How to manage nutrients and irrigation have been major concerns for the turfgrass and ornamental industry in recent decades, especially within densely populated urban areas (Beard and Green, 1994; Carey et al., 2012; Hochmuth et al., 2012). It is estimated that 40% to 60% of residential water use in the United States is applied for irrigating landscapes, which are typically composed primarily of turfgrass (White et al., 2004). In Texas, lawn and landscape use of municipal water is significant (Cabrera et al., 2013). Due to the magnitude of use, water conservation and mitigation strategies have been used in the United States to reduce domestic water usage (Ozan and Alsharif, 2013). The environmental fate of nutrients has also become the focus of government policies restricting fertilizer use (Hochmuth et al., 2012). Several potential environmental concerns have also been attributed to turfgrass management, including offsite movement of water, nutrients, and pesticides in surface and groundwater and excessive use of potable water (Carey et al., 2012; King et al., 2001; King and Balogh, 2001; Racke, 2000). Management practices and/or application of products that enhance water and nutrient use efficiency could therefore aid in producing a more sustainable turfgrass system while reducing environmental impacts (Carrow et al., 2001).
Soil water repellency, or hydrophobicity, is a widespread problem for turfgrass managers, and it is usually associated with sand-based turfgrass systems (Zontek and Kostka, 2012). Hydrophobicity develops due to formation of hydrophobic organic substances around soil particles associated with living or decomposing plants or microorganisms (Doerr et al., 2000; Zisman, 1964). Although all types of soil can become hydrophobic, sandy soils tend to be more susceptible to water repellency due to their lower surface area per unit volume than finer-textured soils (DeBano et al., 1970; Karnok et al., 2004).
Soil water repellency not only reduces water use efficiency but may also increase runoff volumes during rainfall or irrigation events (Doerr et al., 2003; Mitra et al., 2006). Water lost as surface runoff has the potential to transport nutrients including nitrogen, potassium, and phosphorus (Burwell et al., 1975; Göbel et al., 2007; McDowell and Sharpley, 2001). Urban storm water runoff has been considered by the U.S. Environmental Protection Agency (EPA) to be a major factor influencing surface water (rivers, streams, and lakes) quality (Hoss et al., 2016; Novotny and Olem, 1994). Nitrogen and phosphorus losses in urban runoff have received considerable attention due to their impacts on surface water quality, including contributions to eutrophication (Taylor et al., 2005; Wherley et al., 2017).
Wetting agents reduce the surface tension of water, and thus have been widely used to reduce soil water repellency (Laha et al., 2009). Wetting agent molecules commonly consist of a lipophilic/nonpolar head and polar/hydrophilic tail; which, when applied to water-repellent soil, the polar side of wetting agent molecules was bonded to water molecules and the nonpolar side was bonded to water-repellent soil, respectively, wetting soil particles (Karnok et al., 2004). Repeated applications of wetting agents are often necessary to alleviate soil water repellency. A number of wetting agents are available on the market, and Zontek and Kostka (2012) have proposed a classification system for these products based on mode of action and/or interaction with water and soil, which include anionic and anionic blends, nonionic, cationic, or amphoteric wetting agent groups.
Most commercially available wetting agents claim an ability to reduce soil hydrophobicity and/or enhance water infiltration (Karnok et al., 2004; Pelishek et al., 1962). An evaluation of ten wetting agents was conducted over nine predominantly sand-based study sites across the United States, with the authors reporting efficacy for several of the selected wetting agents at reducing water drop penetration time (WDPT) across multiple study sites (Throssell, 2005). Kostka and Bially (2005) tested the synergetic effects of different wetting agent chemistries for the enhancement of hydrophilicity columns filled with water-repellent sand and reported that blends of unrelated nonionic wetting agents markedly improved infiltration over other commercial penetrant products. Most of these prior wetting agent studies have been conducted on sand-based systems, as putting greens are prone to local dry spots resulting from poor moisture retention, and limited studies have conducted on loam or clay soils typical of many lawns (Aamlid et al., 2009; Cisar et al., 2000; Leinauer et al., 2001; Soldat et al., 2010).
