Abstract:
In Ethiopia where crop production overly depends on rainfall and temperature, studying the variability of these climate variables at a local scale is essential to devise proper strategies that enhance adaptive capacity. In light of this, a study was conducted in Abshege Woreda, Gurage Zone to analyze climate variability for maize production and to characterize local farmers’ perception towards rainfall and temperature variability. Data on climate variables (1986-2015) and maize yield (2000-2015) were obtained from National Meteorological and Central Statistical Agency of Ethiopia, respectively. Future climate data were downscaled using (Marksim GCM) the output of CSIRO-Mk3-6-0 and Had-GEM2-ES GCM model under RCP4.5 emission scenario for the period 2017-2046. Trend, variability, correlation and regression analysis were carried out by Instat V3.36 and Stata softwares. Crop water requirement was estimated using CROPWAT8.0 for window. A total of 179 sample households were selected using simple random sampling technique for interview and data acquired was analyzed using SPSSv20 statistical software. The analyzed data indicated a mean onset date, cessation date and length of growing period of the main rain season were May 5, September 14 and 133 days, respectively. The respective annual and kiremt rainfall amounts were found to increase by a factor of 4.5 and 6.15 mm/year. However, the seasonal belg rainfall amount decreased by -2.23 mm/year and it was not statistically significant for the study period of 1986 to 2015. Respective annual and belg maximum temperature showed an increasing trend by a factor of 0.03 and 0.06 OC/year, but a decreasing trend was observed in kiremt maximum temperature by -0.13 OC/year. Minimum temperature revealed a decreasing trend at annual, belg and kiremt seasons by a factor of -0.2, -0.16 and -0.1 OC/year, respectively. Furthermore, the results of Pearson Correlation Coefficients indicated that number of kiremt rainy days has a strongly positive relationship (r= 0.72) with maize yield whereas the respective kiremt total rainfall and rainfall cessation have moderately negative (r= -0.56) and positive(r= 0.58) correlation. Multiple regression analysis predicted that an increase in kiremt total rainfall will cause a decrease in maize yield. However, an increase in kiremt number of rainy days, length of growing period and kiremt maximum temperature will result an increase in maize yield. The result of projected maize yield indicated that there will be variability in yield by the years of 2017, 2020, 2030, 2040 and 2046 due to the impact of unexpected changes in rainfall and temperature. A maize variety with a growing period of 140 days to maturity would requires 423 mm depth of water, while 101 mm would be required as supplementary irrigation depth. The study revealed that most of the interviewed farmers for the studied kebeles perceived rainfall and temperature are changing over time. CSIRO3-6-0 model showed a decreasing trend in kiremt rainfall in the area, this call and recommend the need for further study with several GCM models to confirm the present results and devise adaptation options
