples were collected from 0-15 cm and 15-30 cm depths across major land-use types. SOC concentration was determined by the Walkley-Black method, bulk density by the Hilgard dish method, and SOCS was computed by integrating SOC, corrected bulk density, and soil depth. Results revealed that SOCS ranged from 1.58 to 34.82 t ha⁻¹ in Hiware Bazar and 4.01 to 24.56 t ha⁻¹ in Daithane Gunjal, with consistently higher values in the treated watershed. Forest lands contributed the highest SOCS, followed by croplands, fallows, and barren lands. Across both watersheds, SOCS declined with depth, but the magnitude of reduction was lower in Hiware Bazar, reflecting improved soil resilience. The enhanced SOCS in Hiware Bazar underscores the effectiveness of long-term conservation interventions such as contour trenches, bunding, and vegetative barriers in promoting organic matter accumulation and carbon storage. Overall, the study highlights that watershed-based soil and water conservation practices substantially improve SOC sequestration in semi-arid ecosystems, thereby supporting soil health restoration, climate change mitigation, and sustainable land management.