Best Technical Merit Answers- April 2003
Following the success of the Technical Merit Award 2003, sponsored by Tillers Turf. Pitchcare have started to publish some of the best answers submitted to the monthly scenario questions. This month we have the best of April's answers. Next week the best answers to the May scenario question will be shown.
April Scenario Question:
Before, during and after a seasons play, top dressing may be applied to a playing surface. Please explain the reasons as to when, how much and why, you would apply top dressing to your particular playing surface's.
1.Before planning any topdressing applications it is vital for the turfgrass manager to consider:
Topdressing has many functions, such as, restoring surface levels, increasing green speeds, protecting the crown of the grass plant, providing a source of nutrition, and correcting soil problems.
The timing of application has an effect on the desired result. Topdressing of cricket wickets to restore surface levels can be carried out from the moment the wicket comes out of play until about the end of January. If topdressing is carried out too close to the start of the cricket season the topdressing may not be 'absorbed' by the wickets and cause them to be dusty later on in the season.
Light topdressing during post match renovation of about 25-50Kg of loam may reduce the need to heavily top dress cricket wickets at all. If however, surface levels need to be improved more topdressing is required after spiking the surface, 200Kg and above will be needed.
A great way of applying topdressing to cricket/ tennis surfaces was seen at Wimbledon lawn tennis club last year. Heavy scarification of the surface was carried out prior to re-seeding followed by light topdressing. Once the turf had established more topdressing was added to restore surface levels. The reason for this was that a thick blanket of soil did not smother the germinating seed, and levelling could be carried out without smothering desirable grass.
Hollow coring and topdressing can be carried out to remedy problems with wickets, such as low bounce. Soil exchange maybe the only option on wickets that cannot be taken out of play. This process however takes time; it could take up to 10 years to see an improvement in bounce, and may lead to inconsistent wickets during the process.
Topdressing winter games pitches are generally carried after the playing season finishes to restore surface levels and improve surface drainage. Sand banded pitches will need to be top dressed to keep the tops of the slits open. If spiking has been carried out prior to topdressing to improve surface drainage then about 60-100 tonnes of topdressing will be needed per pitch. If however, the surface is due to have cricket played on it spiking should be avoided as it may cause cracking, and light topdressing of 20-40 tonnes should be added to improve levels.
It is worth mentioning that applications of sand to a heavy silty clay loam will not immediately alter the soils texture. It would take years of heavy applications to change the soil texture to a sandy silt loam.
Light frequent dressings of compatible material is ideally suited to surfaces such as golf greens or bowling greens to maintain surface levels and green speeds.
Topdressing golf greens and fine turf can be carried out at any time of the growing season, provided that the turf can recover. Topdressing too late in the season could smother the turfgrass plant, leading to diseases such as fusarium!
The sand used in greenside bunkers should be compatible with the root zone of the green. Problems with the root zone can arise over time if unsuitable sand is used just because it looks better.
Topdressing should be carried out only when the sward has time to recover.
Spiking should always be carried out before topdressing to incorporate the soils together, but if light dressings of similar material are used spiking is not always necessary.
The reason for topdressing should be apparent before the topdressing procedure is carried out. A suitable material sourced, and a storage area decided in case of bad weather.
2. Working on a cricket square requires careful management and forward planning to ensure you get as true a playing surface for the prevailing conditions as possible along with a quality appearance. Part of this process involves top dressing the square.
Generally, top dressing of a cricket square is carried out at the end of the playing season after which the square has taken a real hammering from general play, wear and tear, rolling and close mowing. The end of a season depends on the situation and usage of a square - as early as July for a school and as late as the first week in October for some club squares.
The best time to renovate however is late September/early October as the ground is still warm; there is normally some warm sunshine and also plenty of rain about - vital for the binding process of the loam and also seed establishment and therefore the best time for top dressing. During the summer months, the ground has been dry for long periods and perhaps not as much watering has been done as would have liked. The ground and turf therefore needs renovating to restore it to its best.
Top dressing is carried out for several reasons, namely to restore levels on the table - for example, bowling and batting hollows on the ends will need topping up as do stud scars, stump holes and any other surface damage. Renovation is also the ideal time to top up any undulations in the square, which may hold water after copious precipitation or offer low/uneven bounce on a particular pitch when in use. This is done by giving extra dressing to the affected areas, but not too much at any one time, as the surface may be too unstable for use next season. Severe hollows should be dressed out gradually over a few years.
Top dressing also aids seed germination as the seed uses the loose soil particles as a tilth in which to get a foothold to grow which can be particularly difficult on a cricket square. For end of season renovation you should be looking to apply 250 kg of cricket loam per pitch. So for an average square of 12 pitches, the square would require 3 tons of loam. However, if your renovation plan involves hollow coring your square and removing the cores, you will need on average another 100kg per pitch to compensate for the lost cores (depending on core depth).
You can apply top dressing to a cricket square before the season commences but this is not recommended as the loam will not have time to bind properly to the existing soil and therefore could be detrimental to the quality of your wickets during the forthcoming season. It could be though that you may have lost all your seed from the previous autumn due to drought or to prolonged rainfall, or you may have had such a wet autumn that you have not been even able to get on your square to do any renovation! (Believe me it has happened!). If it is a real must, then it would be better to loam the really needy areas on the square with the least amount of loam that you can get away with and try to use the affected pitches as late on in the season as possible in order to give time for the loam to bind properly. This process should be carried out when you are able to get on to the square to work but long enough before the process of spring preparation where the new soil will not be picked up on the roller. Early February would be a good time. Topping the ends up should not pose too many problems and will not affect how the pitches play, but again, you should try and refrain from using these pitches until as late in the season as you can. Ends can be dressed out in spring as late as the start of the season if you don't use the affected pitches until well on into the season.
