Productivity and nodulation of pulse crops under Gmelina arborea based agroforestry systems in Central India

Agroforestry systems integrating timber trees with legumes enhance land productivity, soil fertility, and economic sustainability in rainfed tropical regions. This study evaluated the productivity of Gmelina arborea and the growth, nodulation, yield, and economics of three pulse crops namely arhar, cowpea, and green gram under G. arborea-based agroforestry systems in central India during 2021–2022. The experiment was conducted in a randomized block design with seven treatments and five replications. Tree growth was significantly influenced by intercrop species, with G. arborea + green gram recording the highest tree height (5.28 m), diameter (9.78 cm), crown spread (3.61 m), and volume (26.53 m³ ha⁻¹), followed by cowpea, while sole trees and G. arborea + arhar showed comparatively lower performance. Among crops, green gram exhibited the highest nodulation (18.5 nodules plant⁻¹) and nodule biomass (108.7 kg ha⁻¹), whereas cowpea recorded greater fresh nodule weight per plant (0.477 g). Arhar showed reduced nodulation and yield under tree association. Cowpea and green gram maintained higher arhar-equivalent yields (992 and 900 kg ha⁻¹, respectively) and generated superior net returns and benefit–cost ratios compared to arhar. The superior performance of green gram and cowpea is associated with their shorter growth duration and relatively higher nodulation compared with arhar. From a sustainability perspective, integrating green gram and cowpea in G. arborea-based systems enhances soil fertility and improves overall system productivity while reducing risks under rainfed conditions. Based on the results of the present two-year experiment, these species appear to be promising intercrops for G. arborea based systems under similar agroecological conditions and the findings suggest that adoption of such compatible components combinations has potential to support sustainable agroforestry and may contribute to improve economic returns.