Observations of soil water and salt movement under drip and flood irrigation in an apple orchard

Part of a mature apple orchard, previously flood irrigated, was converted to drip irrigation in August 1971 and maintained until May 1975. The remainder of the orchard was irrigated as before.Annual estimates were made of moisture, total soluble salts and chloride content of soil samples and of growth, leaf chloride and yield of trees from the two irrigation treatments. Soil moisture was also monitored with a neutron moisture meter.Very high salt concentrations were observed in the various soil layers in the drip irrigation treatment. The flood irrigation treatment had lower and less variable concentrations of salts.Yields and chloride content of leaves sampled each January did not differ significantly between treatments. Tree girths were smaller under drip irrigation.The drip system, using a low pressure head, filtered water and outlets wrapped in fibreglass, operated satisfactorily for the period of the trial.