Following a study by ABE graduate student Isaya Kiseka that successfully used a ET-based controller in a star fruit orchard, the Water Resource Engineering team installed an off-site ET-based timer on a pressurized irrigation system servicing a young avocado orchard at TREC in Homestead, FL.
This particular controller is of the “off-site” variety, meaning that it receives ET information from a weather service at another location. Beyond this, it is similar to other ET-based controllers in that it uses such factors as plant-type, soil-type, incline, shade factor, and sprinkler head type in calculating how much water should be applied during a scheduled irrigation event.
The set-up for the avocado orchard system includes additional instruments.
Since the off-site signal does no account for instantaneous rain events, a rain sensor was added to the controller. This sensor will suspend irrigation after it collects a specific depth of water and will sustain suspension until it dries.
A water meter was also added to the system’s mainline to track irrigation event frequency and duration.
Several tensiometers were also installed in the field to insure that irrigation is reaching row ends.
Though initiated in late 2009, the avocado orchard's ET-based irrigation system is finally in working order thanks to the recent efforts of Tina Dispenza.
To view short videos about previous Water Resource Engineering team studies conducted in the aforementioned avocado orchard and with the aforementioned ET-based controller, follow these links:
Evaluation of automatic evapotranspiration-based irrigation scheduling controllers for water and energy savings in southern Florida tropical fruit orchards
Assessing nutrient leaching under different nutrient and irrigation management practices