In any sporting environment, the quality of the playing surface is critical to the quality of the players' performance. That fundamental truth also means that superior turf is essential for the sporting venue's reputation and its commercial success. In the golfing world, for example, those courses that combine excellent location with superior fairways and greens become must-visit destinations for golfing enthusiasts the world over and must-play venues for professionals.
But, what's the secret to creating turf that provides the ideal playing surface and lends itself to being maintained and nurtured so that the playing surface remains consistently excellent over the years? The answer lies in the materials used when the playing surface is created, starting with the rootzone.
Getting to the root of the matter
The rootzone is the layer beneath the surface turf where the grass roots interknit with the soil. For healthy grass, the grass roots need an environment that provides enough air, water, space and nutrients in order to grow and flourish. The composition of the rootzone, therefore, is extremely important and it's essential to follow the advice of a well-established, industry accredited supplier who can advise on the particular requirements of an individual installation.
In general terms, an ideal rootzone material should provide a balanced porosity that ensures optimum water retention and aeration: too much drainage, and frequent irrigation and fertiliser application will be required; too little, and the turf is at risk of becoming waterlogged. The ideal approach to providing this balanced porosity is a rootzone composed mostly of well-graded sand, combined with an organic amendment additive, because sand provides the drainage and stability advantages sometimes lacking in natural soils.
There are numerous factors that affect the success of the rootzone in balancing water retention/drainage requirements and aeration, including particle size distribution (the separation of sand grains into distinct diameter sizes), silt and clay content, saturated hydraulic conductivity (the constant rate at which a saturated material is able to transmit water downwards), organic matter content and the pH level.
As a result, the specification of a high grade sand, especially formulated for use as rootzone, is a critical stage in achieving the perfect turf. Such high-grade sand-based rootzone not only ensures that sufficient drainage and stability is achieved, but also helps to maintain consistent drainage and stability levels by preventing high levels of foot traffic from compacting the porous spaces.
Of course, climatic and geographic factors, along with end usage criteria, must all be considered as part of a best practice approach to specifying the most appropriate rootzone formulation, and it is important to work with the rootzone provider to select the right product.
Dressed for success
Choosing the right rootzone is key to creating the perfect sports surface, but it is only part of the story: selecting the ideal topdressing - a surface application of sand, soil and/or organic material - is equally important. Only if the rootzone and topdressing complement each other. and merge over time, will they nurture robust and healthy turf.
The application of a topdressing ensures a balanced, even appearance, effective drainage and increased resilience, improving the playing quality of a surface. A good quality topdressing encourages new microbiological activity that breaks down a green's thatch layer: the spongy layer caused by heavy fertilisation, excessive or infrequent mowing or aggressive grasses. This helps to minimise the risk of disease often caused by organisms and insect activity in the thatch. Prevention of heavy thatch accumulation also ensures better water and fertiliser infiltration, ensuring that tight turf matting is avoided, reducing localised dry spot problems and maximising the effectiveness of irrigation.
The application of an appropriate topdressing is essential for both healthy turf growth and protection of the established turf. The fresh soil material encourages new growth, resulting in a finer textured turf with better upright growth and minimised grain development. During the winter months, it protects the crown of the plant from the winter's drying winds and wide temperature variations, ensuring fewer desiccation problems.
In the world of golf, for example, an effective topdressing assists the greenkeeper in producing a true and level playing surface, smoothing out surface irregularities and alleviating compaction by supporting the grass plant and absorbing compacting forces. It not only offers better 'holding qualities' for the golfer but helps to prevent damage on heavily played courses. Used as part of a verti-draining process, topdressing aerates the underlying root level and improves drought tolerance. The net result is a better playing surface that can help underpin the commercial success of the course.
Given the importance of topdressing performance, selecting the right composition of topdressing for the individual sport surface is essential. The bulk ingredient is sand, but silt, clay and a small percentage of organic matter - soil, or green compost - are also key constituents and, while the percentage of this mix is critical, equally important is the type and grade of sand used, with silica sand providing an ideal material for sports turf construction and maintenance.
Sand is processed according to particle size, colour or chemical composition, and can be supplied in a moist or dried state. Variations in particle size and pH balance can make a significant difference to topdressing performance, which is why we wash our high purity silica sand, then screens it to size, heat treat it and blend and grade it to a fine, uniform consistency.
Before the mixture is ready for use as topdressing, it needs to be sterilised to prevent weeds, and should be mixed and composted for between 8-10 months before it is used on a green.
Consistent quality of the materials used in formulating topdressings is critical, as any variations could affect performance. However, this has not prevented an increasing trend towards the use of recycled composted green waste as one of the organic constituents amongst some top dressing suppliers. As no two batches of recycled waste can ever be the same, this is likely to result in differences in the pH balance, so understanding the nature and provenance of all the constituents is vital. Formulations have also been affected by the blurring of seasons and greater year-round rainfall caused by global warming, causing a move towards slightly coarser dressings.
Meanwhile, developments in application equipment have been a major trend in the sector with new spinning plate 'spray apply' equipment providing a fast solution to delivering a more even spread of topdressing. This innovation has precipitated a move from applying topdressing twice a year to a 'little and often' approach which allows each dressing to sift into the turf, mingle with the grass, and carry out its many important functions.