Accelerated Learning through Characterization of Smallholder Cassava Production Systems.

Closing the yield gap between current cassava fresh root yields of approximately 10 t ha⁻¹ and potential yields of over 30 t ha⁻¹ requires intensification of production systems. The African Cassava Agronomy Initiative (ACAI) aims to deliver knowledge to scale agronomic technologies, including site-specific fertilizer recommendations, fertilizer blending, best planting practices, intercropping, schedule planting and increased root starch content. We carried out a rapid characterization survey with over 1000 cassava growers, selected using a stratified GIS-assisted sampling scheme to ensure representativeness across target areas in Nigeria and Tanzania. Responses covered over 4000 cassava fields, two thirds of which were intercropped. Results showed high levels of variation in crop management practices. For example, main windows for planting and harvesting exist in all areas, but many farmers plant and harvest at other times, purposefully or due to lack of labour during the major planting and harvesting windows. Variation was also observed in methods and intensity of land preparation and weed control. Notably, we found that almost no farmers apply fertilizer in cassava systems in Tanzania, while in Southeast Nigeria, 24% apply urea and 83% apply NPK to intercropped cassava. This high variability suggests there are opportunities for accelerated learning by assessing local yields and conducting detailed measurements in a subset of fields or suggesting simple management modifications in a subsection of fields. The methodology of the survey is presented in detail, as well as how these results allow focusing subsequent research activities.