Hydraulic Evaluation of Loop and Pair Connection of the Lateral Ends in Dripirrigation Eystem

The aim of this research was evaluate end connection types of drip irrigation system laterals affecting on uniformity of water distribution. To carry out research, a drip irrigation system was installed on flat plot with dimensions of 80m × 90 m in Zanjan University Research Farm. Experiments was carried out in 3 different treatments including conventional laterals layout (C.L.) connecting laterals end as pairs (P.C.), and loop (L.C.). Also 3 different input pressures i.e., 0.5, 1.0 and 1.5 bar were used. Results showed, at 0.5 bar input pressure, emitters average discharge ( a q ), variability coefficient (Cv) and Christiansen’s uniformity coefficient (Uc) were 2.9LPH, 11.0% and 92% (respectively) for P.C., 3.0LPH, 10.7% and 91%, for L.C. and 2.8LPH, 13.1% and 89 % for C.L. At 1.0 bar input pressure, Cv in C.L., P.C. and L.C. were obtained 9.1%, 5.7% and 4.9% (respectively), and a q and Uc for 3 different connects were 4.8 LPH and 92% for C.L., 4.1LPH 96% for P.C. and L.C. for C.L. (for both). At 1.5 bar input pressure, due to inflict excess pressure to the system, a q were calculated 5.0 (C.L.), 4.9 (P.L.) and 5.0 (L.C.) LPH. In this input pressure, Cv values for C.L., P.C. and L.C. were 9.7%, 8.4% and 5.5% (respectively), and Uc were 93%, 94% and 96% (respectively). As the results of the research in the case study site, connecting of lateral ends (as pair or loop) were improved and increased water distribution uniformity compared conventional connecting which the increasing was more for loop connection.