Statistical Study of Dry Spells and Their Impact on Rainfed Corn in the Burkinabe Sahel

This study aimed at characterizing dry spells and their potential impact in corn rainfed agriculture in the Burkinabe Sahel in order to help managers of rural environments to better plan the corn growing season in this area characterized by high climatic variability. This characterization was made possible through a typology of intra-dekadal dry spells and an inter-dekadal analysis of dry spells with the first-order Markov chains, allowed proposing a mitigation alternative of the effect of dry spells on corn growing. Results showed that climatic risk which arises for rainfed corn production is reduced if sowing was done in the third 10-day period (or dekad) of June. This is justified by the fact that the probability of having two consecutively dry dekads during the most sensitive periods to water stress (i.e the mid-season) was less than 20% while it was over 30% for two consecutively wet dekads. However, because of the increased potential impact of the dry spells longer than 7 days during the mid-season, the coupling of this sowing scenario to supplemental irrigation would be the robust alternative adaptation to climate variability in the Burkinabe Sahel. Nevertheless, subsequent studies can be carried out to quantify this potential impact of dry spells on corn under rainfed farming.