Saturday, July 24, 2010

What’s going on with the Greens? Part II

In our last update I explained that the primary cause of the decline of our putting surfaces was we have developed an excessive thatch layer over the years. This excessive thatch layer developed from not being aggressive enough with core aeration and cultural practices. The buildup of organic matter has in effect sealed off the greens from air movement into the soil and to the roots. Oxygen is crucial in the root zone for any plant to convert the simple sugars created by the plant during photosynthesis into usable food for cell division.

Anaerobic black layer in removed turf on #14 green
This lack of air also creates an anaerobic black layer in which certain bacteria, who thrive in environments without air, attack the thatch layer as a food source. In doing so, this aerobic bacteria release a by-product of hydrogen sulfide gas which is toxic to roots. This is why we need to continue to vent the greens by poking small holes in them allowing the toxic gas to escape and oxygen to reach the root zone. Fortunately the surfaces have recovered to the point that we can now lightly topdress with sand after we vent them as opposed to a few weeks ago when their condition was much more precarious. Working even light applications of sand into a putting surface can be stressful by itself to a healthy green and devastating to a weak one. However topdressing really helps with putting quality as it smoothes the surface and fills the dimples of the spiking holes.

As I explained in the last update this thatch has to be removed mechanically via core aeration and deep vertical mowing. Both of these processes will remove portions of the excessive thatch layer and allow oxygen back into the soil. In our climate these processes too stressful to do in the heat of the summer particularly when the surfaces are already suspect. This is why we typically do this type of cultivation work in the spring and fall.

You can see why keeping things in balance is crucial when maintaining a modern day putting surface. The demands we put on them to roll true and fast can only be achieved when we have a firm and healthy surface. We know that to get back in balance we have to be more aggressive with our core aeration this coming fall and next spring but how aggressive and how long do we have to be this aggressive? I could speculate but a definitive answer will be found by doing some physical soil testing.

Chemical soil testing is concerned with maintaining an appropriate balance of nutrients. We perform chemical soil testing on our greens at least annually. Physical soil testing is an entirely different animal as it is concerned with maintaining an appropriate balance between air and water properties in conjunction with the soils ability to supply nutrients. Physical soil testing has never been done to our greens after establishment primarily because of its expense. At this point I believe it is crucial to give us a roadmap on how we need to proceed with our greens moving forward. I will have results from this testing in approximately four weeks and will share the high and low lights with you then.

We will be limping through the summer with our greens. We have re-sodded bad areas and will continue if necessary. We will be spiking and light topdressing on a regular basis just to keep oxygen moving into the root zone and gasses displaced. Rolling will continue but we can not cut the greens down as tight as we have done in the past at the risk of further decline.

With the help of sound science along with diligence and patience at aeration times, I am optimistic that we will have the firm, fast and healthy putting surface’s we all desire. Definitely more to come.

Preparing for sod on #14

Installing sod #14

Completed sodding #14

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