Soils are structural and functional elements of terrestrial ecosystems, which are formed in a historical process of development through the interaction of geological, climatic and biotic factors at the respective site. Soil is the fundamental source of life for all living beings. As the physical and chemical properties of soils exert great influence in the distribution and development of vegetation, it needs to be studied and evaluated from time to time. The soil forming process is very slow and time taking. It takes normally thousands of years for the soil formation. Therefore, we are studying the past activities while analysing the soil profile at present. The parent material, topography, geological processes, climatic conditions, vegetation and human interferences play major roles in formation and development of soil profiles in particular area. Similarly, our activities at present will certainly influence the soil profiles in far future.

Soil aggregation is an important process of C sequestration and hence a useful strategy to mitigate the increase in concentration of atmospheric CO₂. We studied water stability of soil aggregates (WSA) and soil organic carbon (SOC) associated with aggregates and primary particles in surface (0-10 cm) and subsurface (10-20 cm) layers of cultivated (khet, irrigated lowland, and bari, rainfed upland) and forest lands (dense Shorea forest, degraded forest and shrub land, pine-Shorea forest, Shorea-pine-Schima forest, and Schima Castanopsis forest) in a mountain watershed of Nepal.

Effects of land use, moisture, temperature and substrate on production of CO₂ and consumption of CH₄ were measured in a series of laboratory incubation experiments on bulk soil samples from 0–10, 10–20, 20–40, 40–60, 60–80 and 80–100 cm soil depths under four dominant land uses [forest, grazing land, irrigated rice on level terraces (Khet), and upland maize–millet on sloping terraces (Bari)] of Mardi watershed (area=144 km²), Nepal. In addition, baseline physical and chemical properties of these soils were measured.