ABC Journal of Advanced Research, Volume 7, No 2 (2018) ISSN 2304-2621(p); 2312-203X (e) CC-BY-NC 2014, i-Proclaim | ABCJAR Page 45 Effects of Operating Pressure, Nozzle Diameter and Wind Speed on the Performance of Sprinkler in Irrigation System during Water Application Dereje Bishaw Nigatie 1* , Megersa O. Dinka 2 , Tilahun Hordofa 3 1 Researcher in Irrigation Engineering; Research & Training, Sugar Corporation, ETHIOPIA 2 Department of Civil Engineering Sciences, Faculty of Engineering and Built Environment, University of Johannesburg, SOUTH AFRICA 3 Ethiopian Institute of Agricultural Research, ETHIOPIA * Corresponding Contact: Email: derejebishaw@yahoo.com ABSTRACT Owing to an increasing demand for irrigation water associated with the massive expansion of irrigated sugarcane farms in Ethiopia, there is a need to use the available water efficiently and effectively. Accordingly, a study was conducted to evaluate the effect of operating pressure and nozzle size on the field performance of dragline sprinkler system at Wonji/Shoa Sugar Estate. The study was conducted under three wind phases (morning, mid-day and late afternoon) using three operating pressures (250 kPa, 300 kPa and 350 kPa) and two nozzle sizes (4.4 and 4.8 mm). Uniformity measurements were performed using single sprinkler and four sprinklers configurations. An application efficiency of low-quarter of 41% to 80.3% and actual application efficiency of low-quarter of 30.1% to 37.5% were achieved under the respective test combinations. Christiansen’s coefficient of uniformity of 71.7% to 86.3%, and distribution uniformity of 61% to 80.3% were achieved under different test combinations for four sprinklers test. The achievable delivery performance ratio was in the range of 0.81 to 1.18. The experimental results illustrated that, lower operating pressure and higher wind velocity were the major factors responsible for the low water distribution uniformity and efficiency. Keywords: adequacy, efficiency, nozzle diameter, operating pressure, uniformity, wind speed 4/29/2018 Source of Support: Nil, No Conflict of Interest: Declared This article is is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. Attribution-NonCommercial (CC BY-NC) license lets others remix, tweak, and build upon work non-commercially, and although the new works must also acknowledge & be non-commercial. INTRODUCTION Inappropriate design, installation or management of irrigation system could be the reason for the poor performances of sprinkler irrigation (Magwenzi, 2000; Smajstrla et al., 2002). The most important aspects in the sprinkler systems performance is the uniformity of