Comparison of Biomass and C Storage in Three Promising Fast Growing Tree Plantations under Agroforestry System in Sub-humid Tropics of Chhattisgarh, India

摘要

The anthropogenic activities are alarmingly increasing the concentrations of CO_(2) in the atmosphere leading to the climate change. Agriculture ecosystem especially tropical agriculture is most vulnerable to climate change posing a serious threat on food, nutritional security and livelihoods of poor farming communities. Agroforestry technologies indeed offer viable opportunity to mitigating the atmospheric accumulation of CO_(2) and other Greenhouse gases, and potential for transforming to resilient farming systems and further help smallholder farmers of many tropical countries like India for adapting to climate change. However, the magnitude of C sequestration in many agroforestry systems is still unknown, which primarily depends on the choice of tree species and managerial practices. The present study corresponds to a part of the long term project on Gmelina arborea, Populus deltoides and Ceiba pentandra based agroforestry systems evaluated for C storage potentials in sub-humid tropics Chhattisgarh, India. At 5 years age, total biomass varied from 12.9 Mg ha~(-1) to 25.1 Mg ha~(-1) in C. pentandra, while 9.9 Mg ha~(-1) to 21.4 Mg ha~(-1) in G. arborea. The biomass was greater under narrow tree spacing. A significant growth and biomass variation was also exhibited by P. deltoides clones, where the total biomass ranged from 48.5 Mg ha~(-1) to 62.2 Mg ha~(-1). At 5 years age, total C storage in G. arborea stands ranged from 4.3 to 9.4 Mg ha~(-1), P. deltoides from 22.5 to 30.1 Mg ha~(-1) and C. pentandra from 4.5 to 10.1 Mg ha~(-1). Soil organic C significantly enhanced under agroforestry system. Soil organic C in G. arborea stands increased from 6.8% to 11.9%, P. deltoides from 12.7% to 20.6%, and C. pentandra from 5.5% to 14.5% under different treatments. P. deltoides showed the greater potential for C sequestration than G. arborea and C. pentandra under agroforestry system. Clones 65/27 and D121 of P. deltoides were found outstanding and suggested to adopt under agroforestry. Soybean and wheat yields were decreased under agroforestry systems, which advocate introducing appropriate tree management practices to improve the complementarity to exploit synergies between tree and crop components. The paper discusses the management implications and strategies for sustainable tree-crop production and improving C sequestration under agroforestry systems for mitigating the climate change.