PhD defence: Using model-based and experimental multi-nutrient approaches to improve fertilization recommendations for maize in Zambia

PhD candidate:SM (Siatwiinda) Siatwiinda MSc. Promotor: prof.dr.ir. W (Wim) de Vries. Co-promotor: dr.ir. GH (Gerard) Ros. External copromotor: Prof. Dr. Olusegun A. Yerokun. Organisation:Wageningen University, Environmental Systems Analysis
Food insecurity and malnutrition are key global challenges exacerbated by population growth and climate change. This is especially true for Sub-Saharan Africa, including Zambia, where the demand for cereals, particularly maize, exceeds the production levels. This disparity is mainly due to significant gaps between the potential and current crop yield. In an explorative model study, I show that current nutrient management has a larger negative impact on maize yields in Zambia than the expected impacts of climate change. Therefore, I further investigated the potential of multi-nutrient management practices to improve nutrient use efficiency and maize yields in Zambia. Results indicate that a balanced application of nitrogen (N), phosphorus (P) and potassium (K) enhances maize yield by more than 30% compared to government subsidized blanket fertilizer NPK application. Additionally, applying sulphur further enhances maize yields. The maize yield and nutrient uptake in response to phosphorus, zinc and boron varies depending on soil status and the interaction between these nutrients. These findings contribute to the development of improved site-specific fertilizer recommendations.

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