By Dr Andy Owen and Henry Bechelet, Technical Managers, ICL Turf and Landscape.
Fine turf management is always challenging during the winter, especially in northern Europe. Through autumn the days shorten, the temperatures drop and the turf growth slows down. At this time the damp conditions usually wake the fungal diseases to bring the potential for havoc. Play usually continues on the greens whenever they are available and so the pressure mounts. Winter is the time when it could all go horribly wrong but with considered and careful handling we find that it is possible to get through. The golfers might even have some fun. Miracles do occur sometimes.
Because turf vigour declines on the way to winter it is important that we prepare in advance, to create a system that is able to survive the rigours of play and the wider environmental pressures without any recovery growth. We deploy management strategies that are designed to sustain turf health and reduce the risk of damaging disease attacks whilst still creating decent playing surfaces. This might be achieved with long-term strategies to maintain drainage and keep the soil healthy (ongoing soil organic matter management, aeration and drainage) or more immediate measures designed to sustain turf health (nutrition programmes, the use of turf hardeners and fungicides). There are a multitude of measures that we can employ to help us prepare for the winter but it doesn’t stop there. We must continue to proactively manage the turf during the winter. Hibernation is not an option.
We would say that the key areas to focus on during the winter are as follows:
• Soil profile aeration and drainage
• Surface moisture removal
• Sustenance of plant health with appropriate nutrition
• Protecting the plant against disease attack
An aerated soil is all important to maintain a healthy functioning system. We would advocate aeration treatments whenever necessary to maintain an open and aerated soil structure. We don’t think that you should spike for the sake of it and you should only choose to aerate if surface/soil conditions are suitable. However, if the soil is poorly drained, thatchy and becomes stagnant in wet conditions then you have some work to do with drainage and organic matter reduction. This should be a key focus for your annual management plan. Moisture probes can be very persuasive tools during the winter if you need to explain the situation in simple terms to your paymasters.
Surface moisture removal is also a crucial issue. When the turf canopy remains damp for sustained periods the turf health can become compromised and disease activity encouraged. Keeping the leaf as dry as possible by brushing and switching, or using a well formulated dew dispersant product such as H2Pro DewSmart, along with shade reduction and improving airflow are key strategies to employ. Penetrant wetting agents such as H2Pro Maximise are specially formulated to move surface water down through the soil profile as long as drainage is available, which can be a real help.
A key element of your integrated turf management approach during winter would be to maintain turf health with nutrition without creating unduly lush growth. If soil temperatures are still above 10°C the grass plant will respond to a late season application of a slow release nitrogen source to assist with maintaining plant health through the winter. You might aim to apply in the region of 1kg of Nitrogen per hectare per month if conditions permit (with additional potassium and phosphate if soil sampling deems necessary). This would equate to an application of SierraformGT K-STEP (6-0-27 +2MgO +TE) at a rate of 15-20 g/m2 or Greenmaster Pro-lite Invigorator (4-0-8 +2MgO +4Fe) at 25-30 g/m2. Check out our latest Product Guide for information on the Nitrogen sources and release patterns of our fertilizers.
It is also important to apply what we call “turf hardeners” during the winter. One nutritional element which can support an integrated approach to disease management is Iron. When applied in a chelated form, Iron is more readily available for plant uptake than when applied as an inorganic compound (Iron sulphate). Greenmaster Liquid Effect Iron (6.3 % Fe), the ICL complexed and chelated iron has been shown in independent trial work to significantly reduce the impact of Michrodochium nivale outbreaks (figure 1) on a fine turf surface.
Effect Iron has also been shown to have the fungistatic effect of reducing fungal growth in a laboratory petri dish study (Picture 1). The agar petri dishes were dosed with Effect Iron at a range of concentrations which was then inoculated with a plug of Michrodocium nivale and kept in optimal conditions for fungal growth. The subsequent daily growth and expansion of the fungal plug was measured.
What became clear was that the Effect Iron significantly reduced the fungal growth at greater than 500 µg/ml in comparison with a control (figure 2), reinforcing the proof that Effect Iron is effective at assisting plant health within an integrated disease reduction strategy.
The understanding and selection of appropriate fungicide technology should also play a part in your integrated winter management. At this time it is important to choose the correct fungicide active ingredient and mode of action that would be effective in cooler conditions. For instance, Medallion TL from Syngenta contains Fludioxonil, which is a contact active ingredient that works on the leaf and in the thatch and soil to inhibit the development of the pathogen and protect the turf from infection. This is best applied preventatively and has been shown to provide outstanding levels of long-lasting control during the winter.
So, the production of turf that is able to perform throughout the winter without undue deterioration requires us to focus our management on the rootzone, the leaf, the plant health and on disease pathogens. If we take a fully integrated approach and focus on “getting everything right” then (with a little luck) we stand a chance of making it through. Winter is a tough time and it can sometimes get the better of our turf but it can also provoke us to improve our methods (and products) and really focus our management plans. That is the way of winter – it forces us all to become better at what we do.