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Doing Nothing vs Trojan Horses

With the end of the bowling season in clear sight, many clubs will have acquired a familiar temporary feature over by the roadside hedge somewhere. If you look closely there will probably be a pallet or five of bagged top-dressing, ready to go on the green as part of the autumn renovation program.

The bags might be plain or they might be covered in text and graphics proclaiming all of the benefits for your turf that are held within.

They are essentially Trojan Horses, in that they appear to be bearing good news and gifts, but they are actually full of sand (up to 90%) and represent the continued insistence of many clubs and consultants to pursue a program of desertification of bowling greens in the UK.

When your green was first constructed, it probably had an 8-10” (200-250mm) deep layer of topsoil (rootzone). An average bulk density for topsoil would be around 1.6 tonnes/m3. If we say that the average green is 36m X 36m we get an area of 1296m2. The volume of soil required to fill this is calculated thus:

 1296 X 0.25 = 324m3

Using our bulk density average of 1.6 we can calculate weight of soil required as follows:

324 X 1.6 = 518 Tonnes. So our average green was built using approximately 518 tonnes of topsoil.

Most hollow tining operations can penetrate the soil to 4 inches (100mm) and this is usually used in conjunction with top-dressing. This then means that top-dressing operations have been concentrated on about 40% of the actual soil used to build the green (the top 4 inches). 40% of 518 tonnes is 207 tonnes.

30 years of top-dressing with 5 tonnes of material each time is equal to applying 150 tonnes of highly sandy material and this disregards the soil being removed by the hollow tiner! This also assumes that your club only jumped on the train to la la land in the 1980’s; many have been at it for at least a decade before that. I also know of some greens where they are routinely throwing 10 tonnes of straight sand on every year, so these figures are only averages and are probably leaning towards the less crazy end of the spectrum.

Is it any wonder then that greens suffer from localised dry patch, excessive thatch build up, powder dry inert soil, compaction, disease, low microbe populations etc, when almost all of the top 4 inches of the green has been replaced by sand?

If this is the plan for your club this autumn it would be better for your green, if you just do nothing. Yes, even neglecting the green and failing to undertake any autumn renovation would be much less harmful to the long term health and performance of the green than following this program.

One comment

  1. John says:

    Thanks George

    I know it takes a lot to convince most people that sand is not good for the long term health of bowling greens. However, when something is elevated to the state of “tradition” even the craziest schemes can take hold and become hard to shift.

    I’m glad you stuck to your guns and that you are now seeing the results.

    If I remember correctly, your green was subjected to the worst of this trend and that very large quantities of straight sand were used routinely. If you look at my “back of envelope” calculations from yesterday you should be able to get a handle on just how much of your green’s top 100mm is now sand.

    I’ve put up a post today that explains my thinking on what goes on during the recovery process.

    At various times in the past I’ve discussed the need for us to accept that just about everything that goes wrong with a bowling green is simply a Symptom of either Excessive Thatch or Compaction. I’ve actually revised my thinking on this recently and would now say that even thatch and compaction are symptoms also; symptoms of inappropriate maintenance.

    Moss is again simply a symptom of inappropriate maintenance practices in the past and, referring to my post of today, if you consider that you are probably only at the stage of slowing down the wheel as yet, you will appreciate that it is early days.

    By far the fastest route to full recovery would be for the green to go “cold turkey” on sand, pesticides, fertilisers etc, but in the real world we need to try to produce a surface for bowling in the intervening period or else we wouldn’t have a club left to produce a performance green for! To that end the treatment of moss with chemicals or even sulphate of iron is one of the forces trying to turn the wheel the wrong way again.

    The real answer to moss is a healthy, living soil and turf which will easily resist pressure from moss, disease, LDP, cold, drought etc, so I think it is probably still early days for the moss to be taken care of completely as there is still weakness in the sward due to the very large quantity of sand and the relatively “inert” nature of the underlying soil as a result of this. Moss is an expert coloniser of any weak spot in the turf. It exists in a myriad of forms able to take advantage of space is almost any environment and not only in wet areas as we have been led to believe over the years.

    Bowling green maintenance over the last 30-40 years has concentrated far too readily on treating symptoms to the detriment of green performance generally. Dare I say that Symptoms move Product!

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