A Recipe For Disaster: Drought, Heat And Water Quality
By Bud White, director, Mid-Continent Region
July 23, 2009
The lower Mid-Continent Region is suffering from a significant drought, and the effects are further magnified by an aggressive heat wave. These conditions have many golf courses struggling with turf health, and to add further challenge, there are several weeks of summer remaining. The drought and heat, coupled with having to use poor quality water in many circumstances, intensifies the stress even more.
Under these conditions, one of the first considerations is golf course traffic, specifically cart traffic. When golf courses experience extreme drought and heat, limiting golf cart traffic on the turf is an easy and effective program to protect the turf and to help minimize the potential damages.
One suggestion for traffic control is to restrict carts to paths on two holes per nine per week, plus the par 3 holes. Another program successfully used by several golf courses restricts carts to the paths two days per week. Both ideas work well, especially in heavy use areas where carts travel from the cart path to fairway in front of the tee, and back to the path in the approach. This temporary minor inconvenience to golfers can result in significantly reduced damage to stressed turf and, as a result, better playing quality and appearance of the course.
During these times, there are many other steps that golf course superintendents take that most golfers never see. Just a few include:
· Testing to ensure that the potassium levels are adequate in the soil. Bermudagrass is best managed with extra potash applications in the late summer to aid recovery from high stress periods.
· Raising cutting heights a bit earlier in the summer before the bermudagrass goes into fall dormancy. Increased cutting heights may be applied in early August instead of late August to further help with extreme weather conditions.
· Making sure nitrogen is low, but adequate. There must be enough nitrogen maintained on all turf areas to sustain proper growth and health, and promote recovery from damage.
· Evaluating the potential for further injury later in the year. Bermudagrass is more susceptible to winter injury when going into dormancy under drought stress.
As another complication, irrigation water quality greatly influences the severity of drought damage. Without the diluting effect of rain, water supplies often experience dramatic increases in salts and bicarbonates. Greens, which are mowed very low and receive concentrated traffic, are particularly sensitive to high levels of these contaminants. As the drought persists, the use of poor quality water results in the steady accumulation of salts and bicarbonates in the green’s rootzone. As the salt levels increase, so do the negative impacts on turfgrass health.
One of the most effective means to minimize salt accumulation is to flush them from the rootzone with deep irrigation. Often misunderstood, flushing is a vital turf management program used by superintendents. It is not just heavy watering with a 30 or 40 minute irrigation cycle. The goal is to move enough water through the soil profile to leach the salts below the turfgrass roots.
It may take hours of irrigation to accomplish this goal. The problem is this can result in the over-saturation of surrounding turf areas and greenside bunkers. This is less of a problem for courses with irrigation systems with part-circle irrigation heads that allow water to be applied only to the green. Golf courses without such control may find it necessary to use a hose and a movable sprinkler placed in the center of the green. The time and amount of water necessary to effectively flush a green varies greatly, depending on factors such as the type of rootzone, the irrigation system used, and the severity of the water quality problem.
Ironically, golf courses that have water higher in salts normally use 20% more water on average than when using a water source with little or no salt. Often, this is opposite of what one might think, as the natural thought is to apply less water and therefore less salts. In contrast, more water must be applied because the management strategy is to keep the water, and consequently the salts, moving downward and out of the root zone. As the drought persists, the need for repeated flushing can result in a significant increase in water usage. This can be a difficult concept to understand and communicate in communities that are undergoing water use restrictions.
Flushing alone is not enough to solve the entire problem. It must be part of a well-planned program that also includes spiking or needle tining to promote air exchange, gypsum applications to help promote the salt removal, and then flushing. Pound for pound, gypsum is the best material to flush salts from the profiles. After flushing, a potash application should be applied to restore potassium in the soil solution and to make it available to replace the sodium that has been removed from the rootzone.
Hopefully, this discussion puts into perspective some of the concerns for the current weather extremes and serves as an educational tool regarding some of the short- and long-term management programs implemented to manage this drought. If further questions arise, contact the Mid-Continent Region staff at: Bud White, (972) 662-1138 or (budwhite@usga.org) and Ty McClellan, tmcclellan@usga.org or (630) 340-5853.
For more information, a USGA Live Meeting was held July 20, 2009 with the Green Section Mid-Continent staff and golf course managers across the region to discuss this topic. The Live Meeting recording can be found at:
Recording URL: https://www.livemeeting.com/cc/usga/view
Recording ID: 4G5Q72-1
Attendee Key: pwC#2{2'n