B11A-0406
Greenhouse gas emissions in natural and agricultural lands in sub-Saharan Africa: synthesizing of available data and suggestions for further studies
Monday, 14 December 2015
Poster Hall (Moscone South)
Dong-Gill Kim, Wondo Genet College of Forestry and Natural Resources, Hawassa University, Shashemene, Ethiopia, Andrew D Thomas, Aberystwyth University, Aberystwyth, United Kingdom, David Pelster, International Livestock Research Institute, Nairobi, Kenya, Todd S Rosenstock, World Agroforestry Centre, Nairobi, Kenya and Alberto Sanz-Cobena, Technical University of Madrid, Madrid, Spain
Abstract:
This paper synthesizes currently available data on greenhouse gas (GHG) emissions from African natural and agricultural lands, outlines the knowledge gaps and suggests future directions and strategies for GHG emission studies. GHG emission data were collected from 42 studies conducted in 21 countries in sub-Saharan Africa (SSA). Soil GHG emissions from African natural terrestrial systems ranged from 3.3 to 57.0 Mg carbon dioxide (CO2) ha–1 y–1, -4.8 to 3.5 kg methane (CH4) ha–1 y–1 and -0.1 to 13.7 kg nitrous oxide (N2O) ha–1 y–1. Soil physical and chemical properties, rewetting, vegetation type, forest management and land-use changes were all found to be important factors affecting soil GHG emissions. Greenhouse gas emissions from African aquatic systems ranged from 5.7 to 232.0 Mg CO2 ha–1 y–1, -26.3 to 2741.9 kg CH4 ha–1 y–1 and 0.2 to 3.5 kg N2O ha–1 y–1 and were strongly affected by amount of discharge. Soil GHG emissions from African croplands ranged from 1.7 to 141.2 Mg CO2 ha–1 y–1, -1.3 to 66.7 kg CH4 ha–1 y–1 and 0.05 to 112.0 kg N2O ha–1 y–1 and N2O emission factor (EF) ranged from 0.01 to 4.1%. Soil GHG emissions in vegetable gardens ranged from 73.3 to 132.0 Mg CO2 ha–1 y–1 and 53.4 to 177.6 kg N2O ha–1 y–1 and N2O EFs ranged from 3 to 4%. Throughout agricultural lands, N2O emissions slowly increased with N inputs below 150 kg N ha–1 y–1 and exponentially with N application rates up to 300 kg N ha–1 y–1. The lowest yield-scaled N2O emissions were reported with N application rates ranging between 100 and 150 kg N ha–1. Overall, total CO2 eq. emissions in African natural and agricultural lands were 56.9 ± 12.7 Pg CO2 eq. y–1 and natural and agricultural lands contribute 76.3% and 23.7%, respectively. Additional GHG emission measurements throughout Africa agricultural and natural lands are urgently required to quantify annual GHG emissions and identify major control factors and mitigation options on emissions.
