High value crops often lead the way in the adoption of new technologies, such as slow release fertilizer. Turf certainly is one of the highest value crops grown, especially turf on a golf green. Over the past 30 years, wetting agents have proven their value in the turf market. They may soon start proving themselves in commodity agriculture as well. Custom formulator Exacto, Inc. is working with irrigation equipment supplier, Valmont Industries, to evaluate the impact of wetting agents on irrigation effectiveness.
Keith Fyhr, marketing manager, Exacto, expects such research efforts to attract interest, especially after this year's widespread drought. Although Exacto offers a broad line of wetting agents in the turf market, the custom formulator has no branded products in field crop agriculture nor plans to introduce current products under its brand. However, Fyhr is confident there are a number of benefits to "treating" soils that have been overlooked by producers and distributors of wetting agent technology.
"It's a challenging story to demonstrate clearly, but anything we can do to increase irrigation efficiencies is worth another look," he said.
OVERCOMING A CHALLENGING STORY
Of course, wetting agents and soil conditioners are not new to commodity agriculture and have found a home in some high value crops. Periodic introduction to row crops has not proven economical going back to the mid 1950s when the potential wetting agent polyacrylamide polymer was first discovered.
The challenge in telling the story comes in part from similar stories being told in the past and being disproven or at least not being told convincingly. The late Herb Sunderman, soil research scientist, Colby Branch Agricultural Experiment Station, Kansas State University, captured the essence of the wetting agent controversy in a 1983 North Central Regional Extension Publication, though the concern at the time wasn't drought.
"The necessity to conserve fuel and reduce production costs has renewed interest in alternatives to tillage for increasing water infiltration rate," he wrote. "Soil wetting agents are being examined for their usefulness as such an alternative. Still others categorically condemn them as useless. Their true worth, as this paper explains, lies between those extremes."
"Wetting agents have proven invaluable in turf and especially golf courses, and the technology has continued to improve," said Doug Soldat, assistant professor, Department of Soil Science, University of Wisconisn. "Golf greens tend to have sand-based soils with a lot of organic matter produced by grasses. The sand gets coated with an organic material, which becomes hydrophobic when the soil dries. At that point, applied water runs off, and the soil continues to get drier."
CHANGES IN TECHNOLOGY
Wetting agents prevent the soil from becoming hydrophobic in the first place by reducing surface tension and enhancing cohesion or the attraction of water molecules to solids. Similar to a good degreaser detergent, early wetting agents stripped the organic coverings off. However, they were often harmful to plants, noted Todd O'Connell, foundation manager, Exacto.
"By the mid 1980s, surfactants were found that worked reasonably well and didn't harm turf," said O'Connell. "Since then they have continued to improve, adding value with formulations that last longer, drive root systems deeper or more shallow. Some are designed to be applied with pesticides and some injected into irrigation systems."
It is irrigation injection products that Exacto is currently exploring. "We are working with Valmont Industries, a major irrigation equipment manufacturer and an independent field research firm to evaluate the impact of a wetting agent injected through the system," explained Sexton.
Frank Sexton is the product manager coordinating the irrigation research. "We are looking at water efficiency, comparing 0.75 inch of water per week with wetting agent, water with no wetting agent and 0.375 inch of water with wetting agent on soybean under a center pivot," he explained. "Each plot is a wedge of the pivot of about 6 1/2 acres that we will take to yield."
Sexton is hoping this summer's trials will lead to more and expanded trials involving the patent pending compound polymer. Expectations are that the wetting agent/soil surfactant in combination with a long-chain polymer will not only increase infiltration and air exchange and reduce crusting, but will also hold on to water in the soil.
"We hope the soil surfactant will drive the moisture down deeper and then hold it longer," said Sexton. "If reduced water works as well as the full 0.75 inch, it means water and energy savings."
LEARNING FROM AUSTRALIA
Although wetting agents have not been accepted in American row-crop agriculture, that's not the case in Australia, noted O'Connell. There, equipment is available for application with seeds as well as with transplants in high value cropping.
"They understand drought in Australia and the use of wetting agents," he said. "Specific products need to be applied for a specific purpose at a specific time in the season if it is going to be cost effective for the end user. Application isn't simply drenching a field and crossing your fingers."
O'Connell is enthusiastic about the research being conducted by his company and hopes it leads to much more. However, he is also concerned that in times of drought, soil wetters can be seen as a panacea. "They are one of a number of tools that can be used along with drought-tolerant crops that the seed companies are working on," he said. "Hopefully, multiple tools will be used in tandem."
This is not to say that every product is equal. The formulation is key as wetting agents have been refined for different scenarios. Fyhr noted the spread of products available in the home and turf market and the claims made, some with nothing behind them. "End users and their retail suppliers need to look for the data behind the product," he said. "Study the claims and the data."
Extreme claims are always a red flag. "The whole thing is about data. Does the product hold water...literally," O'Connell added. "There are products out there that we have seen that are fairy dust. They don't have the right data that shows water being held or moved into the correct part of the soil profile. Without the data, you should be suspicious."