Modelling the Relationships among Climate Variables, Reference Evapotranspiration and Rice Crop Water Requirement in Makurdi, Nigeria

This study assesses the relationships among climate variables, reference evapotranspiration and rice water requirement in Makurdi, Nigeria Reference evapotranspiration (ETo) and rice crop water requirements were estimated using the CROPWAT 8.0 model over a 45-year period (1980–2024). The Mann–Kendall trend test and Sen’s slope estimator was used to detect monotonic increase or decrease in water demand. The result revealed significant increasing trends in both reference evapotranspiration and rice crop water requirements over the study period. Correlation analysis was used to determine the relationship between climatic variables, reference evapotranspiration and crop water requirement of rice. The result indicated strong positive relationships between temperature, wind speed, reference evapotranspiration, and crop water requirements. The study underscores the growing challenges posed by climate variability on agricultural water demand and highlights the need for improved irrigation management strategies. It recommends targeted capacity-building initiatives by agricultural research institutions, including farmer training on decision-support tools such as CROPWAT, dissemination of timely climate information, and the development of drought-tolerant and early-maturing rice varieties. Overall, the findings provide a robust scientific basis for enhancing climate resilience and optimizing water resource management in rice production systems in the study area.