Evaluating irrigation scheduling and application efficiency: baseline to revitalize Meki-Ziway irrigation scheme, Ethiopia

Abstract

Irrigation scheduling and application efficiency were evaluated for Meki-Ziway irrigation scheme in an overall effort to revitalize the scheme. The evaluation was done on three furrows in each of the four farm plots. Field capacity, permanent wilting point and bulk density of the four plots were determined in the laboratory. We monitored furrow inflow rate, cutoff time and soil moisture content in the plots over a period of about 4 weeks. This monitoring was done during both periods of water availability and water scarcity. Our results show that on average 58% (range 42–77%) of the applied irrigation water in this scheme can be considered beneficial for crop growth. The results also show that soil moisture content at farm plots at the canal head sections was always between soil saturation level and permanent wilting point. For farm plots along the middle and tail sections of the main canal, soil water content would even fall below the permanent wilting point. This was caused by the absence of a water allocation system to ensure equity, and by large, channel seepage losses along the unlined main canal. To improve irrigation efficiency therefore, rehabilitation of the physical infrastructure of the scheme, more equitable irrigation water distribution in the scheme and improvement in on-farm irrigation water management are needed.