Assessment of Soil Physical Properties of Barog Dhillon Watershed in Solan District of Himachal Pradesh under Different Land Uses

Abstract

The present investigation was conducted to assess the physical characteristics of soils under various land uses—agricultural land, forest land, grassland, and scrubland, in a project and non-project areas of the Barog-Dhillon watershed Solan district, Himachal Pradesh. A survey of random sampling was carried out, and representative soil samples were collected from two profiles of depth: 0–15 cm and 15–30 cm. Indicators for soil physical health assessment included bulk density, particle density, porosity, aggregate size distribution, maximum water holding capacity, ccumulative infiltration and infiltration rate characteristics of soil .The highest bulk density was observed in scrubland, with mean values of 1.57 and 1.60 g cm⁻³ in the surface and sub-surface soils of the watershed project and non-project areas, respectively. In contrast, grassland exhibited the lowest bulk density, with values of 1.30 and 1.32 g cm⁻³ in surface and sub-surface soils of the respective areas. Similarly, the highest particle density was recorded in scrubland soils (2.67 and 2.72 g cm⁻³) while grassland soils showed the lowest, at 2.35 and 2.40 g cm⁻³, in the project and non-project areas, respectively. The highest average porosity values, 45.95% and 44.98%, were recorded under forest land use in both soil layers. The proportion of soil aggregates larger than 5 mm was greatest in forest land, with average values of 8.23% and 7.97% (surface) and 8.31% and 8.05% (sub-surface) in the project and non-project areas, respectively. Scrubland soils had the lowest values (2.58%, 2.30% and 2.30%, 2.02%, respectively). Maximum water holding capacity was also highest in forest land (45.25% and 46.26%) in surface and sub-surface layers of the project and non-project areas, while the lowest was noted in scrubland (38.91% and 41.38%). Infiltration rate followed a similar trend, highest in forest land (9.1 and 6.6 cm hr⁻¹) and lowest in scrubland (2.8 and 2.0 cm hr⁻¹). Cumulative infiltration was also greatest in forest soils (45.8 and 33.0 cm) and lowest in scrubland (14.00 and 10.20 cm), across both watershed categories. The study clearly indicates that soils within the watershed project area possess superior physical properties compared to the non-project area, highlighting the positive impacts of watershed management practices.