Is Organic Matter Management really necessary
There is an old saying, “do not change a winning team”.
But in the turf industry, one never tires of looking for better solutions or diverse ways to care for turf.
You may have heard that some turf managers say they are no longer concerned about thatch management, or that they are not conducting their thatch management in the most “fashionable” way? Or perhaps you are curious about the possibility of avoiding de-thatching, aerifying, and topdressing your turf? Or do you have concern that thatch management is very costly and a significant disruptive aspect of golf course maintenance?
As much as I would like to inform you that we have come to an end of an era about thatch management that is unfortunately not the case. I would invite you to dedicate some time to reflect on this subject.
Let us begin with a little bit of history.
Do you know how thatch management and soil compaction was dealt with in previous years?
Around 1906, Old Tom Morris (St. Andrews) noticed a change in playability due to soil compaction and that compaction was inevitable due to golf traffic and maintenance. In this picture above you can see the image of a pitchfork. This was the first “device” used to deal with compaction and thatch problems. The pitchfork then later evolved into spike shoes.
Now can you imagine what size team you would require for effective thatch management if equipment had not been invented?
Nowadays, thatch management poses a considerable number of issues. Therefore, it is important to remind ourselves the importance of this subject We know that thatch is an intermingled layer of partially decomposed organic matter between the green vegetation and soil surface. However, it is worth noting that a small amount of thatch or organic matter is beneficial.
According to Dr. Karl Danneberger, Professor at The Ohio State University, a small amount of thatch creates a mat at the soil level that acts as an insulator, and this keeps soil temperatures low, helps retain moisture and improves traffic tolerance.
However, the issues arise when excess thatch exists on a golf course. Healthy turf requires an exchange of oxygen and nutrients, adequate water and microbial activity in the soil. When thatch builds-up, it decreases water infiltration, reduces pesticide effectiveness, reduces tolerance to cold temperatures, and decreases the turf’s ability to thrive and fight disease and insect problems. It leads to a shallow and weak root system, which consists of a soft and spongy surface. Firm, reliable playing conditions are rarely attainable where thatch is excessive.
Why does thatch accumulate?
Usually, thatch occurs when the soil composition is out of balance, causing the production of organic matter to exceed the decomposition rate. It may be due to abundant nitrogen fertilization, the use of chemical pesticides, too much or too frequent water, cold soil temperatures or poor soil aeration, along with the natural growth of the plant.
So, how do we reduce or maintain thatch levels with only minimal disruption to play?
The best approach is to create a programme that combines the best treatments for the specific needs of your turf.
The following are examples of possible treatments:
Reduction in the Development of Organic Matter
We should start by analysing the possibility of reducing the volume of organic matter being produced. This is done by reducing the nitrogen inputs.
One example would be to spoon feed the greens with liquid fertilizers and seaweed, instead of applying nitrogen rich granular fertilizer.
Vertical Mowing
Vertical mowing then needs to be addressed. According to Dr. Beth Guertal of Auburn University in Alabama, vertical mowing is “a pretty significant way to reduce organic matter.” Dr. Guertal recommends vertical mowing as deep as possible, completed twice a year at 19.1 millimeters or four times a year at 6.4 millimeters.
Topdressing
If the decision is made to reduce the amount of thatch with minimal disruption to play, then topdressing through light and frequent applications is a key part of any management programme. Frequent applications are the best way to uniformly dilute thatch accumulation, which is based on the turf growth rate during the growing season. There are several advantages of sand topdressing, including its ability to improve the smoothness of the turf and its ability to make the turf more resilient. It is recommended to sand topdress weekly, or at least three times a month.
Aeration
Core aeration physically removes thatch from the soil. This causes temporary surface disruption but can be of annoyance to golfers. However, incorporating air into the soil helps break the thatch down, which in turn releases locked up nitrogen and the greens then start to self-feed. This also means a reduction in nitrogen inputs, which in turn means small cost savings can be made.
Since the original pitchfork used at St. Andrews in the last century, advancements in aeration equipment have greatly improved. An example of equipment successfully used on thatch management is DryJect. This piece of equipment uses a water-based injection system to make aeration holes through the root zone, which breaks up the soil. The vacuum technology then fills the holes with high volumes of sand. As a result, compaction can be relieved, water infiltration increased, the root zone receives oxygen and the soil can be amended with high volumes of material, all at the same time.
Nowadays, these are the most common practices of organic matter management used around the world. However, what about turf managers that are using non-coring programmes?
There are scenarios where organic matter management does not need to be as intense, and coring not as essential, but this depends on several factors such as climate, grass type, age of soil, soil pH, very low nitrogen input and proper chemical management programmes etc.
Also, non-coring programmes usually rely on topdressing to dilute thatch, which requires a substantial amount of sand, which in turn leads to a substantial amount of money. In addition, a non-coring programme also can mean a bigger problem in the long term. If the topdressing programme is inadequate and the concentration of thatch becomes excessive, damage to the root system and compaction will appear at some point.
The fact is, there is no simple way to help with the decomposition of organic matter.
What works for one facility is not always right for others. It is your decision to choose what is best for your golf course.
In contrast to the first article I wrote for Turfgrass®, this time I would like to conclude by saying that we must be realistic. Organic matter management has been around for a long time, and it is likely to remain in the future.
There is no doubt that there have been many improvements made and hopefully we will see many more, but the fact is core aerification, vertical mowing and topdressing are aspects of turf maintenance that are not likely to go out of fashion any time soon, and we must recognize the merits of such traditional practices.
As the old saying goes “maybe you shouldn’t change a winning team”.
About the Author
Renata Mundim Ms
Technical Advisor To Turfgrass
Renata Mundim Ribeiro is a Biologist passionate about grass. She started her career in turf working as a research assistant at The Ohio State University. She has a Master’ s Degree in Horticulture and Crop Science and studied Golf Course Management, both at OSU. After working in agricultural marketing and teaching, she was chosen as one of the USGA Interns. Now, Renata works as an international speaker and specialises in developing education on turf health subjects.