Sip pulse irrigation on fruit tree crops. Conclusive phase of a research in the plain of Lodi.

摘要

A technical and functional analysis of the open circuit sip irrigation system 'Irrisor' was carried out in a peach orchard under experimental conditions in Italy. The same crop was previously irrigated by the closed loop type of Irrisor system. There were 31 open circuits 4.5 m apart and their length varied according to the number of peach-trees in the row. The distance between the emitters was fixed at 2.5 m so that each peach-tree was irrigated from two emitters. Emitters distributed water through 300degree C distributors situated at 0.6 m from the soil. The whole of the irrigation plant had 979 emitters. Flow rate measurements of the emitters were carried out in the year of irrigation plant installation (1991) and afterwards (1998) on a sample of seven circuits. The mean value of the Christiansen uniformity coefficient was 32%. This value was due to the excessive number of emitters controlled by the pilot valve. Other causes which must be taken into account include the different lengths of tubes connecting the emitters, difference in tube dilatation due to the difference in the geometrical and elastic properties of the tube and difference in the exposure of the tube to sunlight. Finally, the presence of air in the circuit during the trials must be taken into account.