Autumn after a Summer of Rain

Into autumn after a summer of rain (sports pitches)

(Turf Business, September/October 2008)

The unwelcome rains in recent weeks question the arrival of autumn. Even the earthworms seem to think the summer is over. However, with a good high pressure system hovering to the south hopefully there is still warm drier weather to come. Into September though, it is now too late for any major drainage installation or severe disturbance of the grassed surface. It would be expecting too much for grass recovery over drains and the football season is now here. It is common sense to ensure that every effort is made to create as strong and vigorous a grass playing surface as possible at the beginning of the season – and there is still a little time.

Three essentials

Irrespective what has been done in the renovation – if anything at all – there are three vital treatments that should have been undertaken and if they have not, then now is the time with good growing weather expected into September and possibly into early October.

  • Firstly, there should be a regular mowing programme underway with the frequency almost twice a week to create the maximum grass density as well as ensuring there is no accumulation of grass cuttings on the surface.
  • Secondly, the pitches should be well fertilised with good levels of nitrogen and potassium.
  • Thirdly, especially if renovation was neglected after the last playing season, an effective weed control spray must be undertaken if the best possible grass surface is desired before the season is fully underway.

It is too late to consider any worthwhile over-seeding of bare areas as they will have no real chance to establish – unless the pitches can be spared well in to November.

Removing surplus water

October through to November can produce weather extremes but hard frosts are generally not expected until early November. With ryegrass growth and vigour still expected up to Christmas much can still be done.

  • Attention should be given to ensuring there are no depressions where water can collect. This treatment should have been completed in the summer but if not, somehow surface water must not be allowed to pond anywhere on the pitch.
  • Special attention must also be given to preventing surplus water from higher ground entering the pitch area. This surface water run-off can be diverted by a catch-water mound or a swale.
  • Where pitches are located at the foot of a cut slope the creation of a swale drain at this point prevents surplus water entering the pitch though in many cases there is not enough space. If this is the case a cut-off drain at the toe of the slope must be annually cleared of debris, silt and thatch to ensure the drain is as receptive as possible.
  • The drainage outfall should be checked and every effort must be made to lead or divert surplus water to this location.
  • Where a ditch reticulation exists these areas should be checked too and cleared well in advance of the winter rains.

Attention to the playing surface

A firm playing surface supporting vigorous grass cover is the minimum requirement at the beginning of the playing season. Though many items of necessary work should be logical, for one or another reason they can be easily overlooked.

  • At this time it is essential to check the grass cover over all slit and lateral drains and ensure the aggregate at the surface of the drains is firm and level with surrounding ground to avoid injury to players.
  • Compacted surfaces encourage water ponding in micro-depressions within the playing surface. Regular slitting now helps to keep the surface open. The use of the vertidrain can be invaluable to alleviate this condition since the ‘earthquake’ implement, which creates better decompaction in many instances, would be too damaging on the grass surface at this time with play now underway.
  • While the ground is still firm at the surface, the application of the annual sand dressing will prevent the development of a greasy surface. The texture of the sand is important. It should have negligible content over 1mm and less than .15mm. The application rate is in the region of 140 tons per hectare and this can be applied in two applications if the grass cover is not vigorous. The sand layer also promotes lateral movement of the surplus surface water to slit drains or the pitch boundary where there is adequate gradient. It is therefore important that there is an even grade and there are no depressions.
  • To maintain a healthy grass cover earthworm activity must be controlled. Spraying becomes essential as failure to control the earthworm invasion on sports pitches enables the accumulation of clay casts. These soon reduce grass cover and create a slippery playing surface. A sound grassed surface cannot be maintained while earthworms are active.
  • After a warm summer with good growth and particularly following a cricket season, there is a build-up of dead grass and cuttings at the surface. The layer formed tends to hold water and restrict infiltration. If scarifying has not been undertaken at the time of renovation after the previous football season, it is still invaluable now to remove this surplus material even if the treatment is now less harsh.
  • Regular use of a drag mat, brushes or up-turned chain harrows helps maintain and even surface and so prevent the development of depressions that can hold water.
  • In order to maintain durable grass cover in the goal mouths it is advisable to increase the grass height in this area. This endeavour prevents exposing the soil surface to a degree and so restricts the development of muddy areas.

Major works undone must stay undone but at least the best possible grass cover in the circumstances should be sustained. Only by creating a vigorous and even grass cover at the beginning of the season can there be any hope of enduring the cool wet playing season ahead.

Gordon Jaaback

August 31 2008