REAL-TIME MEASUREMENT OF DRAINAGE FROM POT-IN-POT CONTAINER NURSERIES

Abstract

In pot-in-pot nursery production, information on the amount of drainage water loss from the pots due to irrigationand rainfall is beneficial to improving irrigation water use efficiency and optimizing nutrition management. An experimentalfield site was established to determine drainage water loss from pot-in-pot container nurseries with micro-irrigation. Thesite consisted of 50 container-grown trees, 10 tipping-bucket rain gauge units, and a portable weather station. Rain gaugeunits were calibrated four different ways to determine repeatability and reliability for real-time measurement of the drainagewater. Volume of water was calculated from the product of number of tips and volume per tip. Accuracy of measurements wasverified by the amount of drainage water collected weekly in collection buckets located under rain gauge units for variousirrigation applications and rainfall events. The maximum difference in the weekly amount of drainage water collected withthe collection buckets and measured with the rain gauge units was 1.215 L (or 5.3% error) when the daily irrigation applicationto five trees was 15.5 L. The system reported real-time measurement of drainage water due to irrigation and rainfall,and provided a research tool to evaluate strategies for nurseries to better manage irrigation schedules.