A study was conducted to determine optimum time of withholding irrigation period of sugarcane at Omo Kuraz Sugar Factory, Southern Ethiopia. The experiment evaluated two sugarcane varieties (NCo334 and B52-298) in combination with withholding irrigation periods (WIPs) of 20, 30, 40 50 and 60 days in a randomized complete block design with four replications. Data were collected on soil moisture content, cane height and weight, number of millable canes, cane yield, Brix and Pol percent juice and analyzed using SAS package. Soil moisture content, affected by the occurrence of rain during WIPs for 30, 40 and 50 days, differed among the five WIPs. Cane height and weight increased significantly at the subsequent WIPs with maximum at 50 to 60 days. The numbers of millable canes in plots at the five WIPs were on par each other. The optimum period for withholding irrigation for improving yield and yield components and Brix and Pol percent juice increased significantly with increase in WIPs, being highest at 50 and 60 days. The result revealed that optimum period for withholding irrigation was 50 to 60 days for improving yield and yield components and quality parameters.

Keywords: Withholding irrigation periods, soil moisture content, cane yield