Surfactant and Polymer‐Coated Sand Effects on Deficit Irrigated Bermudagrass Turf

Abstract

Sand topdressing and soil surfactants are commonly applied to turfgrass areas but it is unclear whether these practices improve visual appearance or reduce hydrophobicity under defi cit irrigation. A study was conducted from 2011 to 2013 at New Mexico State University in Las Cruces, NM, to evaluate two topdressing materials and a soil surfactant on defi cit irrigated Princess 77 bermudagrass (Cynodon dactylon L.) grown on a loamy sand (mixed, thermic Typic Torripsamment). Treatments consisted of monthly applications of a polymer-coated hydrophilic sand (ACA 3114) or straight sand with or without the soil surfactant and an untreated control. Plots were mowed at 2.0 cm and irrigated at either 70 or 50% of reference evapotranspiration for short grass (ET os ). When results were averaged over the research period, plots irrigated at 50% ET os and receiving ACA 3114 or sand topdressing and the soil surfactant exhibited greater green coverage (85.3 and 88.2%, respectively) and better turfgrass quality (6.6 and 6.5, respectively, with 1 = worst, 9 = best) than control plots (71.6% green coverage, quality = 5.1) or plots receiving sand topdressing only (74.7% green coverage, quality = 5.3). Soil repellency in the upper root zone was detected only in 2011, and applications of both ACA 3114 and straight sand topdressing with the soil surfactant on plots irrigated at 50% ETos resulted in lower water drop penetration times (7s and 1s) compared to sand topdressing (12s) only. Our results suggest that bermudagrass quality can be maintained under defi cit irrigation if either topdressed with a hydrophilic sand or with straight sand combined with a surfactant.

Evaluation of Water Retention Products to Conserve Urban Water Resources in Home Lawns

“…The previously mentioned study by Alvarez et al (2016) included monthly applications of hydrophilic sand, topdressing sand alone, or combinations of liquid surfactants and topdressing sands with irrigation replacing 50 or 70% of ET 0 . The current study only evaluated a single application early in the growing season where hydrophilic sands were mixed with topdressing sand at application.…”

“…Surfactants can decrease soil hydrophobicity by breaking the surface tension between soil particles and have been especially effective in sandy soils where decomposition and root exudates coat soil particles with hydrophobic lipid compounds (Alvarez et al, 2016; Cisar et al, 2000; Leinauer et al, 2007). Golf course superintendents and other professional turfgrass managers regularly apply surfactants as part of their routine turfgrass management (Alvarez et al, 2016). Studies have demonstrated the ability of surfactants to improve water use efficiency and conservation as part of standard turfgrass management programs (Alvarez et al, 2016; Cisar et al, 2000; Leinauer and Devitt, 2013).…”

“…Hydrophilic compounds may include surfactant chemistries or super‐absorbent polymers. Coated hydrophilic sands have also been reported to improve water availability and uptake in soil and to reduce water stress (Alvarez et al, 2016; Gehring and Lewis, 1980; Vinson, 2016). Rather than allowing increased water infiltration and distribution, super‐absorbent polymers retain many times their mass in water, slowly releasing water to plants as the soil dries (Abedi‐Koupai and Asadkazemi, 2006, Mikkelsen, 1994; Vinson, 2016).…”

“…These researchers suggested permanent plant wilting could be delayed by 4 to 5 days when hydrophilic sands were used (Akhter et al, 2004). Additionally, turfgrasses topdressed with hydrophilic sand have been reported to exhibit improved green cover and quality when irrigated to 50 or 70% reference evapotranspiration (ET 0 ) (Alvarez et al, 2016; Vinson, 2016).…”

Surfactant and irrigation impacts on soil water content and leachate of soils and greenhouse substrates

“…Other studies have reported either an increase (Soldat et al, 2010) or no effect (Schiavon et al, 2014) in SWC after APG application. Leinauer et al (2001) and Alvarez et al (2016) reported that the effectiveness of a surfactant in increasing SWC can vary depending on the application rate and weather conditions. The general decline in SWC from Tuesdays to Mondays under both irrigation regimes (Figure 5), is logical since irrigation was applied on Tuesdays only under the ONCE irrigation regime and on Tuesdays and Thursdays under the SPLIT irrigation regime, with no water being applied on Mondays.…”