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.

Borges et al. 2015. Globally significant greenhouse-gas emissions from African inland waters

Borges A V, Darchambeau F, Teodoru C R, Marwick T R, Tamooh F, Geeraert N, Omengo F O, Guerin F, Lambert T, Morana C, Okuku E and Bouillon S 2015 Globally significant greenhouse-gas emissions from African inland waters. Nature Geosci doi:10.1038/ngeo2486.


Carbon dioxide emissions to the atmosphere from inland waters—streams, rivers, lakes and reservoirs—are nearly equivalent to ocean and land sinks globally. Inland waters can be an important source of methane and nitrous oxide emissions as well, but emissions are poorly quantified, especially in Africa. Here we report dissolved carbon dioxide, methane and nitrous oxide concentrations from 12 rivers in sub-Saharan Africa, including seasonally resolved sampling at 39 sites, acquired between 2006 and 2014. Fluxes were calculated from published gas transfer velocities, and upscaled to the area of all sub-Saharan African rivers using available spatial data sets. Carbon dioxide-equivalent emissions from river channels alone were about 0.4 Pg carbon per year, equivalent to two-thirds of the overall net carbon land sink previously reported for Africa. Including emissions from wetlands of the Congo river increases the total carbon dioxide-equivalent greenhouse-gas emissions to about 0.9 Pg carbon per year, equivalent to about one quarter of the global ocean and terrestrial combined carbon sink. Riverine carbon dioxide and methane emissions increase with wetland extent and upland biomass. We therefore suggest that future changes in wetland and upland cover could strongly affect greenhouse-gas emissions from African inland waters.

Kimaro et al. 2015. Is conservation agriculture ‘climate-smart’for maize farmers in the highlands of Tanzania?

Kimaro, A. A., Mpanda, M., Rioux, J., Aynekulu, E., Shaba, S., Thiong’o, M., ... & Rosenstock, T. S. (2015). Is conservation agriculture ‘climate-smart’for maize farmers in the highlands of Tanzania?. Nutrient Cycling in Agroecosystems, 1-12.


Conservation agriculture (CA) is promoted extensively to increase the productivity and environmental sustainability of maize production systems across sub-Saharan Africa and is often listed as a climate-smart agriculture (CSA) practice. However, the impacts of CA on food security, resilience/adaptive capacity and climate change mitigation are location-dependent and it is unknown whether CA can simultaneously address CSA’s multiple objectives. Here we evaluate four variations of CA: reduced tillage plus mulch (mulch), reduced tillage plus mulch and leguminous cover crop (Lablab), reduced tillage plus mulch and leguminous trees (CAWT), and reduced tillage plus mulch and nitrogen fertilizer (CA + F)—for their effect on CSA-relevant outcomes in highland Tanzania maize production. By comparison to conventional practice in the region, intensification of maize production by Lablab, CAWT, and CA + F significantly increases yields by 40, 89 and 77 %, respectively. Likewise, rainfall use efficiency was highest in these three treatments and significantly greater than conventional practices in 7 of 12 comparisons. Seasonal and annual greenhouse gas fluxes were similar across all treatments; however, yield-scaled global warming potential (Mg CO2 eq Mg grain−1) was lower in CAWT (2.1–3.1) and CA + F (1.9–2.3) than conventional practice (1.9–8.3), averaging 62 and 68 % of the emission intensity of conventional practice, respectively. The findings demonstrate that CA can deliver benefits consistent with the objectives of CSA for farmers in this region, particularly when soil nitrogen limitation is alleviated, providing other constraints to adoption are removed.


Goenster et al. 2015. Gaseous emissions and soil fertility of homegardens in the Nuba Mountains, Sudan

Goenster, S., Wiehle, M., Predotova, M., Gebauer, J., Ali, A. M., and Buerkert, A.: Gaseous emissions and soil fertility of homegardens in the nuba mountains, sudan, J. Plant Nutr. Soil Sci., 178, 413-424, 10.1002/jpln.201400292, 2015.


