Biomass estimation models, biomass storage and ecosystem carbon stock in sweet orange orchards: Implications for land use management

Abstract

Sweet orange has great socioeconomic value in India and other parts of the world for their important role in human diet and other properties like sweet flavour, sweet aroma, source of vitamin C etc. Despite its numerous commercial values, and large acreages under cultivation little has been studied on the role of sweet orange orchards in carbon management and environmental sustainability. Therefore, the present study was conducted to (1) develop appropriate models for estimation of sweet orange tree biomass, and (2) assess biomass and ecosystem carbon stock for sweet orange orchards in North East India. Allometric models for biomass estimation were developed using data from 58 harvested orange trees. The height-diameter relationships and allometric scaling between above-ground biomass (AGB), culm height (H) and diameter at breast height (D) were examined using various models. Total biomass carbon and soil organic carbon stock of the sweet orange orchard were estimated at 7.69 and 100.2 Mg C ha−1 respectively. Our finding on biomass carbon stock of the sweet orange orchard was comparable with other fruit orchards across the world. However, the age of the orchard and management systems are two major determinants for carbon sink potential of such systems. We recommend upscaling of sweet orange based agroforestry for restoration of degraded shifting cultivated lands in North East India for environmental sustainability and socioeconomic upliftment of the farmers.