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.

Kimaro et al. 2016. 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?셭, M., Mutuo, P., Abwanda, S., Shepherd, K., Neufeldt, H., Rosenstock, T.S., 2016. Is conservation agriculture 'climate-smart' for maize farmers in the highlands of Tanzania? Nutrient cycling in agroecosystems 105, 217-228.

Abstract

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.

Rosenstock et al. 2016. Greenhouse gas fluxes from agricultural soils of Kenya and Tanzania

Rosenstock, T.S., Mathew, M., Pelster, D.E., Butterbach-Bahl, K., Rufino, M.C., Thiong'o, M., Mutuo, P., Abwanda, S., Rioux, J., Kimaro, A.A., Neufeldt, H.C.J.G., 2016. Greenhouse gas fluxes from agricultural soils of Kenya and Tanzania. Journal of Geophysical Research: Biogeosciences, DOI: 10.1002/2016JG003341.

Abstract

Knowledge of greenhouse gas (GHG) fluxes in soils is a prerequisite to constrain national, continental, and global GHG budgets. However, data characterizing fluxes from agricultural soils of Africa are markedly limited. We measured carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) fluxes at ten farmer-managed sites of six crop types for one year in Kenya and Tanzania using static chambers and gas chromatography. Cumulative emissions ranged between 3.5 – 15.9 Mg CO2-C ha-1 yr-1, 0.4 – 3.9 kg N2O-N ha-1 yr-1, and -1.2 – 10.1 kg CH4-C ha-1 yr-1, depending on crop type, environmental conditions, and management. Manure inputs increased CO2 (p = 0.03), but not N2O or CH4, emissions. Soil cultivation had no discernable effect on emissions of any of the three gases. Fluxes of CO2 and N2O were 54 – 208% greater (p  < 0.05) during the wet versus the dry seasons for some, but not all, crop types. The heterogeneity and seasonality of fluxes suggest that the available data describing soil fluxes in Africa, based on measurements of limited duration of only a few crop types and agroecological zones, are inadequate to use as a basis for estimating the impact of agricultural soils on GHG budgets. A targeted effort to understand the magnitude and mechanisms underlying African agricultural soil fluxes is necessary to accurately estimate the influence of this source on the global climate system and for determining mitigation strategies.

Pelster et al. 2016. Methane and Nitrous Oxide Emissions from Cattle Excreta on an East African Grassland

Pelster, D.E., B. Gisore, J. Goopy, D. Korir, J.K. Koske, M.C. Rufino, and K. Butterbach-Bahl. 2016. Methane and Nitrous Oxide Emissions from Cattle Excreta on an East African Grassland. J. Environ. Qual. 0. doi:10.2134/jeq2016.02.0050

Abstract

Greenhouse gas (GHG) emission measurements from livestock excreta in Africa are limited. We measured CH4 and N2O emissions from excreta of six Boran (Bos indicus) and six Friesian (Bos taurus) steers near Nairobi, Kenya. The steers were fed one of three diets (T1 [chaffed wheat straw], T2 [T1 + Calliandra calothyrsus Meissner – 0.2% live weight per day], and T3 [T1 + calliandra – 0.4% live weight every 2 d]). The T1 diet is similar in quality to typical diets in the region. Calliandra is a leguminous fodder tree promoted as a feed supplement. Fresh feces and urine were applied to grasslands and emissions measured using static chambers. Cumulative 28-d fecal emissions were 302 ± 52.4 and 95 ± 13.8 mg CH4–C kg−1 dry matter for Friesen and Boran steers, respectively, and 11.5 ± 4.26 and 24.7 ± 8.32 mg N2O–N kg−1 dry matter for Friesian and Boran steers, respectively. For urine from Friesian steers, the N2O emissions were 2.8 ± 0.64 mg N2O–N 100 mL urine−1. The CH4 emission factors (EFs) (246 ± 49.5 and 87 ± 12.7 g CH4–C yr−1 animal−1 for Friesan and Boran, respectively) were lower than the International Panel on Climate Change EFs (750 g CH4–C animal−1 yr−1), whereas the N2O EFs (0.1 and 0.2% for the Friesian and Boran feces, respectively, and 1.2% for urine) were also lower than International Panel on Climate Change estimates. The low N content of the excreta likely caused the low emissions and indicates that current models probably overestimate CH4 and N2O emissions from African livestock manure.