Nutrient management for sustainable food crop intensification in African tropical savannas

Abstract

Increased fertilizer use is often an essential component of sustainable intensification for improved food security and economic growth in the upper elevation tropical savanna (UTS) and lower elevation tropical savanna (LTS) of Africa. The UTS and LTS are large "breadbasket" areas with little fertilizer use due to financial and other constraints. Farmers' perceptions of high profit opportunity with low risk are often major drivers of adoption. Representative crop nutrient response functions are needed to maximize farm-level profits from fertilizer use. Such functions were determined from results of past research, and profit potentials were evaluated. The mean yield increases due to fertilizer application at the economically optimum rate, relative to yield with no fertilizer applied, were as follows: 41% for cassava (Manihot esculenta Crantz), 18% for cowpea [Vigna unguiculata (L.) Walp.], 16% for groundnut (Arachis hypogaea L.), 67% for maize (Zea mays L.), 50% for lowland rice (Oryza sativa L.), and 39% for sorghum [Sorghum bicolor (L.) Moench] in LTS, and 46% for bean (Phaseolus vulgaris L.), 81% for groundnut, 58% for maize, 96% for upland rice (Oryza sativa L. or Oryza glaberrima Steud.), 32% for sorghum, and 48% for soybean [Glycine max (L.) Merr.] in UTS. The profit potential varied greatly across nutrient rates applied to individual crops making optimized crop-nutrient-rate choices especially important for cases of financially constrained fertilizer use. Considerations for achieving widespread adoption of increased fertilizer use are discussed. Increased fertilizer use needs to be complemented by mitigation of diverse yield and socioeconomic constraints to meet the growing demand for food.

Soil and Climate Characterization to Define Environments for Summer Crops in Senegal

“…For example, with the introduction of the short-season dual-purpose pearl millet crop in the region, the adoption of high plant density and balanced fertilization are still obstructed due to lack of economic, institutional (access to credit), and socio-cultural barriers [90,91]. A compromised solution needs to be sought in the near future for securing access to fertilizers via subsidies, providing better credits for other farming inputs, crop insurance, and improving access to data-informed and knowledge-based decision support tools [13,90]. In addition, the complex topics of climate change, climate smart agriculture, sustainable agricultural intensification, and soil fertility management require participatory processes to set research priorities and identify the best solutions [91].…”

“…Its relation to food security is critical to establishing a more sustainable pathway maintaining future gains in crop productivity while reducing the impact of this process on the continuous degradation of soils (i.e., loss of soil structure, nutrients, and erosion; [12]). For resource-constrained farmers, the improvement of soil health is critical to providing economic return to fertilizer inputs [13]. A recent large survey highlighted key biophysical and socio-economic barriers and potential opportunities and solutions to address soil fertility issues in Africa [14].…”

Near‐term problems in meeting world food demands at regional levels: A special issue overview

“…(2021) and Wortmann et al. (2021), the situation is more severe in the rural regions of the underdeveloped countries due to limited resources available to the farming communities.…”

“…Wortmann et al. (2021) reviews research results of ley versus fallow rotations with annual crops in research conducted within 15° latitude of the equator in tropical Africa. They conclude that opportunities for perennial grass ley rotated with annual crops are abundant in tropical Africa.…”

“…In Sub‐Saharan Africa, food production increases have not met the regional demand and this has led to significant food insecurity (Wortmann & Stewart, 2021). In response to persistent food insecurity in the region, there are calls for sustainable intensification (SI) of food production.…”