EVAPOTRANSPIRATION-BASED FURROW IRRIGATION SCHEDULING FOR MAIZE (Zea mays L) CROP AT ARBA MINCH, SOUTHERN ETHIOPIA M.Sc. THESIS

Abstract

In semi-arid areas, the quantity and distribution of rainfall are not adequate to sustain crop growth development .Water is the most limiting factor for crop production in these areas. Water-saving irrigation water management is required to increase crop yield per unit volume of water. This study was carried out to evaluate the effect of deficit irrigation practices on yield and water use efficiencies of irrigated maize crops using the conventional furrow irrigation method at Arba Minch University farm, Ethiopia. Three levels of irrigation water application based on ETc (100%, 70%, and 40% of ETc) were used as treatments in a randomized complete block design with three replications. Plant phenology like plant height, leaf length, leaf width, number of leaf, and yield components such as above-ground biomass, cob length, number of grain per cob, and grain yields were measured. Results indicated that different levels of deficit irrigation had a significant (p<0.05) effect on plant height, leaf length, fresh biomass, dry biomass, cob length, number of grain per cob, and a highly significant effect on grain yield. The highest crop water use efficiency and field water use efficiency of 4.24kg/m3 and 3.06kg/m3 , respectively, were obtained from 40 percent of ETc water applications. The highest grain yield of 6934.33kg/ha was obtained from 100 percent of ETc water applications and the minimum grain yield of 4623.33kg/ha was obtained from 40% of ETc water applications. The amount of yield reduction due to water stress by decreasing the amount of water from 100% to 70% of evapotranspiration and 100% to 40% of evapotranspiration are 5.06% and 32.6% respectively. The amount of water saved from T2 and T3 can irrigate 0.284ha and 0.56ha land, respectively, but the yield reduction is very high in T3. From this experimental study, it is recommended that the application of 70% of ETc (full irrigation) during scarcity of water is feasible for maize production without significant yield reduction. Key words: Deficit irrigation, Maize crop, water use efficiencies, furrow irrigatio