Microbial Action is Required the ‘Right’ Peat Reduces Thatch Build-Up

May 2002

Dakota Peat founder and president Mike Pierce isn’t fazed when competitors try to promote ways to advance their unproven shortcuts for constructing and maintaining golf greens. He knows that those attempts will fall short and that the time-proven practices will actually gain as a result.

“It’s like the seven-year itch,” Pierce says of the ways that unproven methods are advanced as a way to cut corners in the top dressing of greens. “We see fads come and go, and they seem to recycle every six or seven years. It’s as if they were on a schedule. This year, it’s back to the notion that a straight sand top dressing won’t add to a thatch or layering problem and is cheaper because it eliminates the cost of peat.”

There have been similar efforts in the past, Pierce notes, to promote different construction methods and/or top dressing blends that have ranged from push-up greens, to soil greens, to peat greens, to compost greens, to inorganic material greens, to rice hulls greens, and to different combinations of the above… all as ways to reduce labor and material costs. None have proven themselves to be either immediately effective or to be long lasting.

In answer to the recent whim that an “all sand” top dressing won’t promote or add to problems of thatch build-up and layering, Pierce says that such thinking is true. “But neither will it do anything to relieve the problem. Sand alone is inert; it doesn’t do anything,” he says.

To address the problem of thatch build-up or layering, the grass clippings that are the cause of the situation must either be removed or broken down. Short of digging these greens out and starting over, the only way to do that is to trigger a process in which microbial activity will degrade the problem materials. And to initiate that process, microorganisms must be introduced to the organic materials to start the decomposition process that will change them into an asset rather than a liability.

The decomposition process will transform the area into an environment that promotes new growth, is resistant to disease, and requires less fertilizer and pesticides. This process is best accomplished (as it has been for years) by a top dressing of a blend of a highly decomposed peat with sand. The peat clings to the sand particles, which penetrate into the thatch to allow the microbes can go to work. The key to the effectiveness of the blend is the use a “highly decomposed” peat as opposed to a peat whose decomposition is at a much earlier stage.

“Instead of adding to the problem,” Pierce says, “a 90-10 mix of sand with a highly decomposed peat actually helps to reduce thatch problems because it promotes the degradation process… it goes to work on the old grass clippings and roots that are the source of the thatch problem.”

Difference in peat -- The importance of using a highly decomposed peat is that it best supports microorganisms. This is backed by some very influential scientific and professional minds and by laboratory testing that shows a stark difference not only in how highly decomposed peat supports microbial activity than does less decomposed peat, but in the highly decomposed peat’s superiority in the critical areas of cation exchange capacity, amount of nitrogen, humic acid, and carbon to nitrogen ratio.

Beyond differences in the raw product, the processing method used by Dakota Peat produces a consistent peat material that is a minimum of 85 percent organic. In simple terms, this means that it is clean or free of dirt. At the other end of the scale, anything that is not at least 92 percent decomposed fails to meet Dakota’s own minimum guidelines.

“The fastest way to add to a thatch and layering problem,” Pierce relates, “is to use a top dressing mix that contains an undecomposed peat… one that readily doesn’t support microbial activity. The next fastest way is to use a straight sand top dressing that does nothing to slow down thatch or layering build-ups because by itself, it is inert. And the third fastest way is to use a blend of contaminated or dirty sand with a peat that is too high in organic, or undecomposed materials.”

An acceptable peat, Pierce says, is one that supports microorganisms by being between 85 and 92 percent organic. “You want a natural peat material that supports microbes but is still clean. Anything over 92 percent organic is too undecomposed and anything under 85 percent is too dirty. There is a controlled window that supports both new growth and the microbial action of microorganisms that will work to degrade thatch and reduce layering.”

Reduces thatch problem -- “The microbiology of turf grass soils,” Dr. Eric B. Nelson of Cornell University wrote in a published technical article several years ago, “holds an amazing diversity of micro-organisms that profoundly affect turf grass health. Organisms play a key role in maintaining the delicate balance between thatch accumulation and degradation,” he said, noting that this is an activity that can be managed.

