Efficiency and efficacy of drip irrigation in a Tasmanian Vineyard Irrigation performance was determined by dye tracer staining, soil hydraulic assessment and modelling

Irrigation performance was determined by dye tracer staining, soil hydraulic assessment and modelling. The dye tracer studies demonstrated that infiltration through the topsoil was almost entirely vertical with little if any lateral water spread below the saturated area of ponding directly beneath the dripper. However in the subsoil, irrigation spread laterally between drippers via macropores rather than as saturated flow on top of the clay subsoil. Irrigation application uniformity was very low as the majority of the root zone was not wetted by irrigation. Pulse irrigation increased the proportion of the topsoil wetted by irrigation, although pulse irrigation was also associated with greater preferential flow beneath the rootzone. This study demonstrated that use of dye tracers is an effective, simple means of evaluating drip irrigation performance.