Preliminary estimate of carbon sequestration potential of Faidherbia albida (Delile) A.Chev in an agroforestry parkland in the Central Rift Valley of Ethiopia

摘要

Agroforestry parklands are a common land-use in Ethiopia and many parts of the tropics. These systems play an important role in climate change mitigation and adaptation, through carbon (C) sequestration. However, C sequestration in both tree biomass and soil has not been extensively studied for parklands of the Central Rift Valley (CRV), Ethiopia. Therefore, here we sampled a small number of F. albida trees and soil from the Adulala watershed, CRV, to provide a preliminary estimate of the C sequestration potential of these systems. Mean above-ground total dry biomass of trees was estimated at 844 kg tree-1. Tree density was 5.80 ha-1, which corresponded to 2.451 C ha in above-ground biomass and 0.761C ha-1 below-ground; and 118 t C ha-1 in soil (0-80 cm depth) under trees, compared to 84 t C ha-1 in the soil of crop-only areas. We speculate that if tree density was increased to 100 trees ha"1, the rate of soil C sequestration could be estimated as 0.481C ha"1 year"1 for 42 years. Faidherbia albidatree density is sparse in the study area, but could be increased by encouraging farmers to protect planted seedlings or natural regeneration.