Hurricane Preparedness and Recovery Tips for Turfgrass Managers
Mike Goatley, Shawn Askew, and David McCall, School of Plant and Environmental Sciences, Blacksburg
Jeff Derr and Adam Nichols, School of Plant and Environmental Sciences, VT Hampton Roads Agriculture Research and Extension Center, Va Beach
Jordan Booth, Research Associate, School of Plant and Environmental Sciences, Midlothian
What problems will turfgrasses face due to the impacts of a natural disaster such as a hurricane or tropical storm? The prospect of hurricanes either directly or indirectly impacting Virginia escalate in the fall and far too often our Tidewater residents in particular have to prepare (and deal) with the fiercest weather phenomenon on the planet. This year’s threat from Florence might cause significant impacts with flooding and wind damage possible across the state if forecasts hold true.
Virginia Cooperative Extension offers a wide variety of very detailed emergency preparedness publications for natural disasters at http://pubs.ext.vt.edu/tags.resource.html/pubs_ext_vt_edu:emergency-preparedness. Much of this information is obviously far more critical than that presented here discussing turfgrasses because many of the publications at this website detail preparedness and safety tips from the standpoint of life, limb, and property. This article specifically focuses on the concerns to turfgrass systems from anticipated hurricane or tropical storm impacts and some ways you might address these issues in preparation for the storm.
Concerns from storm surges/saltwater intrusion. The primary concern to turfgrasses in areas of direct hurricane impact is very often saltwater intrusion, whether it is delivered directly to the soil by tidal surges, or is accumulated in irrigation ponds for future applications to the turf and landscape. Salts in the soil affect turfgrasses in three ways:
1. Physiological drought. The salt levels are so high in the soil solution that water uptake is prevented by osmotic inhibition (i.e., even in the presence of water, there is no water uptake by roots because salt concentrations are so high in the soil.) Physiological drought is not uncommon from excessive fertilizer applications and is one reason that many soil tests include measurements for soluble salts in their testing procedures.
2. Potential toxicity from certain ions in the saline media that may either directly affect the plant or cause an imbalance in the uptake of other nutrients
3. A combination of the above.
Bermudagrass, zoysiagrass, creeping bentgrass and St. Augustinegrass all have excellent salinity tolerance, tall fescue and perennial ryegrass are considered moderate, and fine fescue and Kentucky bluegrass are relatively poor. Soil salt levels are determined by measuring Electrical Conductivity (EC), where higher values (reported in units of dS m-1) mean higher salt concentrations. Growth of most turfgrasses is not affected by salt levels up to 2-3 dS m-1. These values near the soil surface are possible following applications of many water soluble fertilizers used on turf. A thorough irrigation event with potable water is usually sufficient to adequately dilute these concentrations. At levels of 3-6 dS m-1, the least tolerant grasses begin to show signs of stress, and by 6-10 dS m-1, the growth of most turfgrasses frequently grown in Virginia begins to be affected by the salt levels in the soil.
Salt levels must also be considered in combination with sodium (Na) concentrations as well. Our Virginia soils generally do not have problems with Na, so this problem is usually only going to be of concern in conjunction with salt accumulation due to tidal surges and seawater intrusion. Additional tests such as a Sodium Adsorption Ratio [a term reflecting the relative proportion of Na to calcium (Ca) and magnesium (Mg)] and pH determination are often conducted in conjunction with ECe Na by itself is not a potential toxin to turfgrasses, but at sufficient (and persistent) concentrations its deleterious effects on soil structure and water infiltration/percolation are of concern.