Green patches on greens

Happy 4^th of July! The Grounds department is 1/3 of the way through our toughest stretch: June, July, and August. We can’t take anything for granted at this time of year and we manage the turf grass one day at a time.

You may have noticed irregular dark green patches popping up on the greens. They are present on nearly every green and are hard to miss. This is the result of microbes in the soil, breaking down organic matter and releasing nitrogen, which the grass plant is then consuming. Nitrogen makes the grass turn dark green and start to grow, so we are seeing the result of this increased nitrogen available to the grass. There are so many different microbes in the soil it is difficult to say which may be causing this particular event, but it is not really important which microbe or microbes is responsible.

When we see these green patches we automatically know a few things about the turf and soil of the greens.

First, we know we have organic matter. We pretty much know this anyway but it gives us a visual reminder. Organic matter is not bad by itself, but too much organic matter can be. We know we have to stay aggressive with our aeration and topdressing programs.

Second, we know that we have a healthy ecosystem in the soil. There are microbes, which are very beneficial to the grass in many ways, and there is food available for those microbes on which to live.

Third, we can tell that we are managing the greens' turf towards the lean end of the fertilization spectrum, meaning we are not giving it as much food as we could be. In the areas where more food- nitrogen in this case- is available, the grass is greener and growing more.

Managing more lean than lush turf is exactly what we want, especially at this time of year. Over-nitrifying the plant can lead to several problems. With extra nitrogen come extra pests, both disease and insects. Disease pathogens and insects use nitrogen as a food source also, so increased levels equal a hospitable environment for them as well. Also, increased nitrogen in the plant makes it an even more appetizing host for a disease or insect pest. Keeping nitrogen levels down is one way for us to help mitigate pests.

Another problem that too much nitrogen can cause is too much growth. This is obvious, but why is it a problem? Too much growth is bad for playability. When the greens are growing too much and too fast, they become slow and bumpy, which are two of the worst words a superintendent can hear from golfers. We keep the nitrogen levels low to manage our clipping yield so that we are better able to produce a smooth, consistent, and fast playing surface. Furthermore, the plant requires water to grow; the more growing the plant is trying to do, the more water it will need. Again, for playability and plant health reasons, we maintain the turf with less water than it actually wants and needs.

When too much nitrogen is entered into the equation, the plant will outgrow the water available. Plants don’t know when to stop taking in nitrogen. If it is available, they will absorb it, and grow. Trying to grow when it is very warm, with less water than it needs, can cause the plant to suffer very quickly, wilt, and die. Imagine eating a VERY large meal, not drinking enough water before or after, and then running a marathon on a 90+ degree day. You might suffer as well. This is what the plant is trying to do, but it doesn’t have the ability to get to shade or get more water, so we have to monitor and manage all of the inputs.

So what can we do about the patches? Unfortunately, there is no way to get rid of them. We could hide them by fertilizing the green. If the entire green was dark green and lush, the patches would mix right in. However, we just outlined how and why excess nitrogen could be catastrophic, so that is not a viable option. We also continue to manage and remove the organic matter present in the soil to help limit the available food source for the microbes. We could also eliminate the microbes from the soil, but that too would a very bad long term decision.

For now, although unsightly, we must live with the patches. The health of the greens is not affected and we are doing everything we can to make sure that putting remains unaffected.

Etiquette Reminder of the Month

Please don’t stand in one place for an extended period of time to practice putting. Your footprints can be worn into the green.

See you on the course!

Joe

jvillegas@bwrc.org