Issue 5, April 2013 University of Florida ~ Agricultural & Biological Engineering

THE IRRIGATOR NEWSLETTER Feature story: Soil Moisture Sensors Save Water

We began research involving smart technologies in 2004 using soil moisture sensor systems (SMSs). The SMSs were add-on devices that connected to the existing irrigation timer. The system includes a sensor buried in the soil and a sensor controller wired to the timer to act as a disruption switch when the soil moisture exceeds a threshold. When disruption occurs, the soil is considered too wet for additional water and the entire irrigation cycle is bypassed. Since 2004, UF-IFAS has expanded SMS research to include multiple plot studies and residential cooperator studies. Though each study was designed to address specific research questions, the global objective was to determine if SMSs could reduce irrigation application compared to typical residential irrigation systems without sensor

feedback (WOS).

The plot studies were conducted in Gainesville, FL and Citra, FL with sensors buried three inches deep and irrigation runtimes adjusted monthly. In Gainesville, the four SMSs selected for

evaluation were commercially available at the time and programmed with thresholds near field capacity (FC) using manufacturer procedures. In Citra, two SMSs were tested at three different SWC thresholds: low (~50% FC), medium (~80% FC), and high (>=FC). All treatments were programmed to apply the same amount of irrigation per week except for non-irrigated plots that were used as a control for turfgrass quality. Turfgrass quality was rated on a 1 to 9 scale, with 1 representing dead grass and 9 representing

Welcome to the Spring 2013 IrriGATOR newsletter. Just as the changes in weather from winter to spring begin to take effect, our research activities are shifting from frost protection of strawberries to maximizing water conservation during the spring green-up period that historically has little rainfall. Please take a moment to catch up on my team of researchers and our activities. Happy reading, Michael D. Dukes

A note from Dr. Michael Dukes…

In this issue Feature Story: Soil Moisture Sensors Saved Water………………………….. 1 More on Soil Moisture Sensors……... 2

Publications…………………………... 2

Upcoming Events……………………. 3

What’s Up with the Research Team... 4

Did you know…in addition to the EnergyStar program, the EPA now labels certain products as water saving devices through the WaterSense program. Some

products include toilets, showerheads, and ET controllers.

Continued on page 3

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More on Soil Moisture Sensors…

We would like to thank the following agencies for their support on these studies: Southwest Florida Water Management District

Pinellas County Utilities Tampa Bay Water

Florida Turfgrass Association Golf Course Superintendents Association of America

Florida Department of Agriculture and Consumer Services Florida Agricultural Experiment Station

So What’s next?

A complete collection of the UF-IFAS ABE Irrigation Research publications is on our website!

Does it pay?

Research results across projects were consistent and clearly demonstrate that SMSs in Florida—when properly installed, set, and maintained—could lead to important irrigation water savings while maintaining acceptable turfgrass quality. The prices of SMSs have continued to drop from $500+ per unit in 2004 to <$200 by 2011. Considering the high price of the potable water in some localities and the potential water savings when using a SMS, the payback period for these units at an average single-family home could be around 2 years or less.

Due to the increased use of reclaimed water for residential irrigation in Florida, there is the potential for declining SMS functionality from poor soil water conductivity or sensor degradation due to the increased salts in the water. Our current research focuses on testing SMSs at both field plots and homes that use reclaimed water as their source for irrigation. Look for a summary of those results in a future issue of the IrriGATOR.

Relevant Publications The following publications were summarized to provide the feature story:

Cardenas-Lailhacar, B., M. D. Dukes, and G. L. Miller. 2008. Sensor-based automation of irrigation on bermudagrass during wet weather conditions. J. of Irrigation and Drainage Engineering 134(2): 120–128.

Cardenas-Lailhacar, B., M. D. Dukes, and G. L. Miller. 2010. Sensor-based automation of irrigation on bermudagrass during dry weather conditions. J. of Irrigation and Drainage Engineering 136(3): 161-223.

