Agroforestry systems in the mid-hills of the north-western Himalaya: A sustainable pathway to improved soil health and climate resilience

Abstract

Identifying the new tree crop combinations plays an important function in transforming the low input agriculture into land units with high economic returns, increasing carbon (C) sink and nutrients storage capacity, and acting as a panacea to achieve Sustainability Development Goals (SDGs). The present study aims to evaluate various tree-crop combinations for (i) biomass production, (ii) carbon accumulation, and (iii) soil nutrient enrichment of traditional and commercially evolved eight agroforestry systems (AFSs), including agri-silvi-horticulture system, agri-silviculture system, silvi-pasture, fruit tree, fodder tree, bamboo, melia and poplar based AFSs with sole cropping system in the mid-hill zone of the north-western Himalaya. The results demonstrated that poplar based AFS accumulated a higher amount of biomass (130.87 Mg ha−1) and carbon (65.44 Mg ha−1) closely followed by melia-based AFS. The C stored in leaf litter was higher (0.66 Mg ha−1) in poplar-based AFS, however, soil C stock was maximum (114.69 Mg ha−1) under bamboo-based AFS. Overall, the Melia based AFS exhibited a higher rate of carbon dioxide mitigation (19.30 Mg ha−1 yr−1) and C-sequestration (5.26 Mg ha−1 yr−1) than other studied AFSs. Moreover, soil macro-nutrients (available N, P, K, S and Ca) were maximum under bamboo-based AFS, on the other hand, the fruit-based AFS had the higher concentrations of micro-nutrients i.e., Cu (3.05), Fe (31.10 mg g−1) and Mn (17.31 mg g−1). The soil microbial counts were higher in poplar-based AFS, whereas, the soil quality index improved significantly under bamboo based and fruit tree based AFSs. Hence, it can be concluded that the experimentally evolved AFSs represent an effective approach for boosting C-sequestration, soil fertility, regenerating the soil and sustainability of hill agriculture in the north-western Himalayas over traditional AFSs and sole cropping.