Characterization of Rainfall Trends, Variability and Their Implications on Crop Growing Seasons in Eastern Amhara, Ethiopia

This study investigates the characterization of rainfall season trends and variability and their implications on crop growing seasons in Eastern Amhara, Ethiopia. Understanding rainfall patterns is very important for agricultural planning, water resource management, and climate resilience in a region heavily dependent on rain-fed agriculture. Different researches clearly show the influence of global climate phenomena on regional precipitation patterns and the challenges posed by climate variability in Africa, particularly in Ethiopia. This study is done using CHIRPS data based on the geographical location of 20 areas in the study area over a 40-year period (1981-2020). R Instate software is used to determine onset and cessation dates and Mann-Kendall trend analysis, Coefficient of Variability, Standardized Anomaly Index and Precipitation Concentration Index are used to see the variability and trend of rainfall, rainfall onset and cessation dates. Findings reveal a consistent rainfall onset in early June across most locations, with some areas experiencing earlier or later starts, indicating regional climatic heterogeneity. The cessation of rainfall typically occurs in mid-September, although some areas report variations. CV result shows moderate to low variability in rainfall distribution across Eastern Amhara. Mann Kendall trend analysis showed that all months except June have shown no significant trend with P values over 0.05. An increasing trend is only seen in June for the month June with a p-value of 0.004. No significant trend in onset dates observed in the study area. 5 shows increasing trend and the rest showed no trend on cessation dates. 3 out of twenty areas show significant increasing trend (Amba Mariam, Majete and Wegeltena) on LGP. The SAI, PCI and CV results show a range of results for all the areas and years. Adaptive strategies are necessary to address the identified trends and variability. Farmers are encouraged to adjust cropping calendars, adopt drought-resistant crop varieties, and invest in water harvesting and irrigation infrastructure. The recommendations include integrated water resource management approaches, including investments in rainwater harvesting, storage reservoirs, and efficient irrigation systems. Collaboration among policymakers, researchers, local communities, and development practitioners is crucial to enhance resilience to changing rainfall patterns.