Over the years I have come up against a lot of friction when I have proposed that a club stops top-dressing its green with sand laden top-dressing compost.
The reasons for stopping this practice are well documented on this site (recap here) so I won’t go over old ground here today.
My guess is that a lot of greens, especially in the South East of the UK will be seeing some of the performance issues related to this “tradition” coming home to roost this year. The major disruptive force in bowling green maintenance is Localised Dry Patch (LDP) and this is a perfect year for it to show up at its worst. Again, LDP is extensively discussed on the site (recap here).
Another tradition which I suppose first came about for reasons of economy Read more
Already the relatively dry April and start to May has seen bowling greens suffering from Localised Dry Patch (LDP).
As we have discussed many times on this site before, this condition is a major problem for bowling clubs throughout the UK and if your bowling green is aready showing the tell tale signs then you need to take rapid and relentless action to avoid major disruption to your bowling green surface this season.
Meantime for greens already showing signs of the problem here is my Read more
We have had a few queries asking about thatch; actually a few readers asking for a definitive description of thatch and its associated problems, so here it is:
What is it?
Thatch is the name given to the mat of dead roots and shoots that accumulates on the surface of the green. Where moisture, nutrition and cultural practices are optimised for the desired grasses, thatch rarely becomes a problem. However, when soil air content is low, or if drainage is poor and the fertiliser program is not optimised for the prevailing conditions, thatch can become a problem. In severe cases the major root mass might only exist within this layer and this leaves the green susceptible to drying out in summer and to the heads “skinning” (loss of turf cover) in wet weather. Thatch is also a major contributor in the Read more
Localised Dry Patch (LDP) is a condition that causes turf to become hydrophobic (water repellent).
Once LDP has taken hold, irrigation simply causes the unaffected areas to get lusher while the LDP affected areas get drier. This exacerbates the problem making the green increasingly frustrating to play on.
Soil sampling will reveal powder dry soil. Unsightly brown patches of turf start to spread over most of the green. The turf on these areas recedes causing a bumpy surface and in most cases the weakened grass will be taken over by moss. But what can be done to cure the problem?
Research shows that fungi can contribute to the onset of this problem. Fungal mycelium may coat individual soil particles making it impossible for water to adhere to them.
Thatch control and irrigation management are the two most critical factors in the management of this problem.
By the time the problem is visually evident it is already too late to achieve an effective cure. This is because the problem is inherent in the green and usually only becomes visible at the height of the season.
Infrared photo of green showing LDP
Irrigation management requires an understanding of Water Balance in the soil and this is detailed in Performance Bowling Greens. Just look at the infra-red thermographic image on the left, it shows an infrared image of a bowling green. The red areas show the extra heat that is being kicked out by the LDP affected areas, and that is directly related to the lack of moisture retained in the soil in these areas. In the standard photo, the LDP is barely noticeable at this stage, but will get steadily worse.
…but there is still no real sign on the surface
Frequently we are now seeing that areas affected by dry patch disorders have suffered a complete depletion of moisture and that the soil structure has failed, turning to powder. Traditional wetting agents have sought to address dry patch from a very limited viewpoint, namely the reduction of water surface tension making it easier for water to be attracted and held around individual soil particles.
Although Wetting Agents can be used to good effect on LDP once dry patch has progressed to what we call breaking point, no amount of simple surfactant wetting agent will help it re-wet sufficiently to ensure a full recovery of the turf with full grass cover. Typically the manager has to wait for the turf to over-winter before full grass cover is returned.
This makes it all the more critical that we ensure that the products we use are effective in both results and cost.
As LDP is a disorder within the soil it is important to keep one eye on re-wetting and one on re-building the soil’s health. This can best be achieved by ensuring that you use a wetting agent product which can supply carbohydrates to the soil in addition to their soil re-wetting properties. The addition of a high volume of Carbohydrates ensures that the products also contribute to the maintenance of soil structure while helping stressed grass plants hang on to life for longer while the soil is re-wetting.
Excessive use of sand on bowling greens over the years has been the single biggest influence on the occurrence of LDP.
My post yesterday looked at the huge extent to which the top 100mm (4inches) of our greens have been subjected to sand over the previous 3 or 4 decades.
Today I’d like to elaborate a little on my thinking about taking a green from that state to one of High Performance.
The recovery process is based on encouraging that same top 100mm to return to a state that is akin to a natural, healthy living soil. This of course takes time as we are actually waiting for nature to produce more organic matter to ameliorate the sand to bring the soil back to a state where it can support a large, thriving population of soil microbes.
If you imagine my sketch of the “Circle of Decline” as a water wheel spinning fiercely in a clockwise direction; in other words out of control due to inappropriate maintenance. Each application of sand, pesticide, excessive N fertiliser, etc only serves to set the wheel spinning ever faster in the wrong direction.
The performance greens program is aiming to make the wheel turn in the opposite direction so a lot of the effort at the beginning is simply to slow the wheel down gradually until it is eventually stopped. The program then needs to get the wheel to start turning in the other direction.
Once it starts to turn in the right direction every bit of the correct maintenance program just makes it go faster and faster, so although the recovery process is slow at first, it builds very quickly once things are turned around.
We then start to see the action of what I am going to call the Circle of Improvement due to lack of imagination!
