The ongoing debate relating to the condition of the playing surface at Ethiad Stadium has again hit the headlines with Hawthorn President Jeff Kennett relentless in his criticism while voicing concerns relating to duty of care. Good on’yer Jeff. Somebody has to blow the whistle.
As a horticulturist with extensive experience in turf management of public playing fields as well as in urban garden situations I have watched and read with interest. Even from a distance it is obvious that there is a problem with the instability of the surface and that it appears to have caused injury to players.
The peeling of grass is similar to what happens to a lounge room rug on polished boards when children run riot. My understanding of how sports turf grows, even from a distance, indicates it is a no brainer. The turf is underdone and it’s root system is inadequate.
Without analysing the type of growing medium, depth or other salient cultural factors, and considering there have been a substantial amount of intellectual, financial and physical resources thrown at the problem (what problem?) it is still obvious to an experienced and qualified observer that the grass is not holding. Many lay people see this. A few movers and shakers don’t.
Plant growth is governed by limiting factors. Without one, or all, the successful growth of plants is restricted or stopped unless they have evolved to grow in specific micro climates. Ferns, epiphytes and xerophytes, etc.
These limiting factors are light, moisture, temperature, nutrients and wind. A growing medium for the roots; this can be soil, a mixed medium or even water (hydroponics). This is the area where osmosis happens and the nutrients / water are taken in through the root hair cell membranes.
Carbon dioxide (taken through stomata) is also required.
Roots are also essential to anchor plants. (I am not sure how the itinerant ‘Trifids’ managed to cause so much havoc.)
Compaction is also an issue effecting premium (or any) turf growth. Compacted medium, especially around root zones is not conducive to optimum plant growth. You may have noticed where the players run out onto the ground or the cattle / sheep move through a gate on the farm the soil is compacted and grass won’t grow.
I believe the crucial issue with respect to the playing surface at Ethiad Stadium is insufficient light.
This associated with constant changeover of turf, crumbing structure of the medium (needed to allow drainage) having an effect on the root system, more specifically it’s capacity grow long and strong roots good enough to hold the grass rhizomes or clumps and bind the soil.
Constant wetness to provide a softer playing surface would not be an insignificant factor.
The issue of wear and tear on turf growing in less than optimum conditions also has an effect.
The performance of a turf grass root system relates directly to the performance of the above ground bits; the leaves / blades. As you would be aware photosynthesis happens here. That process converts carbon, nutrients and water to sugars and oxygen.
Light is a key factor. Due to the structure of the stadium the playing surface does not get the amount of light required for optimum growth. Coupled with the winter less sunlight hours scenario at the peak use time turf, management will always be a challenge no matter how good the drainage and genetically modified (or selected) the plant material.
Heat from natural sunlight would not be constant.
Protection from excessive wind is a plus but there are too many other deficiencies.
It is well and good to scalp large swards of grass, or the entire surface, from time to time as the playing surface deteriorates but when the factors I have mentioned come into play the grass does not grow well enough to support a root system strong enough hold the turf intact. Hence the problem. (Again, what problem?)
The type of the grass cultivar / blend, the growing medium and other technical and commercial factors may give management and the AFL hierarchy some comfort. Their arguments are no doubt based on the best available contemporary research. But as we are becoming more and more aware, nature seems to always have the final say.
Also when plants are grown in a closed modified environment and totally dependent on human intervention there is always the increased chance of disease. I wonder what chemicals are used and what is the timing of the application regimes?
The plants grown in these conditions are less robust. There would also be an expectation of some transplant shock as the grass slabs are moved from nursery environment to the ground.
Also new cultivars, not withstanding their capacity to perform in specific micro climates or to a desired standard, usually have original but what are considered to be less ‘sexy’ genes bred out for economic advantage.
‘Plant rights’ is another issue.
I am not sure whether the turf has a synthetic netting system to hold it together. If it does, this will give lateral hold but not vertical hold if the root system is inadequate.
The micro climate within the shell of Ethiad Stadium and the usage pattern is not totally compatible to good turf management. Unfortunately the trade off appears to be an issue of safety, shrouded in denial.
It is time for the AFL to come clean, recognise the ‘bleeding obvious’ and do something about it.
There doesn’t need to be an inquisition, just a solution.