Seasonal Rainfall Variability and Its Impact on Wheat Crop Production Over North Showa Zone, Amhara Region, Ethiopia

Rainfall play an important role in crop management and monitoring, as it directly influences planting calendar, irrigation needs, crop growth and yield outcomes. This study was attempted to analyze seasonal rainfall variability and its impact on wheat crop production to understand association of seasonal rainfall characteristics with wheat crop production over North Showa Zone Amhara Region. Both time series station and satellite gridded rainfall data sets were obtained from Ethiopian Meteorology Institute from 1985 to 2021. Wheat crop production for main rainy season (Meher) was obtained from Ethiopian Statistical Service from 2010-2021, collected from household farm association level. Analysis of rainfall data sets was provided with climate data tool (CDT V8), R studio and Microsoft excel and ArcGIS 10.8. Coefficient of variation, precipitation concentration index and Standardized anomaly index (SAI) were applied to analyze long year seasonal and annual rainfall variability. Man-Kendall trend analysis methods were applied for rainfall trend analysis. Correlation coefficient on the other side has been applied to analyze rainfall variability impact on wheat crop production. The findings of this paper indicate irregular variation of spring (Belg) rainfall, moderate to low variation in summer and annual rainfall over the study area. Using correlation and coefficient of determination (R²) analyses, significant spatial variability was observed in the rainfall-crop relationship. Strong positive correlations were found in districts such as Ensaro (r = 0.7, R² = 0.4384) and Tarmaber (r = 0.7, R² = 0.5223), where over 40% and 50% of the variability in wheat production can be attributed to rainfall, respectively. Conversely, weaker correlations were evident in areas like Mojana Wodera (r = 0.5, R² = 0.2049), and Ankober (r = -0.3, R² = 0.097), suggesting that in these districts, rainfall plays a less dominant role in determining crop production, with other factors such as soil fertility and agricultural practices possibly having a greater influence.