Denmark
March 22, 2023
The greenkeeper team at Golfbaan De Woeste Kop in Axel has successfully made efforts to significantly reduce the percentage of annual meadow grass (Poa annua) on the greens. Each year, the head greenkeeper, Paul Mannaert, overseeds five times with a different creeping bentgrass variety from DLF. For tees and fairways he uses a 4turf® mixture.
Since 1986, the 18-hole golf course has been located in the Smitsschorre nature reserve on the edge of Axel. This is between creeks and forests, which is bordering the typical Zeeland polders with dikes and poplars. One of the holes is nearby the striking landmark, Axel water tower. For ten years the golf course have been maintained by a golf course contractor.
Significantly improved
Paul Mannaert has been the head greenkeeper of this A-status, 18-hole course for two years. He says that the golf course at De Woeste Kop golf club was built on reclaimed soil from the Ghent-Terneuzen Canal, which was widened in the 1960s:
“The course is largely built on pure sand. Below is a loam-sand mixture that adversely affects water permeability, and it often remains a bit damp after heavy rain. Furthermore, the course is about 7 meters higher than its surroundings.”
“I really like it here"
About seventeen years ago Mannaert started working at the De Woeste Kop golf club and the last two years has been as the head greenkeeper.
“It's a beautiful golf course and I really enjoy it here. And I can honestly say that the quality of the golf course has improved considerably thanks to the outsourcing of the maintenance. In those ten years we have made a considerable improvement. This is also reflected in the number of members: in 2012 there were 450 members; now there are 1100. About 44 percent of this comes from nearby Belgium: we are the only 18-hole course in this area.”
Proportion of bent grass on the greens has increased to almost 80 percent
Mannaert says that regular overseeding plays a big role. “I overseed the greens five times a year with creeping bent grass (Agrostis Stolonifera). I do this as soon as most of the night frost has passed: shortly before the start of the competition, after the competition, at the beginning of September and again at the end of September/beginning of October. I divide the amount of grass seed, which I sow, over five sowings. This way I spread the risks that the overseeded grass will have a bad establishment. This approach has led to an increase in the proportion of bent grass on my greens from 20 percent to almost 80 percent in eight years. Moreover, I change varieties to avoid a monoculture. In 2021, I sowed with Cobra Nova, this year with CY-2 and in 2023 I will use Independence again.''
Overseeding
Different equipment is used for overseeding. Mannaert overseeds the greens with a Maredo seeder: “The contractor H4A purchased two Vredo machines. One large for the fairways and tees and one smaller Vredo for smaller surfaces that are more difficult to access.The fairways and tees are overseeded twice a year with 4turf®, a mixture of tetraploid perennial ryegrasses (Lolium perenne) known to have a higher drought and salt tolerance. I plan to overseed the fairways and tees with red fescue (Festuca rubra sp). I think this is even more resistant to drought, although 4turf® is resistant to heat. We will all have to deal with those changes in the future.”
Irrigation and flushing
Mannaert wants to limit the use of water on the fairways. “In a dry nature reserve, fairways that looks like a green oases will raise questions among recreational users.” And he wants to take this into account: A major additional problem is that the irrigation water has an EC-value that is too high (3.0-3.5). The moment we start watering during the day, while the sun is also shining, the grass burns. Our biggest challenge is to choose grass types and varieties that have greater drought and salt tolerance. More 4turf® and red fescue are desirable, however, we probably cannot escape the use of wetting agents if the irrigation is reduced.
Constant check of salinity
“We have four water sources here. Two of these have recently been struck out of necessity and they provide excellent fresh water. The other two are slightly saline, but they can be used by mixing them with pond water. So I constantly check the salinity of the water. If the salinity of the bottom of the greens is too high, you will immediately see it in the withering grass. Nevertheless, I check the salinity with the EC-meter. If the salt content is too high, we apply flushing. This technique has been used in Spain on golf courses with a risk of salinization for some time. The sodium is bound with chemistry and with a huge dose of water at once, about 20 millimeters, you rinse the product out of the top layer, which immediately reduces the salt content of the top layer of your green.”
Mowing
Does Mannaert have a special approach to maintaining the turf? In terms of the greens, he says: “The creeping bent grass on the greens gets a vertical mowing almost weekly during the growing season. We do this to promote its propagation. So the grass on the greens gets quite an aggressive treatment; which it thrives well off. We use a cutting height of 3.6 millimeters there, and 3.0 millimeters when there are tournaments. We also roll the greens intensively. In terms of disease infections, the low proportion of annual meadow grass on the greens automatically reduces susceptibility to disease. However, our greens remain sensitive to dollar spots on a summer day and from August we usually have to deal with Fusarium.”
Seed supplier
Belgian Greenmix supplies all the necessary grass seed to the De Woeste Kop golf course and the fertilisers intended for the tees and fairways. They also supply winter fertiliser for the greens. This is a classic product based on dried sand with 1 percent nitrogen and 9 percent iron chelate. This gives a nice green cover and prevents moss and mold formation. It is applied four to five times, until the grass starts growing again in the spring.
Greenmix's activities started here about eight years ago, when Greenkeeper of the Year 2018, Arjan Westeeng, was the head greenkeeper there. Due to the extremely high percentages of annual meadow grass on the greens, they made the plan of action to frequently overseed the greens with creeping bent grass.
“I thought that was a very ambitious plan because of the very high percentage of annual meadow grass,” Hoekstra remarks. “But the approach was successful. The roles between creeping bent grass and annual grass are completely reversed! For the fairways we initially chose to overseed with ProMaster Golf 50 Golf GM. This is a mix of tetraploid perennial ryegrass and red fescue. During the dry summer of 2018, it was striking how well the 4turf® varieties performed. That is why, in 2019, we switched to full overseeding with the Masterline sports field mixture 4-4-2 Master GM with three exclusive 4turf® varieties. The result after some time was astonishing and left an incredible turf. The semi-rough was also overseeded with this. Even out of the reach of the sprinkler, the semi-rough remained green right up to the trees in the rough, with nice coverage”
Even wihtout irrigation, the semi-rough remained green
In practice, the tetraploid perennial ryegrass varieties turned out to be extremely drought-resistant. The Masterline 4-4-2 Master GM sports field mixture also worked wonders on the areas of the fairway that had been affected by the brackish water. The salt tolerance of the varieties used in this mixture is also quite high.
"The semi-rough with the same grass composition turns a lot darker due to the slightly higher mowing. That gives a nice contrast, more than what you see with other diploid varieties.
Topics
Species
