Variability in soil moisture retention curve with altitude and aspect in northwestern Himalaya

This study investigated soil moisture retention dynamics across different altitudes and aspects in a 2.13 km² conservation reserve in the northwestern Himalaya, ranging from 1,230 to 1,845 m amsl. Soil samples were collected in October 2021 from various altitudes and aspects, with moisture retention curves determined using the pressure plate method at tensions of 0.3, 1.0, 5.0, 10.0 and 15.0 bar. Results revealed that altitude significantly influenced moisture retention, with higher water content observed at increased altitudes. Northern aspects consistently showed greater water retention and available water content compared to western aspects. The study also found that vegetation type played a crucial role, with deodar and mixed oak forests exhibiting higher water content than chir pine forests. Specifically, water content at 0 bar tension ranged from 41.38-48.70 per cent, field capacity (0.33 bar) from 22.51-25.13 per cent and permanent wilting point (15.0 bar) from 9.71-11.78 per cent. Available water content ranged from 12.80-13.52 per cent. These findings underscore the complex interplay of topography, soil characteristics, climate and vegetation in determining soil moisture dynamics, highlighting the importance of understanding these interactions for effective land management and ecological assessments in mountainous regions.