Key Tasks for July
As with last month, you will need to be guided by your governing body regarding usage and procedures. However, signs are positive and a slow return to some form of normality appears to be on the way.
With the long daylight hours and warm temperatures, grass growth will be quite prolific if there is plenty of moisture about.
- Continue to carry out routine maintenance tasks, mowing, verticutting, fertilising, watering to keep the green in a playable condition.
- Grass growth will dictate mowing frequencies, in most cases clubs are cutting daily or on a three to four times a week regime.
- Only apply fertilisers if you have significant moisture in the green; clubs that are struggling to water should refrain from applying feeds whilst the greens are dry.
- Try and keep a diary of what work you have undertaken on your green, and keep records of how it has performed; take some pictures of the green and make note of any issues/problems you have.
- Get into the habit of taking a number of soil core samples to monitor what's happening underground; a visual look at a soil profile will enable you to monitor thatch content, moisture levels and root depth.
Mowing. With regard to mowing, ensure your mower is kept sharp and set at the correct height. No two greens are the same; Height of cut (HOC) will vary from green to green, with HOC influenced by several factors, type of mower used, condition of the green, sward composition and surface levels. In general, HOC will range between 3mm-8mm during the growing season, with most clubs cutting at around 5mm.
Some clubs will reduce their mowing heights, perhaps down to 3mm, to help speed up the greens for club competitions. Prolonged mowing at these heights will lead to plant stress. As an alternative, instead of reducing the height, do a double cut (in different directions), this will speed up the greens without reducing the grass height. The speed of greens can be affected by other factors - too much thatch is the main cause of slow greens, or the fact that the greens have not had enough topdressings to maintain levels.
Irrigation. Nowadays, irrigation is an important and integral part of the turf grass management industry, especially as the demand for better quality playing surfaces has increased. Therefore, careful consideration and investment in a decent watering system is a key requirement to managing fine turf surfaces. Irrigation is essential for a number of reasons:
- for plant survival and growth
- for soil formation
- for soil strength
- for chemical transport
- for managing playability
- for presentation
Water is influential in all chemical, physiological and biological processes of plant growth. The soil/plant water relationships is critical to the sustainability of any grass plant. Having an understanding of these relationships is critical.
All grass plants are a continuum of water movement. Over 90% of the plant's water requirements are transported through the plant from the soil profile, via the roots and stem tissues into the leaves and out into the atmosphere. Knowledge of these relationships is important when designing and operating irrigation systems. The main aim is to achieve a water balance within the soil profile ensuring that the grass plant is able to access available water from the soil.
Irrigation scheduling by the water balance approach is based on estimating the soil water content. In the field, daily evapotranspiration (ET) amounts are withdrawn from storage in the soil profile. Any rainfall or irrigation are added to storage. Should the water balance calculations project soil water to drop below some minimum level, irrigation is indicated. Weather forecasts enable prediction of ET rates and projection of soil water balance to indicate whether irrigation is needed in the near future.
It is also important to state that overwatering can equally be damaging to your surface. Keeping the surface waterlogged will reduce air porosity and decline plant growth; constant shallow watering will also increase Poa annua populations. Ideally, you should apply a sufficient amount of water to flood up the green and then allow to drain for two - three days. This allows the water to get deeper into the soil profile.
Aeration is a key activity to ensure that there is a good air/gas exchange going on in the soil profile. Providing the green is adequately irrigated, the use of a sarrel roller (depth 5mm) helps keep the surface open without disturbing the playing surface. Deeper aeration should only be done with micro tines when conditions allow, as we do not want to risk disturbing the surface, especially during the playing season.
Topdressing is usually carried out in spring and autumn in conjunction with the renovation programmes. However, some bowling clubs have a policy of applying topdressing materials during the season. It is important that an appropriate material is sourced to ensure compatibility with the existing rootzone materials of your green. The last thing you want to encourage are rootbreaks in the green.
This is often a contentious point between groundsmen and players.
Many players and committees insist on keeping the ends in the same position and direction, usually for obscure reasons such as "it's my lucky rink".
Playing in the same direction with the rink ends in the same position will cause uneven wear on what should be a flat, level green. Ruts and depressions will occur, causing the bowl not to roll true.
The rink settings should be moved laterally and directionally every 3 days or so, playing across and up and down the green.
On the same basis, all rinks should be used in rotation so that wear is evenly spread across the green. Just using the centre links will quickly affect the level of the green.
