Keep your greens up to par, not parched; successful golf-turf maintenance in times of drought depends on where you live.

Turfgrass textbooks of the past discussed drought as though all droughts were alike. The rains stop, the turf dries down and the plants go brown if they're not irrigated. One size fits all, right?

Over the years, turf superintendents have begun to question this simplistic approach to drought and its management. Also, as turf graduates from Eastern schools migrated to the sunny Southwest and Midwest, they discovered that many of the drought principles they learned in school no longer applied. One of my students from my teaching days at Oklahoma State University told me that he considered a rainstorm to be a hindrance to his golf management in the California desert. Irrigation in the desert, lie explained, is finely tuned, and the occasional rain that blusters through throws his whole management system for a loop.

As time passed, turfgrass researchers also began noticing inconsistencies among drought principles developed in various parts of the country. Bob Carrow, a noted turf soils and water researcher in Georgia, was one of the first to point out that drought and irrigation formulas developed in the desert Southwest did not precisely apply to Southeastern droughts. In a scholarly publication, he concluded that "under humid environments ... drought resistance based on relative evapotranspiration does not correlate well with field observations of drought resistance based on wilt and leaf firing."

Given the type of lawngrass present, irrigation scheduling and drought resistance in the arid West can be expressed in precise formulas. In the humid East, however, these formulas don't always predict symptoms such as wilting or leaf discoloration. The occasional droughts of the humid East behave differently than droughts in an arid climate. Therefore, their management should be handled differently.

Managing Drought in a Moist, Humid Climate

Droughts in a temperate, humid climate like Cincinnati, Ohio, or Raleigh, N.C., are rarely predictable. Drought can occur nearly any time from spring to fall, whenever the hit-and-miss nature of summer storms causes significant browning of unwatered lawns. Mid-summer droughts are naturally the most acute.

In moist climates, turf gets most of the water it needs from natural rainfall. For the sake of this discussion, I'll refer to moist climates as those receiving 30 or more inches per year of fairly evenly dispersed rainfall. It's only during significant rainfall lapses that turf requires supplemental watering. (The exception, of course, is specialty turfs, such as putting greens and the like, which are always irrigated.)

Root training is a key drought strategy in moist climates. Grass roots can be trained to ferret in search of moisture. Their size and depth can be altered and trained almost as miraculously as common shrubbery can be trained into likenesses of Snow White and Dumbo at Disney World. Roots can be sent plummeting into the soil to extract moisture from the greatest possible soil volume.

Here's where the advantage lies: Consider a grass plant with one-foot-deep roots compared to another plant with two-feet-deep roots. A water droplet sitting two feet underground is totally unavailable to the stubbier rooted plant; that plant will go into summer dormancy if not splashed with a fresh supply of water. In contrast, its longer-rooted neighbor can extract that deep moisture and grow without discoloration.

Roots are trained by purposely letting the turf dry out in the springtime. For the most part, spring droughts are easy on the plant and seldom cause disfigurement. To do root training, see if you can resist for as long as possible turning on your sprinklers. East of the Mississippi, it should be possible most years to abstain from sprinkling on lawn and landscape turf until July 4 (if you overlook the occasional spring blemish). These natural cycles of wetting and drying will train the roots to extend and explore. By summer, when a real drought appears, the roots will be longer and deeper, The plants will be able to cruise unscathed through minor droughts--while others' pampered turf will require daily sprinkling.

Mid-summer drought management is also unique in a moist climate. As you've no doubt heard many times, irrigations should be infrequent and deep. Irrigate as infrequently as possible; when you do, wet the ground to six inches. Between waterings, watch for footprinting, the first purplish sign of wilting. This is your clue that irrigation is needed. Don't rely on the calendar--although modern electronics make it possible to water on a precise timetable, the most conscientious irrigation happens when you, not the timer, select each date.

Managing Drought in the Desert

Root training in the desert is virtually a waste of time. Irrigation--not rainfall--supplies the grass' moisture needs, so it doesn't really matter if the roots are short or long. Nearly all of the plant's moisture needs are coming from you. The only advantage of deeper roots would be as a safety cushion in the event of a skipped watering cycle or stuck sprinkler head.