During the season, it is good practice to top dress individual pitches during use and after retirement of a pitch, but only on the ends. If you are retiring a pitch after play, you should dress the hollows and scars with the same loam, as you would normally use for end of season renovation to enable you to restore the levels on the pitch. This will help you to have a rut free pitch should you come to use it again later on in the season and also give you the possibility to establish some grass if desired. Top dressing these ends is also important as there is always the possibility that a ball may fly up or deviate in a rut whilst play is on another pitch causing frustration or even injury to a cricketer. Be very careful, however, not to get too carried away when dressing ends by hand, too much will ultimately lead to problems with saddled ends over the years which become a problem with regards to drainage on the square and become an unsightly addition! Better to dress out ruts little and often as required without making each application proud of the surrounding soil. You can always add loam but it is difficult to remove it once bound. You can also dress a pitch that is still in play.
If you are using a pitch on consecutive days e.g. a two-day game, then the scars and ruts will need repairing overnight. There are many methods in doing this and each is individual to a Groundsman. My preferred way is basically to make a plasticine paste out of loam and water and to smooth it into the hollows, cover with grass cuttings, tamp down and to leave overnight before rolling in the morning. Again, make sure you don't over do it as you could still cause yourself problems with saddles over time.
Top dressing of a whole pitch during the season should only be done if a pitch has been severely damaged, e.g. masses of divots taken out at both ends due to play on a wet pitch (knocking the top out). Give the pitch a light dressing (no more than 100kg) and water out. This may well help the pitch recover in time to be used again later in the season depending on the time of year. Try and carry out this operation during any significant break in play on the square (e.g. a half term break in a school or a two week break from home fixtures, etc.). Remember, you still have to use the whole square during a game so you don't want cricketers sliding about on a damp sticky pitch! If you are unlikely to use a pitch as damaged as this again during the season then leave it till the end of season renovation to repair.
3. You would apply topdressing as needed in accordance with the growth rate of thatch on your particular sports surface. You would also consider the quality of the surface levels. If your surface were relatively uneven you would apply topdressing more frequently than someone whose surface is truer. The best times to apply topdressing are when the plants in the sward are actively growing. Applying topdressing to dormant plants runs the risk of suffocating plant parts and lowering the quality of the grass surface. Disease outbreaks are encouraged by topdressing in warmer conditions because once the application has been made, a microclimate is formed. Before the grounds person has worked it in, pathogens can germinate. Pathogens germinate within a one half-degree range of their ideal temperature so topdressing during the season can be dangerous as well as beneficial. The grass type will also dictate the frequency of topdressing. Creeping bentgrass requires regular light topdressing whereas a tufted Fescue will cope with lower application frequencies.
How much you would apply will be dependent on what you are trying to achieve. You would put on more to fill the holes created by a hollow-coring operation than if you were simply trying to encourage new growth. The spring topdressing may require higher amounts because of the degradation from wind and rain over the winter months. The summer and autumn amounts would be less because they adding to the initial spring amounts.
There are many reasons why you would apply topdressing.
-To increase surface levels.
-To stimulate new root and shoot growth.
-To cover seed allowing it to make contact with soil and therefore providing insulation and maximising the germination rate.
-To increase the water holding capacity of the soil and reducing the amount of water stress during the summer months.
-To increase soil structure by adding a medium that will improve infiltration rates, soil strength, saturated hydraulic conductivity, aeration capacity, nutrient retention, and fertility levels within the soil.
-To allow a soil exchange to take place working in conjunction with hollow-coring to remove a lower quality soil and replace with a fresh, active medium.
-Topdressing with a soil/compost mix has been found to reduce disease instances. Topdressing with an organic substance will increase the microbial populations that attack pathogenic fungi.
-Topdressing also raises the quality of growing medium for grass roots, which increases plant visual and functional qualities such as density, uniformity, colour, texture and so on.
-Topdressing also provides a habitat for micro-organisms within the thatch layer and helps to maximise the thatch layer's decomposition rates.
-Finally topdressing also helps to reduce dry patch from forming within turf. Diluting the sticky mucilaginous residues within the thatch layer improves the water absorbency properties and reduces the hydrophobic nature of thatch.
6. What is top dressing- a dressing that is applied to a surface or area, to improve its performance, it could be sand, soil, a mixture of the two, or peat, manure, leaf mould, compost, applying top dressing has the following benefits:
Improves the roll of the ball (golf mainly), can "sweeten " the soil, improves the levels, can aid either natural drainage, or enhance drainage systems with the application of suitable particle size materials can be part of a soil exchange maintenance programme, vital to seed germination, by ensuring soil-seed contact, can help stabilise sports surfaces, can compliment a fertiliser programme by ensuring the dressings that are being applied are exactly right for your own unique situation.
When to apply top dressing?
Generally on most sports pitches top dressing is applied at the end of the playing season, whenever this may be, the exception to this is golf, where it tends to be applied at monthly intervals, however, the difference in quantity tends to be minimal, as golf greens take a "dust dressing " regularly, other pitches will receive a "blanket dressing" once or twice a year, the timing of top dressing has to be carefully planned so as not to affect the germination of grass, the sport being played, and other management practices (mowing, verti cutting).
How much to apply?
As a general rule, no more than 5mm should be applied at any one time, as any more will smother the grass and create a thatchy fibrous surface, but this is really down to the funds available, there are machines available that can generate top dressing from existing surfaces, and these may be of some use to organisations with limited budgets.