Intensification of homegardens in the Nuba Mountains may lead to increases in C and nutrient losses from these small-scale land-use systems and potentially threaten their sustainability. This study, therefore, aimed at determining gaseous C and N fluxes from homegarden soils of different soil moisture, temperature, and C and N status. Emissions of CO2, NH3, and N2O from soils of two traditional and two intensified homegardens and an uncultivated control were recorded bi-weekly during the rainy season in 2010. Flux rates were determined with a portable dynamic closed chamber system consisting of a photo-acoustic multi-gas field monitor connected to a PTFE coated chamber. Topsoil moisture and temperature were recorded simultaneously to the gas measurements. Across all homegardens emissions averaged 4,527 kg CO2-C ha−1, 22 kg NH3-N ha−1, and 11 kg N2O-N ha−1 for the observation period from June to December. Flux rates were largely positively correlated with soil moisture and predominantly negatively with soil temperature. Significant positive, but weak (rs < 0.34) correlations between increasing management intensity and emissions were noted for CO2-C. Similarly, morning emissions of NH3 and increasing management intensity were weakly correlated (rs  = 0.17). The relatively high gaseous C and N losses in the studied homegardens call for effective management practices to secure the soil organic C status of these traditional land-use systems.

Hickman et al. 2015. A potential tipping point in tropical agriculture: Avoiding rapid increases in nitrous oxide fluxes from agricultural intensification in kenya

Hickman, J. E., Tully, K. L., Groffman, P. M., Diru, W., and Palm, C. A. C. J. G.: A potential tipping point in tropical agriculture: Avoiding rapid increases in nitrous oxide fluxes from agricultural intensification in Kenya, Journal of Geophysical Research: Biogeosciences, doi: 10.1002/2015jg002913, 10.1002/2015jg002913, 2015.


There are national and regional efforts aimed at increasing fertilizer use in sub-Saharan Africa, where nitrogen (N) inputs must be increased by an order of magnitude or more to reach recommended rates. Fertilizer inputs increase N availability and cycling rates and subsequently emissions of nitrous oxide (N2O), a powerful greenhouse gas and the primary catalyst of stratospheric ozone depletion. We established experimental maize (Zea mays L.) plots in western Kenya to quantify the relationship between N inputs and N2O emissions. Mean N2O emissions were marginally, but not significantly, better described by an exponential model relating emissions to N input rate in 2011; in 2012, an exponential relationship provided the best fit compared to linear and other nonlinear models. Most N2O fluxes occurred during the 30 days following the second fertilizer application. Estimates of fertilizer N lost as N2O annually were well below the 1% Intergovernmental Panel on Climate Change default emission factor, ranging from 0.07% to 0.11% in 2011 and from 0.01% to 0.09% in 2012. In both years, the largest impact on annual N2O emissions occurred when inputs increased from 100 to 150 kg N ha−1: fluxes increased from 203 to 294 g N2O-N ha−1 yr−1 in 2011 and from 168 to 254 kg N ha−1 in 2012. Our results suggest that exponential emission responses are present in tropical systems and that agricultural intensification in western Kenya may be managed for increasing crop yields without immediate large increases in N2O emissions if application rates remain at or below 100 kg N ha−1.

Sommer et al. 2015. Nitrogen dynamics and nitrous oxide emissions in a long-term trial on integrated soil fertility management in western Kenya

Sommer, R., Mukalama, J., Kihara, J., Koala, S., Winowiecki, L., and Bossio, D.: Nitrogen dynamics and nitrous oxide emissions in a long-term trial on integrated soil fertility management in western kenya, Nutrient Cycling in Agroecosystems, 10.1007/s10705-015-9693-6, 2015.


Integrated soil fertility management (ISFM) is a concept that includes the management of organic matter in smallholder farming systems for sustainable intensification. To determine whether ISFM is also eco-efficient, we measured and simulated nitrogen (N)-dynamics and nitrous oxide (N2O) emissions in an ISFM long-term maize trial in Western Kenya. The total annual N-balance averaged over 10.5 years was negative for all continuous maize treatments that received only inorganic N-fertilizer. The N-balance was zero or positive when maize was grown in rotation with the green manure cover crop, Tephrosia candid, and/or to which 4 Mg ha−1 season−1 farm yard manure (FYM) added. These results thus substantiate the importance of organic matter management in tropical ecosystems. They also underpin that mineral N-fertilizer application alone does not guarantee agro-ecosystem sustainability, which should be considered in fertilizer (subsidy) policies. Treatments that included Tephrosia and FYM application emitted the largest amounts of N2O. Highest emissions (12.0 kg N2O–N ha−1) were simulated for the maize–Tephrosia rotation to which FYM and 30 kg ha−1 of mineral fertilizer N was added and 2 Mg ha−1 maize stovers retained. Such treatments had the highest N-emission intensity. The slope of the linear regression equation describing the N2O emission–N-input relationship of all considered treatments (0.023) was twice as high as the IPCC-Tier-1 emission factor. Maize–Tephrosia treatments had the highest seasonal maize yields. These were, however, not high enough to compensate for the inclusion of Tephrosia into the system as compared to growing maize continuously, compromising adoption by smallholder farmers.