Healthy turf with less water

A few years back, a forester colleague and I were asked to present information on turf and tree maintenance to a neighborhood association in my area. I went first, using the traditional approach, utilizing PowerPoint to illustrate the finer points of effective turf techniques, and was greeted warmly and politely afterward – sort of the “golf clap” response. The forester then stood up and smiled at the audience full of high-powered and wealthy landowners and simply said, “Top trees? No! Plant more trees? Yes!” and then sat down. He added a couple of expletives that start with the letter “F” before the yes and no, but you get the drift. I sometimes wonder which of us was more effective … probably the forester.


Risers not functioning well will result in poor irrigation uniformity.
PHOTO BY JOHN C. FECH, UNL.

Attempts to maintain healthy turf while conserving water can be thought of similarly, in that the whole notion is rather straightforward and obvious. After all, who would want to maintain healthy turf while wasting water? Not any sports turf manager I know. Saving water reduces costs, decreases the likelihood of foliar diseases and lowers the environmental footprint of the facility.

Prioritization

Begin your conservation efforts by focusing on the fields that receive the most use and the most irrigation volume. Though these fields are the most visible and need to be kept in the best condition, by association they also receive the greatest inputs of any in the facility. As such, they bear the burden of the most scrutiny. Directing attention to them will produce the greatest results. On the other hand, keep in mind that because the turf in the end zone and near the center of the field receives the same amount of sunlight, oxygen and air circulation, it all needs a similar amount of water. Sure, cultivar usage and water infiltration rates can vary depending on location within a field, but the large-scale constants remain the same.

The underlying notion

Perhaps the least mentioned or most overlooked factor in making water conservation attempts is the tendency to “irrigate for the brown spots.” That is running a sprinkler system until all turf areas respond by turning from brown to green. This notion is present in all areas of the green industry: golf course management, grounds management, lawn care and, yes, sports turf management. It’s easiest to see in lawn care, where the customer remembers paying $3,000 to have the system installed and, doggone it, they want to see it work. Of course, if the system is not operating efficiently, the brown spots will eventually turn green, but in doing so, the areas that are currently receiving the proper amount will receive twice or three times as much as they need, resulting in the waste of water, unnecessary expense, root rot and various other disease problems. Sports turf managers often feel the same kind of pressure from facility owners to keep the fields green no matter what.

Monitor and audit

Fortunately, increasing the distribution uniformity and overall reduction in irrigation volume is relatively easy to accomplish. By definition, irrigation systems are filled with moving parts that break or wear out. Making necessary repairs can create huge improvements in irrigation efficiency and water conservation.


Symptoms of a leaking irrigation head.
PHOTO BY ROCH E. GAUSSOIN, UNL.

Depending on who is speaking at the time, estimates for the efficiency of a given irrigation system run from 30 to 80 percent. Much of what determines exactly how well the system delivers the output is based on age, spacing of heads and system design. Sure, just like with other products we all need and use, such as car and truck tires, substantive strides have been achieved in improving irrigation equipment including the design of the nozzles, orifices and spray patterns, but the basics of spacing and condition of the parts remain as the most important factors to evaluate.

Inspect and repair

The first step in any examination is to simply turn the system on and watch it run. All the specifications and product claims in the world won’t help to conserve water if the pressure, head alignment and valve operation is out of whack.

A reasonable approach is to locate the turf area that is most concerning (again, those troublesome brown spots) and run each zone that covers it for 10 minutes. In some cases, parts of three or more zones may contribute to the problematic area. While each zone is operating, make a quick note to locate the spot and write in general notes. Typical comments are “heads on third base side not turning properly,” “looks like someone drove over that riser” and “this one is probably leaking.” If obvious problems exist, address them by repair or adjustment.

The second step is to determine how effective the first round of repairs was. Set out collection cans in the irrigation spray pattern of each head by placing one 2 feet away from a head and another halfway between it and another head. Continue until all turf areas are covered by collection cans. Fortunately, collection cans are inexpensive. My favorites include empty cat food and tuna cans. Of course, official irrigation auditing devices are available, and probably would be a better choice, especially if you want to look really official. However, each will deliver the same information about irrigation efficiency.


Problem areas are a good place to start when auditing irrigation systems.
PHOTO BY JOHN C. FECH, UNL.

The number of specific flaws that an irrigation system can have seems endless. Here are some of the more common ones:

  • Heads that don’t turn – Heads that are sufficiently worn so that they no longer turn deliver too much water in one part of the pattern and none in the other.
  • Heads that turn, but don’t follow the preset pattern – Quarter patterns can turn into 360-degree patterns if they become misaligned; they simply need replacement or adjustment.
  • Leaking heads and pipe connections – When there is a crack or leak in the piping, water seeps out into the surrounding soil, causing it to be wetter than normal. This often results in darker than desirable grass or root rot.
  • Bent risers – If a utility vehicle mistakenly runs over a properly installed irrigation head, there are usually no resulting ill effects. However, if the riser is slow to close when it is struck or installed a bit on the high side, the potential for damage is high. Bent risers don’t deliver water at the proper angle, resulting in too much on one side and not enough on the other.
  • Risers that don’t rise above the turf – When risers become past their prime or the water pressure is too low, it’s common for them to fail to rise as high as they should be. When this occurs, they deliver water in the turf canopy rather than above it, resulting in poor coverage.
  • Geysers – When the nozzle is completely missing due to vandalism or age, lots of water is wasted and a lack of adequate coverage occurs.
  • Clogged orifices – Sand and other debris can become deposited in the emitters/orifices, where they significantly distort the spray pattern. These problems usually require auditing to become evident.
  • Pressure, either too high or too low – As mentioned previously, low and high pressure cause problems of inefficiency. A pitot tube can be use to check for proper pressure.

Disease and insect conflicts

Pests can mask the symptoms of systems that run inefficiently or improperly. For example, if an important part of a field is infested with white grubs, the roots of the turf plants in this area are likely to be incapable of extracting sufficient water from the soil to keep the turf plants vigorous. Based on the aforementioned human tendency to irrigate for the dry spots, sports turf managers tend to increase the run time for the zones that cover infested areas, which may result in a benefit to the suffering turf, but may also result in an overapplication of water for adjacent areas. Another unintended influence from irrigation adjustments of this type are the effects on foliar and root diseases, both of which are encouraged during periods of excessively frequent applications or cycles that deliver overly abundant amounts.

Healthy soil helps conserve water

Finally, focusing efforts on soil improvements will result in water conservation. The common techniques of core aeration, topdressing, pH adjustment and using soil tests to determine the optimal amounts of each nutrient to apply go a long way towards creating healthy soil. Think about it. If you were a turf root, where would you rather grow – in a nutrient poor, compacted, high pH soil or one that is characterized by being moderately fertile, well oxygenated and having a slightly acid soil pH?

John Fech is an extension educator specializing in turf and ornamentals at the University of Nebraska-Lincoln.