## Turfgrass Notes From Korea

##### 29 April 2013

I was at Korea last week, where I visited six different golf clubs. Two were 18 hole facilities, one of which is under construction, one has 9 holes and is open 24 hours a day for half the year, two have 36 holes, and one has 72 holes.

That is Sky72 Golf Club, adjacent to Seoul's Incheon Airport, and as is typical of many courses in Korea, the course is lighted so that rounds can begin before sunrise and continue into the middle of the night. Two of the courses at Sky72 do well over 100,000 rounds per year, and that amount of traffic brings with it certain challenges.

There is of course the challenge of just getting the maintenance work done, but also the wear from all the traffic is severe. This is especially a challenge when zoysiagrass (Zoysia japonica) is used, as it so often is because of the climate, because there are less than six months of growth for zoysia in Korea.

At the beginning of spring, we can see in the photo above that the creeping bentgrass green has excellent grass coverage, but the zoysiagrass surround at the back of the green has been worn completely away through traffic during the winter. And the traffic makes for some unusual maintenance on bentgrass greens, where the hole location is changed multiple times per day. This is usually about every 80 to 100 players, or up to six times a day, I was told, at courses such as Korea Public GC, which hosts about 110,000 annual rounds and is open 24 hours a day from May to November.

Greens of course require relatively high rates of nitrogen when they receive so much traffic. I've written extensively about the growth potential and how it can be used to predict nitrogen requirements. Calculating the cool-season growth potential (GP) for Seoul and estimating a monthly nitrogen use of 3.5 g N/m2 when the GP is 1, we get an estimated annual use of 18.1 g N/m2. But the busy courses are using, generally, 30 to 40 g N/m2, to achieve the necessary growth rates to recover from traffic of more than 100,000 golfers each year.

During construction, it is customary to plant zoysia using stolons embedded in biodegradable nets that are rolled out across the fairways. After just visiting sod farms in the United States and finding that zoysia sod was selling for just over $3/m2, it was interesting to note that these zoysia rolls in Korea are the same price, and the installed price, including a layer of sand topdressing, is close to$5/m2. Once the rainy season and the hot weather of summer comes, this grass will fill in rapidly, and the fairway pictured above will be ready for a soft opening by October.

I saw cool technology too. At Golfzon County Sunwoon, I played 18 holes, the caddy kept our score on a tablet computer and recorded the number of putts for each hole, and she also took photos of our group on the course. When I returned to the clubhouse, I simply entered my locker number into a kiosk, and the scorecard was printed with a photo from our round, the hole by hole score, and the number of putts I had taken. It looks like I've got some room for improvement!

But that could be checked too, for there were two holes on which a video camera recorded my tee shot, archiving the swings on a website for my viewing at a later date as a record of the round, and immediately viewable on the in-cart tablet computer through the on course WiFi network. There is really some cool technology involved with these systems, and it is something that made my round of golf more fun than it otherwise might have been.