Document Type : Research Paper
Authors
1 Department of reclamation of Arid and Mountainous Region, Faculty of Natural Resources, University of Tehran, Iran
2 Faculty of Natural Resources and Environment, Ferdowsi University, Mashhad, Iran
Abstract
Mountainous regions, as sensitive ecosystems, play a vital role in providing water resources, regulating climate, and preserving biodiversity. However, these areas are vulnerable to threats such as soil erosion; therefore, sustainable soil management in these regions is of particular importance. This study aimed to investigate the influence of topographic variables, including slope direction and the topographic wetness index (TWI), on the effectiveness of watershed restoration measures in improving the hydrological conditions of soil in the paired watershed of Gonbad, located in Hamadan province. Soil properties were sampled and analyzed in restored and control areas, across north-facing and south-facing slopes, and within three TWI classes. The results indicated that restoration measures generally enhanced soil quality, leading to reduced bulk density, increased porosity, aggregate stability, organic matter, saturation moisture content, infiltration rate, and vegetation cover. However, the extent of these improvements was influenced by topographic characteristics. North-facing slopes and areas with high TWI exhibited the greatest improvements in soil parameters, particularly organic matter and aggregate stability. The correlation matrix among soil parameters revealed positive correlations between organic matter and aggregate stability, porosity and infiltration rate, as well as negative correlations between bulk density and bare soil with other soil quality indicators. These findings highlight the positive impact of restoration measures on various aspects of soil quality. Additionally, the results suggest that slope direction and TWI play a decisive role in the effectiveness of restoration measures, with north-facing slopes and high TWI areas recommended as priorities for implementing such interventions. These findings can be applied in planning and implementing restoration measures in similar regions.
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