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Rising nutrient availability may have much more impact than climate change on pearl millet in Senegal. P2.045

Garcia L., Affholder F., Sultan B., Muller B., Kouakou P.K.. 2017. Sitges : Elsevier conference, 1 p.. Agriculture and Climate Change "Climate ready resource use-efficient crops to sustain food and nutritional security". 2, 2017-03-26/2017-03-28, Sitges (Espagne).

Introduction Our objective was to assess the impacts of climate change and crop intensification on yields for a typical case of semi arid Africa. Methods Future climate scenarios derived from the CMIP5 ensemble of climate models were built by applying projected changes in temperature and rainfall to the observed local weather data in Senegal. All climate models predict temperature increase in the future, whereas rainfall is predicted as increasing or decreasing depending on the model. To span uncertainty in climate projections we combined different rainfall projections with the time horizon (1985, 2050 or 2080) and with the radiative forcing hypothesis (RCP8.5 or RCP2.6). A crop model, CELSIUS, was specifically built to simulate a millet crop grown under severe and moderate nutrient limitations. CELSIUS was calibrated against observed data from 150 situations of varying weather, soil, and nutrient management, in Senegal. Millet crop was then simulated under present and future climate of the several scenarios, under severe and moderate nutrient limitations. Results Under a given nutrient limiting level and whatever the climate scenario, yield interannual variability increases in the future, and yield increases or decreases in scenarios with rainfall increase or decrease respectively. These differences, in yield, however, are of the same order of magnitude as the error of CELSIUS (35%). Much more substantial is the increase in yield, of 200 to 300%, simulated when shifting from severe to moderate nutrient limitation whatever the climate scenario. Discussion Millet is currently grown under severe nutrient limitations, due to continuous cropping with insufficient recycling and external supply. Our simulations suggest that current scenarios of climate translate into changes in millet yield (positive or negative) of less amplitude than the marked yield increase expected from increasing organic or inorganic fertilization.

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