Among the strategies that Dr. Nelson endorsed were: “Using organic amendments composed of readily available carbon. Avoid sphagnum peat because it does not support adequate microbial activity. Reed-sedge peat, composted animal manures, and composted industrial and municipal sludges are preferable.”

More recent thinking about composts, etc., warns of the possibility that there could be serious health risks if these materials are not fully decomposed, especially human and animal wastes. This risk further elevates Dakota Peat, which is reed sedge, as the preferred amendment in a sand mix.

Clings to sand particles -- To illustrate how Dakota Peat clings to sand and doesn’t easily wash away, Pierce will have you put your hand into a bag of the product. Upon pulling it out, particles of peat literally have to be rubbed or wiped off your skin. They just don’t fall off.

“It clings to sand the same way. And because it is so fine, it mixes very uniformly with sand. By contrast, conventional peat mulches are much more coarse, which makes them more likely to be separated from the sand particles and more susceptible to being picked up by mowers or to being washed away,” Pierce says.

As a result of its ability to attach itself to particles of sand, Dakota Peat has a greater ability to penetrate soil and get to the root zone of plants where its growth promoting properties can go to work. In combination with its greater ability to hold water, Dakota Peat reduces maintenance costs because there is less need for irrigation and for fertilization.

And the more substantial grass growth that results acts as a natural insulation to reduce stress and evaporation. Beyond all of that, Dakota Peat has a life expectancy that is several times longer than other peat products and mulches.

Why not sand alone? -- The “pure sand greens” idea isn’t new. It was addressed 10 years ago in an article by James T. Snow, national director, USGA Green Section, who wrote: “There’s usually a price to pay for taking a shortcut and hundreds of superintendents (and their clubs) around the world have paid a high price for taking the ‘easy’ way with pure sand greens and untested modifications.”

He wrote then, and it holds today, that pure sand greens are “often extremely droughty,” have no buffering capacity, require extremely high rates of fertilizer, have high rates of disease problems, are harder and less resilient to surface wear, and that “the grow-in layer of sloughed off root zone organic material on pure sand greens is often quite dense.”

Snow’s article continued: “As far as adding water-absorbing polymers and other unproven inorganic amendments into the top several inches of the profile is concerned, this is nothing more than gambling with other people’s money and the golf superintendent’s job security. The Green Section specs are based on decades of field experience and university-based research.”

Environmentally irresponsible -- On the related issue of environmental responsibility, Snow asked how the “golf industry could accept pure sand greens, or any other method that requires heavy use of water and fertilizer? It’s environmentally irresponsible. Who wants to be the first in line at an environmental forum and be challenged about what happens to 40 pounds N/1,000 sq. ft./year applied to a droughty, pure sand root zone?”

The article ended with this statement: “Pure sand root zones and their untested modified versions should not be encouraged or condoned.”

At least some of the thought in favor of “all sand” greens is/was the perception that blending a sand-peat mix was not only more costly, but highly labor intensive and difficult to do. With the uniform and fine consistency of Dakota Peat, blending is not a problem. It can be done in a bucket, or more realistically for a golf course by using one of the world-class excellence blenders in Dakota Peat & Equipment’s line of equipment. This equipment, too, ends the discussion about blending and application being too labor-intensive.

The cost factor, too, has been rendered non-existent by the long life of Dakota Peat and the ways in which it not only fertilizes growth but works to reduce thatch as well.

Naturally superior -- So, back to the question: “Will organic materials add to my thatch problem?”

And the summation, Pierce says, is this: “Some organic materials can add to a thatch problem. Thatch is caused by a build-up of undecomposed organic materials. This layer will interfere with air and water movement. Often, this build-up can be traced to a lack of microbial activity. Many organics, like sphagnum peat, hulls, composts, young peats, and sawdust, are in the early stages of decomposition. When these are added to turf and to the decaying organic matter from that turf, the problem can be compounded. Other organics, like Dakota Peat, are highly decomposed and have a great deal of microbial activity. This microbial activity will help relieve the thatch problem.”