Rufford Sports Surface Technology
TOP DRESSING Explained A
frustratingly unpredictable climate, economic pressures and increasing numbers of players all demanding perfect playing conditions seven days a week, 52 weeks of the year. It’s all a far cry from the challenges faced by Greenkeepers and Groundsmen 30 years ago and leaves today’s successors nursing some major headaches.
Establishing consistency and quality in such a fast changing industry is the key to creating successful sports turf and that very much involves the need for testing.
Basic considerations
The first consideration for the Greenkeeper or Groundsman is to understand his or her soil type and profile. To have knowledge of what’s going on under the turfgrass and what the roots have to grow in is fundamental to healthy turf. If we for a moment try to imagine ourselves as grass roots and what we would ideally order up for our living area: it would be enough space for unimpeded root development, moisture availability for drinking and transpiring, nutrients for feeding and air for breathing. So their basic requirements for life are similar to our own in this matter.
Current rootzone
The rootzone is the layer under the sward in which the grass roots live and breathe and this is really the starting point in the long-term success of any
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green or pitch. An ideal rootzone for healthy grass is natural, well structured sandy loam and if you were building a lawn at home then this would be the first choice. But then you wouldn’t anticipate hundreds of golfers walking over your turf every day of the year (even in saturated winter conditions) or soccer players running and tackling on it. If they did then your new lawn would quickly turn into a mud bath! Naturally occurring soil simply cannot
provide the drainage (or, in the case of football and rugby, the stability) needed for a good commercial playing surface. This is basically because there is insufficient pore space between the particles in a compacted soil. Water drains through soil primarily via voids created by earthworms and particle aggregation. However, excessive foot traffic and play quickly compacts these voids and subsequently slows drainage right down leading to a waterlogged profile. Hence, to create a rootzone for commercial applications, an addition is needed, and this comes in the form of sand, the physical properties of which provide the drainage and stability usually lacking in natural soils. This is because the space between sand particles (provided you use a correctly graded sand) remains even when it is compacted, thereby allowing drainage. So today, the fundamental ingredient
in rootzone materials for golf, soccer and other sports (excluding cricket) is sand. This is also true for the top dressing we apply to the rootzone, which I will
By PETER JEFFORD General Manager
discuss later. Considerable expertise is required to grow grass on the sand- dominated rootzones. We only have to visit the seaside to see the problems marram grass has establishing itself on the dune sands to appreciate the problems Greenkeepers face trying to establish fescues and bents on sand-dominated rootzones. The organic amendments used are mainly soil, peat, bark and composts. The USGA have recently revised their recommendations for golf to allow the use of zeolite and others for increased moisture and Cation exchange capacity. Furthermore, the stress we put these grass species under is extreme and the expertise required to create and maintain a healthy growing environment is high. With players and the public now seeing the best playing surfaces in the world via TV coverage, their expectations are greater than ever.
What does top dressing mean?
A farmer would interpret top dressing to mean the surface application of fertiliser (usually nitrogen) to the growing crop. This has caused some interesting comments from farmers who have developed golf courses from their farm land and when they have applied top dressing, they have expected grass growth from what they think will be a nitrogen source.
So, in sports turf, the term top
dressing is used almost exclusively to describe the surface application to turf of
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