Adam Adam

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.

This paper offers a new approach to the philosophical foundations of information systems through feminist philosophy and, in particular, feminist epistemology. This can be used to expose the universalizing tendency of many information systems and to show the importance of using real-life complex examples rather than the simplified examples often favored by philosophers. Within traditional epistemology and its relation to IS, subjectivity, the propositional/skills distinction and epistemic hierarchies are subject to arguments from feminist epistemology. With respect to the emerging critical school of IS, feminist epistemology, and within that, feminist standpoint theory, are used to examine the complexities of the positivist/anti-positivist position and the related concept of emancipation. In addition, it is argued that the liberal version of emancipation encapsulated in such systems may have an effect opposite to that of emancipation These issues are illustrated in an existing expert systems project.