Title: Surfactant seed coating - a strategy to improve turfgrass establishment on water repellent soils Authors
Submitted to: International Symposium on Adjuvants for Agrochemicals
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 6, 2013
Publication Date: April 22, 2013
Citation: Madsen, M.D., Kostka, S.J., Hulet, A., Mackey, B.E., Harrison, M.A., Mcmillan, M.F. 2013. Surfactant seed coating - A strategy to improve turfgrass establishment on water repellent soils. International Symposium on Adjuvants for Agrochemicals. p.205-210. Interpretive Summary: Turfgrass managers can experience pore seeding success when trying to establish golf course greens and sports fields on water repellent soils. Soil surfactants can be effective in mitigating soil water repellency but treatments can be costly and difficult to deliver in certain environments. The purpose of this research was to: 1) describe a novel approach for applying soil surfactants to tall fescue seed using seed coating technology, and 2) compare seed coating applications of two different surfactant seed coating chemistries. The results of this study demonstrate that in water repellent soil both evaluated surfactant seed coating chemistries dramatically increased soil water content and stand establishment. Seeds coated with ethylene oxide-propylene oxide block copolymers at lower loading rates tended to be the top performing seed coating treatments.
Technical Abstract: Turfgrass managers can experience poor seeding success when trying to establish golf course greens and sports fields on water repellent soils. Nonionic soil surfactant formulations based on ethylene oxide-propylene oxide (EO/PO) block copolymers are commonly used to treat water repellent soils. Recently developed formulations of alkyl polyglycoside (APG) and EO/PO block copolymer surfactants have also proven to be particularly useful at increasing root-zone water reserves under this soil condition. Typically, irrigation water is used as a carrier in the application of these soil surfactants. While this approach is effective, it can be costly and difficult to apply in certain environments. The purpose of this research was to: 1) describe a more efficient approach for applying soil surfactants using seed coating technology, and 2) compare turfgrass establishment between non-coated seed, EO/PO block copolymer surfactant coated seed, and seeds coated with an APG and EO/PO block copolymer surfactant mixture. Tall fescue (Schedonorus phoenix) was used as the test species. Seeds were coated according to Madsen et al. (WO2010111309) in a rotary seed coater. Within a laboratory grow-room study we compared the response of non-coated seed to EO/PO coated seed and APG EO/PO coated seed, with a surfactant loading rate of 60, 80, and 100 % weight of product to weight of seed (wt/wt). Seeds were sown in round 13-cm diameter pots containing either a severely water repellent or non-water repellent soil [(2 surfactants X 3 loading rates + 1 untreated control) X 2 soil types = 14 treatments]. In the water repellent soil, all seed coating treatments were highly effective in ameliorating water repellency and increasing soil water content, turfgrass density, cover, total biomass, and ratio of root biomass relative to shoot biomass. For example, during the first nine days of the study when tall fescue was germinating and emerging, soil water content in the water repellent soil was on average 93.9% higher in pots sown with surfactant-coated seed, than non-coated seed. Depending on day of measurement and treatment, plant cover was between 213.7–1405.4% higher from plants grown from surfactant-coated seed than non-coated seed. Root biomass and shoot biomass produced from surfactant coated seed was between 388.2-578.0% and 266.5-324.2% greater than non-coated seed, respectively. Slight improvements were also found between surfactant coated seed and non-coated seed in wettable soil for some response parameters. Seeds coated with EO/PO block copolymers at lower loading rates slightly outperformed APG EO/PO coated seed. These results provide evidence that soil surfactants can be affectively applied using seed coating technology. Future research is justified for testing surfactant seed coatings to establish golf course greens and sports fields from seed.