Assessing the Effect of Current and Future Climate Variability on Sorghum and Wheat Production in Waghemra Zone of Amhara Regional State, Ethiopia.

Abstract

Climate variability has a direct and in most cases adverse influence on quality and quantity of agricultural crop production. This study aims at understanding the effect of the past and future climate variability on rain-fed wheat and sorghum production in Waghemra zone, Ethiopia. The observed daily rainfall and temperature data were collected from National Meteorological Agency, Ethiopia for the period of 1986-2016 and the future projected daily rainfall and temperature data were downscaled from 20 General Circulation Models under Rcp4.5 and Rcp8.5 emission scenarios for the period 2050s and 2080s.Temporal variability of rainfall and temperature were analyzed using coefficient of variation and standardized anomaly method. Trends were evaluated using Sen‘s slope estimator and Mann-Kendall trend test methods using XLSTAT 2014 software. To evaluate the effect of climate variability on crop yields using multiple regression analysis. The analysis revealed that rainfall exhibited large inter-annual and seasonal variation in the amount and distribution .The rainfall trends showed decreasing in belg while increasing in both annual and kiremt .However; the detected trends are non-significant. On the other hand minimum and maximum temperature showed significantly increasing trends during annual and seasonal time scales. It is very likely that the number of cold days and nights has decreased and the number of warm days and nights has increased. The result of the regression analysis shows rainfall and temperature jointly contributed 84% and 86% in explaining the variations in the yield of wheat and sorghum per hectare respectively in the Waghemra Zone. Projections for future climate suggested that annual rainfall will likely be decreasing by 1.6-2.8% by 2050s and 2080s under Rcp4.5 emission scenario while that of Rcp8.5 scenario showed increment by 1.1-4.3% for the period 2050s and 2080s respectively. The mean annual temperature is projected to be increased within the range of 1.9-2.4 OC under Rcp4.5 for the period 2050s and 2080s respectively .Similarly under Rcp 8.5 scenario the mean annual temperature will be also increasing by 2.8-4.1 OC for the period of 2050s and 2080s respectively. The past and future climate trends, especially in terms of rainfall and temperature and its variability pose major risks to rain-fed agriculture. Specific adaptation strategies are needed for the study area to cope with the risks, sustain farming and improve food security.