Green Performance Explained in terms that show the multitude of characteristics of turfgrass plants and their environment that work together to make up the bowls green eco-system. By working in harmony with this eco-system, greenkeepers can shorten the learning curve on turf surface performance dramatically.
The relationship between sand and bowling green performance has become a thing of legend with the majority of clubs still throwing more sand on their greens every year, despite a worrying trend showing poorer and less predictable green performance due to problems like Localised Dry Patch and excessive thatch. It seems that for many clubs the dots aren't being connected between too much sand and poor performance. In this article I will explain the fundamentals that greenkeepers must keep in mind with regard to their bowling green soil.
We are familiar with the concept of our grass plants being composed mostly of water (75-85%), but what else is in a grass plant? The answer is that the dry matter of the plant is made up of a mix of 16 elements, commonly referred to as the essential nutrients. We describe them as essential because the plant can’t exist or complete it’s life cycle if any of these nutrients are lacking to any great degree.
Bowling Green Nutrition
Some of these elements are used in bulk by the grass plant. These are Carbon, Hydrogen, Oxygen, Nitrogen (N), Phosphorus (P), Potassium (K), Calcium, Magnesium and Sulphur. Some others like Iron (Fe), Manganese (Mn), Boron, Molybdenum, Copper, Zinc and Chlorine are used in smaller amounts. I’ve added the chemical symbol for the ones we commonly see on fertiliser bags.
A large part of this dry plant matter is made up of the three big elements Carbon, Hydrogen and Oxygen. In my introduction to Photosynthesis we saw that the plant takes Carbon (CO2) and Oxygen directly from the air by absorbing them as gasses through the leaf stomata. Last time we looked at Osmosis, the process used by our grass plants to take up water (H20) from the soil and this is where the Hydrogen (H) comes from as well as more Oxygen. The plants can always find an abundant supply of these three elements and if the day comes when they can’t, then we won’t need to be worried too much about how the bowling green looks!
The remaining 13 essential nutrients are accessed via the soil from 2 main sources, but regardless of the source, the grass plant can only absorb these nutrients once they’ve been dissolved and contained within the soil water, more accurately referred to as the soil solution as it isn’t just water anymore.
One source of nutrition is the process of decomposition that happens when plant tissue dies. This organic (carbon rich) material is broken down by soil organisms and micro-organisms and returned to the soil as readily available plant nutrition in the soil solution. This is why the bowling green needs to be considered as an eco system; nothing happens in isolation.
As we saw, nutrients can only be accessed by the plants if they are able to be taken up by the plant roots in the soil solution, but many of the essential elements needed to complete the grass plant life cycle are securely tied up in the soil minerals. These are made available by the slow weathering of the minerals by rain and wind and are washed into soil solution where they are available to the plants. However, the majority of soil nutrients are bound up and unavailable in what are called insoluble compounds.
To be accessible to the grass plant roots, the mineral and organic nutrients must be broken down to their simplest forms called ions and some of these are negatively charged (anions), while others have a positive electrical charge (cations). The most common form of Nitrogen used by plants is N03– which is an anion due to its negative charge, whereas Calcium is taken up as Ca++ which is a cation due to its positive charge, notated as two + signs in its chemical symbol.
These plusses and minuses are important in soil chemistry and in the relative success or otherwise of our bowling green maintenance. More + signs in the chemical symbol for any ion means a stronger bond to the soil colloid, the name given to the negatively charged clay and humus particles in the soil which hold on to cations and stop them from leaching through the soil. Incidentally, this is one reason we need to apply Nitrogen frequently as fertiliser; it’s negative ions are easily leached out of the soil by rain as they aren’t bound to the soil colloid. It also explains why it is futile to double up on fertiliser applications in the hope of a better result.
Before they can be made available to plants as ions in soil solution between 15% to 25% of the essential nutrients need to be dislodged from the soil colloid by an ion exchange and the relative ease or difficulty of this in a soil is called the Cation Exchange Capacity (CEC). The CEC is simply a measure of how many exchange sites exist on the colloid.
Now here is another of those wonders of nature that is difficult to appreciate when you’re looking out the clubhouse window at that square of grass. The root hairs of the grass plants release hydrogen ions (H+) and when these come into contact with the soil colloid, they each take up a place on the colloid, breaking or weakening the colloidal-nutrient bond of one of the other nutrient ions. Each + in a nutrient’s symbol is equivalent to one exchange site, meaning you need 3 H+ Hydrogen ions to knock a Fe+++ Iron ion off the colloid and into soil solution. Once these nutrients are knocked free they become more available to the plants, where they are taken up in soil solution through the root hairs.
Hydrogen ions H+ are at the very heart of another important soil mechanism called pH, but that’s for another day.
Next time we will look in more detail at the physical construction of the soil and find out why we need to be more thoughtful when considering top-dressing.
Cure Localised Dry Patch on Greens with this step by step guide to dealing with hydrophobic soil in bowls greens.
Essential Greenkeeping tasks for March include aeration, moss control, microbe boosting, disease prevention and keeping the surface clear of worm casts. Now is the time to make soil nutrient balance corrections and to get some starter fertiliser and bio-stimulants on to boost soil microbial activity and get the grass growing well. Take advantage of my soil analysis service for a positive start to the 2019 season with a done for you greenkeeping schedule.
With the new bowling season bearing down on us fast, I’ve received a good few emails and calls asking me whether or not it’s worth trying to start the Performance Greenkeeping Program from scratch so close to the new season?
Several of these contacts had the feeling that there was no point starting at this late stage and that it might be better to wait until the autumn, but all that would guarantee is yet another season of conventional greenkeeping and mediocre green performance.
The truth is that of course it would be great if every club could get in touch well in advance of the season opening day and request a full soil analysis and greenkeeping plan to work from, but all is not lost if you haven’t done that yet and there is a way you can usefully get started now.
If you’ve been a reader of Bowls Central and/or Performance Bowling Greens for any length of time, you will know that the conditions that make greens perform badly, on the whole originate from decades of conventional greenkeeping.
This has featured excessive use of high salt mineral fertilisers, lawn sand, sulphates of iron and ammonia and in many cases the over use of sand top-dressings. To top it off, there has been a frequent need for fungicides to combat outbreaks of turf disease.
All of these problems combine to form what I’ve termed the Circle of Decline.
Therefore changing this condition around is the answer and you can do that by starting to liven up your soil’s biology now.
Performance Greens Program Spring Kick Start and FREE Soil Analysis
I’ve put together a package of materials you can use to get started on improving the soil in your green this spring.
If you look after the soil, it will serve you well by encouraging the finer, perennial grasses and start to reduce the percentage of annual meadow grass and it’s associated problems.
Getting the mower ready is often seen as someone else's responsibility during the close season, but great care should be taken to make sure you are not falling foul of tradition again. Relief grinding and back lapping have become an unfortunate norm in cylinder mower set up, but can be more damaging to the turf and the mower than you might expect. John Quinn explains the theory and suggests a solution that will ensure your mower gives you trouble free service and impressive results all season long.
The Bowling Green Opening Day preparations are vital to the playability of the green in the early weeks of the season, but don't try to force things along too much. John Quinn details some of the most important considerations for this critical period in bowls green maintenance
Opening day preparation is upon us, but where do you start? In the first of a new series of articles, John Quinn lays out a failsafe plan for getting the green ready for the big day.