Summary of project

Ethiopian home gardens are sustainable traditional agroforesty systems that grow crops such as ensete (Ensete ventricosum) and coffee (Coffea arabica) that can coexist with various tree species to provide households with food, fuel and cash income, while protecting the soil and biodiversity. They can also enhance resilience to drought and contribute to mitigating climate change by enhancing soil carbon (C) sequestration. Soil C sequestration can provide additional economic benefits to communities by providing them carbon credits that can be traded in the global carbon market. However, there is a growing concern about the effect of the home garden systems on soil C loss through increasing soil greenhouse gas carbon dioxide (CO₂) emissions. Therefore, there is an urgent need to quantify net soil C gain through assessing soil C gain as soil C sequestration and soil C loss as soil CO₂ emissions in the systems. Our hypothesis is that Ethiopian home gardens have more net soil C gain than monoculture cropping systems on the same soils and that by diversifying the agroforestry systems even more, higher amounts of soil C sequestration are possible.  The study will be conducted in Wondo Genet, Southern Ethiopia. This study will compare 3 major types of home gardens (ensete-tree, ensete-coffee-tree and coffee-fruit crop-tree systems) with adjacent control sites of fertilized monoculture cropping systems (i.e., maize) that have the same age structure and soil type. By quantifying soil C sequestration as soil C gain and soil CO₂ emissions as soil C loss in these sites, this study can determine the net gain of soil C in home gardens compared to that in mono-culture crop fields. The results will provide evidence of the potential of home gardens for mitigating climate change, and also potentially provide communities with scientific data to participate in C trading schemes.