PETER McMAUGH AM
Transitioning to a tee Peter McMaugh AM looks at the secrets to successfully transitioning out ryegrass from a couchgrass sward.
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ne of the most troubling questions for any turf practitioner who oversows couchgrass for better winter presentation and wear, be it a golf course tee or a football ground, is when and how to take out the ryegrass to affect a good transition back to healthy couch. There are four elements to this question that all need to slot together smoothly for the operation to be successful. These are; l Choosing the best couchgrass to be oversown; l Choosing the best ryegrass for its transition performance; l Choosing the appropriate chemical to assist the transition; and l Choosing the right ‘time’ to carry out the exercise Regarding the first point, in some ways it would be best to talk about this subject last and maybe we will have the last word. In the 52
meantime, what the answer is to this question really comes down to what couchgrass will give the greatest recovery potential; in other words, ‘what’s left’ at transition time. Many of the couchgrasses used on tees and football grounds are chosen for their density and their ability to carry high wear with high recovery rates. For this reason they are often difficult to oversow unless there is a dethatching programme carried out beforehand. For the overall health of the couchgrass, this is not the right time of the year to be dethatching. Damage done in late summer and autumn can leave plenty of open wounds for fungal invasion, to say nothing of removing food reserves that normally would be used for recovery at green-up in spring. The major problem that couchgrasses have is with the density of the oversow, because it often really transforms the oversown area into a pure ryegrass sward that excludes 90 per cent or more of the incidental light
AUSTRALIAN TURFGRASS MANAGEMENT 22.3
from the couch. This is rather disastrous for Australian-bred couchgrasses which are bred to stay green into winter and also for hybrids like Santa Ana that have late dormancy and early green-up. They are deprived for many months of the chance of storing more food for recovery in spring. Australian-bred couchgrasses are usually selected for very flat growth which means that when they are oversown they consume stored energy that they would normally use in spring to produce upright growth to compete with the ryegrass for light. This is a survival response which makes for a negative in spring. These considerations lead to only one conclusion – that only couchgrasses with the ability to store lots of goodies in reserve will have the ability to transition successfully. How many of our currently popular varieties have this innate genetic ability? The answer to that will come later, but for now we need to carry it uppermost in our mind.