Abstract

Abstract: The objective of this study was to evaluate water productivity of alfalfa (Medicago sativa) under centre pivot irrigation system. The experimental works were conducted at three centre pivot irrigation projects (Indian, Arab Authority for Agricultural Investment and Development (AAAID) and Sedonix projects) located at Khartoum State during the period from April 2011 to April 2013. In each project, three irrigation systems were randomly selected for the study treatments. Crop water requirement was obtained using CROPWAT 8 computer model. The parameters tested were Christiansen coefficient of uniformity (Cu%), distribution uniformity (Du%), Scheduling uniformity (Su) and Water productivity (kg/m3). SAS (statistical package) was used to analyze the data. The variations among means were checked by the least significant difference (LSD). The results showed that Cu%, Du%, Su and water productivity significantly affected by the management practices in different irrigated projects. Sedonix project gave the highest values of hydraulic characteristic (Cu 85%, Du 81% and Su 1.23) while AAAID project recorded the lowest values (Cu 74%, Du 70%, Su 1.43). Water productivity significantly increased in Sedonix project (0.45 kg/m3/cut) followed by Indian projects (0.38 kg/m3/cut) and AAAID which ranked the least (0.27 kg/m3/cut). It is concluded that for improvement water productivity; proper technical guidelines for system management, operation and scheduling should be followed.