Yavor Atanasov worked as the Superintendent at Pravets Golf Club since 2011, a Peter Harradine designed 18-hole golf course in Bulgaria, one of the top Golf Courses in Eastern Europe.
The Festuca/Agrostis greens have been used since 2010. To keep on top of thatch development, Yavor intensified his efforts from 2021. TourTurf® Thatch-Less® ETD Enzyme Thatch Degrader was an important part of his strategy.
TourTurf® Thatch-Less® ETD Enzyme Thatch Degrader is a biological activator for more rapid thatch degradation; it contains 15% cellulase enzymes and four different cellulase producing microorganisms. The combination of readily active enzymes and steadily performing microorganisms effectively degrades thatch into plant nutrients, sugars, and soil humus.
European Turfgrass Laboratories tested the greens Organic Matter content (OM) by loss-on-ignition in spring before the treatment and again in autumn (Loss-on-Ignition measures the weight of an oven-dried soil sample before and after burning its organic matter for 2 hours at 360°C, with the loss in weight expressed as a %). The rootzone was tested in the following depths separately: 0-20 mm, 20-40 mm, 40-60 mm, 60-80 mm, 80-100 mm, and 100-120 mm. Not surprisingly, the OM content was highest in the top layers, 0-20 mm and 20-40 mm.
Mid-June: TourTurf® ETD 10 l / ha
End June: TourTurf® ETD 10 l / ha
Mid-July: TourTurf® ETD 10 l / ha
End July: TourTurf® ETD 10 l / ha
The organic matter in the top layer of the rootzone 0-20 mm reduced by 21% in 2021. Interestingly, at the same time, the OM in the deeper layers increased slightly, maybe because of organic matter being broken down and mobilised, increasing microbial activity in deeper soil layers.
Yavor repeated the tests the year after, and we followed up on the development.
In the 2022 season, the same effect could be observed. The organic matter in the top layer of the rootzone 0-20 mm was reduced by 18% during the growing season.
At first glance it was surprising to see that, between March 2021 to March 2022 there was an increase in the OM of 36 % in the top two cm. For the complete 12 cm root zone OM increased from 2,0 % to 2,5 % that’s an increase of 30 %. There was even a stronger increase if you compare autumn to spring.
How is this possible? Do we really want to reduce OM more and more? We did some further research:
Fact 1:
We can only compare OM levels measured yearly at the same time of the year to see a trend. It doesn’t make sense to compare the lower levels measured in autumn to the much higher levels the following spring.
As you can see from Yavors weather data, winter temperatures and perspiration levels in his location reduced microbial activity in the soil drastically, leading to a build-up of organic matter in spring. (Growing Degree Days or GDD is calculated as the average air temperature minus the base temperature of 0 °C for cool season grasses. The daily GDD values are added together to get the cumulative GDD. GDD is correlated to plant growth.)
Fact 2:
An increase in organic matter is positive! Often, the greens with the highest OM levels are the best performing greens on a golf course. The problem greens are often those with the lowest OM. This makes sense, since increased organic matter increases microbial activity in the soil. The microbes in turn will help to break down and metabolize thatch.
Fact 3:
What we want to avoid is excess thatch, not organic matter. The testing method used by the lab (ASTM F1647-11a) measures LOI (The weight difference after all the organic material is burned at high temperature). Organic matter does not only consist of thatch but also of the plant itself, shoots, roots and other organic material.
During the growing season 2021 the OM in the top 2 cm reduced by 21 %, in 2022 by 18 %. But overall, there is a trend that OM in the greens of Pravets Golf Club increases from year to year. And so does the quality. Yavor regularly checks the soil profile, and we asked him about his observations:
Are the greens too soft?
“No, the greens are firm and true. No complaints from golfers at all.”
How is the water infiltration rate?
“I do not see any issues.”
Is there a thick thatch layer?
“I cannot see any thatch layer.”
How is the overall performance of the greens?
“The golfers/guests love them. No issues.”
How do they hold up in drought situations and under disease pressure?
“With a wetting agent program, they are holding OK during summer. Twice during the season, we have been affected by brown patch. There is a danger for that the whole season, and that is a problem we deal with every year.”
What is the development of roots like?
“The roots are to the bottom of the hole cutter – approx. 20 cm.”
Our goal is to produce a firm, consistent and healthy putting surface.
Increasing the organic matter in the rootzone will have many positive effects resulting mainly from increased microbial activity.
Frequent light top dressing, increasing soil oxygen by aerification in combination with cellulase enzymes and cellulase producing microorganisms in TourTurf® Thatch-Less® ETD Enzyme Thatch Degrader can significantly reduce thatch and further increase microbial activity in the soil and help to produce healthy turf.
If the firmness of the greens and the water holding capacity is good, continue with the mechanical program and the topdressing regime.
If the greens become too soft and hold too much moisture in the top layer, you must reduce the organic matter by incorporating more sand.
If the greens are too hard and don’t hold enough water, you can try to increase the level of organic matter.