We have created this Blog and the database to provide a place where the scientific community can share and update the fast growing knowledge and data on the study of greenhouse gas CO2, CH4, and N2O fluxes in Africa.

We are grateful for the numerous researchers and technicians who provide invaluable data. It is impossible to cite all the references due to limited space allowed and we apologize for the authors whose work has not been cited.

Sugihara et al. 2012. Effects of land management on CO2 flux and soil C stock in two Tanzanian croplands with contrasting soil texture

Sugihara, S., Funakawa, S., Kilasara, M., and Kosaki, T.: Effects of land management on CO2 flux and soil C stock in two Tanzanian croplands with contrasting soil texture, Soil Biology and Biochemistry, 46, 1-9, 2012.


Evaluation of carbon dynamics is of great concern worldwide in terms of climate change and soil fertility. However, the annual CO2 flux and the effect of land management on the carbon budget are poorly understood in Sub-Saharan Africa, owing to the relative dearth of data for in situ CO2 fluxes. Here, we evaluated seasonal variations in CO2 efflux rate with hourly climate data in two dry tropical croplands in Tanzania at two sites with contrasting soil textures, viz. clayey or sandy, over four consecutive crop-cultivation periods of 40 months. We then: (1) estimated the annual CO2 flux, and (2) evaluated the effect of land management (control plot, plant residue treatment plot, fertilizer treatment plot, and plant residue and fertilizer treatment plot) on the CO2 flux and soil carbon stock at both sites. Estimated annual CO2 fluxes were 1.0–2.2 and 0.9–1.9 Mg C ha−1 yr−1 for the clayey and sandy sites, respectively. At the end of the experiment, crop cultivation had decreased the surface soil carbon stocks by 2.4 and 3.0 Mg C ha−1 (soil depth 0–15 cm) at the clayey and sandy sites, respectively. On the other hand, plant residue application (7.5 Mg C ha−1 yr−1) significantly increased the surface soil carbon stocks, i.e., 3.5–3.8 and 1.7–2.1 Mg C ha−1 (soil depth 0–15 cm) at the clayey and sandy sites, respectively, while it also increased the annual CO2 fluxes substantially, i.e., 2.5–4.0 and 2.4–3.4 Mg C ha−1 yr−1 for the clayey and sandy soils, respectively. Our results indicate that these dry tropical croplands at least may act as a carbon sink, though the efficiency of carbon accumulation was substantially lower in sandy soil (6.8–8.4%) compared to clayey soil (14.0–15.2%), possibly owing to higher carbon loss by leaching and macro-faunal activity.

Saunders et al. 2011. Agricultural encroachment: Implications for carbon sequestration in tropical African wetlands

Saunders, M.J., Kansiime, F., Jones, M.B., 2011. Agricultural encroachment: Implications for carbon sequestration in tropical African wetlands. Global Change Biology, 10.1111/j.1365-2486.2011.02633.x.


Tropical wetlands have been shown to exhibit high rates of net primary productivity and may therefore play an important role in global climate change mitigation through carbon assimilation and sequestration. Many permanently flooded areas of tropical East Africa are dominated by the highly productive C4 emergent macrophyte sedge, Cyperus papyrus L. (papyrus). However, increasing population densities around wetland margins in East Africa are reducing the extent of papyrus coverage due to the planting of subsistence crops such as Colocasia esculenta (cocoyam). In this paper we assess the impact of this land use change on the carbon cycle and in particular the impacts of land conversion on net ecosystem carbon dioxide exchange. Eddy covariance techniques were used, on a campaign basis, to measure fluxes of carbon dioxide over both papyrus and cocoyam dominated wetlands located on the Ugandan shore of Lake Victoria. Peak rates of net photosynthetic CO2 assimilation, derived from monthly diurnal averages of net ecosystem exchange, of 28-35 μmol CO2 m−2 s−1 and 15-20 μmol CO2 m−2 s−1 were recorded in the papyrus and cocoyam wetlands respectively, while night time respiratory losses ranged between 10-15 μmol CO2 m−2 s−1 at the papyrus wetland and 5-10 μmol CO2 m−2 s−1 at the cocoyam site. The integration of the flux data suggest that papyrus wetlands have the potential to act as a sink for significant amounts of carbon, in the region of 10 t C ha−1 yr−1. The cocoyam vegetation assimilated ~7 t C ha−1 yr−1 but when carbon exports from crop biomass removal were accounted for these wetlands represent a significant net loss of carbon of similar magnitude. The development of sustainable wetland management strategies are therefore required, to promote the dual wetland function of crop production and the mitigation of greenhouse gas emissions especially under future climate change scenarios.

Werner et al 2007. A global inventory of N2O emissions from tropical rainforest soils

Werner, C., K. Butterbach-Bahl, E. Haas, T. Hickler, and R. Kiese (2007), A global inventory of N2O emissions from tropical rainforest soils using a detailed biogeochemical model, Global Biogeochem. Cycles, 21, GB3010, doi:10.1029/2006GB002909.

Beside agricultural soils, tropical rainforest soils are the main source of atmospheric N2O. Current estimates of the global N2O source strength of tropical rainforest soils are still based on rather simplistic upscaling approaches and do have a large range of uncertainty. In this study, the biogeochemical ForestDNDC-tropica model was recalibrated and intensively tested on the site scale prior to inventory calculations. For this, the model was coupled to a newly developed global GIS database holding relevant information on model initialization and driving parameters in 0.25° × 0.25° resolution. On average, the mean annual N2O emission source strength of rainforests ecosystems worldwide for the 10-year-period 1991–2000 was calculated to be 1.2 kg N2O-N ha−1 yr−1. Using a total rainforest area of 10.9 × 106 km2, this amounts to a total source strength of 1.34 Tg N yr−1. The result of an initialization parameter uncertainty assessment using Latin Hypercube sampling revealed that the global source strength of N2O emissions from tropical rainforests may range from 0.88 to 2.37 Tg N yr−1. Our calculations also show that N2O emissions do vary substantially on spatial and temporal scales. Regional differences were mainly caused by differences in soil properties, whereas the pronounced seasonal and interannual variability was driven by climate variability. Our work shows that detailed biogeochemical models are a valuable tool for assessing biosphere-atmosphere exchange even on a global scale. However, further progress and a narrowing of the uncertainty range do crucially depend on the availability of more detailed field measurements for model testing and an improvement of the quality of spatial data sets on soil and vegetation properties.