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Research Continues on Fertigation's Benefits

Applying fertilizers and other water-soluble nutrients through irrigation systems shows promise for landscaped properties
By Cindy Grahl


Today's turf managers face a number of challenges, from becoming more environmentally sustainable to working within stricter budgets. Now, experienced industry experts are helping turf pros get greener commercial landscapes, in the environmental sense, as well helping these business establishments save on the bottom line. And they're doing it through the use of fertigation, combined with new methods of water reduction.


To date, fertigation has been used more on golf courses and sports fields than on commercial and residential properties. That could change as its benefits are better documented.
PHOTO COURTESY TURF FEEDING SYSTEMS, INC.

Fertigation is the application of a metered amount of fertilizers, soil amendments or other water-soluble products through an irrigation system. To date, the practice has been more widely used on specialty crops in agriculture, typically in drip irrigation systems, and on golf courses rather than on commercial or residential landscapes, admit proponents.

Fertigation's performance will be documented in a series of case histories, and its benefits and other inputs documented as these consultants work with commercial properties to save on water, labor and energy. In this way, the environmental and economic benefits can be quantified, and even replicated.

The initiative is the brainchild of Michael Chaplinsky, a major proponent of fertigation and a principal at Turf Feeding System in Houston, Texas. Fertigation uses low but frequent applications of soluble nutrients through a facility's irrigation equipment, delivered to the root system, according to its irrigation cycles. Chaplinksy is referencing a study done by University of Florida researchers that says the practice lowers the use of water for irrigation by up to 50 percent, and also reduces labor, chemical and energy costs for equipment (http://turf.ulf.edu/research_fertigation.shtml).

Turf Feeding Systems is now capitalizing on these benefits through an initiative called The Sustainable Community to help turf managers and landscapers reduce maintenance costs by lowering the use of water for irrigation by up to 50 percent, and also reducing labor, chemical and energy costs for equipment.

Chaplinsky is working with Tim Long, an agronomist with over 20 years of experience in golf and resort construction and management. He created the first Gold Audubon International Certified Cooperative Sanctuary in Texas and is working with Trinity Waters, a nonprofit agency, to restore wildlife habitat and improve water quality. Long's part in the initiative is to develop fertigation management systems for the projects and then quantify program success, using stringent scientific guidelines to document the effects.

"Fertigation works with best management practices and affects water use, energy use, labor and fertilizer costs, which are all going up. The efficiencies I have seen from fertigation are pretty amazing," says Long. "There's no need to keep watering the land, and the fertilizer arrives in a form ready for plant uptake, with a uniform application. The efficiency is the important part. We're trying to put together good quality information on the financial side, to see how it affects water use."

Tryout in Texas

Long is developing BMPs for Banyan Water, formerly Acequia, a leading domestic water management firm, which is also involved in the project to quantify how fertigation can be used to improve operations on a variety of properties throughout the country. In fact, it was this firm that brought a 96-acre public sport complex, Town and Country Optimists Sports Fields, of Austin, Texas, into the mix. The club hosts a wide variety of sports, including baseball, basketball, soccer, football, lacrosse, softball and volleyball.

The site has 36 fields in all, and half of that acreage is irrigated. It's run by the Optimists Club, and, being a nonprofit, the complex lacks deep pockets for maintenance. In fact, Executive Director Dennis Burton has only a one-man ground crew. Plus, the brutal 2011 Texas drought has only added to the facility's upkeep burden. Contributors were being asked online to kick in to a Water Relief Fund for the purchase of water from the city of Austin.

When Agronomist Chris Cook of Banyan Water/Acequia, a former user of the complex, saw this appeal, he wanted to bring to it his own kind of help. He approached Burton to take on a three-year contract with his water management company.

"Chris used to play ball here, and it's their first big sports complex," says Burton. The water management system is based on measuring environmental factors to determine exactly how many gallons of water will benefit plants and landscapes, based on soil types, rootzone depth, species, slope, compaction, shade and wind blockage.

The firm is now installing fertigation tanks, herbicide/pesticide tanks and telemetry monitors at its own cost, as measurement is ultimately what its all about.

Banyan Principal Ken Cook, Chris's father, notes that the quality of the water used for irrigation is what drives its consumption, and fertigation technology can be used to introduce nutrients that mitigate salt and other chemical uptake, thus allowing plants to absorb more water, and ultimately reduce their water usage.

Cook says the complex's water bill had gone from $70,000 to $200,000 annually, due to the drought, made even more expensive in that it was potable water from the city. The water management firm's plan is to cap that budget and take on risk for exceeding it. Part of that plan would also include finding non-potable sources, such as graywater, for fertigation.

Benefits of fertigation

Long also notes that fertigation does away with fertilizer loss due to volatilization, when nutrients are blown onto nonproductive areas, and from runoff and leaching. Ultimately, application can become more measurable, and thus more precise, saving on the cost of nutrients and reducing the need for pesticides and herbicides.

He says that fertigation has been seen to use only about 50 to 60 percent of the nitrogen needed as conventional fertilization. Plus, it can also save on use of phosphorus in areas where this is seen as negatively affecting waterways.

Fertigation systems can also be used to apply micronutrients and also wetting agents that will help the water used work more efficiently, says Long, to lower sodium and pH levels.

"In the Southwest, with this drought, water is often from wells and has more sodium in it," he says. "It is harder to get the water to infiltrate." Microbial inoculants can also be used to deliver beneficial bacteria to combat diseases and pathogens, he adds.


Precisely monitored amounts of nutrients applied in irrigation water keeps this Austin, Texas, property picture-perfect and also saves on water costs.
PHOTO COURTESY OF BENCHMARK LANDSCAPES.

But, the biggest upshot on the Town and Country study, Long points out, is that doing actual tissue analysis on the plants allows fertilization to be done according to what the plant itself needs rather than on what the soil is deemed to need. "Efficiencies come in when we know what the plant can absorb," he says.

The case studies at the course and the sports complex are to go on for at least a year. "The big thing will be to see the field trials," says Long. The project is just starting, with photo documentation, soil analysis and GIS studies. "I am anxious to see the results," says Burton. "I'm very excited about it and hoping for the best."

But the senior Cook says his goal is to take the complex from a current 27 million gallons use yearly to 11 million gallons, and to reduce water costs by $70,000. "It's a beginning," he adds. "Using these combined technologies and practices can help us preserve and use these valuable green spaces."

Cindy Grahl has more than 30 years experience writing about contractors and their business issues from her office in Cleveland, Ohio.