Haley, M. B., M. D. Dukes. 2012. Validation of Landscape Irrigation Reduction with Soil Moisture Sensor Irrigation Controllers. J. of Irrigation and Drainage Engineering 138(2), 135–144.

McCready, M. S., M. D. Dukes, and G. L. Miller. 2009. Water conservation potential of smart irrigation controllers on St. Augustinegrass. Agricultural Water Management 96(11): 1623–1632.

Issue 5, April 2013

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University of Florida ~ Agricultural & Biological Engineering

Results showed that homes with SMSs applied 65% less water than the comparison homes during the mostly dry weather conditions. Despite savings, no differences in turfgrass quality were detected among treatments. Furthermore, homes with SMSs averaged fewer irrigation events (2.3 times/month) than the total possible events under local watering restrictions (4 times/month). Therefore, SMSs could curb over-irrigation by regulating inappropriate timer scheduling.

Upcoming Events

Project team members will be attending the following upcoming conferences.

December 1-5, 2013 Championsgate, Florida

November 6-7, 2013 Austin, Texas

Water Smart Innovations October 2-4, 2013

Las Vegas, Nevada

SMS, cont. from page 1

excellent grass with minimum acceptable quality rating of 5.

Results from the plot studies during normal to wet weather conditions showed that SMSs significantly reduced irrigation application, 42 – 72%, without a reduction in turfgrass quality when compared to traditional residential irrigation systems with no sensor feedback. Even the non-irrigated treatments remained at the minimum acceptable rating. Conversely, during dry weather conditions, SMS-based treatments resulted in water savings ranging from -1 to 64%. The turfgrass quality sometimes declined for SMSs with settings at the lower limit. The non-irrigated plots always resulted in turfgrass quality below minimum acceptable levels and, in some cases, even death.

Threshold settings were important in sandy Florida soils with field capacities around 7 to 11%. The medium thresholds on the SMS-based treatments universally resulted in good quality whereas the high threshold treatments over-irrigated and the low threshold resulted in poor to unacceptable turfgrass quality during dry weather conditions. Therefore, the

medium threshold settings appear to be adequate to balance turfgrass quality and water conservation in Florida. However, the irrigation frequency, run time, and threshold setting should be carefully considered to ensure proper turfgrass health when under sustained dry weather conditions.

After positive field results, a study was conducted to determine “real world” SMS performance in a residential setting. Twelve SMSs were installed at cooperating homes in Palm Harbor, FL with thresholds of 10%. The irrigation schedules were not adjusted for any treatment on any home resulting in the WOS treatments (46 homes) equating to actual homeowner practices.

June 2-4, 2013 Sarasota, Florida

The IrriGATOR Newsletter Issue 5, April 2013

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The Irrigator Newsletter

Agricultural & Biological Engineering Institute of Food and Agricultural Sciences

Frazier Rogers Hall P.O. Box 110570

Gainesville, FL 32611-0570

If you are interested in receiving this newsletter, please email irrigation@ifas.ufl.edu

Further information can be found on our website http://abe.ufl.edu/mdukes

Meet Sara!

Sara Wynn joined the IrriGATOR research team in October 2011 as an undergraduate research assistant. While still in school, Sara worked mostly on the strawberry frost protection project, assisting with field work and data analysis. After graduating with a dual Environmental Management in Agriculture and Natural Resources/Chinese Language degree, she continued working with the research team on a variety of projects. Most recently, she has been assisting with distribution uniformity (DU) tests for a sprinkler nozzle performance project. Sara hopes to be accepted to National Taiwan University in Taipei, Taiwan for the fall 2013 semester to begin a master’s program in Agricultural Economics. In the future, she would like to work in agricultural development in Asia. Wherever she ends up, Sara will always remember the start she got at UF and with the IrriGATOR team!

Updates to our website!

If you haven’t been to our website recently, then we encourage you to check it out. We’ve added short, introductory videos for each research team member that can be found near our contact information.

If you would like to contact anyone on the IrriGATOR research team, please see the contact details on our website: http://www.abe.ufl.edu/mdukes/project-team/index.shtml

What’s up with the Research Team