No core aeration and why!
It’s been a while since I posted a blog and that’s partly because of a busy schedule both at home and at work these days.
So you may be wondering why I’ve aerated our greens and no longer pull out messy cores. The answer is a relatively simple one and it all revolves around management techniques. There’s more than one way to skin a cat and some manage their surfaces with high nitrogen feed and higher irrigation volumes to produce greens that recover well from damage and look nice and green throughout the season, others manage their surfaces with less nitrogen feed and less water that requires less of some other inputs to produce firm greens that putt well.
The science behind those techniques is a simple one too. When turf grasses grow they produce thatch or Organic matter (OM), the faster they grow the faster the OM produces. We greenkeepers and groundsman force grass to grow sometimes by adding nitrogen feeds and we can also control growth by water inputs and plant growth regulators (PGRs), one thing we can’t control is the weather but the rest is under our control to varying degrees. If I want to slow the grass down I can either limit it’s water, limit it’s food, add PGR or use all of the fore-mentioned.
One thing all turf managers need to do is dilute thatch and possibly remove and dilute thatch if levels become excessive. We dilute thatch by topdressing and adding sand then working this into aeration holes and the turf surface. These holes can be made by solid tine or by hollow tine that removes some organic matter at the same time.
Now we know the basics of thatch (OM) production and what causes it, it’s easy to see that more growth = more thatch and requires more sand or removal to dilute it. This is when a light switched on for me and many other turf managers. Slow the growth you slow the thatch. Before my appointment our greens went through a couple of years of mismanagement with high levels of nitrogen and lots of water and even hollow coring the greens was not enough to stop the thatch (OM) levels becoming high as there was not enough sand to dilute with such excessive growth. This led to soft spongy greens that wouldn’t drain well when the rain came.
As you know I pretty much record every bit of data that I can possibly record and that enables me to keep track with some accuracy where I believe growth will be and therefore where thatch (OM) levels will be, then soil tests every year are sent to the lab to confirm it. These results are then used to adapt my current program to improve management the following season.
As I mentioned earlier I can control nitrogen, water and plant growth regulators, then use sand to dilute the thatch (OM). I control growth by feeding using a model called growth potential (GP). GP is a temperature based model that uses a mathematical equation to predict grass growth potential. So In winter when the grass isn’t growing I need very little and in summer when the grass has potential to grow fast I give it what it needs to grow fast but hold it back with plant growth regulators and keep the water to a sensible level (best I can with our irrigation system).
I can now track growth in the form of clipping volume, which takes who ever cuts the greens 10 seconds per green to measure how much has been removed from that green once cut, I know how much Nitrogen I’m adding from the GP model, I can track thatch (OM) levels in the form a lab test result and also the amount of sand I’ve added to dilute the thatch. This gives me a way of tracking the efficacy of my programme.
Well it’s been over 2 years since our last hollow core and things seem to be working nicely without doing it. Hollow coring is labour intensive, very disruptive to play and takes a long time to recover surfaces unless you over feed for recovery and produce more thatch again which is counter productive and intuitive to me. One thing you won’t get from me is “well we’ve always done it…so”, I’m always adapting the programme to improve the performance of our greens and do it in the cheapest way I can. Solid tines are literally just a solid spike that goes in the ground and exits leaving a hole, On the vertidrain machine we can add some heave to help decompact the soil. The solid tines are very good for adding oxygen to the soil too and helping with infiltration in our clay subsoils. The added oxygen and my compost tea programme which adds beneficial bacteria and fungi to the soil, are great for naturally breaking down thatch (OM) and for forming symbiosis with the plant to help fight plant diseases. One for another lengthy blog post!. I’m not saying never again to coring, it has its place but at the minute there’s no need. Thanks for reading.