Thursday, August 20, 2009

Moisture Deficit, Irrigation Status, & Fairy Rings.

Moisture Deficit:
After record rainfall earlier in the year, the past 6 weeks have been quite dry. July’s total rainfall was only about 1”. Average rainfall for July, is approx. 3.7”, so the deficit was 2.7”. The first 2 weeks in August were also very dry with only about 0.33”. This week we have had some welcomed rains, but until now, we were experiencing a fairly large moisture deficit.

The lack of moisture is evident below. This picture also shows the negative impact trees have on turf, as this tree is winning the battle for water. The healthier green rough 'outside' of the rectangular shape benefited from root pruning - a benefit from the installed irrigation pipe.

Irrigation Status
In a warmer year, this deficit would have been more noticeable on fairways and especially bunker faces. However, our new irrigation system has performed quite well, as we’ve been able to irrigate easily and with more selectivity. We’ve been fine tuning the system lately; adjusting arc’s, spray trajectories, run times, flow rates, and developing irrigation programs for all areas. We still have much to do, but we’re making good progress. We’re already watering much more uniformly and accurately than ever before, but this “fine tuning” will allow us to be as efficient as possible with irrigation inputs.

One thing hasn’t changed - even the best irrigation system doesn’t seem to have the same benefit as rainfall. Rain infiltrates better, doesn’t miss many places, and is free, but in its absence, our irrigation system provides us options that rainfall cannot. Of course the main option is placing water where we want, and when we want. This past Derby was a prime example.

The flexibility of the system gives us options we've never had before.

In the 2 weeks prior to Derby we watered fairways, approaches, and greens very seldom, since our new system would provide rapid re-hydration in these areas when needed. In the meantime, we maintained regular watering of tees, green banks, roughs, and high traffic areas. This was something we couldn’t do in the past and allowed us to provide firm and fast conditions and new challenges from those in the past. Many of you commented favorably about the ground and turf conditions.

The ball roll, the opportunity to play bump and run shots, the need to think more about club selection, conserving water, reducing electrical costs and equipment wear to pump it, and more, are all nice benefits to firmer, drier conditions. Aside from the “less green or more brown” color (which may appear to some as unhealthy when in fact it’s not, it’s just slightly dormant), one issue I’d like to discuss that is more prevalent when dry is a disease called Fairy Ring.

Fairy Ring:
I’ve written about this disease in the past as it’s been active on many of our greens and fairways over the last several years, but with it becoming more noticeable recently, I thought it would be an apropos blog topic.

In 2006, Fairy Ring became a big problem on many greens. Below is Type I (brown to dead rings) Fairy Ring, which causes hydrophobic conditions in the soil leading to severe wilt stress.

Fairy Ring is the common name given to this little understood and highly complex (more than 50 different fungi have been isolated) turf disease that expresses itself in three different ways; green rings, green rings with multiple stunted mushrooms, and brown to dead rings. We’ve had all three here in the past. The green ring phase is not deadly to turf but it does cause the soil to become hydrophobic or water repellent and the rings often become depressed leading to an uneven surface with high and low spots. This can affect your stance and shot making ability.

Other, less injurious Fairy Ring examples.
Practice Green
#18 Fairway

Complete control of Fairy Ring, with a given cultural or chemical treatment, has not been realized so a multiple faceted approach is needed to manage this disease and keep its deleterious results to a minimum. Our approach utilizes several processes including; aeration, needle tine ventilation, wetting agents, judicious handwatering, nutrient application, and fungicide treatments both prior to symptoms in early spring and after any occurrences in mid-summer.

Aeration provides holes to help water infiltrate into hydrophobic areas of the soil.

All of these management tools and techniques are employed for the greens, but the size of the fairways adds costs to an already tight budget. Our early spring fungicide applications on greens have shown very good results (better than post occurrence treatments) in minimizing the development of the “brown to dead ring” phase that we’ve often seen when we didn’t preventively treat. With fungicide treatment the less damaging “green ring” phase is most common on the putting greens, and we can often mask this cosmetic appearance with macro and micronutrient applications.

With the general rainfall deficit and our intentional “drier, firmer, faster” conditioning, the drier fairways have shown an increased amount of “green ring” fairy ring and the associated depressed areas, but also a few locations where the “brown to dead ring” phase has begun. We have recently aerated and applied wetting agents to help offset the hydrophobic soil conditions on a few fairways and we will continue to monitor all others and perform similar operations as needed to minimize any playability issues and/or turf damage. The one management item we did not perform this year (due to cost saving measures), is an early preventive fungicide treatment on fairways which may have helped reduce the amount of fairy ring. Perhaps next year, with the Western Amateur Championship taking place here at about the same time of year that Fairy Ring typically becomes most prevalent, a prudent decision would be to apply at least one early season preventive fungicide treatment.

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