Water Injury
Water Injury
The proper balance of water needed for healthy turf is critical; an improper balance of water in a turf ecosystem can result in both biotic and abiotic problems. There are two examples of water injury; flood or standing water and drought injury. We will focus on drought injury. The first step is to know how to properly identify water injury, so turf managers can minimize damage. In addition, water conservation remains a goal for many turf managers.
Drought Injury
Drought is defined as prolonged water stress that limits or prevents turf growth. The severity of drought depends on the duration of low water availability. Turfgrass species differ greatly in their ability to withstand drought conditions; this is referred to as drought resistance. Drought injury is related to and often hard to distinguish from high temperature injury.
Symptoms
Symptoms of drought stress begin with the turf taking on a bluish tinge, followed by leaf rolling and, under severe drought, it will eventually turn brown. Drought stressed turf is often found near sidewalks, driveway, or buildings, and at the tops of slopes where increased air movement occurs. Drought stress also can be observed in localized dry spots (hard-to-wet areas) which appear as irregular patterns of dead and dying turf. As a result, causes of localized dry spots include sandy soils, compaction, buried building materials, algal infestations, and fairy rings.
Drought stress can be confused with injury cause by subsurface feeding insects such as billbugs, sod webworms, and white grubs. To differentiate drought from insect injury, examine the turf and determine if insect root feeding has occurred. There are various curative measures for drought stressed turf and localized dry spots. In particular, the use of wetting agents, aerification to improve water penetration and lateral water flow, removal of buried materials, selection of more drought resistant grasses, and deep watering.
A drought related abiotic problem is leaf and crown bruising. During drought conditions, many turfs go into a state of dormancy and their tissues become brittle and are susceptible to bruising. Bruising is when the entire shoot appears brown if the crown was damaged or brown streaks on the blades. This can often appear after dormancy is broken and growth resumes as brown leaves and shoots which fail to grow. The pattern of injury often is associated with footprints or wheel tracks.
Reference
L. J. Giesler. (1997). Abiotuc Turf Injury. In F. Baxendale, Ph.D., & R. Gaussoin, Ph.D., Integrated Turfgrass Management for the Northern Great Plains (pp. 165-168). Location: Nebraska