AERATION
After time, bent grass used on golf greens and fairways plus turf grass suffer from soil compaction and the formation of an impervious layer on the top of the soil. Aeration is the act of venting the ground to allow moisture and air to get in, helping the plants to grow and thrive.
In the words of Rob Crompton, Kinipela Golf Club, Victoria BC, Canada
The reasons we aerate our greens are, # 1 To relieve compaction and to help control thatch accumulation. # 2 To improve air & water movement into the root zone mix. # 3 To release the build up of Carbon Dioxide gas in the root zone mix into the atmosphere.
There are several means to aerate the ground.
Mechanical Methods
Spike Aerators
These devices open the ground by piercing it with a rod or sharp point. They are effective for fast aeration and opening holes for seed trapping, but the small opening tend to close up quickly.
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| Aeration Sandals | Pull Behind Spike Aerator | Manual Push Spike Aerator |
Core Aerators
These devices, although
considerably more expensive than spike aerators, do a much better job. They
remove a core of soil, typically 1/2" to 3/4" in diameter from between 2 to 6"
deep. These holes will remain open for and extended period. They can be
backfilled with topdressing sand essentially keeping them open for air and
moisture travel infinitely.
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| Topdressed aerated green growing in after about 1 week and a heavy rain. |
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Earthworms
Earthworms are "Good News / Bad News". They are a "free" source of aeration and do an excellent job of keeping the ground open. Although they are welcome in turf grass (rough) they reek havoc on the shorter grass of tees, approaches, collars and greens. They leave "castings" (soil which has passed through their bodies) that smears into the grass surface and dulls mower blades. Extra time must be spent to remove the castings before mowing to prevent damage.
When asked "Can you tell me how to deter earthworms from my greens?", David A. Oatis, Director, Northeast Region, USGA Green Section replied:
.......sand topdressing is the key. Sand is irritating to earthworms and it will help to suppress their activity. Some courses are now topdressing fairways for just this reason. A few (very few now) pesticides have activity on earthworms, but none are labeled for their control.
