Benoit Sarr, Sheick Khalil Sangare, Mouhamed Ly, Ibrah Seidou Sanda, and Harald Kunstmann
Climate Research


The estimation of the response of rainfed crops to heat stress and water stress requires adequate accounting for the uncertainty in climatic and non-climatic factors that affect impact assessments. The objective of this research is to narrow the range of values characterizing the limits within which estimates are expected to fall in the diagnostics of agroclimatic risks. Assessments are made by analyzing historical observations and evaluating the influence of heat stress and rainfall variability on crop water demand, on biomass and on grain yields of short-cycle cultivars of pearl millet and maize. We use a wide range of consistent and practical sets of crop model ensemble analyses (based on crop management practices: seedling densities, fertilization levels, early/late sowing dates and soil types), and climate model ensembles from two climate change hypothesis (A1b & RCP8.5) over the West African Sudan-Sahel (WASS). Recent rainfall developments shows that hazardous sub-seasonal rainfall distribution affects crop productivity with increased frequency and intensity of daily rainfall, false start, early cessation of the rainy season and decreasing diurnal temperature range. In 2011-2050 perspectives, relative to the 1981-2010 baseline, a slight increase in temperature (i.e. +0.6 to +0.8 ° C) combined with a stationary-to-moderate decrease in precipitation leads to a 10-15% (8-15%) decrease in above-ground biomass production (grain yield). When the warming is moderate (i.e. +1.4 to 1.8°C), the decline in grain yield worsens (10-20%) despite a slight increase in rainfall projections. At these rates of loss in crop production, resilience can be re-enforced. However, it will require that climate-smart crop management practices are embedded in sub-seasonal and interannual monitoring and early warning systems.