Decadal Impact of an Integrated Farming System on Soil Organic Carbon Stock and Carbon Sequestration across Diverse Land Use Systems

Abstract

Integrated farming systems (IFS) may improve soil carbon storage by diversifying biomass inputs and reducing reliance on continuous cereal cultivation. This field study assessed depth-wise soil organic carbon (SOC) stock and surface-layer carbon sequestration in a decade-old IFS model at the Farming System Research Centre, SKUAST-Jammu, Chatha, relative to an adjoining existing farmer’s farming system (EFFS) under continuous rice–wheat cultivation. Composite soil samples were collected from four depths (0–15, 15–30, 30–45 and 45–60 cm) and analysed for organic carbon using the Walkley–Black method, while bulk density was determined by the core method. Carbon stock and sequestration were calculated from SOC concentration, bulk density and soil depth, and the data were analysed using a randomised block design. Soil carbon stock decreased with increasing depth across all land uses. The highest SOC stock up to 60 cm was recorded under boundary plantation with turmeric intercropping (46.64 Mg C ha⁻¹), followed by fodder, horticulture and crop blocks, while the lowest occurred under EFFS (26.34 Mg C ha⁻¹). Overall, the IFS model accumulated 38.91 Mg C ha⁻¹ up to 60 cm, representing about 48% greater carbon storage than in EFFS. Surface-layer carbon sequestration ranged from 2.94 Mg C ha⁻¹ under perennial fodder to 7.90 Mg C ha⁻¹ under boundary plantation, whereas EFFS showed a negative value (–0.65 Mg C ha⁻¹). Over ten years, the IFS model achieved an overall carbon sequestration of 4.47 Mg C ha⁻¹, demonstrating its greater potential for soil carbon accumulation compared with continuous rice–wheat cultivation.