Analysis of El Niño Southern Oscillation and its impact on rainfall distribution and productivity of selected cereal crops in Kembata Alaba Tembaro zone
Bereket Tesfaye Haile, Tadesse Terefe Zeleke, Kassahun Ture Beketie, Desalegn Yayeh Ayal, Gudina Legese Feyisa
Abstract
El Niño Southern Oscillation could likely distort the hydro climatological processes and adversely affect agricultural production at various magnitudes. This study explored the manifestations of ENSO-induced rainfall variability and its impact on selected cereal crops in Kembata Alaba Tembaro Zones of southern Ethiopia. Accordingly, precipitation, temperature, crop, and Sea Surface Temperature (SST) data were collected from the National Meteorology Agency of Ethiopia, and the National Oceanic and Atmospheric Administration (NOAA). Rainfall variability was analyzed using the Coefficient of Variation and various anomaly indices. Spatial and temporal relationships between SST and yield of selected crops were established using the person correlation method. Mann-Kendal trend test was also used for trend analysis. The results revealed a statically significant (P < 0.05) decreasing trend and highly variable spring and summer rainfall. Global SSTs strongly influence both summer and spring rainfalls. El Niño and La Niña events were shown to influence the local rainfall distribution and crop production at varying magnitude over different spaces and times. The yield reduction due to ENSO increases from wheat, barley, maize to Sorghum, respectively, while Enset (ventricosum) was found to be less influenced by ENSO-caused rainfall variability. This implies that sorghum and maize crops are more sensitive to El Niño and La Niña events in the study area compared to the other crops considered in this study. The conformity of Enset yield with rainfall variability could be attributed to its tolerance to moisture stress. From the results, one can conclude that the overall cereal crop productivity was adversely, but differentially, affected by ENSO-induced climate variability.