The practice of oversowing fairways with rye grass had until 5 years ago been a regular maintenance procedure at Northbridge. We were doing this for about 10 years. It looked great from May through September however it became increasingly difficult to transition the rye in the Kikuyu in spring / early summer. The decision was made to discontinue this practice.
A legacy of this oversowing has been many patches appeared in fairways and roughs of thin, weak Kikuyu with clumps of rye grass scattered in the bare patch. After chemically removing the rye, these patches persisted. The Kikuyu was very weak, riddled with fungal disease (Helmo) and exhibiting symptoms of mite damage. After re turfing many of these patches the new turf struggled to stay healthy, showing the same symptoms as the turf it replaced. Even after digging out the soil to a 300mm depth and replacing with new soil the Kikuyu turf was still struggling. This was making us look stupid, indeed it was a perplexing problem. After several attempts of re turfing with Kikuyu, I tried using Santa Anna couch. This worked perfectly with the couch having no problems at all.
One of the consultants who visits most of the golf courses in Sydney sees this interaction between ryegrass and Kikuyu in random patches regularly. There is sufficient anecdotal evidence to suggest there is an allelopathic effect from rye grass toxins effecting the Kikuyu. My assistant Brendan Brown who is currently doing his Masters degree at Sydney Uni suggested to Dr Peter Martin that he could do his research project on identifying the cause of this problem. Dr Martin felt this was more of a PhD project in respect to the amount of work required.
Anyway, I know some of the members have questioned why a grass other than Kikuyu is being used in the fairways. I hope this helps to answer the question.
