Create turf that can take it
One of the greatest threats to turf, and the turf industry, is drought. That threat increases in uncertain climate times such as this, yet there is a lot that can be done by turf managers to lessen vulnerability.
Doug Welsh, a Texas A & M professor and extension horticulturist, has been a proponent of water-wise landscapes for decades. Through research, radio and TV shows and online exposure, he’s been preaching about the need to create and maintain landscapes that conserve water and resist drought.
|Doug Welsh has promoted water-wise landscapes and turf for years as Texas A & M Extention horticulturist.|
Turf is the factor that creates the peak water demand in the many parts of the nation where it is irrigated, Welsh says, and as such, it is turf facilities that will bear the brunt of any droughts that occur. Furthermore, the green industry will bear the brunt of any local, regional or national regulations created to conserve water where necessary.
“We’re either going to be educated or regulated,” he predicts. “I’d prefer the education.”
Fortunately, he has many handy tips on how to create and maintain drought-tolerant turf. Welsh readily acknowledges all the benefits of turf, but emphasizes that its one big negative factor is that where irrigated turf grows, it usually requires the use of drinking water for its health and vitality.
First of all, he says that we should focus on the “people issues” associated with turf water use. People should be aware of the types and varieties of turf that are best adapted to their region, and be aware that tests on types such as zoysiagrass and new bermudagrass varieties show great water reductions. They should also be aware of the principles of xeriscaping and how they affect turf. Welsh cites the fact that narrow strips of turf should be avoided where possible because they are difficult to irrigate and maintain.
Irrigation systems should be designed for efficiency, and once installed they should be overseen by people trained to understand turf’s needs. Those people should know how to schedule irrigation for turf. This important job should not be left to untrained property managers or others who don’t understand the needs of turf throughout the year.
This would avert the situation where an irrigation controller would be set on 20 minutes every other day, no matter what the season. A Texas A & M study showed that biggest waste of landscape water is in the spring and fall, because it is applied liberally at a time when it isn’t needed. An irrigation audit should be undertaken to curtail inefficient systems and timing. Control the controller, don’t let it control you. Welsh recommends revisiting the controller on a monthly basis, based on measured turf needs.
A great way to create a buffer against drought is to increase both the time between irrigations and the length of irrigations. The first reason for this is usually obvious to turf managers. It fills up the bank of moisture in the soil to some depth so that plants don’t need to be irrigated as often and don’t need as much water overall.
The second reason for this is that every time an irrigation system runs, the system becomes less efficient. Not only does reducing the number of total irrigations reduce the waste from runoff and evaporation into the air, it also gives the system a longer lifespan.
This brings up a principle that Welsh teaches on the A & M Drought Web site, http://www.aggie-horticulture.tamu.edu/plantanswers/drought/drought.html: weaning turf from excessive water use. He says turf can be weaned to use less water, and can be gotten to the stage where the manager can determine the amount needed to get quality turf with a minimum of water. Tests have shown that plants have the ability to adapt to the conditions we provide for them.
Lush growing conditions can actually lead to weak plants, while cutting back on water to a certain point can promote tough plants able to withstand periods of drought or a temporarily broken water system. Roots will be forced to follow deeper moisture and endure a certain amount of stress. They should be watered when they start to show stress symptoms but before they are injured. Professional turf managers understand these principles and should teach them to their clients.
“The larger the root system, the more hardy the plant is,” Welsh says. The use of soil moisture gauges, from soil probes and simple digging to more sophisticated meters, will help determine the break point.
There is also nothing wrong with experimentation, he points out. A turf manager can wait for longer periods of time—and then irrigate for longer than usual—until stress factors appear. This provides a great look at how efficient the system is, because if dry spots appear here and there, it indicates that the system isn’t uniform. Simple mechanical fixes, such as changing sprinkler heads can bring the system into line. Then the manager won’t have to water the whole plot prematurely just to keep the dry spots from dying.
By forcing those plants’ roots deeper, the manager will give himself a buffer in a particularly hot summer, or in a drought when the local water utility is rationing. Or, just to reduce irrigation costs. His turf will be tougher than the plot next door.
The same principle can be said of fertilizer, Welsh says. The less used at certain times of the year, the less the turf will grow and require water. The first thing a commercial turf manager should do is get a reliable soil sample to see just what nutrition his turf needs. Pollution, especially of phosphorus, is a big problem nationwide, so putting on fertilizer unnecessarily has two huge drawbacks.
Welsh says that fertilizing most turf (sports turf is an exception) twice a year, in spring and fall, is sufficient. Minimum turf maintenance should call for only 2 to 4 pounds of nitrogen per 1,000 square feet per year, and often it may need little or no phosphorus. He notes that in the old days, a recommended fertilizer ratio was 3-1-2, now it may be more along the lines of 5-1-5. What does that have to do with drought? Adding nutrition in the summer can only lead to unnecessary growth, and water usage.
Although Welsh acknowledges that keeping mowing heights high is somewhat controversial, he recommends that strategy where possible. His experience has shown that when turf is allowed to grow out, roots will go deeper.
He says that most turf types, including ryegrass and fescue, will grow more slowly and still thrive if left to grow beyond normal established cutting heights. He says that bermudagrass can be very healthy if left to grow to an inch in height, and St. Augustine can go to 4 inches without ill effects. Cutting it shorter during drought leads to repeated regrowth, which requires spurts of water and fertilizer
Welsh, who has a book called “Doug Welsh’s Texas Garden Almanac,” is also a big proponent of mulch and compost as means of keeping moisture in the soil. He notes that it is the “most low-tech, high-impact” method of conserving water at the same time that organic matter is gradually added to the soil. Moisture evaporation from the soil is greatly reduced—by up to two-thirds in one test—with the addition of mulch. It is also cheap and easy to apply. The same principle that is in effect with flower beds and shrub landscapes also applies to turf.
Without being able to cite any scientific evidence to support this, Welsh says that topdressing turf with a fine compost can achieve the same effect. Combine this with core aeration, and there is a long-term and gradually building of the soil which enables roots to grow deeper. It also allows better water penetration, and both of these factors can be big health boosts in a time when water is more scarce.
One of the major challenges to face the turf industry in the future is going to be the ability to maintain quality turf in a time of decreasing water availability. In a drought, that challenge is going to be huge, because turf will (as it already is in some states) bear the brunt of any cutbacks in water. As such, a drought will hit the industry earliest and hardest.
This is why Welsh says that Texas isn’t the only state that will see challenges to the turf industry ahead. All of the southern tier of states and the Midwest, where irrigation is a necessity, will feel the bite.
“You’re always seven days from a drought in Texas,” Welsh says. Nobody should be fooled by the large amount of rainfall in the state early this year, because as soon as it stopped in August there were 100-degree days and water was being pumped like crazy. As the population of the United States grows and water becomes more precious, it will become even more important to make turf as drought-tolerant as possible.
Don Dale is a freelance writer and a frequent contributor. He resides in Altadena, Calif.