Fertilizer and grain prices constrain food production in sub-Saharan Africa
Abstract
Crop yields across sub-Saharan Africa are much lower than what is attainable given the environmental conditions and available technologies. Closing this 'ecological yield gap' is considered an important food security and rural welfare goal. It is not clear, however, whether it is economically sensible for farmers to substantially increase crop yields. Here we estimate the local yield response of maize to fertilizer across sub-Saharan Africa with an empirical machine-learning model based on 12,081 trial observations and with a mechanistic model. We show that the average 'economic yield gap'-the difference between current yield and profit-maximizing yield-is about one-quarter of the ecological yield gap. Furthermore, although maize yields could be profitably doubled, the economic incentives to do so may be weak. Our findings suggest that agricultural intensification in sub-Saharan Africa could be supported by complementary agronomic approaches to improve soil fertility, lowering the fertilizer cost, and by spatial targeting of fertilizer recommendations.
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“For example, Bonilla-Cedrez et al. 70 showed for maize that (i) the average economic yield gap (the difference betweencurrentyieldandthosethatwouldmaximizepro fi t)wasabout25% of the agronomic yield gap; (ii) although maize yields could, in theory, be pro fi tably doubled, actual economic incentives are weak due to unfa…”
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“Consequently, intercropping could be one of the cropping systems that could reduce the ‘ecological yield gap’ by enhancing soil fertility and minimizing fertilizer expenditures (Bonilla-Cedrez et al. 2021).”
Trade dynamics, performance and positioning of the Peruvian dairy agroindustrial system
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“Together with recent analyses of nutrient management and input gaps in SSA (Bonilla-Cedrez et al 2021, Aramburu-Merlos et al 2024), this suggests that adaptation strategies should jointly manage productivity gains and climate risk, rather than treating them separately.”
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Plot size misperceptions and soil health: A New research agenda
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Beyond yields: Smallholders’ realities matter for biodiversity
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“For example, studies have quantified irrigation benefits in the U.S. (Partridge et al 2023) and sub-Saharan Africa agriculture (Falchetta et al 2023) and fertilizer price constraints sub-Saharan Africa (Bonilla-Cedrez et al 2021).”
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“Moreover, some suggest that inorganic fertilizers alone often provide only limited profitability for smallholder farmers in sub-Saharan Africa, due to high costs and subpar crop response to fertilizer, especially when SOM levels are low (Bonilla-Cedrez et al 2021, Chivenge et al 2022).”
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“Climate variability, particularly erratic rainfall, further exacerbate the risks of rainfed maize production (Cairns et al ., 2021; Silva et al ., 2025), often compromising the return on investment in fertilizer use (Bonilla-Cedrez et al ., 2021).”
Kaste, J. A. M., Ji, R., Sydow, P. W., Sawers, R. J. H., & Matthews, M. L. (2026) · PLANT PHYSIOLOGY · doi:10.1093/plphys/kiag327
“Our results show that in both the USA and SSA, the potential profitability of a nitrogen-fixing maize crop is greater than that typically observed with regular nitrogen fertilizer additions, with a VCR of 44.3 vs 3.4 for the USA and a VCR of 10.7 vs 2.3 for SSA, respectively.”
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- Authors
- Bonilla-Cedrez, C., Chamberlin, J., & Hijmans, R. J.
- Affiliations
- International Maize and Wheat Improvement Center (KE)
- University of California, Davis (US)
- Venue
- Nature Food
- Published
- 2021-10-07
- Volume
- 2
- Issue
- 10
- Pages
- 766-772
- ISSN
- 2662-1355 (ISSN-L)
- OpenAlex
- W3203527942
- Cited by
- 104
- References
- 71
- Citations by year
- 2026: 22 · 2025: 19 · 2024: 17 · 2023: 21 · 2022: 23 · 2021: 2
- FWCI
- 9.20
- Type
- journal article
- Language
- en
- Open access
- closed
- Licence
- Locations
- Nature Food (publishedVersion)
- PubMed (publishedVersion)
- Funders
- Bill and Melinda Gates Foundation (INV-008260)
- Topics
- Life Sciences › Agricultural and Biological Sciences › Soil Science › Agricultural Science and Fertilization
- Life Sciences › Agricultural and Biological Sciences › General Agricultural and Biological Sciences › Agricultural Innovations and Practices
- Social Sciences › Safety Research › Agricultural economics and policies
- Keywords
- fertilizer prices, grain prices, agricultural intensification, soil fertility, food security, sub-Saharan Africa
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