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Livestock are an important source of livelihoods in agricultural systems in sub-Saharan Africa (SSA), while also being the largest source of national greenhouse gas (GHG) emissions in most African countries. As a consequence, there is a critical need for data on livestock GHG sources and sinks to develop national inventories, as well as conduct baseline measurements and intervention testing to mitigate GHG emissions and meet ambitious national climate goals. Our objective was to review studies on GHG emissions from livestock systems in SSA, as well as soil carbon storage in livestock-dominated systems (i.e., grasslands and rangelands), to evaluate best current data and suggest future research priorities. To this end, we compiled studies from SSA that determined emission factors (EFs) for enteric methane and manure emissions, along with studies on soil organic carbon (SOC) stocks in SSA. We found that there has been limited research on livestock GHG emissions and SOC relative to national ambitions for climate change mitigation in SSA. Enteric methane emission factors (EFs) in low productivity cattle systems may be lower than IPCC Tier 1 default EFs, whereas small ruminants (i.e. sheep and goats) had higher EFs compared to IPCC Tier 1 EFs. Manure EFs were equal to or lower than IPCC Tier 1 EFs for deposited manure (while grazing), manure applied as fertilizer, and manure management. SOC stocks for grasslands and rangelands in SSA show broad agreement with IPCC estimates, but there was a strong geographic bias and many studies did not report soil type, bulk density, or SOC stocks at >30 cm depth. In general, the largest data gaps included information for manure (quantity, quality, management), small ruminants, agropastoral/pastoralist systems, and in general from West Africa. Future research should focus on filling major data gaps on locally appropriate mitigation interventions and improving livestock activity data for developing Tier 2 GHG inventories in SSA. At the science-policy interface, all parties would benefit from enhanced coordination within the research community and between researchers and African governments to improve Tier 2 inventories and harmonize measurement for mitigation in livestock systems in SSA.

The Livestock and Manure Management Component (LMMC) of the CCAC Agriculture Initiative to reduce Short-Lived Climate Pollutants (SLCPs) supports the adoption of integrated manure management practices across the globe by increasing knowledge and awareness, removing barriers to action and enhancing practice change. Livestock play an important role in global food production and in agricultural and rural economies in many developing regions. While the livestock sector is one of the fastest growing subsectors of agriculture, it is also an important contributor to anthropogenic greenhouse gas (GHG) emissions, in which manure and manure management account for 10% of total livestock emissions. Manure is a valuable source of nutrients, organic matter and renewable energy. However, manure management is often poor and as a consequence, nutrients and organic matter are lost, causing environmental and climate problems and threatening public health. Technologies for and knowledge of integrated manure management are available; however implementation is often challenged by (1) a lack of awareness of manure’s potential; (2) a lack of knowledge and a supporting knowledge infrastructure; (3) ineffective policies; (4) dispersed expertise; (5) a lack of resources and investments. Integrated manure management encompasses all activities associated with management of dung and urine; from excretion; collection, housing, and storage; anaerobic digestion, treatment, transport to application, and includes losses and discharge at any stage along this ‘manure chain’. To-date, very little is known about manure management at a global scale. A global assessment has been performed to improve insight on manure management at farm level, barriers to adoption of integrated manure management practices, and understanding of the existing policies, institutional and incentive frameworks. The assessment targeted diverse regional and national key stakeholders ranging from farmers, extension workers, researchers and policy makers. Regarding existing manure management practices, there is a wide variation. However, a common trend emerging from the survey is the difficulty in managing urine and liquid manure especially in non-mechanized situations and on smaller farms. Proper management of liquid manure requires investments in infrastructure. Labour availability was cited by several farmers as a constraint to improve their manure management. Four key barriers have been identified in the assessment. The first and most important is the limited awareness of the importance of integrated manure management in contributing towards food security and reducing SLCP emissions. The value of manure is often not recognised by farmers, local extension staff and policy-makers. Additional to this, is the level of knowledge. This is often linked to a) the level of education of many small-scale farmers, in some regions the low level of literacy is still an obstacle; and b) the lack of a knowledge infrastructure, to support farmers in improving manure management. Knowledge development is not a one-off intervention, but requires continous investment. Thirdly, the limited access to financial credit and other incentives remains an important barrier especially for small-scale farmers who lack collateral to acesss credit to undertake investments. Proper integrated manure management is associated with high investments in capital, labour and knowledge which, on the short term, increases the costs of production. Finally, ineffective manure (or related) policies and legislation often do not support sound manure management. The main drivers for manure policies are focused on energy production or problems regarding environmental or public health issues. The fertiliser and soil improving value and the food security benefits of using manure are often not drivers for policy. Improved coordination between relevant ministries (e.g. Ministries of Agriculture, Energy, Public Health and Environment) is important for the development of coherent and holistic policies. This assessment has provided an insight into the potential improvement strategies. An effective manure management improvement strategy, focussing on the added value of manure as a fertiliser, should focus on the following main barriers: the lack of awareness and knowledge, the access to credit and the development of customised solutions for simple manure storage and application equipment. In many countries, bio-digester programmes have proven to be a successful strategy. Manure policy should facilitate this strategy using a coherent approach, by balancing the potential fertiliser and energy value and the potential risks. This global assessment provided not only insights on manure management and the barriers for improvement. It also identified (a) a number of opportunities where manure management can be improved: the Opportunities for Practice Change and; (b) the need to leverage stakeholder engagement to improve awareness and create networks targeted at enhanced engagement in improved manure management.

