Browsing by Author "Leta, Teshome"
Item Estimation of Actual Evapotranspiration for Rain Fed Agriculture Using Veget Model in the Meki – Wabe Catchment, Central – Ethiopia(Addis Ababa University, 2013-06-06) Leta, Teshome; Ayenew, Tenalem (Professor)The major impact of climate change is manifested through increased temperature that results in increased evapotranspiration and therefore enhanced soil water deficits. Thus, the study was conducted with the aim of estimation of actual evapotranspiration for Rain fed Agriculture specifically to determine the effect of moisture deficit on crop production in Meki – Wabe Catchment, Central – Ethiopia. It was addressed by using VegET model that integrates commonly used water balance algorithms with remotely sensed Land Surface Phenology (LSP). A time series advanced very high resolution radiometer (AVHRR) NDVI, rainfall estimate (REF) satellite and potential evapotranspiration data for the years 2001-2010 were utilized as input data for the model while grain yield data was used in explaining the impact of moisture deficit on agricultural yield. The result conformed that the average seasonal water requirement of the area varies from 341 mm - 412mm whereas water use varies from 322mm-372mm. The correlation result of WRSI and major agricultural crops of the area indicated with the linear regression correlation coefficients of 0.82, 0.77 and 0.48 for Teff, Maize and Wheat respectively. The impact of moisture deficit on crop production was measured through estimation of yield reduction. Compared to other cropping seasons of the analysis period, 60% yield reduction occurred in 2002 has an area coverage 11.25 percent and 40% percent yield reduction occurred in 2002, 2004, 2008 and 2009 having area coverage of 15%, 26.25%, 16.25% and 13.75 of total area respectively. The relationship between the water balance model WRSI and yield reduction estimation have good negative linear correlation determination coefficient (r=0.74). In the study area, seasonal water requirement vary spatially in the entire catchment. Therefore, the supply of agricultural technologies and type should be made to fit in to the seasonal water requirement of the area.