Irrigation Science and Technology

Abstract

n the United States, turfgrass represents a signifi cant component of urban landscapes. These turfgrass areas include residential lawns, commercial plantings, public roadside areas, parks, athletic fi elds, cemeteries, and golf courses. Using high-resolution photographs in 13 major urban centers, Milesi et al. (2005) estimated a total turfgrass area in the United States of 163,812 km 2 and suggested that turfgrass represents the single largest irrigated crop in the United States, an area three times larger than that of irrigated corn. Although not all of this turfgrass is subject to high-intensity irrigation management, the majority of it, with the exception of turfgrass grown in wet humid regions, receives at least supplemental water during the peak summer months. However, in the arid West, turfgrass cannot exist in an acceptable state without regular supplemental water. For example, in Las Vegas, NV, rainfall is typically less than 12 cm yr −1 , which means that turfgrass grown under golf-course conditions would receive more than 95% of its water requirement via irrigation. On the other hand, in Mobile AL, the National Weather Service (NOAA, National Climatic Data Center, 2009) reported an average rainfall for the period 1996-2008 of 15 ± 4.6 cm mo −1 , which would suggest that only high-maintenance turfgrass might require supplemental water during drier periods. The amount of irrigation required by turfgrass varies from region to region on the basis of climate, species, water quality, irrigation management, cultural management, and soil type. Christians and Engelke (1994) described the general bioclimatic zones for turfgrass in the United States. Such zones were separated according to their suitability for cool-season and warm-season species. The authors noted that many turfgrass species are being grown in areas for which they are not well suited or environmentally adapted. To compensate for that use, environmental modifi cations must be made, such as signifi cant increases in irrigation, fertilization, and pesticide applications. Smaller, regional zones are

Plant Growth Regulator and Soil Surfactants’ Effects on Saline and Deficit Irrigated Warm‐Season Grasses: I. Turf Quality and Soil Moisture

“…In contrast, subsurface drip irrigation (SDI) applies water directly to the root zone, avoiding the problems an inefficient sprinkler system might create. Arguments against the use of subsurface irrigation include high installation costs, difficulty in determining spacing and depth of pipes or emitters, potential interference with maintenance practices (such as aerification or pesticide applications), difficulty in monitoring underground systems, potential root intrusion and clogging of the drip emitters, the inability to establish turf from seed when irrigated below the surface, and the inability to leach salts (Leinauer and Devitt, 2013). Beard (1973) predicted limited or no success for subsurface irrigation on turf.…”

“…Surfactants disrupt the cohesive forces of water molecules responsible for expressing surface tension, which in turn allows water to distribute more evenly over sand particles and allows for better penetration of water into hydrophobic root zones (Baird, 1993;Karnok and Tucker, 2000). More recently, these surfactants have also been proposed for their role in water conservation (Leinauer and Devitt, 2013). Plant growth regulators are chemical compounds that decrease plant growth by inhibiting either cell division (type I) or gibberellic acid synthesis (type II) (Fry and Huang, 2004).…”

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

“…In efforts to conserve potable water for turfgrass irrigation, several strategies have been proposed and one of the suggestions encompasses an increase in irrigation efficiency via improved soil water distribution (Leinauer et al, 2010;Leinauer and Devitt, 2013). Such an approach could be pursued through the use of soil surfactants which have been shown to distribute soil water more uniformly and consequently improve the moisture retention of root zones (Kostka and Bially, 2005;Leinauer et al, 2001;Mitra et al, 2005).…”

“…Such an approach could be pursued through the use of soil surfactants which have been shown to distribute soil water more uniformly and consequently improve the moisture retention of root zones (Kostka and Bially, 2005;Leinauer et al, 2001;Mitra et al, 2005). Therefore, soil surfactants not only offer remediation of LDS and hydrophobic soil conditions, but may also contribute to reduced irrigation requirements by improving water use efficiency (Kostka et al, 2007;Leinauer and Devitt, 2013). Several studies documented improved turfgrass performance under drought or decreased irrigation when soil surfactants were applied (Cisar et al, 2000;Kostka, 2005;Kostka et al, 2007;Leinauer et al, 2007;Park et al, 2004).…”

“…Several studies documented improved turfgrass performance under drought or decreased irrigation when soil surfactants were applied (Cisar et al, 2000;Kostka, 2005;Kostka et al, 2007;Leinauer et al, 2007;Park et al, 2004). Due to their ability to weaken the surface tension of hydrophobic compounds and permit the penetration of water not only into repellent rootzone areas, but also into meso and micropores, soil surfactants have been proposed to be used for water conservation (Leinauer and Devitt, 2013).…”