The Livestock and Manure Management Component (LMMC) of the CCAC Agriculture Initiative to reduce Short-Lived Climate Pollutants (SLCPs) supports the adoption of integrated manure management practices across the globe by increasing knowledge and awareness, removing barriers to action and enhancing practice change.Livestock play an important role in global food production and in agricultural and rural economies in many developing regions. While the livestock sector is one of the fastest growing subsectors of agriculture, it is also an important contributor to anthropogenic greenhouse gas (GHG) emissions, in which manure and manure management account for 10% of total livestock emissions.Manure is a valuable source of nutrients, organic matter and renewable energy. However, manure management is often poor and as a consequence, nutrients and organic matter are lost, causing environmental and climate problems and threatening public health.Technologies for and knowledge of integrated manure management are available; however implementation is often challenged by (1) a lack of awareness of manure’s potential; (2) a lack of knowledge and a supporting knowledge infrastructure; (3) ineffective policies; (4) dispersed expertise; (5) a lack of resources and investments.Integrated manure management encompasses all activities associated with management of dung and urine; from excretion; collection, housing, and storage; anaerobic digestion, treatment, transport to application, and includes losses and discharge at any stage along this ‘manure chain’.To-date, very little is known about manure management at a global scale. A global assessment has been performed to improve insight on manure management at farm level, barriers to adoption of integrated manure management practices, and understanding of the existing policies, institutional and incentive frameworks. The assessment targeted diverse regional and national key stakeholders ranging from farmers, extension workers, researchers and policy makers. Regarding existing manure management practices, there is a wide variation. However, a common trend emerging from the survey is the difficulty in managing urine and liquid manure especially in non-mechanized situations and on smaller farms. Proper management of liquid manure requires investments in infrastructure. Labour availability was cited by several farmers as a constraint to improve their manure management.Four key barriers have been identified in the assessment. The first and most important is the limited awareness of the importance of integrated manure management in contributing towards food security and reducing SLCP emissions. The value of manure is often not recognised by farmers, local extension staff and policy-makers.Additional to this, is the level of knowledge. This is often linked to a) the level of education of many small-scale farmers, in some regions the low level of literacy is still an obstacle; and b) the lack of a knowledge infrastructure, to support farmers in improving manure management. Knowledge development is not a one-off intervention, but requires continous investment.Thirdly, the limited access to financial credit and other incentives remains an important barrier especially for small-scale farmers who lack collateral to acesss credit to undertake investments. Proper integrated manure management is associated with high investments in capital, labour and knowledge which, on the short term, increases the costs of production.Finally, ineffective manure (or related) policies and legislation often do not support sound manure management. The main drivers for manure policies are focused on energy production or problems regarding environmental or public health issues. The fertiliser and soil improving value and the food security benefits of using manure are often not drivers for policy. Improved coordination between relevant ministries (e.g. Ministries of Agriculture, Energy, Public Health and Environment) is important for the development of coherent and holistic policies.This assessment has provided an insight into the potential improvement strategies. An effective manure management improvement strategy, focussing on the added value of manure as a fertiliser, should focus on the following main barriers: the lack of awareness and knowledge, the access to credit and the development of customised solutions for simple manure storage and application equipment. In many countries, bio-digester programmes have proven to be a successful strategy. Manure policy should facilitate this strategy using a coherent approach, by balancing the potential fertiliser and energy value and the potential risks.This global assessment provided not only insights on manure management and the barriers for improvement. It also identified (a) a number of opportunities where manure management can be improved: the Opportunities for Practice Change and; (b) the need to leverage stakeholder engagement to improve awareness and create networks targeted at enhanced engagement in improved manure management.

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 10 farmer-managed sites of six crop types for 1 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