Profitable Model of Grassland for Carbon Stock and CO₂ Mitigation Potential of Wheat (Triticum aestivum) Agroecosystem in Shivalik Tarai Region of Himalaya

Unbalanced land use and unsustainable farming practices are exerting pressure on soil ecosystems, shifting ecological instability and disturbing resilience, particularly in fragile regions such as the Himalayan foothills. In these landscapes, soils play a vital role in regulating carbon cycles, nutrient turnover, and hydrological balance, but remain vulnerable to degradation under poor management regimes. The present study compared soil properties and carbon stocks in two contrasting land-use systems in Pantnagar, Uttarakhand, India: a natural grassland and a wheat-based agroecosystem. Soil samples were collected bimonthly over two consecutive years at surface and subsurface soil layers to evaluate soil pH, soil organic carbon, available nitrogen in soil, potassium content, phosphorus, bulk density, and moisture content. The findings revealed pronounced depth- and season-related differences. Soil organic carbon as well as nitrogen were consistently higher at surface layers and increased in the second year, reflecting greater organic inputs and microbial activity. Phosphorus and potassium concentrations declined with depth but were relatively elevated in the wheat system, likely due to fertilizer application. Subsurface soils displayed higher bulk density and pH values. Grassland plots contributed more organic matter through continuous biomass turnover, resulting in improved fertility and carbon sequestration compared with wheat fields. Overall, the results highlight the pivotal role of land use in regulating soil carbon and nutrient dynamics, with grasslands functioning as significant carbon sinks and supporting climate change mitigation.