The potential of traditional agroforestry practices as nature-based carbon sinks in Ethiopia

Traditional agroforestry practices have economic, social, and environmental benefits to sustain human and ecological systems. The demand for short-term economic benefit has derived from the traditional agroforestry practices towards monoculture cash crop production in the tropics. This study aimed to assess the greenhouse gas emission reduction capacity of traditional agroforestry systems concerning biomass and soil carbon stocks in the districts of Amhara Region, Ethiopia. From three agroforestry practices, namely, multistory, woodlots, and parkland, 300 smallholder farmers’ farms were randomly selected to carry out vegetation inventory and 180 farms for litter and soil sampling. The soil samples were taken the depths 0–20 cm, 20–40 cm, and 40–60 cm. The biomass of all woody plants was estimated using already developed allometric equations. The mean total biomass carbon sink of multistory is 40.7 ton ha−1 which was significantly (p < 0.001) higher than woodlot, 20.8 ton ha−1, and parkland 5.4 ton ha−1. The mean total ecosystem (biomass plus soil) carbon of the multistory, 199.5 ton ha−1 was significantly (p < 0.001) higher than woodlot, 134.4 ton ha−1, and parkland, 108.0 ton ha−1. Soil organic carbon stocks accounted for 72–88, 83–88, and 92–98% of the total ecosystem carbon is stored in multistory, woodlot, and parkland, respectively. The study revealed that agroforestry practices could contribute to carbon sinks in the biomass and soils making it one of the nature-based solutions to climate change mitigation. This reduces greenhouse gas emissions and hence enhances the climate change mitigation and adaptation roles of the existing land uses.