The control of rootzone moisture is a critical part of the successful integrated turf management plan. The use of wetting agents has become standard practice for efficient moisture management for the maintenance of fine turf. Getting maximum performance from the selected product will make moisture control more effective. Here are ten points for efficient wetting agent use.
1. Identify the problem.
If your turf shows regular drought stress, there are a number of potential influencing factors which could be improved. For example, how effective is your irrigation coverage? Do you have excessive thatch at the surface of your rootzone? Is the rootzone compacted? How deep is the turf rooting? How sandy is your green rootzone? These issues will all affect your moisture management, and can be improved through sensible maintenance practices which can be complimented by a wetting agent programme. However, if your rootzone shows water repellency then only a quality wetting agent applied according to a full season application programme will be effective.
2. Monitor soil moisture content.
The soil moisture meter should be considered an essential piece of equipment. It will allow you to monitor the volumetric rootzone moisture content on a regular basis. Regularly measure a few greens and record the moisture values. As you build up a picture of how moisture changes with the seasons you can implement the correct watering programme. Timing the start of irrigation applications, adjusting the amount of water applied, and setting targets for water management for healthy turf on your site. The detail will detect the development of dry patches within the rootzone of a golf green before visual symptoms appear so early initial treatment with wetting agents can be utilized.
3.Choose a quality wetting agent supported by independent research.
In many countries there are no effective controls or legislation over what can be marketed as a turf grass wetting agent and this has led to the appearance of quite a few products that have little or no data available to support their use. These materials are often attractive in the first place due to low prices but with wetting agents, as is true in many other areas, you really do get what you pay for. Purchase your wetting agent from a reputable supplier and ask to see the research reports that support the products use on fine turf. Dry Patch and water repellent soils are severe problems and for effective treatment a top-quality product is needed.
4.Follow a managed preventative application programme.
It is generally agreed across the wetting agent industry that all products work best if they are applied early on a preventative basis and their use continued at regular intervals through the season. This is because the wetting agents build up in the soil to maximum concentrations at the peak of the summer period when the soils are driest. Under N European conditions the first 2 applications should be made in March/ early April and thereafter monthly until September/ October. Typically, a golf course, depending on soil type and duration of dry weather will make 7 or 8 applications in a season. Allowing the symptoms of Dry Patch to develop before trying to rehydrate these areas often takes much more wetting agent that when it is used preventatively.
5.Follow the label instructions.
Wetting agents have been designed to be used in certain ways to maximize their effectiveness. Apply the product according to the label use rates. Some wetting agents are effective when loaded into the soil at higher rates early in the season, others suggest lower applications more regularly. Cutting down the dose rate – below recommended rates - always leads to reduced performance. Water volumes recommended for spray application are usually quite high compared to other products as the wetting agent needs to infiltrate into the soil not stick on to the leaf. This is a soil application, not a foliar application.
6.Water in after application.
Several modern top quality wetting agents can be applied without watering in and will generally give satisfactory results if this is done. However, for all wetting agent products watering in ensures the material reaches the driest parts of the rootzone where it can achieve its maximum effect. It is perfectly acceptable and a useful way of ensuring the wetting agent is watered in is to apply the material during or just prior to rainfall.
If a full managed programme is followed then there will be very few if any stressed areas that will require additional treatment. However, in extreme cases, for example the high spots above bunkers or greens with severe contours additional spot treatments using a knapsack sprayer or watering can can be beneficial and cost-effective in comparison to treating the whole green. Pellet wetting agents used in hose-end applicators and granular wetting agents are ideal for spot treatment in these areas.
For ease of application turf managers will occasionally apply several products together in the sprayer as a tank-mix. Care needs to be taken that the two products are complimentary and will have the desired effect at the recommended water volume. Addition of a wetting agent can enhance another component of a tank-mix – as it ensures a very even coverage and spread through the soil. The water volumes recommended for wetting agents are often higher than those recommended for other products such as liquid irons as the latter are designed to be applied to the leaf surface not the soil.
The traditional usage period for wetting agents has been the spring to autumn period to coincide with dry weather. Recent studies have shown that use during the winter months can improve drainage and removal of surface water and in cases where there is severe dry patch can lead to virtual elimination of the problem the following year. Often this can be achieved using reduced dose rates when compared to what is recommended for in season use. Soil penetrants are also available which can be particularly effective in wet weather, and can help dry the turf surface and improve winter playing conditions. A penetrant wetting agent is designed to lower the surface tension of water and will only be effective if the water has a viable drainage route to move to.
10. Fungicides and fairy ring control
Wetting agents can improve symptoms of Fairy Rings by treating the water repellency they cause. If a wetting agent is applied prior to a fungicide treatment for Fairy Rings then this will increase the chance of the fungicide meeting its target. Treatment programmes combining fungicides and wetting agents are available for the treatment of the traditional Fairy Rings and also for superficial fairy rings (Thatch Fungi).
An effective moisture management plan for golf green turf depends upon a combining a number of factors. The selection and use of a quality wetting agent as an integral part of the plan brings improved water use efficiency and improved surface quality not least through prevention of localized water repellency.