In a very real sense microbes are a grounds manager’s best friends
this subject. For more than 25 years, Redexim has been manufacturing a specialised line of aerators, the Verti-Drain. The products have become such a part of turfgrass cultivation that the phrase Verti-Drain is often mistakenly, but flatteringly, used as a verb by turf professionals the world over. For years, we have observed the beneficial results of Verti-Drain treatments: improved drainage, enhanced root growth, improved turf colour, and better drought resistance. But no one has ever really been able to say how the Verti-Drain worked from a scientific standpoint, or why…until now. Aeration is certainly one of the most common cultivation practices. In this area of study, the research work of Dr. Donald J. McGregor, conducted at the Royal Holloway campus of the University of London, in Surrey, England, breaks new ground in establishing a greater level of understanding. According to Dr. McGregor, there is much that we simply don’t know about microbes and their interactions – directly and indirectly – with plants and other living things in the soil. This complex set of biological processes make up what he calls “the hidden world” beneath the surface. Just a few years ago, it was impossible for aeration equipment manufacturers – and their customers in the turf maintenance field – to know how effective their products were without understanding the composition of microbial communities in the soil around the turfgrass. This is as true of the Verti- Drain as it is of its various competitors. The new research work at Royal Holloway marks a turning point in that regard.
A little biology refresher lesson…microbes, a conveniently short phrase for microbial organisms, are a rather broad category comprising bacteria, fungi, viruses and protozoa. Most microbes are, in fact, beneficial to higher life forms and form an integral and significant portion of the life processes of any ecosystem.
In a very real sense, microbes are a
grounds manager’s best friends. “Microbes are the foundation of everything we see around us; without them we would not exist,” claims Dr. McGregor. “If anything goes wrong in the environment, the microbes are an early indicator. They will show subtle changes before anything else.” And, as we shall see, the health and number of these microbes in the soil has a strong correlation with the health of turfgrass, as it does with other life forms co- existing with the microbes in the soil. Anyone with an interest in healthy turfgrass is somewhat familiar with the basic processes that make up what we’ll call the soil habitat. What biologists are discovering, however, is that this habitat is full of surprises. (Did you know, for example, that the characteristic “fresh smell” we’ve all sniffed right after it rains is the scent of chemical secretions from mysterious microbes called actinomycetes, organisms that seem to be halfway between bacteria and fungi? Even today, no one is sure exactly what these microbes do.) One thing we are sure of, when it comes to microbes, is that some are aerobic and others are anaerobic, and that only the aerobic ones show a strong benefit to turfgrass, which is why the potential to link the Verti- Drain to aerobic microbial activity in the soil was an exciting prospect. But microbes are only part of the
picture. They exist in the soil structure right alongside earthworms, organic matter, plant roots and other living and once-living things – the so-called “biota” in the soil. Within this biota we find incredible diversity – aerobic and anaerobic, acidic and basic, wet and dry, and the list goes on. This diversity – and the interdependence of the life forms involved – is the very core of understanding this soil habitat. It is the interactions of these elements that influence all aspects of turfgrass health, and which have a strong relationship with practices like aeration. When you stop to consider what
The complex interdependent concept of the ‘soil habitat’ provides a scientifically useful basis for turfcare professionals seeking answers to cultivation challenges. (Illustration by Peter Hartel)
microbes are capable of, in a biological sense, the effect is mind-boggling:
• Enhancement of plant growth • Enhancement of drought resistance • Disease protection • Reduced need for fertilizers
• Control of Poa annua without using chemicals
And those examples are just biological. Microbes do even more when you examine their roles in the chemical and physical processes of the soil habitat:
• Breakdown of organic compounds • Breakdown of cellulose and lignin • Formation of humus • Soil stabilisation • Nutrient cycling • Nitrogen fixation
It’s fascinating to contemplate that all this activity is going on beneath the surface. But let’s not forget the appearance of the turf plants is also affected. In fact, it is the highly visible condition of the grass, whether it appears healthy or unhealthy, that gives a strong indication of a healthy and productive soil habitat – or the lack of it.
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