Effects of Management Practices on Carbon Allocation in the Semi-Arid Savannahs of the Borana Region, Ethiopia

Publikations-Art

Kongressbeitrag

Autoren

Rathjen, L., Pfister, J., Asch, F.

Erscheinungsjahr

2012

Veröffentlicht in

Resilience of agricultural systems against crises

Herausgeber

Tielkes, E.

Verlag

DITSL GmbH , Witzenhausen

Seite (von - bis)

24

Tagungsname

Tropentag 2012

Tagungsort

Göttingen / Kassel

Grassland systems cover 3.9 billion ha, 25 % of the earth ́s terrestrial area, and could,according to FAO (2009), sequester up to 2 GT CO2equivalents worldwide if ap-propriate management of vegetation and soil resources would be applied. Carbon isstored in different pools: dead and alive biomass like plant roots in the soil, and livingbiomass (grasses, shrubs and trees) and litter aboveground.Livestock production has been a major source of income generation and food securityin the semi-arid savannahs of the Borana region, Ethiopia, ever since. The dependencyon traditional livestock-based pastoral and agro-pastoral livelihoods under ecologicaland economic pressures (droughts, population growth, overgrazing, etc.) is no longersufficient to sustain food security. To overcome vulnerability of these communities,diversification of income is of crucial importance. Payment for environmental ser-vices (PES) based on reduction of carbon emissions and carbon allocation linked tolivestock production could be one tool to diversify income of the vulnerable group ofBorana pastoralists. Range and herd management may have exceptional impacts oncarbon fluxes in the grass- and bush-land savannahs of southern Ethiopia.Four vegetation types; namely grassland, tree savannah, bush land and tree-grass-bushsavannah, have been distinguished in the research area. The pastoralists differentiatebetween year-round and seasonal grazing by installing “enclosures”. Seasonal grazingpatterns were found in grass and tree savannah. Therefore, five 900 m2plots each werelocated in year-round grazed and seasonally-used grass and tree land. Soil sampleswere taken in four different depths up to 100 cm to analyse for total carbon, soilorganic matter and soil organic carbon content as well as to examine bulk density, pHand texture of the soil. Aboveground biomass was harvested and tree biomass wascalculated by using allometric equations. A regression analysis was run to portraychanges in organic carbon pools and allocation across vegetation type, managementpractice and soil depth.The results will help to evaluate the impact of management practices on carbon fluxesin the soil and on aboveground biomass production. Carbon allocation processes willbe better understood and information can be used to improve these grazing systemstowards higher sustainability and crisis resilience.