In fact, deep watering can be counterproductive. If the grass' root system extends four inches deep, and you wet the ground to eight inches, then half of the water you applied was wasted. Although a small amount of water may wick back up into the root profile, most will percolate downward and be lost. This loss can be a double disadvantage if the percolating water carries with it dissolved fertilizers and pesticides into the aquifer.

Drought in the desert should be treated with more alarm. Unlike the humid East, the arid zone can parcel out for more droughts with far more intensity than any grass can withstand. Most grasses can bounce back from one or two drought episodes, but arid climates can serve up multiple dormancy events each year, pushing the turf beyond recovery.

Ideal irrigation in arid climates is a balancing act between moisture added and moisture subtracted. Moisture comes from only two places: clouds and sprinklers. And it exits by only two routes: evaporation into the sky and deep percolation into the soil. Optimal irrigation efficiency occurs when inputs balance outputs. In the most efficiently balanced system, there should be no loss from percolation--all of the withdrawals should be via evaporation.

Meteorologists gauge evaporative loss by a simple open pan of water. In a typical summer week, one to two inches of water will evaporate from a pan of water left in the sun. The actual quantity depends on cloud cover, wind speed, temperature and relative humidity. On the basis of this pan evaporation standard, agricultural meteorologists use a percentage value to express how much water a typical crop evaporates. For example, a crop with a coefficient of 100 percent would use the same amount of water per week as an open water pan.

Recent research has found that most cool-season turfgrasses--bluegrass and rescue can survive and even thrive with less than 100 percent open-pan evaporation levels. They can easily withstand irrigation replacement at 80 percent with no loss of quality. Warm-season turfgrasses like bermudagrass are even more water-efficient, and are able to prosper down to levels of 60 percent. Ultra-tolerant grasses, such as zoysia and buffalograss, can survive and prosper at levels as low as 40 percent. This efficiency is far better than most trees and shrubs, even so-called desert trees like mesquite.

Regardless of where you live, efficient drought management comes down to two factors--knowing your climate and knowing your grasses. It's important to recognize that droughts in different regions affect the grass differently; as managers, then, we need to manage the turf appropriately. Having the most drought-hardy turf species and varieties will go a long way to solving your water management problems.

RELATED ARTICLE: Benefits of water conservation.

Saving money on your utility bill isn't the only reason to conserve water. Reduced irrigation--more specifically, smarter irrigation--has many side benefits for turf. (Adapted from Turfgrass Maintenance Reduction Handbook--Sports, Lawns and Golf, by Doug Brede, Ph.D.)

Better wear       Optimal wear tolerance occurs at a point just
tolerance ...     slightly drier than the point of ideal leaf growth.
                  Overwatering promotes soft, succulent growth,
                  rather than the tougher, hardened tissue of
                  slightly underwatered turf.

Fewer weeds ...   Many weeds are more prevalent under overwatered
                  conditions, including large and smooth crabgrass,
                  yellow and creeping woodsorrel, dalli grass, annual
                  and rough bluegrass, velvetgrass, yellow and purple
                  nutsedge, common and mouseear chickweed, moss and
                  algae. Excess moisture also promotes the seed
                  germination of weeds that later persist even when
                  conditions turn drier, such as knotweed,
                  goosegrass, buckhorn plantain, dandelion and
                  white clover.

Fewer diseases    Overwatering is one of the prime triggers of
insects ...       disease. Excessive irrigation, particularly on
                  steamy summer nights, can incite pythium blight,
                  brown patch, dollar spot and take-all patch.

                  One type of watering, however, has been shown to
                  cut down on disease. A brief, predawn
                  irrigation--known as syringing--flushes dew and
                  nutrient-rich guttation water exuded by the plant.

                  Moisture is key to the life cycle of most turf
                  insects. Perennially damp turf ensures insects'
                  survival through their developmental stages.
                  Reduced moisture disrupts them.

Fewer             Leaf topgrowth is moderated when moisture is
clippings ...     restricted. Giving turf slightly less water than
                  it desires will reduce the quantity of clippings
                  produced and save money on mowing costs.

                  Reduced irrigation also makes mowing easier. Mowers
                  do a cleaner job--producing fewer clumps and less
                  shredding--when the grass blades aren't damp. Mowing
                  wet turf can leave wheel marks and streaks.

