Comparative performance of Dalbergia sissoo AFRI clones in improving soil fertility under agroforestry system in the IGNP command area, of Western Rajasthan

Abstract

Soil fertility maintenance is a major challenge in arid and semi-arid regions where coarse-textured soils, low organic matter, and nutrient deficiencies limit sustainable productivity. This study evaluated the comparative performance of Dalbergia sissoo clones (AFRI DS-1, AFRI DS-2, and AFRI DS-4) in improving soil fertility under an agroforestry system in the Indira Gandhi Nahar Pariyojana (IGNP) command area of Jaisalmer, Rajasthan, during 2023-2025. The experiment followed a randomized block design with four treatments (three clones and a seed-origin control) and three replications. Intercrops of Isabgol (Plantago ovata), Chickpea (Cicer arietinum), and Moth bean (Vigna aconitifolia) were uniformly grown in all plots. Soil (0-30 cm) was analyzed for pH, electrical conductivity (EC), soil organic carbon (SOC), and available N, P and K using standard methods. After two years, soil pH showed a marginal decline from the initial mean (8.03) to values between 7.90 and 8.07 across treatments, while EC remained within non-saline limits. SOC increased significantly among treatments (F = 5.371; p = 0.039), with AFRI DS-1 recording the highest SOC (0.383%) a 35.3% increase over the initial value (0.283%). Available N, P and K showed increasing trends under clonal treatments, with AFRI DS-1 recording the highest mean values (N = 189.67 kg ha⁻¹; P = 15.47 kg ha⁻¹; K = 341.67 kg ha⁻¹), although treatment effects on these macronutrients were not statistically significant at α = 0.05 (N: p = 0.061; P: p = 0.258; K: p = 0.531). Overall, the order of soil fertility enhancement was AFRI DS-1 > AFRI DS-2 > AFRI DS-4 > Control. Results indicate that clone-based D. sissoo agroforestry, particularly with AFRI DS-1, can improve SOC sequestration and maintain or enhance available nutrients in canal-irrigated arid soils of Western Rajasthan.