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This report addresses Milestone 1.4. 2 (a baseline report quantifying the current level of BNF and its contributions to rural livelihoods) together with the baseline report (Franke & de Wolf, 2011, and also links to Milestones 1.6. 1 (A report on the impact of N2 fixation technologies on farmers’ livelihoods), and 2.6. 1 (Household benefits from specific BNF interventions quantified for the four major grain legumes in the impact zones). It contains an evaluation of the available information on the current amount of nitrogen fixed by grain legumes in the action sites where N2Africa works, as well as a first preliminary assessment of the potential impact that N2Africa technologies have on N-fixation at field and farm level. Information for this report was largely collected from results found in literature, as well as data collected as part of the N2Africa activities:-farm characterisations

-baseline survey-agronomy trials-dissemination trials

Detailed biological nitrogen fixation (BNF) assessments by legumes in the project are limited to the agronomy trials and farm characterisations. Accurate BNF assessments at a field and farm level are difficult to achieve because of inaccuracies related to quantifications of the fraction or percentage of plant N derived from air (% N from N2-fixation) in legumes, of total N accumulation by legumes, and of the exact area covered by legumes on a smallholder farm. Therefore, in most crop data collection activities for N2Africa, grain yield or total aboveground biomass yield is measured and not BNF. However, biomass yield is a strong indicator of BNF and with the help of estimates of plant N concentration and% N from N2-fixation from …