ANALYSIS OF DRY SPELLS AND ITS IMPACT ON THE YIELDS OF MAIZE AND WHEAT CROPS, IN HADIYA ZONE, SNNPRS, ETHIOPIA

Abstract

This study is focus on the analysis of dry spell and its impacts of the yields of maize and wheat crops in Hadiya zone, southern Ethiopia. The study area is geographically located between 7.010

to 7.6o N and 37.2o to 38.1o E and 2307m above sea level. Statistical analysis was made using coefficient of variation (CV), precipitation concentration index (PCI), standardized anomaly index (SAI), standardize precipitation index (SPI), Markov chain order one (Instat v+3.36), Multiple regression model and bias correction methods to assess the climate of study area over last three decades, predicting future climate and to find out their impact on productivity of selected crops. Accordingly, the rainfall in the area was characterized by alteration of wet and dry years. Dry years recorded as low as 60.65% below the long term average. Maize and Wheat production show considerably relation with the rainfall of main rainy season. Three RCP future climate scenarios, RCP2.6, RCP4.5 and RCP8.5 of future periods (2015-2100) dynamically downscaled data were obtained from CORDEX-Africa, and then bias corrected for study area. The changes in the status of the climate between the baseline period and the three future scenarios were recognized. The study revealed that in the case of bias correction average annual rainfall is going to increase by 28.26% and 0.56% in 2020s, for RCP2.6 and RCP8.5 scenarios respectively, but it will be decreased by 15.5% using RCP4.5 in the same period. Dry spell years of the baseline period and the future scenarios were identified using SPI (standardized precipitation index) and used to estimate the impacts on percentage yield losses of maize and wheat using multiple regression model and INSTAT software v+3.36. The results investigated that dry spells will become less frequent and more severe for RCP4.5 less frequent and moderate for both RCP2.6 and RCP8.5 scenarios relative to dry spell of the baseline (1988-2014). The analysis generally indicated that the occurrence of prolonged dry spell will have higher yield loss impacts on Maize with the percent loss of 21% in the observed period and 40.6% for the future. And medium impact on Wheat with the percent loss of 17% in the observed period as well as 18.7% for the future emission scenarios will be indicated. So that the farmers of the area should adjust the future farming system in different techniques such as using the small scale irrigation in the suitable areas, also by using different soil and water management techniques and by arranging the planting time of selected crops.