August Bowls Diary
By Laurence Gale MSc
Despite the recent rains, many greens are showing signs of drought stress. They are brown in colour, cracking up and becoming bumpy due to uneven growth.
The very dry weather for most of July has been the problem. Once the greens are allowed to dry out, they often become difficult to re-wet. Many clubs either do not have a suitable irrigation system or do not totally understand the principles of watering fine turf.
Once the soil has dried out it becomes hydrophobic, tending to repel water. In such cases it is important to ensure the green gets a thorough soaking with a fine spray and, if required, using a wetting agent. Time must be allowed for it to soak in.
Adequate water is especially critical for plants growing under stress conditions. Fine turf grasses experience heat and moisture stress during the hot summer months. Closely mown turf tends to have shallow rooting systems.
Water repellent soils are a result of non-wetting organic compounds coating soil particles over a period of time. Sandy soils are very prone to water repellency. The rough and very low specific surface area of sand particles makes them easily coated by organic compounds as they leach through the profile; sandy soil favours the growth of fungi and fungal hyphae. Fungi feed on organic matter leaving behind waxes which contribute to water repellency.
There are a number of cultural practices that can help alleviate dry patch and help promote efficient watering of dry surfaces.
Reduce the build up of organic matter by managing your thatch level with regular grooming and de-thatching.
Dilute thatch layers by the application of topdressings.
Aeration using several types of tine types (solid, knife or hollow tines) to allow uniform wetting and deeper penetration of water into the playing surface.
Irrigate longer to prevent shallow root development.
Localised hand watering of dry areas.
Watering at night/early mornings to reduce water loss from evaporation.
Regular applications of wetting agents.
Water should be applied uniformly. It is important to water to a consistent depth, take care not to over flood the surface, you do not want to be wasting valuable water resources. See the following link for additional information about irrigation - Irrigation for sportsturf.
The summer bowling green maintenance regime continues, with regular mowing, grooming, feeding, brushing and watering.
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 sarrel roller (depth 5mm) helps keep the surface open without disturbing the playing surface. Deeper aeration should only be done with micro tines when moist conditions allow penetration.
Brushing/switching of the playing surface keeps the green clean and removes any dew or surface water. Keeping the surface dry will aid resistance to disease.
Fertiliser treatment and turf tonics can be continued in accordance with your annual programme. If you haven't got a fertiliser programme, have your soil tested; try an independent soil analysis company for an impartial set of results.
To help prevent constant wear in the same locations it is important to move markers and rinks on flat greens.
Mowing frequency will often be dependant on the resources available to the clubs. Ideally most clubs will be mowing daily or at least three times a week. Regular mowing will be required to maintain sward height at around 4-8mm. Some clubs will 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 top dressings to maintain levels. Many bowlers nearly all ways complain about slow, inconsistent greens, often resulting in many clubs trying to speed them up by shaving off more grass. In the short term this may increase green speed but, in the long term, it will be very damaging to the green:-
The grass plant will become weak and susceptible to disease.
The sward will thin out and become bare, allowing the opportunity for less desirable grasses and weeds to populate these areas.
The grass plant may even die out completely.
Root biomass will be reduced, which in turn effects the plants ability to take in sufficient water and nutrients.
Remove and control the rate of unwanted vegetative growth (thatch & side growths) by regular grooming and verticutting operations.
Light applications of surface topdressings will restore and maintain surface levels thus increasing greens speed.
Mowing in several directions to reduce nap layering will help increase green speeds.
Double cutting for matches will help increase green speeds.
Controlling soil moisture will help influence green speeds.
Timing of fertiliser products, applying NPK fertilisers can affect greens speed.
Rolling the greens will increase greens speed. However, over rolling will lead to problems. There are a number of specially designed turf irons that have been developed for increasing greens speed, ride on machines that evenly spread the weight of the rollers.
Remember, it is important to balance the health and state of the green when considering surface playability.