Carbon sequestration potentials of semi-arid rangelands under traditional management practices in Borana, Southern Ethiopia

摘要

A study to determine carbon sequestration potentials and soil attributes was conducted in Borana rangelands of southern Ethiopia under communally grazed areas, grazing enclosures (rangelands enclosed for 20 years for dry season grazing) and rangelands managed by prescribed fire for more than five years after fire application. Soil attributes were collected from three soil depths (0-10 cm, 10-20 cm and 20-30 cm) and both aboveground and belowground carbon were estimated in all treatments. Belowground carbon stocks were higher than the aboveground carbon stocks in all management systems in Borana rangelands. Tree and shrub carbon and soil organic carbon stocks were higher (P 0.01) in rangelands enclosed for 20 years than other rangeland management systems, whereas grass carbon stocks was higher (P 0.05) in rangelands managed by prescribed fire. Total carbon stock was higher (P 0.01) in enclosed rangeland areas (300.4 t C ha(-1)) than in rangelands managed by prescribed fire (184.9 t C ha(-1)) and in communally grazed areas (141.5 t C ha(-1)). Therefore, rangelands enclosed for more than 20 years for dry season grazing and rangelands managed by prescribed fire had good carbon sequestration potentials both in the soils and aboveground vegetation. Consequently, pastoralists land management can be an important source for sequestering carbon to offset carbon emissions as mitigation of climate change. (C) 2016 Elsevier B.V. All rights reserved.