10. Effects of Climate Variability on Crop Diversity Over the Agroecological Zones of Gumara Watershed, Northwest Ethiopia

This study demonstrated the trend of climate and the decadal dynamics of the crop diversity in the Gumara watershed, Ethiopia. The Gridded Satellite and observed historical climate data from the period of 1987–2016 and the crop-climate history were the data sources. The Mann–Kendall test and Sen’s slopes estimator were used for trend analysis. Ratings from the Food and Agriculture Organization (FAO) crop-climate requirements were used for crop diversity dynamics. The results indicated a nonsignificant increase in decadal Kiremit rainfall of 27 mm at Weyna Dega and 43 mm at Dega agroecological zones. The Kiremit season temperature variables exhibit statistically significant increasing trends in all zones. In general, decadal increments of 0.4 °C for minimum and maximum temperatures and 0.5 °C for mean temperature were recorded in the watershed. The recent period of decadal increment in maximum temperature negatively affected most selected indigenous crops at the lower elevation and helped to move the crops forward to the higher elevation. The study revealed that improved crop varieties should be introduced according to the watershed agroecological zones. The traditional agroecological zone classification system of Ethiopia must be systematically updated. In addition, to detect detailed information on crop-climate associations and the effects of climate variability on crop diversity, yearly analysis rather than decadal analysis is suggested for governments and future research.