a. h. nazemii

In this research، five-drip irrigation systems were selected in Sattarkhan Channels Network and technical performances of them were evaluated. In each system one manifold was randomly selected and four located lateral pipes، at the beginning، one-third، two thirds and end of each manifold were selected. By considering the same proportionality، four apple trees were identified a long each lateral pipe. Emitter discharges of two drippers at each of these trees، pressure at the beginning and at the end of the lateral pipes were measured in the all selected manifold pipes. Also، the minimum lateral inlet pressure at each manifold was identified by measuring the flow pressure of the all lateral inlets. Results showed that the water Emission Uniformities of the systems (EUs) were within the range of 48. 1 to 82. 8 percent and the systems performances based on this index were classified poor to good. Potential application efficiencies of the low quarter of the systems (PELQs) were varied from 43. 3 to 74. 5 percent. So that، only the irrigation system at one of the farms had relatively good performance and the systems'' performances in the other farms were poor. Application efficiencies of low quarter of the systems (AELQs) were in the range of 52. 7 to 80 percent. Based on AELQs index، only one system had good performance while the performances of the others were poor. In general، the reasons for the low system performances were pointed as inappropriate distribution of pressure، high-pressure difference in the systems، the unsuitable irrigation water depth، low skills of irrigators and poor operation management of the systems.