May 26, 2011

University of Arkansas, Division of Agriculture

Turfgrass Science Program ( – Turf Tips

Rain, rain go away...

Wow, the last 60 days have dumped anywhere from 10 to 35 inches of rain on Arkansas and the surrounding region (see map). The highest amounts are almost our yearly total and the rain is still falling or predicted to fall over the next few days.

What does all this rain mean for turfgrass managers in the region? Well, there are a number of factors in play, not the least of which is that many athletic fields and golf courses have been unplayable over the last 4-6 weeks, so revenue or schedules are obviously affected by loss of play. Secondly, many facilities have experienced significant damage from the widespread flooding in the region, so unexpected costs associated with cleanup or repair have played havoc with budgets. We have included a number of pictures below from local courses that were hit hard.
From a management standpoint, just getting the mowing done has been a challenge in many areas. Just remember that if the turf has experienced excessive growth since the last mowing, it would be beneficial to raise the mowing height for your first cutting to avoid scalping damage and then bring the mowing height back down to the desired height over the next couple of mowings. The use of growth regulators can certainly help deal with increased mowing intervals and could minimize scalping.

Probably one of the bigger issues that will affect turfgrass managers over the next month is the potential loss of fertility associated with excessive rains. This will be especially true if soluble fertilizer sources, especially soluble nitrogen or potassium, have been applied over the last couple of months. Much of that fertility has probably been lost due to leaching or runoff and reapplication may be merited to replace that lost fertility. Sandy soils are more prone to leaching, so putting greens or sand-based athletic fields are likely on the lean side after all these storms. If organic or slow-release N sources have been used, then loss of nutrients will be minimized, but the source could affect those losses. Sources such as methylene urea or organic sources are probably still around, since they require microbial activity for release of the N, where sources such as IBDU and some coated materials release N by diffusion, so some of the nutrients may have been lost during these excessive moisture conditions. For potassium fertilization, it might be worth a second round of soil tests to see if K levels are still adequate.

All the wet weather has created prime conditions for diseases to pop up and we are starting to see a lot of dollar spot on various grasses. Since dollar spot likes lean turf, the loss of nutrients could also contribute to this. We are also seeing diseases, such as large patch on zoysiagrass, remain active later in the spring than would normally be expected. The cool, wet weather is allowing new infections to continue and most of the applied fungicides have likely been metabolized by this point and no longer effective. In very high-profile locations, such as tees or greens surrounds, another fungicide application may be needed to prevent further injury.

Weed control programs, especially spring pre-emerge applications, should still be in good shape, although Dr. John Boyd has mentioned that your pre-emerge may breakdown a little sooner with all the rains, so managers should be scouting to ensure they can get after annuals with another plan if the pre-emerge quits working.  Sedges, algae, and moss are commonly associated with wet soils and could be a bigger problem this year.  Long-term wet conditions could also cause general thinning of the turf and allow for more weed invasion.

I hope we see a break in the weather in the coming weeks and let us know if we can be of assistance…

Mike Richardson and Doug Karcher
University of Arkansas Turfgrass Program

Images courtesy of Jason Miller, The Blessings Golf Club in Johnson AR and Casey Crittendon, Bella Vista Golf Club, Bella Vista AR

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