Taking Maize Agronomy to Scale in Africa (TAMASA)

The overall objective of the "Taking Maize Agronomy to Scale in Africa" (TAMASA) project is to work with extension service providers (i.e., input suppliers, government and private research and extension services, agro-dealers, and others) to co-develop systems and applications/tools that enhance capacity to effectively develop and disseminate site-specific nutrient and agronomic recommendations. The project is implemented in collaboration with CIMMYT, IITA, and national research institutions in three pilot study countries in Ethiopia, Nigeria, and Tanzania. IPNI has been leading the development of the site-specific nutrient management (SSNM) recommendations, focusing on the Nutrient Expert® (NE) fertilizer decision support tool. Nutrient Expert uses SSNM to develop strategies to manage fertilizer macronutrients, nitrogen (N), phosphorus (P), and potassium (K), and secondary and micronutrients taking into account nutrients from both indigenous and mineral sources.

Over 700 on-farm multi-location nutrient omission trials (NOTs) were conducted in a wide range of maize production areas in Ethiopia, Nigeria, and Tanzania between 2015 and 2017 to generate yield, yield response, and nutrient uptake datasets for calibration of NE. The nutrient omission trials, located at multiple sites, were designed as a diagnostic tool to identify which of the macronutrients (N, P, or K) are limiting maize growth, and to determine other possible constraints related to soil secondary and micronutrients. Consequently, Nutrient Expert for maize (NEM) was co-developed for Ethiopia, Tanzania, and Nigeria. Approximately 420 on-farm validation trials were conducted in Ethiopia, Nigeria, and Tanzania, in which recommendations generated using NE were compared with soil-test based nutrient recommendations, the current regional fertilizer recommendations, and a control plot with no fertilizer applied.

Data collected from NOTs showed that maize response to different nutrients varied from farm to farm, and this was most pronounced in Nigeria and southern highlands of Tanzania. The validation trial results showed that use of NE improved yields (up to about 5 t/ha on average), agronomic fertilizer use efficiency, and profits over farmer management practices and current recommendations. Nutrient Expert was used by extension agents to generate over 1,886 fertilizer recommendations for individual farmers in 2017 in Ethiopia, Nigeria, and Tanzania. Similarly, Nutrient Expert was used by OCP agronomists to generate 4,841 recommendations for individual farmers in spillover countries in Nigeria, Ghana, and Togo under the OCP School Lab Program. Overall, the use of NE was highly effective as a simple and cost-effective tool for improving fertilizer recommendations in smallholder farming systems characterized by highly variable soil fertility conditions.