Comparative Assessment of Soil Organic Carbon Stock Potential under Agroforestry Practices and Other Land Uses in Lowlands of Bale

Abstract

Soil organic carbon is the carbon associated with soil organic matter that is made up of decomposed plant and animal materials. This study was conducted in Dallo Mena district to estimate the amount of soil carbon stock stored in shade grown coffee (SC) and homegarden agroforestry practices (HG), and adjacent natural forest (NF) and annual crop field (CF) and to show the potential of agroforestry practices in soil organic carbon storage capacity. The study site was selected based on spatial analogue approach.From each land uses nine plots were selected by using systematic sampling method following the transect line. Soil organic carbon stock (100cm depth) were the highest for the NF(170.11 ± 14.59 Mg ha Agroforestry and other land uses of Dallo Mena districts are providing various ecological as well as economical benefits for the community. It is used as income source, conserving different plant species diversity and at the same time storing large amounts of soil organic carbon. Therefore, there is significant difference among natural forest, shade grown coffee agroforestry practice, homegarden agroforestry practice and annual crop field in soil organic carbon storage capacity.

Woody species diversity and carbon stock potentials in homegarden agroforestry and other land use systems, northern Ethiopia

“…However, it was higher than a report (mean: 109.75 ± 29.95 Mg ha −1 ) from Northern Ethiopia [ 67 , 74 ], as well as from India [ 74 ]. On the other hand, the surface layer (0–30 cm) SOC stocks of HGAF in the study area were lower than in previous reports [ 33 , 34 , 66 ].…”

“…Homegarden agroforestry had a great role in conservation of woody species around the house than exclosure in the study area. The total number of woody species recorded from HGAF in the study area was relatively higher than reports in HGAF land use systems in various parts of Ethiopia [ 27 , 33 , 57 ] . The present study result relates to woody species diversity from Jabithenan, and Dilla Zuria districts, respectively [ 25 , 58 ], but lower number of woody species than earlier studies [ 5 , 59 , 60 ].…”

“…Higher amount of SOC was stored on the surface than that on subsoil in the current study. Similarly, numerous scholars reported a decrease in SOC value with an increase in soil depth [ [33] , [34] , [35] , 62 , 67 , 72 ]. SOC is normally estimated to a depth of 0–30 cm(the top layer) where root activity is effective in this horizon [ 73 ].…”

“…Agroforestry systems through afforestation and reforestation programs of the Clean Development Mechanisms promote Carbon sequestration [ 65 ]. Biomass carbon stocks of HGAF of the study sites were substantially lower than homegarden in the south-eastern Rift Valley escarpment of Ethiopia [ 34 ], Wolayita [ 66 ], Bale [ 33 ], Sidama [ 64 ], and Gurage Zones of Ethiopia [ 35 ], and India's north-eastern hill region [ 7 ]. This could be linked to the differences in the agroclimatic condition, where there were trees with a small diameter class in the study area than the aforementioned findings.…”

“…Few area-specific kinds of researches have been conducted in Ethiopia on the relationship of woody species diversity with carbon stock potentials in different land use types, including church forests [ 32 ], homegarden agroforestry [ [33] , [34] , [35] , [36] ], and in exclosure [ 37 , 38 ]. Lastly, there was little or no reliable scientific information about woody species diversity and the carbon sequestration potential of different land uses in the study area [ 39 ].…”