So far in this series of articles on the subject of bowling green performance we have used some of the common visual clues to assist in our evaluation of the turf. Today we'll break from that to dig a little deeper into the physiological aspect of the different turf grass species that influence what we see on the surface. Turf Grass Growth Habit can play a big role in the ultimate performance of the bowling green. so let's get started on indentfying the main differences.
In part 4 of our series on the Performance Evaluation of the Bowling Green we move on to examining turf texture. Texture is closely tied in to some of the other aspects of Bowling Green Performance we have looked at so far in this series. Texture is one aspect of turf management that the greenkeeper can influence greatly, but seems so simple that it is often overlooked.
In the performance evaluation of the bowling green, one of the key factors is turf grass density which is important due to its ability to influence other performance factors and in monitoring bowling green and soil health generally.
The Performance Evaluation of the Bowling Green we embarked on last time relies on our ability to appraise a range of factors. Some of these are purely visual, while others are functional and can be quantified more readily. The trick lies in gaining the experience to merge the visual data with likely performance traits. Good old fashioned greenkeeping and the greenkeeper's "feel" for the turf are still as relevant as they've always been. Today we get started on the process of evaluating bowling green performance.
By far the best selling of my eBooks available on this site is Performance Bowling Greens; it out sells all of the others by 10-1. Bowling green performance can seem a bit sketchy and hard to tie down to any sort of measurable parameter, but that's more to do with the lack of a joined up approach to the subject in the industry than it is a lack of measurable components. This article introduces the subject of the Performance Evaluation of the Bowling Green.
I've had a lot of requests to supply a general set of recommendations for winter maintenance for bowling greens. Although the full program for any green should be based on a thorough inspection and soil analysis, there are some general rules you can follow. I've also put together a suggested package of materials to help you apply this program more easily.
Life after pesticides for bowling clubs, what a scary thought, or is it? Master Greenkeeper John Quinn explains why he believes the death of pesticides could be the start of a revolution in bowling green performance.
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 its 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; its 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.
Another very popular subject on this site is over-seeding of greens in Autumn.
Over-seeding is commonly carried out as part of the autumn bowling green maintenance and renovation program and is very often a disappointment.
You would expect this work to quickly fill in the bare patches and spaces in the sward left by disease, localised dry patch and a host of other green problems, but this is very often not the case…why?
The answer to most disappointing results from over-seeding is “competition”. Competition from the mature, indigenous grasses whether fine or weed grasses like annual meadow grass usually reduces the success or survival rate from over-seeding to a very small percentage.
This quite often comes as a surprise to greenkeepers who have observed a very good “take” shortly after seeding (7-14 days). At this early stage it is not uncommon to see vigorous lines of dense new seedlings bursting forth from the green. This however, is usually a false reading.
At this very Read more
The Role of Microorganisms in Soil Health is vast and in many cases misunderstood. For decades we have been obsessed with the potential harm that just a few pathogenic microbes can cause, instead of learning to think of the soil as an eco-system. We've learned the hard way about that approach and now that pesticide availability is being reduced we need to start taking this seriously. Excellent article here from Christopher Johns, Research Manager, Northern Australia and Land Care Research Programme