Abstract
The objective of this study is to evaluate the impact of climate change on the hydrological balance of the Comoe basin, an area of rainfed agriculture. Frequency analysis of cropping seasons, with estimation of cumulative water deficit through a daily water balance simulation (1950\textendash2000), was used to explore the impact of variation in climate conditions on the cropping season. The performance indicators show an uneven evolution of agroclimatic potential: in a unimodal regime centred on the north of the basin, the cropping season duration, which did not change significantly, is consistent with the small changes in onset and end dates to that season; however, the cumulative water deficit increased from 750 mm to more than 850 mm. In contrast, in the bimodal regime, the western fringe, while less affected by both the recession and the rainfall deficit, undergoes an unusually short duration of cropping season. Thus, the second cropping season no longer lasts 90 days and seems less compatible with some cropping cycles. Such drought could increase the risk in annual cereal production without, however, being a leading limiting factor. Editor Z.W. Kundzewicz; Guest editor D. Hughes