Ingeniería de Sistemas de Riego y Drenaje

Evaluation of Irrigation Scheduling for Sprinkler Irrigation System under Existing Condition in Beles Sugar Development Project, Ethiopia

Abstract

Abshiro FK

Appling appropriate field irrigation practices safeguard that crops could get peak supply of water in their root zone for achieving best yield of crops without facing water stress and damaging the quality of soils. Sugar cane fields at study area irrigated to irrespective of the soil type, growing month, and stage of crop growth with the design application efficiency of 70%. Currently the system was not working with the full design capacity so that evaluating the irrigation scheduling under existing condition was very important. Therefore, this study was conducted to evaluate irrigation scheduling with design standards, and develop irrigation scheduling based on the actual existing water application with respect of soil, growing month and stage of growth. Representative soil samples were taken for soil texture, bulk density, field capacity and wilt point test. Secondary data collected were weather data, effective root depth and crop coefficient. The performance parameters analyzed were, crop evapotranspiration, net irrigation requirement, net depth of application, irrigation interval, sprinkler set hour, and application efficiency. The average sprinkler discharge at 3.0 and 2.5 bar operating pressure was 0.9 and 0.8 m3/h respectively. The sprinklers had an average actual application efficiency of 62%. Sprinkler set hours obtained for the age of 0-3, 3-6, 6-15 and >15 month was 13, 19, 25 and 38 h respectively. Irrigation interval obtained for age of 0-3, 3-6, 6-15 and >15 month varied with growing month and had a range of 7-10, 6-21, 7-20, and 16-24 days respectively. According to the study the system was not working under full design capacity. The irrigation scheduling based on the system actual working condition was recommended with respect of growing month and stage of growth.