Increasing fertilizer use is required for meeting future food demands for the growing population in sub-Saharan Africa (SSA). However, increased fertilizer nitrogen use can raise N2O emissions. 4R Nutrient Stewardship promotes Best Management Practices (BMPs) that optimize fertilizer use and minimize N2O emissions while increasing yields.
We conducted a scenarios analysis on the potential effects of increased adoption of 4R Nutrient Stewardship BMPs customized to control on-farm N2O emissions in SSA by 2030 and 2050. Data on projected greenhouse gas (GHG) emissions from the application of synthetic fertilizer for 2030 and 2050 were downloaded from the Food and Agriculture Organization of the United Nations (FAO) FAOSTAT database. Potential emission reductions were calculated by country using three different 4R practice adoption rates for each timeline (10, 20 and 30% for 2030; and 30, 40 and 50% for 2050 based on arable cropping areas) and five different emission reduction rates representing increased specificity and efficacy of 4R practice adoption (5, 10, 15, 20 and 25%).
Our results revealed that large amounts of N2O emissions could be avoided with increased adoption of the 4R Framework. Annual N2O emission reductions of up to 1,229 and 3,418 kt CO2e by 2030 and 2050, respectively, could be achieved in SSA with 30% and 50% adoption rates of 4R Nutrient Stewardship at a 25% emission reduction rate.
These correspond to overall emission reductions of 7.5% by 2030 and 12.5% by 2050 from total FAO annual N2O emission projections for SSA of 16,392 ktCO2e and 27,345 ktCO2e, respectively.
The adoption of 4R Nutrient Stewardship practices has material climate change mitigation potential through reduced N2O emissions and will help SSA to sustainably intensify food production and improve soil health in the region.