Irrigation Time

With the dry weather the irrigation system has been getting a workout! It seems no matter how much we test the heads, controllers and pumpstation problems creep up through the season. The system waters about 60 acres of the 240 we have at Rolling Meadows with irrigation in greens, tees and fairways.  The pumpstation can pump over 1400 gallons a minute to feed the miles of pipe and over 500 irrigation heads.

The pumpstation pumps from the main irrigation pond that is fed by runoff from the upper half of the golf course in addition to a high capacity well. The pumpstation maintain a pressure of 90 pounds per square inch in the system. Green heads are spaced in a square pattern and put out 30 to 40 gallons per minute 55' to 85' feet. The big heads in the fairway throw 60 gallons per minute up to 98'.

This week we had a faulty sensor four feet under the water in the pumphouse that would tell the pumpstation it was out of water so the pumps would stop running. In the morning we would see the error and assume we ran out of water and the 2 foot inlet filter was clogged. However we could not recreate this problem during the day no matter how much water we pumped. After three nights of a total system failure and watering 10-15% of the course we figured out we did not have a water flow problem but a faulty sensor. It was a quick fix but something you do not expect.

Because of that you may of noticed the challenge we have greening the turf areas back up after they brown due to our heavy soils. They hold moisture well but when they get dry and turn brown or dormant they stay that way for days no matter how much water we apply. Although we have caught up on our application rates the areas still look off color and will for the next few days until they slowly come back. This is different than the courses I have worked at previously with normal or rocky soils. At those facilities areas would be wilted grey and brown in the afternoon and a little water would turn them emerald green the following morning.

With over 500 irrigation heads one or two of them break every time we water either through wear and age along with partially clogged nozzles that change distribution. We spend the first few hours each morning trying to find those broken heads and improving coverage.

Often golfers ask why if we have a automatic system we still have sprinklers on at 7 AM. Early morning is the best time to water for plant health and to reduce fungus and disease problems so we start the system as late as we can but we can only water so many heads at a time without pressure and performance loss. So we water the early holes (1-5, 10-14 and 19-22) early in the morning and the later or finishing holes around dawn.

The worst time for us or you to water is in the mid to late afternoon. The grass does not like to be wet during the heat of the day and a lot of the water evaporates before it hits the ground.

How do we decide when and how much to water? We use information from our weather station and a e-mail service from UW-Madison to determine our Evapotranspiration Rate (ET Rate). The ET is a combination of how much water a the grass plants would use in a day plus the amount of water evaporated into the atmosphere. The ET rate is calculated by temperature, sunshine, wind, humidity and dew point. Believe it or not the rate is usually higher in June than it is the hot dog days of August because the humidity is lower in June.

So far in the month of June our ET has averaged an amazing .23" or almost a quarter inch a day of water use or evaporation with peak days of .34". University research has shown that plants are healthiest if we replace 80% of the ET. .23' x 80% equals .18" of water a day we need to apply for healthy turf.  Under normal circumstances we try to water ever second or third day so we try to apply .36" or .54' of water per application.

No matter how new or technologically advanced a irrigation system is they do not replace rain and in Wisconsin they are designed only to supplement rain. Long term dry periods lead to wet spots from too much water and dry spots from too little water. We do our best to find these areas and increase or decrease coverage but our biggest problem is right around the heads or right in the center of the fairway where extra water is spilt when the heads turn on and off and with the single row spacing the area is hit by three heads.

Perfect green is not our goal with irrigation. Our goal is healthy but playable turf and dry and a little brown is better than wet and bright green.

Greens aerification

This weeks players may have noticed we poked pencil thin holes in the greens to allow air and water to penetrate the soil profile and loosen the soil underground. Although this process does lead to a couple days of less than perfect putting the holes are almost invisible 5 days later.

I realize the greens had been near perfect the past three weeks but with the long spring and upcoming hot humid weather it was a perfect time to give the greens a break. Also the greens are good for three weeks at a time because of the verticutting, aerification, spiking and topdressing we do to them every 3 to 4 weeks.

It would be great to have perfect conditions all the time but greens are a living thing and need to be fed, groomed and protected just like your body does. Fast and firm and tightly mowed is great for periods of time but maintenance has to be done also.

At the same time we applied a light layer of sand topdressing and a granular fertilizer because we knew we would not mow greens for a couple days after the sand was applied. The challenge for us is working the sand into the tight turf so we do not pick it up with our mowers reducing the effectiveness and damaging the mowers.

As I discussed last time the sand has many purposes.

1. It smooths the surface by filling in little holes and marks to allow for smoother puts.
2. It reduces the thatch layer that can make the greens soft and bumpy by diluting the dead roots and shoots and rhizomes the bentgrass greens produce.
3. Protects the crown or growing point of the bentgrass plant by slightly buring it.

The greens were mowed, aerified, mowed, rolled, mowed again, rolled again, topdressed, fertilized and watered. The next two days they were only rolled and on the fourth day they were mowed. That fourth day we get some sand but by the 5th day we only get a little sand and the greens are nearly back up to speed.

The challenge of the process is the wet sand and fertilizer sticks to the ball when players putt in the morning dew. Also the sand tracks on shoes and drops off in uneven piles to cause small bumps until we roll or mow again.

Believe me when I say we only do the maintenance that is for the best of the golf course and if we could skip the work we sure would. Thanks again for your patience as we maintain the playing surfaces you love and for the next three weeks, putting should be near perfect!