AN ASSESSMENT OF THE EFFECTS OF CLIMATE VARIABLES ON SORGHUM (Sorghum bicolor) YIELD: THE CASE OF MIESSO WOREDA, WEST HARARGHE ZONE, OROMIA REGIONAL STATE, ETHIOPIA

Abstract

Climate variability is among the major environmental challenges of the 21st century. Temporal and spatial rainfall and temperature variation during cropping season induces an important challenge to sorghum yield and in turn to food insecurity. Therefore, this paper intends to assess climate variability and its effects to sorghum yield of Miesso woreda. Both Primary and secondary data were used. Station data of Temperature and rainfall for the period of 1991- 2019 were used for analysis. Data have been analyzed using coefficient of variation, precipitation concentration index and regression model. Furthermore, Mann-Kendall test and Standard normal homogeneity test was used to detect the variability and time series trend of rainfall and temperature. Result revealed that, 33.3 0C the highest amount of maximum temperature and whereas 17.9 0C was lowest amount of minimum temperature. The coefficient of variation of maximum temperature was 1.77 and the coefficient of variation for minimum temperature was 1.36. The highest amount of rainfall was recorded in summer season and the lowest was recorded in winter. The coefficient of variation of rainfall was highest in winter with CV 98.7 and lowest in summer season. Therefore, the summer season had highest amount of rainfall with smallest variation. The MK test shows that there is an increasing trend for both minimum and maximum temperature. The MK test for minimum temperature is statistically significant during the season of autumn and insignificant on spring, summer, winter, and annual period. In the case of rainfall all seasons indicate decreasing trend. Monthly results of coefficient of variation values indicated high rainfall variability. Correlation analysis result showed that the relationship between climate variables and sorghum yield, rainfall and minimum temperature have positive correlation with sorghum yield, whereas the correlation between maximum temperature with sorghum yield is negative. annual regression analysis result indicates that climate variables accounts for only 2.28% of sorghum yield variation. Whereas, the summer climate variables accounts for 31.28% sorghum yield variations and the remaining 68.72% of the variation of sorghum yield could be explained by other climatic and non-climatic factors. Since there is strong irregularity of rainfall in Miesso Woreda and climate variability has negative effects on sorghum yield, there is a need to formulate comprehensive policies, and strategies that specifically address effects of climate variability and mitigation mechanisms