Beyond N and P: Toward a Land Resource Ecology Perspective and Impactful Fertilizer Interventions in Sub-Saharan Africa

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Crop plants require essential nutrients from the soil in specific quantities and proportions for optimal growth and yield. Inadequate nutrient availability can lead to poor crop performance. While soil may contain sufficient nutrients, it may not be readily accessible to plants. In such cases, plants employ nutrient acquisition mechanisms like root exudation or mutualistic interactions with soil biota. However, there are instances where one or more nutrients still need to be improved, necessitating fertilizer application to achieve significant yield improvements. This report focuses on the potential of impactful fertilizer interventions that result in substantial yield increases at low doses, making them more affordable for small-scale farmers in sub-Saharan Africa. It highlights the importance of considering a broader spectrum of essential plant nutrients beyond nitrogen and phosphorus, as these could be limiting factors in tropical soils. The research conducted in Africa has primarily concentrated on nitrogen and phosphorus fertilizers, despite evidence suggesting deficiencies in other essential nutrients. The paper examines the variability of crop yield responses to nitrogen and phosphorus fertilizers and emphasizes the need for site-specific fertilizer applications considering nutrient dose and composition. It presents case studies conducted in the Miombo woodland biome, a prevalent vegetation type in Central-South Africa, to assess soil fertility and key soil chemistry factors influencing nutrient deficiencies. These case studies explore the impact of essential nutrients like calcium, potassium, magnesium, sulfur, and micronutrients (boron, copper, iron, manganese, molybdenum, nickel, and zinc) on crop yield. The report acknowledges the scarcity of comprehensive data and statistical analysis on combined nutrient impacts under prevailing soil and climatic conditions. However, it utilizes available data sets from selected case studies to gain insights into nutrient deficiencies beyond nitrogen and phosphorus. The findings emphasize the importance of addressing critical nutrient deficiencies and developing tailored fertilizer technologies specific to the Miombo biome and sub-Saharan Africa as a whole. Furthermore, the report compares soil fertility data from the Miombo biome with the Brazilian Cerrado, highlighting similarities and differences. It discusses the success of agricultural productivity advancements in Brazil and suggests a similar research approach for sub-Saharan Africa to identify nutrient deficiencies and develop appropriate fertilizer technologies.
Fertilizer technology, Soil fertility, Nutrient deficiencies
R. Voortman and P.S. Bindraban, 2015. Beyond N and P: Toward a Land Resource Ecology Perspective and Impactful Fertilizer Interventions in Sub-Saharan Africa. VFRC Report 2015/1. Virtual Fertilizer Research Center, Washington, D.C. 49 pp.; 15 tables; 17 figs.; 2 text boxes; 67 ref.