Research Supports Water-Saving Claims


Soil surfactant technology might be unfamiliar to lawn care newcomers, but wetting agents have been available and their use has been growing for turfgrass and many other plant health markets for more than a half-century.

Robert A. Moore, a chemical engineer, is generally acknowledged as introducing AquaGro, the first commercially available soil wetting agent. Moore founded Aquatrols in 1955. The New Jersey-based company, remains a leader in the surfactant technology, sells product worldwide and is still operated by the Moore family.

Surfactants are widely used in agriculture, sod production, plant nurseries and greenhouses, golf course and sports turf maintenance but less so in the landscape/lawn segment of the green industry.

The acceptance and growth in both the variety and sale of surfactants in this past half-century is a testament to their value in changing the way water moves in the soil and the way soil accepts water. The utility of these polymer-based products has been validated by university research at various test sites.

Dr. Sowmya Mitra, with the department of horticulture/plant and soil sciences, California State Polytechnic University, Pomona, conducted a compelling study in 2003. Mitra is now head of marketing for ornamentals, turf and landscape at Syngenta Asia.

Wrote Mitra in the report he released at the conclusion of the study: “The quantity and quality of irrigation water are limiting factors in maintaining high-quality turfgrass for landscapes and golf courses in Southern California.” Sound familiar?

Mitra evaluated three different surfactants and their interaction with two different water sources at the Center for Turf Irrigation and Landscape Technology at Cal Poly Pomona. During the experiment, he irrigated 12 plots of GN-1 Bermudagrass with potable water and 12 plots of GN-1 with recycled water. He injected three different surfactants into the irrigation lines on some of the plots. Each plot was irrigated separately.

He started the experiment in May 2003 by irrigating the plots at 100 percent of the reference evapotranspiration (ET) for that month. In June, the amount of water was reduced to 70 percent ET, followed by a further reduction to 30 percent ET in July. Finally, in August, the plots were irrigated at 10 percent ET to induce moisture stress.

“Overall the surfactant injection treatments helped in retaining moisture in the soil,” Mitra wrote in the conclusion to his report. “The treatment effect was more pronounced under moisture stress (30 percent and 10 percent ET). We could maintain a live growing surface with only 10 percent of the ET demand but the turf quality was not optimum.

“Bermudagrass could be maintained under optimum growing conditions with 30 to 50 percent of the ET demand when grown on a fine-textured soil. The irrigation schedule has to be modified when bermudagrass is grown on a more coarse textured soil. The infiltration rate in that particular soil should also be taking into consideration when growing turf on a coarse textured soil”

The take-home message of the research project is stated in the final sentence of Mitra’s report: “Hence, we could conserve water by developing a proper program of systematic injection of surfactants into the irrigation lines.”