Key Tasks for August
Mowing daily, or at least three times a week, to maintain sward height at around 4-8mm. Some clubs reduce their mowing heights further, perhaps down to 3mm to help speed up the greens for club competitions. Prolonged mowing at these heights will lead to plant stress.
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.
Many bowlers complain about slow, inconsistent greens, often resulting in clubs trying to speed them up by shaving off more grass. In the short term, this may increase speed but, in the long term, it will be very damaging to the green.
- Remove and control the rate of unwanted vegetative growth (thatch and side growth) by regular grooming and verticutting operations.
- Light applications of topdressing will restore and maintain surface levels, thus increasing green speed.
- Mowing in several directions to reduce nap layering will help increase green speed.
- Double cutting for matches will increase green speed.
- Controlling soil moisture will help influence green speed.
- Brushing/switching of the playing surface keeps the green clean and removes any dew or surface water. Keeping the surface dry will improve resistance to disease.
Mowing. Too many bowls clubs choose to cut their greens far too low during the summer months, mainly influenced by club members who want faster greens. Do not be tempted to cut below 4mm unless you have the expertise, resources and knowledge to support this type of maintenance regime. Mowing the green below 4mm will, in the short term, give the members what they want - fast greens - however, there is often a cost to bear for doing this. It generally comes in the form of the green suffering in many ways, grass cover begins to thin out, bare areas develop which allow weeds and mosses to establish. Beneath the surface, the constant rolling will have compacted the soil profile, reducing the air spaces. This leads to poorer root growth, less movement of water and resulting in flooded surfaces.
In fact, the most common cause of slow bowling greens is the presence of a layer of accumulated organic fibre, commonly known as thatch. This is found just below the surface and is caused by the accumulation of matted grass stems. This is easily detectable when you walk across the green and the surface feels soft.
Aeration is a key activity to ensure that there is a good air/gas exchange going on in the soil profile. The use of a sarel roller (depth 5mm) helps to keep the surface open without disturbing the playing surface. Deeper aeration should only be done with micro tines when moist conditions allow penetration.
Irrigation. 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.Soil water relationships are key drivers in maintaining plant health, so it is vitally important you readily water your bowling green and ensure the plant does not become stressed from the lack of water, on the other hand you do not want to be over watering, as this may bring you other problems.
Renovations
Generally, you should be looking at a programme of scarifying in several directions to remove unwanted thatch layers and dead matter, aerating with some deep solid tines to break up compaction, topdressing with some 70-30 topdressing to restore levels, and overseeding with some new grass seed.
Unfortunately, one of the deciding factors that often reduces the effectiveness of these planned works is the amount of money the club has available, especially given the current circumstances. It can cost anything between £1200-£1500 for a contractor to come in and do all the work. Savings can be made if the club undertake the work themselves, however, the effectiveness of the work carried out will be determined by the equipment they have at their disposal.
Savings can also be made if clubs buy materials in bulk (several clubs group buying).
Entering August signals the start of late summer, and with it shorter days and cooler nights. After a very dry spring, June and July have been months where rain showers have prevailed. Coupled with the warmth these months naturally convey, it is hard to think of more useful period for plant growth. As it happens, the same conditions have been quite useful for pathogen growth too.
Nutrition
Strategic application of nutrition aimed at providing the grass plant with the means to maintain consistent health are as important as ever. Calcium is a key nutrient to regulate water use efficiency, as well as increase tolerance to biotic and abiotic stress via thickening of the plant cell wall.
Sufficient nitrogen is always a delicate balancing act and, with frequent showers utilising a granular form as a foundational base will help to provide a more stable supply that little and often feeds with liquids; however, they can still be utilised to top up granular feeds as growth and plant health dictates.
Disease
Towards the end of the month, dews will become heavier potentially providing suitable conditions for microdochium patch. At the start of the month, the risk of high temperatures combining with high humidity will promote disease such as rhizoctonia. High temperatures during July’s hot periods may have activated Anthracnose. Other diseases such as take-all patch and waitea patch and dollar spot may occur.
The key here is to understand the environmental and cultural triggers, and then employ nutritional and cultural strategies to counteract the risks. Increasingly, with the withdrawal of chemical fungicides the turf manager is responsible for seeking out the knowledge to understand the drivers of each disease and then employ multiple tactics to combat the risk. For example, take-all patch attacks the base of the plant and root system, acidification in the rhizosphere helps to combat this; something which can be achieved via the regular application of manganese through high risk periods. Anthracnose, it’s a saprophyte, which means once triggered by hot temperatures it lies in wait for senescent (dying) plant material to trigger its attack into full blow foliar blight. Avoiding the stress mitigates the pathogens ability to pounce. Therefore, adequate moisture, consistent appropriate nitrogen levels and the avoidance of other diseases (Anthracnose often occurs as a secondary infection) will help to keep it at bay.
Pests and Diseases
Effective integrated pest management necessitates monitoring of local target pest populations as a precursor for taking action. Chafer beetle lures set out in May will have given an indication of hot spots for adult activity. Lifting back turf in zones identified to be high risk for grubs allows turf managers to eyeball larvae and take action. The same can be said of leatherjackets; simply sheeting the surface with a 1m2 sheet of plastic overnight may encourage larvae to rise to the surface. Knowing what your high-risk areas are, and then identifying the level of pest incidence, allows for targeted treatment with Entomopathogenic nematodes. This biological control requires warmth and moisture in the soil to be most effective. Targeting this year’s larvae when they are small and susceptible gives your army of microscopic worms an increased chance of success. With chafer and crane fly larvae hatching out in August and September, these are the key months to gain preventative control and prevent problems in spring and early summer 2021.
Renovation
Preparation for end of season renovations should be in full force; the prime aim being to manage organic matter accumulation and promote recovery of the grass plant in time for autumn and winter. Biostimulants, such as liquid seaweed and humic acids, will promote seed germination and establishment in combination with the usual fertilisers.
James Grundy
Senior Technical Manager – Amenity | MBPR
- 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.
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