Irrigation study to examine 'smart' home irrigation units
New technologies promise water savings and healthier lawns
New "smart sensor" irrigation technologies hold the promise of preventing over-watering of home lawns, athletic fields and public parks, said a Texas AgriLife Extension Service expert.
Over-watering not only wastes water, energy and money, it may also encourage several turf diseases and cause nutrient leaching and runoff, said Dr. Karl Steddom, AgriLife Extension plant pathologist.
A new study conducted by Steddom and Dr. Lloyd Nelson, ryegrass breeder with Texas AgriLife Research, will compare the effectiveness of different irrigation systems.
Steddom and Nelson are conducting the study at the Texas AgriLife Research and Extension Center at Overton in East Texas. The East Texas Irrigators Association is cooperating with the study.
"Water conservation is a big issue in Texas," Steddom said. "Legislation is coming that will require professional turf grass managers--and eventually homeowners,v too--to install smarter irrigation systems."
Though the study is being done in East Texas, the results should be applicable to much of the state, Steddom said.
"Turf irrigation demands in East Texas are highly variable," he said. "Our sandy soils and intermittent rainfall patterns result in frequent fluctuations between periods of low water demand and high water demand. This makes this location an ideal or 'worst case scenario' to evaluate these new approaches to irrigation scheduling."
Nelson, who has developed and released several successful turf grass varieties including Axcella, Axcella 2 and Panterra, said there is a real need for data on water usage by cool-season grasses.
"We (typically) overseed ryegrass in the fall, and it's water-intensive," Nelson said. "We're particularly interested in the moisture requirements of the ryegrass during the colder winter months. We'd like to see how little water we can apply to an overseeded lawn and still maintain a high-quality lawn."
Todd Magatagan, past president of the East Texas Irrigators Association, said professional landscapers and irrigation installers are some of the most important stakeholders in the research. As smart controllers become more widely used, it will be the commercial installers like himself who will need to know which products and technologies prove to be the most reliable for customers.
"We're in phase one of this project," Magatagan said. "Phase one creates a baseline, but phase two will run actual products that are on the market and give us an independent testing method where this type of intelligent controller or this one works better."
Phase one of the study will have four treatments. One treatment will be timed irrigation units, which are the most common type installed in home lawns today. With timed units, sprinklers are turned on for a set time. In the irrigation study, the sprinklers will be turned on for 15 minutes every other day, providing approximately 0.3 inches of water.
In the second treatment of phase one, a timed system is used identical to the first, except if there is a substantial rain, the system won't turn on for a couple of days. This is also a common home setup, Steddom said.
The third treatment will utilize a system that has sensors to measure soil moisture. When and how much water is applied will depend upon soil moisture readings from 2 to 8 inches deep.
The fourth treatment is the most sophisticated, said Steddom and Magatagan. Irrigation applications are based on evaportransporation determined by the center's research-grade weather station. The automated weather station takes multiple measurements of humidity, temperature, solar intensity and wind speed to estimate how much moisture is lost daily. Combined with rainfall records, a formula is used to determine how much moisture will need to be applied.
All test plots will use St. Augustine grass overseeded with ryegrass in the winter. Actual water use will be recorded, as will soil nutrient levels, to determine leaching from over-watering. Also, Steddom will keep a close eye on any turf grass disease problems, he said.
The second phase of the study will compare commercial smart-irrigation systems.
In commercial sysyems, the sophistication of off-the-shelf smart controllers ranges from those that try to estimate evapotransporation to those that actually measure soil moisture, Magatagan said.
"The number of (commercially available) smart controllers is growing every year," Magatagan said. "(At this time) we expect to be testing about a dozen smart-controller systems."
Manufacturers of smart-controller systems who want to know if their systems are among those being tested may contact Magatagan at 903-445-5151 or LVATM@earthlink.net.
East Texas Irrigators Association completed installation of the test plots at their expense and paid for the maintenance of the scientific weather station that calculates evapotranspiration. A grant from the Texas Turf Research, Extension and Education Endowment paid for the sensors, equipment and water meters. The Texas Nursery and Landscape Association also helped fund the project, Steddom said.
Results from phase one should be available in early 2010; phase two results in late 2010 or early 2011, Steddom said.
Magatagan emphasized that learning which systems work better is not only good business, it makes environmental sense.
"Watering with smart-controller systems can save up to 50 percent of water used," he said.