Better            Too much irrigation can rinse foliar chemicals off
fertilizer        the blades and into the soil, where it's wasted.
and pesticide     Excessive irrigation can also cause fertilizers
efficiency ...    and pesticides to leach and become pollutants.
                  Products may rinse clear through the soil profile
                  and into the ground water or be carried away on
                  the surface into nearby lakes and streams.

Less wastage      Water overspray onto walkways, driveways and
from              buildings wastes water, makes surfaces slippery
over-throw ...    and hazardous, and, over time, can leave unsightly
                  lime deposits. Adjust or replace sprinklers that
                  throw water onto sidewalks. If the water savings
                  is not enough to motivate you, then consider that
                  the typical out-of-court settlements for someone
                  slipping on a wet walkway and breaking their hip
                  runs about $200,000.

Less thatch ...   Wet, waterlogged soil can cause anaerobic soil
                  conditions, leading to excessive thatch buildup.
                  The microbes that degrade thatch function best
                  when they're neither too wet nor too dry.

RELATED ARTICLE: Grasses that conserve.

Switching grasses isn't a quick fix. Retrofitting your golf course to a grass that can withstand less moisture certainly isn't the easy way to deal with drought, but in the long run, it will save money and resources. Here are some tips for picking grasses that provide real savings.

* First and foremost, choose the best adapted grass for your location.

Pushing a grass beyond its normal range of adaptation will waste water. Find the best grass by examining state and regional trial data and observing what local golf courses have found successful.

* Does grass color affect water use?

It's well accepted that lighter-colored fabric is cooler and more comfortable to wear in the summer than dark. But does the same concept apply to grass? Do lighter shades of grass have less heat buildup and use less water? According to recent research, darker-colored grasses may be more water-efficient than lighter shades. The green color in plants comes from chlorophyll, the light-receiving energy substance. Darker grasses have more chlorophyll and can forage more effectively for water. Their added vigor seems to offset any heating effects from dark color.

* Select endophyte-enhanced varieties.

Some researchers have found a link between endophyte infection and drought tolerance. Endophytes are beneficial fungi intentionally introduced by the breeder into certain varieties of tall fescue and perennial ryegrass. The fungus grows harmlessly inside the grass leaves and helps bolster insect resistance. Researchers theorize that endophytes somehow quell a grass' thirst for water.

* [C.sub.4] warm-season grasses are more water-efficient.

Bermudagrass--a [C.sub.4] warm-season grass--uses 20 percent less water than Kentucky bluegrass (a [C.sub.3] cool-season grass). The difference traces to the physiological difference between [C.sub.3] and [C.sub.4] grasses. Southern grasses ([C.sub.4]) have evolved a more efficient cellular architecture, where photosynthesis can continue even with the stomates (the leaf's ventilation system) closed. This reduced ventilation shrinks water loss. Where adapted, warm-season grasses should be chosen preferentially over cool-season grasses for maximum moisture efficiency.

* Choose species with good rooting depth and drought recuperative potential.

Turf species, ranked by Ali Harivandi and Vic Gibeault at the University of California, in order of decreasing drought tolerance are: Kikuyugrass, bermudagrass, seashore paspalum, St. Augustinegrass, zoysiagrass, tall fescue, fine fescue, Kentucky bluegrass, perennial ryegrass, colonial bentgrass and creeping bentgrass.

* Select varieties with drought tolerance in mind.

Data from the 1995-2000 National Turfgrass Evaluation Program Kentucky bluegrass trial lists Rugby 2, Odyssey, America, Total Eclipse, Unique, Apollo and NuGlade among the top cultivars in drought dormancy resistance. Data from the 1998-2001 fairway bentgrass trial lists GolfStar Idaho bentgrass, Seaside and Penneagle creeping bentgrass, and SR7100 and Tiger II colonial bentgrass among the most drought-tolerant. (Idaho bentgrass, a native species to the U.S., is found naturally throughout the arid regions of the West.

Doug Brede, Ph.D., is research director for Jacklin Seeds/Simplot in Post Falls, Idaho. He joined the company after becoming a tenured professor and researcher at Oklahoma State University in Stillwater. His earned his doctorate degree in agronomy from Penn State University. Brede is the author of Turfgrass Maintenance Reduction Handbook--Sports, Lawns and Golf (Ann Arbor Press, 2000). The book devotes a chapter to specialized drought-management strategies.