Coping with winter stress on grass pitches

Editorin Football

Before1With colder than average winters affecting the UK over the last few years, British turf managers face an uphill battle against the elements. And a thought must be spared for groundsmen and greenkeepers in colder climate countries who see the treacherous effects of freezing temperatures and snow cover on turfgrass year after year. On some of the worst affected sportsfields and golf courses in Norway, however, turfgrass managers are contending with winter desiccation and restoring the health of their turf through a method of creating and sustaining a living soil.

Head Groundsman at Viking Football Stadium in Stavanger, Ivar Alstadsaeter, is no stranger to the damages of winter desiccation, not to mention the effect it can have on his own stress levels. Following last winter's very low temperatures in Norway, the playing surface at Viking Football Club's home ground was barely recognisable: most of the grass was dead; the roots were no longer than 3cm and the turf could take very little water.

The bitterly cold winters in Norway cause damage to turfgrass in various forms. Freezing injury is caused by ice formation, not low temperatures, per se. In the event of a rapid, extreme drop in temperature, ice forms inside cells; this is referred to as intra-cellular freezing. Freezing of water inside the plant cell is lethal as ice crystals rupture membranes.

Before2Ice can also form between cells when temperatures drop slowly below freezing, resulting in extra-cellular freezing injury. Extra-cellular freezing is not usually lethal, but it can cause metabolic damage and kill plants if temperatures are very low for an extended period of time.

Leaf discolouration, a water-soaked appearance, and tissue death are typical symptoms of freezing stress on turfgrass, all of which were present on the playing surface at Viking Stadium earlier this year. Ivar and his team worked hard all spring: "Very little maintenance had been done on the pitch in previous years, so it was in extremely poor condition," says Ivar. "We had a very good fertiliser programme, but we realised that something was missing."

The stadium's playing surface was suffering due to environmental stress from shade, turf maintenance operations and severe winter injury, all resulting in impaired photosynthesis, which meant a reduction in carbohydrate production. Carbohydrates are the essential fuel by which plants can recover from environmental stress but, as Norway's freezing weather had depleted the carbohydrate reserves in the turf, the playing surface became weak and susceptible to disease and injury.
In June this year, Ivar invited Scotland-based turfgrass biology specialists, The Great Turf Company, to conduct a seminar at Viking stadium after hearing about their 'Activated Microbial' programme from the company's Norwegian partners, Grønt AS.
Activated Microbial Turf Management, which is popular amongst English Premiership football clubs, involves increasing and maintaining soil microbe populations and supplying carbohydrates the plant cannot make because of sub-optimum environmental conditions and the pressures of preparing playing surfaces.

Having tried various turfcare products in the past, Ivar was not completely convinced that a new product regime could solve the many problems affecting his pitch. But, after speaking to other Norwegian turf managers that had been using the programme with much success, Ivar decided to test the products.

The groundscare team started out by brewing, and then spraying, compost tea onto the turf. Compost tea inoculates turf with billions of beneficial microbes which improve the life in the soil and on plant surfaces. Ivar could not believe the results, saying, "When I got to work the day after spraying the compost tea for the first time, Viking's Operations Manager called on me and asked me what had happened to the pitch; it was so incredibly green. I smiled and said that we had sprayed living microbes to increase life in the soil."

Viking's grounds team saw a noticeable improvement following application of living microbes to the turf.
Boards going down1
The compost tea treatment was followed by an application of MolTurf, a concentrated carbohydrate soil microactivator and plant energy source, and GöemarTurf, a seaweed liquid extract with a high concentration of growth and stress relief hormones to improve turfgrass recovery.

Last month, Ivar was faced with an even tougher challenge than winter desiccation. The stadium was to become the country's biggest playground as it played host to the Solberg Extreme Motor Show. Boards were placed on the pitch and 600 tonnes of tar laid on top to form the track for a number of rally drivers and motor cyclists to parade in front of around 7,000 spectators. The grass would, of course, be subjected to a lot of pressure, but Ivar's greatest fear was that the temperature of the tar would kill the grass. Fortunately, the damage was minimal. "We were relieved when we removed the boards and saw that most of the grass was green," says Ivar. "Only in a few areas, where boards had parted slightly allowing tar to pour through, were there some brown spots and small lumps of tar on the grass."
Boards uplift
With his new Activated Microbial Turf Management programme, Ivar is confident that the grass will take very little time to fully recover from the Motor Show, saying; "Our management team is very pleased that we can lay 600 tonnes of tar onto the pitch and the surface still looks almost as great one week later. It shows that, with good treatment of turf and soil, playing surfaces can survive the elements and maintain full health."

As forecasters warn of another 'Big Freeze' in the UK this winter, British turf managers may face similar problems to those seen at Viking Stadium earlier this year. In Ivar's experience, the solution to turf damages is simple: look after the life in your soil and the soil will do the rest.

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