Water Dynamics and Irrigation Demands for Food Crop Production in the Santa Agrarian Basin, Cameroon: A Spatio Temporal Assessment of Surface and Groundwater Resources

Abstract

As the global population continues to rise, food demand is projected to increase by 60% by 2050. The global water–food nexus is under increasing pressure as agricultural systems struggle with growing climate variability, unsustainable water extraction, and rising competition for limited water resources. Agriculture is the largest consumer of freshwater globally, accounting for 70% of all withdrawals, with surface and groundwater serving as its primary sources. Water is a vital input that influences every stage of food crop development, from germination to harvest. This paper investigates the spatio-temporal interplay of surface and groundwater resources on food crop production in the Santa Agrarian Basin. A mixed-methods approach was employed, combining secondary data from satellite imagery (ASTER, HydroSHEDS), climatic records (1980–2024), and agricultural statistics. Primary data were collected through 397 questionnaires, 12 key-informant interviews, and two focus group discussions conducted across 10 communities. Geospatial analysis using QGIS and ArcGIS quantified changes in surface and groundwater potential, while crop water requirements were calculated using the FAO CROPWAT 8.0 tool for tomato and Irish potato. Findings revealed a 50% decline in first-order stream length between 1980 and 2024, with groundwater emerging as the primary irrigation source after 2010. Crop water requirement analysis showed high irrigation dependencies: tomatoes (571.3 mm) and Irish potato (514.3 mm), with supplemental needs exceeding 40–50%. Crop output followed hydrological trends, with peak yields of water-intensive crops reaching 15,100 tons in 2007–2008, then falling to 6,000 tons by 2024 due to aquifer depletion. The paper recommends integrated water governance and the implementation of managed aquifer recharge in high-potential areas such as Pinyin and Mbu to promote water sustainability and agricultural resilience.