The The multifunctionality benefits of Gmelina arborea agroforestry systems: Insights into productivity, carbon sequestration, microbial ecology and economics in Central India

Abstract

Agroforestry is increasingly recognized as a sustainable land use system in agriculture. To evaluate its effectiveness in terms of crop productivity, carbon sequestration, soil microbial activity, and economic returns, a study was carried out at Jawaharlal Nehru Krishi Vishwa Vidyalaya, Madhya Pradesh, Central India, during 2021-23. The experiment included eight treatment combinations: Gmelina arborea with pigeonpea (T1), cowpea (T2), and greengram (T3); G. arborea as a sole crop (T4); sole cropping of pigeonpea (T5), cowpea (T6), and greengram (T7); and a control of open field having no plant (T8). The G. arborea trees used in the study were 6 years old, spaced at 8.0 × 2.5 m. Crops grown in control conditions generally outperformed those under agroforestry systems in terms of yield. However, in terms of mean annual biomass production, the G. arborea + greengram combination produced the highest annual biomass. G. arborea + pigeonpea led in annual carbon sequestration, recording 3.082 and 3.088 tonnes per hectare in the first and second years, respectively, but remained at par with G. arborea + greengram. G. arborea + cowpea treatment supported the highest rhizobium counts (41.92 × 10⁷ cfu/g soil in year one and 43.81 × 10⁷ cfu/g soil in year two). Fungal populations were highest under the G. arborea + pigeonpea combination, while the G. arborea + greengram treatment showed the greatest abundance of bacteria and actinomycetes. The G. arborea + cowpea treatment delivered the highest economic returns in both years, though it was statistically on par with the G. arborea + greengram system. With regard to the multifunctional benefits point of view, G. arborea + greengram were a superior land use system over others tested. Overall, agroforestry systems generated significantly higher multifunctional benefits compared to sole cropping approaches.