Given the benefits of wetting agents at improving water infiltration and consequent nutrient availability in the root zone of plants growing in coarse textured soils, there is growing commercial interest in evaluating wetting agents for use in home lawns. Application of these products may also be beneficial for lawns established on nonhydrophobic but poorly drained native soils given their reported potential to improve water infiltration and water content uniformity at greater soil depths (Lehrsch et al., 2011; Lowery et al., 2002; National Cooperative Soil Survey).
With a hypothesis that applying a wetting agent can improve turf quality and allocate more water and nutrient in the soil, the objectives of this research were to 1) evaluate the potential of wetting agents to improve turf performance and 2) test the effect of wetting agents on water and nutrient conservation, in terms of soil moisture content and the losses of water and nutrients in runoff from st. augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] lawns.
Aamlid, T.S., Espevig, T. & Kvalbein, A. 2009 The potential of a surfactant to restore turfgrass quality on a severely water-repellent golf green Biologia 64 620 623
Arriaga, F.J., Lowery, B. & Kelling, K.A. 2009 Surfactant impact on nitrogen utilization and leaching in potatoes Amer. J. Potato Res. 86 383 390
Barton, L. & Colmer, T.D. 2011 Ameliorating water repellency under turfgrass of contrasting soil organic matter content: Effect of wetting agent formulation and application frequency Agr. Water Mgt. 99 1 7
Beard, J.B. & Green, R.L. 1994 The role of turfgrasses in environmental protection and their benefits to humans J. Environ. Qual. 23 452 460
Bisdom, E.B.A., Dekkerand, L.W. & Schoute, J.T. 1993 Water repellency of sieve fractions from sandy soils and relationships with organic material and soil structure Soil Structure/Soil Biota Interrelationships 56 105 118
Bowman, D.C., Cramer, G.R. & Devitt, D.A. 2006 Effect of salinity and nitrogen status on nitrogen uptake by tall fescue turf J. Plant Nutr. 29 1481 1490
Burwell, R.E., Timmons, D.R. & Holt, R.F. 1975 Nutrient transport in surface runoff as influenced by soil cover and seasonal periods Soil Sci. Soc. Amer. J. 39 523 528
Cabrera, R.I., Wagner, K.L., Wherley, B. & Lee, L. 2013 Urban Landscape Water Use in Texas. TWRI EM-116. 15 Jan. 2020. <https://twri.tamu.edu/media/2526/em-116_urbanlandscapewateruse.pdf>
Carey, R.O., Hochmuth, G.J., Martinez, C.J., Boyer, T.H., Nair, V.D., Dukes, M.D., Toor, G.S., Shober, A.L., Cisar, J.L., Trenholm, L.E. & Sartain, J.B. 2012 A review of turfgrass fertilizer management practices: Implications for urban water quality HortTechnology 22 280 291
Carrow, R.N., Waddington, D.V. & Rieke, P.E. 2001 Enhancing turfgrass nutrient-use efficiency, p. 33–41. In: Turfgrass soil fertility and chemical problems: Assessment and management. Ann Arbor Press, Chelsea, MI
Chaichi, M.R., Keshavarz-Afshar, R., Lu, B. & Rostamza, M. 2017 Growth and nutrient uptake of tomato in response to application of saline water, biological fertilizer, and surfactant J. Plant Nutr. 40 457 466
Chang, B., Wherley, B.G., Aitkenhead-Peterson, J.A. & West, J.B. 2019 Irrigation salinity effects on Tifway Bermudagrass growth and nitrogen uptake Crop Sci. 59 2820 2828
Cid-Ballarin, C., Muñoz-Carpena, R., Socorro-Monzón, A. & González-Tamargo, G. 1998 Wetting agent effects on peat properties related to nutrient solution losses and plant growth Acta Hort. 458 161 170