June was a month where we saw warm and hot conditions give way to persistent rain and heavy thunderstorms in many areas, and with it much needed rainfall. Consequently, the dormant road verges and stressed sports turf surfaces at the end of May have given way to lush green vigorous growth. If April and May were challenging, then June has been a somewhat optimal month for plants, warmth, long daylight hours and plenty of rain; perfect.
Of course, even perfect weather is not without its challenges as heavy rainfall can wash nutrition through low CEC surfaces and humidity contributes towards the growth of fungal pathogens. Long range weather indications suggest July looks set to be a similar pattern of one extreme to another and back again. Therefore, keeping an eye on the upcoming forecast to best inform action today is vitally important when it comes to optimising windows of opportunity.
Facilitating water percolation rates by surface organic matter management, over the long term, helps water to penetrate into the surface rather than be held in the base of the plant, where it reduces the ability of life-giving oxygen to enter the rootzone and waste gasses to escape. Less water in the surface of the soil profile reduces humidity in this area, which helps to mitigate the ability of fungal diseases to proliferate. Facilitating water percolation and reducing surface humidity breaks the causative disease triangle in two ways: it promotes the overall health of the plant and limits conditions suitable for pathogen development. Practically speaking, little and often aeration from a sarrel tine aerator, in combination with regular deep tine aeration throughout the year, works to assist water’s passage down the profile, as well as helping maintain plant root health and organic matter decomposition via beneficial microbial action.
Aside from good aeration practices, useful tools in the product armoury, which will assist water management when weather conditions are wet, include penetrant wetting agents, which grab hold of water and pull it down through the soil profile faster and more effectively.
Plenty of excess moisture, combined with available warmth, are of course excellent conditions for germinating and establishing seed, so any areas requiring patching should infill quickly and easily.
The flipside of excess water is, of course, deficient water. Weather forecasts suggest that the trend for July is for the extremes of wet to be counteracted quickly by dry weather. With the sun high in the sky, long warm sunny days can very quickly push water levels in the opposite direction, as excessive moisture is replaced by moisture deficit. Keeping a close eye on weather forecasts, and intervening with timely applications of cold pressed liquid seaweeds, calcium and potassium silicate, prior to challenging conditions, are all inputs which assist the plant in preparing for and resisting the rigours of water deficit.
In advance of forecast hot and dry weather, ensuring irrigation systems are running optimally is sensible practice. Being able to objectively monitor the levels of water in the soil at different depths via a Thetaprobe water meter, and cross referencing this against local evapotranspiration rates, takes the guess work out of irrigation and facilitates applications which are appropriate for the plant, the environment and the budget. Investing in weather stations does not have to be an expensive course of action, and working with your irrigation supplier to understand the volume of water your system is supplying, in litres and millimetres, are core areas of knowledge for any sports turf manager at any level.
Allowing dry down periods in the soil following intensive irrigation is an important operation. This allows the soil to breathe, encourages the grass plant to develop roots to chase water and minimises surface humidity, which would otherwise lead to conditions favourable for fungal pathogens and other ailments such as cyanobacteria and algae which will colonise and clog the soil surface, impeding the passage of water and air.
Whilst conditions are wet and warm, growth levels are likely to be strong; in such circumstances, applications of the growth regulators, such as trinexapac-ethyl or the newly available prohexadione-calcium, can prove useful in checking growth, with the added benefit of increase tolerance to moisture deficit should conditions take a turn. Keep a close eye on nitrogen inputs and avoid applications if growth is strong, as promoting even softer growth will assist virulent fungal diseases to attack.
Warm and humid conditions will promote a number of diseases, but once temperatures exceed 28 degrees Celsius, anthracnose foliar blight will be become activated. Little and often applications of nitrogen have been shown to mitigate the spread of the disease as effectively as a fungicide.
An emergency authorisation for Acelepryn was issued on the 16th May for the treatment of chafer grubs only.
The treatment window for chafer grubs expires on the 30th August 2020. Note that a separate authorisation is actively being sought for Leatherjackets, but this is yet to be approved. As with previous years, all applications must be approved by a BASIS qualified advisor.
For anyone not able to apply Acelepryn, cultural and biological controls in the form of Entomopathogenic nematodes are the only legally authorised controls available. As with the specific restrictions of application for Acelepryn, these are in line with best practice Integrated Pest Management.
- Keep machines overhauled and clean.
- Inspect and repair any watering or irrigation systems.
- Continue to check and service your floodlighting systems.
- Replace any worn tines on your aeration equipment.