Water Management in Hot Humid Weather
August 10, 2009
Everyone knew it was only a matter of time before hot, muggy weather patterns would develop. Proper water management is absolutely critical under hot and humid temperatures. Water management is comprised of two parts: drainage from natural rainfall and supplemental irrigation. Turf managers fortunate enough to be managing turf on sand-based root zones have both internal and surface drainage capabilities. Those with push-up greens, however, rely primarily on surface drainage and often fear their lack of internal drainage during hot and wet weather.
Hand irrigation (Figure 1) and syringing (Figure 2) are extremely different from one another and confusion can cause significant turf decline. Proper irrigation training is essential during stressful weather patterns.
Water held tightly in the upper root zone profile (because of excessive thatch or fine soils) is prone to scald, rapid root damage, and wet wilt under hot temperatures, all of which can be lethal to turf. Just as turf can’t distinguish between different nitrogen products, it doesn’t matter where the water comes from either. Both natural rainfall or excessive supplemental irrigation can be devastating if they occur in excess at the wrong time. When the soils are saturated and the temperatures climb, afternoon syringing may be ineffective. In fact, it may be adding fuel to the fire. The physical temperature of the water may cool the turf for a second or two, but, if the water cannot evaporate, it will just sit there and heat up. The end result isn’t a pretty one.
Careful water management is always important, but it is even more critical during the most stressful part of the summer. Now is the time to forget about overhead irrigation. If the hoses haven’t been out yet, they certainly should be now. Hand syringing several times a day, literally just misting the turf canopy, may be costly and marginally disruptive to play but to quote a former colleague, "there’s nothing funny about dead grass." The key is to ensure excessive irrigation is avoided, especially for those who have excessive thatch or poorly draining root zones.
Turf management revolves around providing turf with all the physiological requirements (sunlight, water, and oxygen) necessary to grow and survive during weather extremes. Microenvironments lacking sunlight and airflow compromise plant health and are usually the first place damage is observed during tough weather. Creating and maintaining a functional root zone with adequate drainage and soil aeration by seasonal core cultivation and light, frequent sand topdressing pays dividends when drainage and soil aeration are needed the most during July and August. Failure to address poor microenvironments and proper root zone management becomes evident during stressful weather.
USGA agronomists can provide insightful and invaluable information involving all areas of golf course maintenance, which will help maximize turf health, playability, and efficiency. Contact Dave Oatis, director firstname.lastname@example.org; Adam Moeller, agronomist email@example.com; or Jim Skorulski, senior agronomist firstname.lastname@example.org for a Turf Advisory Service visit this season.