Cisar, J.L., Williams, K.E., Vivas, H.E. & Haydu, J.J. 2000 The occurrence and alleviation by surfactants of soil-water repellency on sand-based turfgrass systems J. Hydrol. (Amst.) 231 352 358
Cole, J.T., Baird, J.H., Basta, N.T., Huhnke, R.L., Storm, D.E., Johnson, G.V., Payton, M.E., Smolen, M.D., Martin, D.L. & Cole, J.C. 1997 Influence of buffers on pesticide and nutrient runoff from bermudagrass turf J. Environ. Qual. 26 1589 1598
Cooley, E.T., Lowery, B., Kelling, K.A., Speth, P.E., Madison, F.W., Bland, W.L. & Tapsieva, A. 2009 Surfactant use to improve soil water distribution and reduce nitrate leaching in potatoes Soil Sci. 174 321 329
DeBano, L.F., Mann, L.D. & Hamilton, D.A. 1970 Translocation of hydrophobic substances into soil by burning organic litter Soil Sci. Soc. Amer. J. 34 130 133
Doerr, S.H., Shakesby, R.A. & Walsh, R. 2000 Soil water repellency: Its causes, characteristics and hydro-geomorphological significance Earth Sci. Rev. 51 33 65
Doerr, S.H., Ferreira, A.J.D., Walsh, R.P.D., Shakesby, R.A., Leighton-Boyce, G. & Coelho, C.O.A. 2003 Soil water repellency as a potential parameter in rainfall-runoff modelling: Experimental evidence at point to catchment scales from Portugal Hydrol. Processes 17 363 377
Fontanier, C.H., Aitkenhead-Peterson, J.A., Wherley, B.G., White, R.H., Thomas, J.C. & Dwyer, P. 2017 Deficit irrigation and fertility effects on NO3–N exports from St. Augustinegrass J. Environ. Qual. 46 793 801
Hochmuth, G., Nell, T., Unruh, J.B., Trenholm, L. & Sartain, J. 2012 Potential unintended consequences associated with urban fertilizer bans in Florida—A scientific review HortTechnology 22 600 616
Hoss, F., Fischbach, J. & Molina-Perez, E. 2016 Effectiveness of best management practices for stormwater treatment as a function of runoff volume J. Water Resour. Plan. Mgt. 142:05016009, doi: 10.1061/(ASCE)WR.1943-5452.0000684
King, K.W., Harmel, R.D., Torbert, H.A. & Balogh, J.C. 2001 Impact of a turfgrass system on nutrient loadings to surface water J. Amer. Water Resour. Assoc. 37 629 640
King, K.W. & Balogh, J.C. 2001 Water quality impacts associated with converting farmland and forests to turfgrass Trans. ASAE 44 569 doi: 10.13031/2013.6117
Kostka, S.J. & Bially, P.T. 2005 Synergistic surfactant interactions for enhancement of hydrophilicity in water repellent soils Intl. Turfgrass Soc. Res. J. 10 108 114
Kostka, S.J. 2000 Amelioration of water repellency in highly managed soils and the enhancement of turfgrass performance through the systematic application of surfactants J. Hydrol. (Amst.) 231 359 368
Laha, S., Tansel, B. & Ussawarujikulchai, A. 2009 Surfactant–soil interactions during surfactant-amended remediation of contaminated soils by hydrophobic organic compounds: A review J. Environ. Mgt. 90 95 100
Lehrsch, G.A., Sojka, R.E., Reed, J.L., Henderson, R.A. & Kostka, S.J. 2011 Surfactant and irrigation effects on wettable soils: Runoff, erosion, and water retention responses Hydrol. Processes 25 766 777
Leinauer, B., Rieke, P.E., VanLeeuwen, D., Sallenave, R., Makk, J. & Johnson, E. 2001 Effects of soil surfactants on water retention in turfgrass rootzones Intl. Turfgrass Soc. Res. J. 9 542 547
Leinauer, B., Karcher, D., Barrick, T., Ikemura, Y., Hubble, H. & Makk, J. 2007 Water repellency varies with depth and season in sandy rootzones treated with ten wetting agents Appl. Turfgrass Sci. 4 doi: 10.1094/ATS-2007-0221-01-RS
Lowery, B., Arriaga, F.J. & Kelling, K.A. 2002 August. Use of surfactant to decrease nitrate leaching and improve nitrogen use efficiency in potato production. In 17th World Congress of Soil Science, Bangkok, Thailand, Symposium Vol. 54:1–6
