Enhancing Soil Fertility in Arid and Semi-Arid Climates by Using Leguminous Trees: A Species-Specific Agroforestry Approach

This study evaluates the species-specific impacts of leguminous trees on soil fertility in arid and semi-arid climates, focusing on their influence on key soil physicochemical properties across multiple depths. A three-year field experiment assessed four native leguminous species Dalbergia sissoo , Vachellia nilotica , Prosopis cineraria , and Albizzia lebbeck using a randomized complete block design. Soil samples were collected beneath and outside the canopy at four depths (0–15 cm, 15–30 cm, 30–45 cm, and 45–60 cm) for laboratory analysis. Significant differences (p < 0.05) were found among tree species and depths for parameters such as pH, moisture, saturation, electrical conductivity, organic matter, and macronutrients. D. sissoo had the highest soil pH (8.26), moisture (19.72%), and saturation (36.77%) at 0–30 cm. V. nilotica showed consistent organic matter and had the highest nitrogen content (11.1 mg/kg), while A. lebbeck contributed the most potassium (109 mg/kg), and D. sissoo led in phosphorus (9.1 mg/kg). P. cineraria and A. lebbeck significantly reduced soil electrical conductivity. Among all species, V. nilotica emerged as the most effective for enhancing soil fertility due to its balanced contributions to nitrogen and organic matter. The findings emphasize the critical role of species selection and depth-specific assessments in designing agroforestry systems aimed at improving soil health, boosting productivity, and supporting sustainable livelihoods in dryland farming systems.