# Soil-crop long-term feedback matters to assess climate change impact on maize yield in Sub-Saharan Africa

Antoine Couedel, Gatien Falconnier, Myriam Adam, Rémi Cardinael, Kenneth J. Boote, Eric Justes, Alex C. Ruane, Ward N. Smith, Anthony M. Whitbread, Marc Corbeels

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## To cite this version:

Antoine Couedel, Gatien Falconnier, Myriam Adam, Rémi Cardinael, Kenneth J. Boote, et al.. Soil-crop long-term feedback matters to assess climate change impact on maize yield in Sub-Saharan Africa. EGU General Assembly 2024, EGU, Apr 2024, Vienna, Austria. 2 p., 10.5194/egusphere-egu24-9930. hal-05181913

HAL Id: hal-05181913

https://hal.science/hal-05181913v1

Submitted on 23 Jul 2025

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# Soil-crop long-term feedback matters to assess climate change impact on maize yield in Sub-Saharan Africa

Antoine Couëdel<fnref n="1" />, Gatien N. Falconnier<fnref n="1" />,<fnref n="2" />, Myriam Adam<fnref n="4" />,<fnref n="5" />, Rémi Cardinael<fnref n="6" />, Kenneth Boote<fnref n="7" />, Eric Justes<fnref n="8" />, Alex Ruane<fnref n="9" />, Ward Smith<fnref n="10" />, Anthony Whitbread<fnref n="3" />, Marc Corbeels<fnref n="1" />,<fnref n="3" />, and the co-authors*

Sub-Saharan Africa (SSA) faces significant food security risks, primarily due to low soil fertility leading to low crop yields. Climate change is expected to worsen food security issues in SSA due to a combined negative impact on crop yield and soil fertility. A common omission from climate change impact studies in SSA is the interaction between change in soil fertility and crop yield. Integrated soil fertility management (ISFM), which includes the combined use of mineral and organic fertilizers, is expected to increase crop yield but it is uncertain how this advantage is maintained with climate change.

We explored the impact of scenarios of change in soil fertility and climate variables (temperature, rainfall, and CO₂) on rainfed maize yield in four representative sites in SSA with no input and ISFM management. To do so, we used an ensemble of 15 calibrated soil-crop models. Reset and continuous simulations were performed to assess the impact of soil fertility vs climate change on crop yield. In reset simulations, SOC, soil N and soil water were reinitialized each year with the same initial conditions. In continuous simulations, SOC, soil N and soil water values of a given year were obtained from the simulation of the previous year, allowing cumulative effects on SOC and crop yields.

Most models agreed that with current baseline (no input) management, yield changed by a much larger order of magnitude when considering declining soil fertility with baseline climate (-39%), compared with considering constant soil fertility but changes in temperature, rainfall and CO₂ (from -12% to +5% depending on the climate variable considered). The interaction between change in soil fertility and climate variables only marginally influenced maize yield (high agreement

<footnote n="1">¹AIDA, Univ Montpellier, CIRAD, Montpellier, France</footnote>

<footnote n="2">²International Maize and Wheat Improvement Centre (CIMMYT)-Zimbabwe, 12.5 km Peg Mazwe Road, Harare, Zimbabwe</footnote>

<footnote n="3">³International Institute of Tropical Agriculture (IITA), c/o ICIPE Compound P.O. Box 30772-00100, Nairobi, Kenya</footnote>

<footnote n="4">⁴UMR AGAP Institut, Univ Montpellier</footnote>

<footnote n="5">⁵National University of Battambang, Battambang Province, 021402, Kingdom of Cambodia</footnote>

<footnote n="6">⁶Department of Plant Production Sciences and Technologies, University of Zimbabwe, Harare, Zimbabwe</footnote>

<footnote n="7">⁷University of Florida, Gainesville, FL, USA</footnote>

<footnote n="8">⁸PERSYST, Univ Montpellier, CIRAD, Montpellier, France</footnote>

<footnote n="9">⁹NASA Goddard Institute for Space Studies, New York, NY 10025, USA</footnote>

<footnote n="10">¹⁰Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, ON, Canada</footnote>

<footnote>*A full list of authors appears at the end of the abstract</footnote>
between models). The model ensemble indicated that when accounting for soil fertility change, the benefits of ISFM systems over no-input systems increased over time (+190%). This increase in ISFM benefits was greater in sites with low initial soil fertility. We advocate for the urgent need to account for soil-crop long-term feedback in climate change studies to avoid large underestimations of climate change and ISFM impact on food production in SSA.

**co-authors:** François Affholder, Juraj Balkovic, Bruno Basso, Arti Bhatia, Bidisha Chakrabarti, Regis Chikowo, Mathias Christina, Babacar Faye, Fabien Ferchaud, Christian Folberth, Folorunso M. Akinseye, Thomas Gaiser, Marcelo Galdos, Sebastian Gayler, Aram Gorooei, Brian Grant, Hervé Guibert, Gerrit Hoogenboom, Bahareh Kamali, Moritz Laub, Fidel Maureira, Fasil Mequanint, Claas Nendel, Cheryl H. Porter, Dominique Ripoche, Leonard Rusinamhodzi, Shikha Sharma, Upendra Singh, Johan Six, Amit Srivastava, Bernard Vanlauwe, Antoine Versini, Murilo Vianna, Heidi Webber, Tobias Weber, Congmu Zhang