ORGANIC MATTER AND OTHER GEEKY STUFF
As we near the end of winter its natural to start looking forward to spring. Lambs, daffodils, hayfever and having to mow the lawns more often are all signs that warmer temperatures are around the corner. As the days improve, so does the golfers desire to get out and play which is completely understandable as winter golf isnt a whole lot of fun.
Spring traditionally signals something else is on the horizon at the course too: Coring of greens
No operation or task carried out on a golf course has the ability to frustrate golfers more than those bloody greenkeepers out there tearing up the greens again.
The sight golfers loathe!!
In a previous blog post on coring we discussed some of the reasons it might be required and the benefits. It also covers a few of the issues we faced last time we cored which was April last year.
Since then, a few things have happened and there has been a shift in maintenance practices. Emphasis has been placed on how we can manage the surfaces to try and reduce how much organic matter (thatch) is actually produced in the first place.
We asked ourselves the question:
"Can we potentially get away without regular coring?"
WARNING: Science Alert!!
As grass grows, not all of it grows vertically. Many leaves, tillers and in the case of Browntop its rhizomes, grow laterally both on and below the surface. This lateral growth is one of the key advantages of Browntop as it allows the grass to actively spread at certain times of year and "creep" into surrounding areas. The downside to all this lateral plant matter is that a combination of both living and decaying plant tissue, essential knits together form a mat-like layer commonly referred to as thatch or organic matter accumulation. Therefore, the faster the grass grows, the faster this organic matter is produced.
So, whats the plan?
Step one is to try and manage growth through fertiliser and water applications where possible. By only supplying what the grass can actually use, there is no "luxury" consumption of nutrients which leads to excessive grass growth causing extra thatch to be produced.
Step two is to then balance growth and organic matter production with light sand topdressing which dilutes the thatch. This is achieved by sanding on roughly a 2 weekly cycle and adjusting the volume applied based on how much growth is present. This process is now much more achievable as a result of the new sanding equipment purchased last year
The sander that last years fundraising tournament allowed us to purchase
Step three is to spike the greens regularly with small solid spikes to allow water through the surface and air into the profile. The air will aid in the natural decomposition of the organic matter. By using small (8mm - 12mm) solid tines, we can carry this out fairly often with minimal disruption to golfer enjoyment.
Step four is to annually test the greens for their organic matter content. This is done by sending off small plugs of the greens to and independent testing lab which are able to produce objective data showing levels, trends and patterns.
How did we do?
The graph above shows the test results for the top 10mm of the greens profile. We are focusing on this because this is the zone where the organic matter content is usually the highest due to the grass plants primarily being located in this zone.
What this shows us is that from 2017 to 2018, we have actually been able to decrease our organic matter levels without the need for coring. By following the steps outlined above, golfers have not had to experience the discomfort of invasive renovation and the prolonged period of recovery.
Does this mean we will never core again?
No. As we are dealing with a living system and the many factors out of our control that can influence such decisions, it would be unwise to apply such an absolute stance. What we might see is the occasional need to carry out a coring but it will be based on the ongoing test results. We will certainly aim to manage the things within our control that will give us the best chance of not needing to core however. The minimally disruptive spiking and frequent light sanding will continue so please be understanding if you happen to be playing at the time they are being carried out.
While we've got you here, lets also take this opportunity to get a little bit in depth about grass growth, winter conditions and what changes will start happening from now.
We monitor and therefore are able to illustrate this as we record how much grass is being removed each time we mow the greens. When the greens are cut, the staff empty one of the catchers into a measuring jug. The volume, in litres, is then recorded so we can accurately see what is happening. Applications of fertiliser and growth regulators are also noted and we can see their impact reflected in the grass volume being removed.
Note how the growth curve follows the temperature more than the fertiliser applications
What this allows us to now do is to recognise the optimum timing for certain practices but also to appreciate that we cant really force what nature wont allow to happen.
It is easy to see on the above graph that growth through the months of June, July and August is certainly much lower than the warmer months. What we can also see is that the red lines show last September was where we applied the most fertiliser in of any month. It also shows that December we applied a relatively low amount. Interestingly, the growth recorded in the month of December is 3 1/2 times greater than was seen in September despite more fertiliser being applied. This serves to highlight that we cant really force grass to grow if the conditions dont allow it.
This is why, that at the end of winter, surfaces tend to be thinner as continued play and traffic contribute to wear and tear that there isnt sufficient growth to offset.
Thanks for reading and if have you any questions please pass them along so we can try provide some helpful answers for you.
The Maintenance Team
Hamilton Golf Club