Friday, December 30, 2011

Winter Injury to Turf

I know that with all of the warm weather we have been getting a lot of questions if we are going to take the greens covers off and open. I am sorry to say that the answer to that question is no. I would like to take this space to post an article on winter play that was written by a USGA Agronomist back in 1987. I did not include the entire text from Jim's article, just pertinent information for us in our climate. Make sure you read the last part of the article. Thank you.

Politics Religion and Winter Play on Greens
By James T. Snow
Director, Northeastern Region, USGA Green Section
Reprinted from the USGA Green Section Record
1987 November/December Vol 25(6): 1-4

It is common knowledge that three topics are simply too controversial for polite conversation, and should never be brought up at social functions: politics, religion and winter play on greens. Not familiar with the last? If not, then you apparently haven't spent much time at northern golf courses during late fall and early winter.

Few subjects raise such an emotional response from golf course superintendents and golfers alike. Golfers can become irate at actions restricting their access to regular greens during late fall, winter, and early spring, while superintendents are just as unyielding in their view that play should be kept off the greens at those times.

Who's right?

As with most topics of this nature, qualifications have to be tacked on to any firm answer. It is safe to say, however, that winter play can only harm the greens, and in many instances it has a significantly negative impact on the health and playability of the turf during the following golf season.

Repercussions of Winter Play

It is not hard to understand why many golfers are sometimes skeptical about claims concerning the negative effects of winter play, because to them the turf on greens that have been played throughout the winter usually appears the same as the turf on greens that have been closed. The effects of winter traffic, however, need not be obvious and dramatic to have significant and long-lasting repercussions.

Direct wear injury

Thinning of the turf due to direct wear injury is an obvious and important result of winter traffic. Unlike during the growing season, when turf is able to regenerate new leaves and stems to replace injured tissue daily, winter weather completely halts turf growth; the grass is continually thinned throughout the winter in direct proportion to the amount of traffic. This thinning of the turf canopy can, and often does, encourage the establishment of such weeds as Poa annua, crabgrass, goosegrass, moss, algae, pearlwort, spurge, and other weed pests during the spring and summer. True enough, weeds can indeed be a problem on greens that aren't subjected to winter play, but winter traffic causes them to be just that much more abundant and difficult to control.

Soil compaction

Soil compaction is a more subtle and perhaps more important consequence of winter traffic. Because of the cold winter temperatures and lack of active turf growth, the loss of excess soil moisture through evaporation and transpiration is greatly reduced. In addition, frozen sub-surface soils may completely block the movement of excess moisture through the soil profile. During the summer, a very heavy rainfall often creates soil conditions that warrant closing the course for a day or two until the excess moisture is eliminated by the way of evaporation, transpiration, and downward percolation through the soil profile. Because these moisture losses are often non-functional during the winter, saturated soil conditions can persist for weeks or longer. Yet the golfers who can appreciate the need to close the course during the summer are sometimes completely unsympathetic to the same conditions and concerns during the winter.

The effects of soil compaction on the health and playability of the turf are insidious at any time, but because wet soils are especially prone to compaction, the likelihood of traffic causing the collapse of good soil structure is of constant concern during the winter. As soil particles are compacted and pushed closer and closer together, the pore space that facilitates drainage and root growth during summer is gradually lost. As the season finally commences, golfers often complain the these compacted greens are hard. From an agronomic standpoint, turf begins the season in a weakened state, predisposed to a host of summer problems. In addition to the potential for weed encroachment, the turf on greens played during winter tends to wilt more readily during hot weather, and often is more susceptible to a wide array of primary and secondary disease organisms.

Effects on playability

With the loss of turf density from direct wear injury and the loss of turf vigor caused by soil compaction, greens played during winter tend to be hard, slow, and bumpy, and they are slower to develop during the spring, compared to greens that are not subjected to winter traffic. Footprinting is often a problem, and golfers tend to complain about the lack of trueness even after several topdressings in the spring. Finally, the effects of compaction on the health of the turf can last to a certain extent for much of the season, making it difficult or impossible to keep the greens as closely cut and intensively groomed as some golfers might desire.

Many winter golfers have heard these arguments before and have dismissed them as being ravings of overprotective golf course superintendents and turfgrass scientists. A favorite response is, "I pay plenty to play golf at this club, and I'm going to use the regular greens during the winter. That's why we pay the superintendent - to fix up the greens in time for spring. Besides, the Let-'Em-Play-Anytime Golf Course down the street lets them play through the winter, and they don't lose any grass during the summer. Anyway, we only have a few groups that play much during the winter. How much damage can we do?"

Factors to consider

On the surface, these comments seem quite valid; after all, everything is a matter of degree. But many factors should be taken into account in developing a logical policy on winter play.

Anticipated traffic

If a single round of golf were played on the course during the winter, most would agree that the potential for serious damage would be nil. Same for ten rounds? How about 100, 500 or 1,000? If the weather is mild and there is little snow, how many more rounds will it add? Where do you draw the line?

Soil type

Winter golfers argue that sand-based greens drain well and don't compact, making them very suitable for winter play at any time. While it is true that sand-based greens don't suffer from compaction to the extent that older soil-based greens might, it is also true that direct-wear injury is likely to be more severe on sand greens. Turf density can be greatly compromised, and weed encroachment can be a real concern. It is also true that most golf courses in the North do not have good sand-based greens. Obviously, courses with older soil-based greens are especially vulnerable to both types of winter injury.

Specific weather conditions

Though traffic on dormant turf will indeed cause some injury, the weather and soil conditions at the time of play will dictate the type and extent of the damage. Traffic on dry, unfrozen soil will cause the least damage, but this condition is rare during the winter. Frozen soil can cause significant wear injury but little soil compaction. Play on wet, unfrozen soil can result in significant soil compaction but less wear injury. Play on a thawing soil(wet on the surface, frozen below) can result in severe soil compaction and wear injury, and should be avoided. Finally, frosted turf is extremely susceptible to direct injury, and play should never be allowed.

Grass species

Do you have bentgrass greens and want to keep them? Then don't allow winter play. Thinned turf and compacted soil is just what Poa annua is looking for in the spring.

Standards for play

One of the most important questions to ask in contemplating whether or not to use the regular greens in winter concerns what the golfers want from the greens during the regular season. If they want top-quality turf from spring through fall, involving very close, frequent mowing, double mowing, frequent verticutting, lean fertilization, minimal irrigation, or other stress-inducing practices, then it is best to avoid winter play. If the golfers don't mind higher cutting heights, slower speeds, and greater inconsistency, then winter golf was made for them. Some bias in that statement? Perhaps, but too many golfers want to trample their dormant greens during the winter months and then enjoy U.S. Open conditions from April through November. There are still some things money can't buy.

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