Biomass carbon stock and sequestration potential of tree-based agroecosystem in Tripura, Northeast India

Abstract

The people of Northeast India have traditionally practice tree-based agroecosystems since time immemorial. These systems may be considered as good atmospheric carbon sequesters because of their forest-like appearance and structure. This study aimed to investigate the varieties of tree-based agroecosystems prevalent in Tripura and their carbon sequestration potential. A total of 254 quadrats covering approximately 25 ha and 90 field plots were studied during the research period. In this study, Ten (10) different tree-based agroecosystems were identified. A few tree-based agroecosystems are restricted to specific areas, whereas pineapple and citrus-based systems and home gardens are the most common agroecosystems recorded throughout the study area. The carbon content of the dominant tree species was evaluated based on ash content. The mean ash content of studied tree species was found to range from 0.40 to 46.36%. The maximum carbon content was recorded in Schima wallichii (49.80 ± 1.23%). The vegetation carbon stocks in tree-based agroecosystems ranged from 7.03 Mgha⁻¹ to 147.41 Mgha⁻¹. The vegetation biomass stock and carbon sequestration potential were found to be the maximum in the Homegarden agroecosystem i.e., 298.93 ± 15.57 Mgha⁻¹ and 2.37 ± 0.12 Mg C ha⁻¹ yr⁻¹ respectively. The proportion of vegetation carbon sequestration value ranged from 0.27 to 2.56%, whereas the soil carbon sequestration exhibited a range from 97.44 to 99.73%. Total carbon stocks in tree-based agroecosystems are in the order Homegarden (HG) > Pineapple Plantation (PIP) > Areca Plantation (ARP) > Tea Garden (TEG) > Coffee Plantation (COP) > Oil Palm Plantation (OIP) > Citrus Plantation (CIP) > Banana Plantation (BAP) > Riparian (RIP) > Jhum Cultivation (JHC). A well-known improved type of tree-based agroecosystem is the tea garden agroecosystem. However, this study also suggests that a riparian agroecosystem may be a new option for sustainable agricultural production. It can be concluded from this study that Homegarden, Pineapple, and Citrus-based agroecosystems may be considered good practices in terms of biomass and carbon stock management. These traditional tree-based agroecosystems can be replicated in other parts of the region for further carbon management as an initiative for climate change mitigation and biodiversity conservation.