Carbon Stock of Indigenous Agroforestry Practices in Dellomenna District Southeast Ethiopia: Implication for Climate Change Mitigation

Abstract

Trees in agroforestry systems are potential sinks of atmospheric carbon (C) due to their fast growth, productivity, high and long-term biomass C stock. Soil under forest and agroforestry also plays a major role in global C sequestration. This study was initiated to assess woody species and soil C sequestration of traditional agroforestry practices. Three study sites (namely: Buriketu, Chire and Erba) were systematically selected based on the presence of traditional agroforestry practices. Forty eight sample quadrats (16 quadrats in each site) having an area of 20m x 20m (400 m²) were used for vegetation biomass estimation. Soil organic carbon (SOC) was sampled by using “X” design at depths of 0-30cm within each quadrats. Woody species biomass carbon stocks were estimated using an allometry equation of Y (Kg) = 34.4703 - 8.0671 DBH + 0.6589 DBH². The types of agroforestry practices found in the study area are scattered trees in farm lands (parkland agroforestry), homegarden and live fence system. The mean AGBC stock showed an increasing trend from DBH ≥ 5 cm to 71 cm while a decreasing trend was noticed greater than 71 cm diameter classes. The mean carbon stocks (Means±Std) of different carbon pools in the indigenous agroforestry practice were 47.82±10.09, 11.96±2.52, 59.77±12.61, 150.61±6.9, 210.39±14.1 for AGBC stock, BGBC stock, TBC stock, SOC and TCSD, respectively. CO₂ assimilation by total biomass of woody species ≥ 5cm DBH in traditional agroforestry practices was estimated to be 219.15ton/ha. Estimation of CO₂ sequestration indicated that indigenous agroforestry practices of the area have been sequestered (772.02 ton/ha). The results of the present study confirmed that indigenous agroforestry practice play a major role in climate change mitigation. This study was focused on the biomass carbon stock of woody species ≥5 cm DBH, however, woody species <5cm DBH, dead wood, dead standing trees, fallen branches and litter-fine woody debris were also have a potential for C stock, thus further study on these components is recommended to provide reliable information.

Keywords  Biomass carbon, Ecosystem services_, Global warming, Soil organic carbon.

DOI: 10.7176/JRDM/54-01

Publication date: April 30^th 2019