Soil quality index response to land use change in Barog Dhillon watershed, Himachal Pradesh

Abstract

The current investigation aimed for determining the Soil Quality Index (SQI) across various land use categories—namely agricultural land, forest land, grassland, and scrubland—within both project and non-project areas of the Barog-Dhillon watershed in Solan district, Himachal Pradesh. A comprehensive field investigation was undertaken, involving random sampling and the collection of site-representative soil samples from two depths: 0-15 cm (surface) and 15-30 cm (sub-surface). Among the land use types, forest land exhibited the most favorable physical, chemical, and biological characteristics, registering the highest SQI scores within the watershed project area: 0.71 at the surface and 0.61 at the sub-surface depth. In the non-project area, forest land also showed relatively high SQI values—0.67 for the surface and 0.56 for the sub-surface—classified under Group 3 and Group 2, respectively. Conversely, scrubland recorded the lowest SQI values: 0.51 (surface) and 0.39 (sub-surface) in the project area, and 0.42 (surface) and 0.31 (sub-surface) in the non-project area, corresponding to Group 2 and Group 1. Overall, SQI values were consistently higher in the watershed project area compared to the non-project area, underscoring the beneficial effects of watershed development interventions. These outcomes indicate that the adoption of scientifically designed soil and water conservation practices within watershed management frameworks can significantly enhance soil quality across various land uses. The comparative analysis further reinforces that agricultural lands, in particular, benefit from improved soil productivity and quality under such programs.