Land use effect on carbon stocks in Aleta Chuko, Southern Ethiopia

Abstract

Land use conversions from agroforestry practices into cash crop monocultures become prime determinant of the carbon stocks and this remains widespread problem in Aleta Chuko, Ethiopia. Therefore, aim of this study was to measure carbon stocks in coffee-enset-based agroforestry (CEA), Eucalyptus monoculture woodlots (EW) and Chat monocropping (CM) systems. Three transect lines were drawn based on a spatial analog design, with 4 plots for each land use from each transect (12 plots per land use), for a total of 36 plots. Soil samples (0–30 cm depth) were taken from three diagonal pits within 20 × 20 m, which was also applied for biomass carbon measurement. Tree, shrubs and herbaceous aboveground and belowground biomass were estimated using appropriate species-specific and generic allometric models. ANOVA was applied to test significant variations in carbon stocks using SPSS software, followed by the Dunnett T3 test. SOC stock was significantly greater in the order of CEA (70.3) > CM (52.9) > EW (47.6) Mg ha −1 ( p < 0.05). The total carbon stocks were 224.7, 176.7, and 54.2 Mg ha −1 in the EW, CEA and CM treatments, respectively. Although harvestable in a short time, biomass carbon was highest in the EW while negligible in the CM treatment. The expansion of monoculture over traditional agroforestry also affects litter inputs into the soil, soil quality and the sustainability of agroecosystems. To lessen land conversion to monocropping, climate-focused initiatives and regional government should support smallholders in maintaining sustainable land use.