Abstract

Researchers have shown that rainfall variability has significantly impacted on crop production with manifestations in frequent poor yield in Sub–Saharan African. This study examined the relationship between rainfall variability and sorghum yield in Potiskum Local Government Area of Yobe State, Nigeria. Rainfall data for 62 years (1956 – 2018) and yield data for sorghum were both analyzed. The standardized coefficients of skewness and kurtosis statistics were used to test for normality of the rainfall series. Pearson’s moment product correlation coefficient was used to show the relationship between the trend in rainfall distribution and its impacts on the yield of sorghum. The results were presented in tables and graphs. The results showed that rainfall series was negatively skewed and had no significant deviation from the normal curve (1.96) at 95% confidence level showing normal distribution of data. The analyzed data showed an anomaly and decline in rainfall. The Pearson’s Coefficient of Determination (R) calculated for sorghum yield (R²=0.364) indicated a negative correlation between rainfall variability and sorghum yield. 36.4% of the variation in sorghum yield was associated with the rainfall variation during the study period. The findings further showed that sorghum is a drought resistant crop in the study area; despite the decline in annual rainfall, sorghum yield was increasing as a result of other factors. The study thus, recommended the provision of early warning weather information to farmers; use of climate-resilient varieties, high and early maturing cultivars and fertilizer management which will play a major role in improving the productivity of sorghum in the study area.

Key words: Climate change, productivity, rainfall variability, temperature.