Research, dissemination and monitoring and evaluation teams to work together to understand applicability of N2Africa technologies in heterogeneous conditions of smallholder farmers

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Agronomic trials conducted for two seasons in East and Central Africa and for one season in West and Southern Africa are yielding interesting results. We have observed a lot of variations in crop yields within treatments, between farms and across agro-ecological zones. We attribute this huge yield variation with the existing soil fertility and management gradients as well spatial and temporal environmental differences. For example, at Mushomo site in-DRC soybean yields in the control treatments varied enormously between different farmers; from 200 kg/ha to 2500 kg/ha. The application of P fertiliser led to 43% of the fields having a yield increase of more than 10%, relative to the control treatment (Figure 1A). However, in 20% of the cases, yields were actually decreased by more than 10% in treatments with phosphate application only. Soybean treated with inoculant gave a grain yield that was more than 10% higher than that in the control treatment in 83% of the fields. The application of P fertiliser and inoculant gave a yield increase of more than 10% in 94% of the fields. The results show that, at this site, the use of inoculant alone had a stronger and more consistent impact on grain yield than the use of P fertiliser only, while the combination of P fertiliser and inoculant inputs gave the highest yield increases.

Almost the same trend was observed in Nigeria in villages within Kano state (Figure 1B). There are other sites where  soybean grain yields were generally low (less than 1.2 t/ha) and no consistent impact from P fertiliser or inoculant inputs and others where low yields coincide with a lack of response to P and inoculant inputs, probably because other limiting factors are overriding.

Figure 1. Yield response of soybean to phosphate (P) fertiliser and/or inoculant (I) at Mumosho site (A) in DR Congo and in villages in Kano state Nigeria (B).
However, data reported above have been collected from relatively few sites, which is not sufficient to allow us to confidently provide information that will help scientists and farmers to understand the importance of the crop variety (GL), the use of inoculum (GR), the type of soil and climatic conditions etc (E) and then the farmer management practices such as use of fertilizer, date of planting, plant spacing, weeding and harvesting (M). The plan is that the N2Africa team of Agronomy, Rhizobiology, Dissemination and Monitoring and Evaluation teams work together on about 200-300 farmers’ fields per country and take good records and observations of farmers practices (using the farm monitoring book) to collect the most important management practices in relation to the (GL x GR)x E part of the equation. This rigorous team approach in data collection will start in Ghana and Nigeria this growing season and will extend to East and Central Africa in September then later to Southern Africa in December. 
By Freddy Baijukya and Linus Franke