McDowell, R.W. & Sharpley, A.N. 2001 Approximating phosphorus release from soils to surface runoff and subsurface drainage J. Environ. Qual. 30 508 520
Miller, W.W., Valoras, N. & Letey, J. 1975 Movement of two nonionic surfactants in wettable and water-repellent soils Soil Sci. Soc. Amer. J. 39 11 16
Mitra, S., Vis, E., Kumar, R., Plumb, R. & Fam, M. 2006 Wetting agent and cultural practices increase infiltration and reduce runoff losses of irrigation water Biologia 61 S353 S357 doi: 10.2478/s11756-006-0188-4
Miyamoto, S. 1985 Effects of wetting agents on water infiltration into poorly wettable sand, dry sod and wettable soils Irr. Sci. 6 271 279
Morris, K.N. & Shearman, R.C. 2007 NTEP turfgrass evaluation guidelines. National Turfgrass Evaluation Program, Beltsville, MD. 12 Aug. 2019. <http://www.ntep.org/pdf/rat-ings.pdf>
National Cooperative Soil Survey. National Cooperative Soil Characterization Database. 2 Dec 2019 <http://ncsslabdatamart.sc.egov.usda.gov/>
Novotny, V. & Olem, H. 1994 Water quality: Prevention, identification and management of diffuse pollution. Van Nostrand-Reinhold Publishers, New York
Racke, K.D. 2000 Pesticides for turfgrass pest management: Uses and environmental issues, p. 45–64. In: Fate and management of turfgrass chemicals, ACS Symposium Series, Vol. 743, American Chemical Society, Washington, D.C doi: 10.1021/bk-2000-0743.ch003
Schiavon, M., Leinauer, B., Serena, M., Maier, B. & Sallenave, R. 2014 Plant growth regulator and soil surfactants’ effects on saline and deficit irrigated warm-season grasses: I. Turf quality and soil moisture Crop Sci. 54 2815 2826
Sebilo, M., Mayer, B., Nicolardot, B., Pinay, G. & Mariotti, A. 2013 Long-term fate of nitrate fertilizer in agricultural soils Proc. Natl. Acad. Sci. USA 110 18185 18189
Shuman, L.M. 2002 Phosphorus and nitrate nitrogen in runoff following fertilizer application to turfgrass J. Environ. Qual. 31 1710 1715
Soldat, D.J., Lowery, B. & Kussow, W.R. 2010 Surfactants increase uniformity of soil water content and reduce water repellency on sand-based golf putting greens Soil Sci. 175 111 117
Steele, M.K. & Aitkenhead-Peterson, J.A. 2013 Salt impacts on organic carbon and nitrogen leaching from senesced vegetation Biogeochemistry 112 245 259
Taylor, G.D., Fletcher, T.D., Wong, T.H., Breen, P.F. & Duncan, H.P. 2005 Nitrogen composition in urban runoff—implications for stormwater management Water Res. 39 1982 1989
Wherley, B., Dukes, M.D., Cathey, S., Miller, G. & Sinclair, T. 2015 Consumptive water use and crop coefficients for warm-season turfgrass species in the Southeastern United States Agr. Water Mgt. 156 10 18
Wherley, B.G., White, R.H., McInnes, K.J., Fontanier, C.H., Thomas, J.C., Aitkenhead-Peterson, J.A. & Kelly, S.T. 2014 Design and construction of an urban runoff research facility J. Vis. Expt. 90 e51540 doi: 10.3791/51540
Wherley, B.G., Shi, W., Bowman, D.C. & Rufty, T.W. 2009 Fate of 15N-Nitrate applied to a bermudagrass system: Assimilation profiles in different seasons Crop Sci. 49 2291 2301
Wherley, B.G., Aitkenhead-Peterson, J.A., Stanley, N.C., Thomas, J.C., Fontanier, C.H., White, R.H. & Dwyer, P. 2017 Nitrogen runoff losses during warm-season turfgrass sod establishment J. Environ. Qual. 44 1137 1147
White, R., Havlak, R., Nations, J., Pannkuk, T., Thomas, J., Chalmers, D. & Dewey, D. 2004 How much water is “enough”? Using PET to develop water budgets for residential landscapes. Texas Water Resources Institute TR-271:1–8. <http://hdl.handle.net/1969.1/6100>