Spatialization and Zoning of Agro-Climatic Constraints in the Department of Zou in Southeast Benin (West Africa)

In the Zou department of southeastern Benin, agriculture remains highly dependent on rainfall and seasonal water dynamics. Interannual variability in precipitation, water deficits, excess humidity, and irregularities in the agricultural season constitute major constraints on production systems. This study analyzes the spatial distribution and zoning of agro-climatic constraints in the Zou department, with the aim of identifying the most vulnerable areas and better guiding agricultural adaptation strategies. The study is based on the analysis of climate data on rainfall, temperature, and potential evapotranspiration for the period 1993-2022, supplemented by agricultural statistics on yields, cultivated areas, and production of five major crops: maize, cassava, tomato, cowpea, and groundnut. Field surveys conducted with producers allowed for the integration of local perceptions of climate constraints and adaptation practices developed at the farm level. The analysis relied on rainfall anomalies, water balance, the relationship between water and crops, and constraint mapping to arrive at an agro-climatic zoning of the territory. The results show a high degree of irregularity in rainfall patterns in the Zou department, marked by alternating years of deficit, normal rainfall, and surplus rainfall. Deficient years, characterized by low precipitation and periods of drought, disrupt the agricultural calendar and particularly affect crops sensitive to water stress. Conversely, surplus years increase the risks of flooding, soil saturation, and crop degradation in the most exposed areas. Analysis of the water balance highlights a pre-wet period from March to May, a wet period from June to September, and a post-wet phase from October to November, with direct impacts on water availability for crops. The results also reveal a spatial differentiation of constraints, with some areas more exposed to water deficit, others to excess water, and intermediate areas where vulnerability depends on the intra-seasonal distribution of rainfall. This study highlights the value of spatial analysis and agro-climatic zoning as decision-making tools for agricultural planning in the Zou department. It underscores the need to adapt cropping calendars, promote water management practices, and strengthen local resilience strategies to sustainably improve agricultural productivity in the face of climate variability.