PRODUCTS IN PRACTICE: Aeration for all seasons
While aerating turf is a common enough practice these days, many turf professionals restrict this important cultivation practice only to the spring or fall growing seasons. While there is no doubt that aerating during both seasons is recommended, aeration is, in fact, a practice that can and should be done year-round.
Gaining a broader understanding of the important benefits of year-round aeration can prove useful to turf professionals.
The case for year-round aeration
It's important to point out that aeration is not handled in the same manner in every region. Both the method of aeration and the timing are heavily influenced by location.
According to one of England's foremost agronomists, Martyn T. Jones, section head of Turf Science at Myerscough College in Lancashire: “Generally, one should aerate to achieve soil de-compaction when the demand for oxygen is high, when the plant is actively growing and soil microorganisms are respiring.” In short, there is no straightforward answer. Generally speaking, during spring and fall, temperatures are near optimum for microorganism growth and roots need a great deal of oxygen. Hence, the popularly held misconception that these are the only times one should aerate.
It all depends on how healthy you want your turf to be. According to Jones, frequent aeration can only help improve soil conditions. “Professionals should not hesitate to aerate as frequently as possible. That said, there is enormous pressure on turf professionals to make fields and golf courses available for use. If you aerate often, the real key is to use the right equipment, equipment that won't damage the playing surface,” he noted.
At St. Andrews in Scotland, no doubt one of the world's preeminent golf courses, aeration is done very frequently, though admittedly with greater emphasis on spring. Walter Woods, who ruled the turf at St. Andrews for 22 years as its head greenskeeper and course manager, recalls his early experiences with aeration.
“In 1982, aeration machines with long tines were quite a new idea,” says Woods. “On the old courses at St. Andrews we had this odd ridge or seam made up of a heavy sand material. We had a resulting problem with drainage, shallow roots and poor plant health.” With a major championship coming up the following year, Woods had to fix the problem quickly.
“The first day we put this huge tractor and aeration machine on the back of the 18th green, everyone was totally suspicious since nothing like this was done at the time. I must admit, putting this heavy monstrosity on that fine turf frightened the life out of me.”
Since Woods' early experiment in using aeration equipment on fine turf, the idea has gained popularity at St. Andrews. The hallowed course continues its emphasis on aeration today — on fairways, greens and tees — and remains a trailblazer in conducting aeration all year long.
A season-by-season guide
As stated already, aeration is most useful when turf plants are actively growing and their demand for oxygen is high. Ironically, the warm season is the same timeframe when the grounds professional has to fight for access with the sports field user or golfer, because of the perception that aeration can cause a disruption of play.
In the spring, grounds professionals have their best opportunity to aggressively attack that agronomic evil of evils, compaction. Compaction causes much-needed air pockets within the soil to close, providing less room for oxygen and water to move through the root zone.
As a side note: A variety of aeration methods (solid-tine versus pulling cores, for example), often used in combination, can be used to combat this common hurdle. The temptation to over-simplify aeration practices should be avoided as there is no one perfect method for getting the job done; each practice has its own benefits and drawbacks.
- Deep tine
To eliminate hardpan conditions, a deep-tine method that shatters the soil or creates sideways fissures may be necessary; this approach, which creates a network of fairly large pores, is most useful in the spring. It should be repeated during the remainder of the year if the turf suffers a heavy degree of use.
Such aggressive aeration techniques will have few drawbacks in the spring, when deep-rooting grasses will benefit most and turf is most likely to heal quickly.
The slitting aeration technique (using triangular blades to create lots of short, narrow, close slits) is particularly useful in the spring (and fall) to help “connect” the surface of the soil with the underlying drainage layers, though it has shortcomings in its ability to solve compaction problems. Also, because of a slitting machine's light weight, it can be used during periods of heavy rainfall in spring and fall, when other types of aerification are not possible.
- Needle tines
In the summer, when most recreational fields are in highest demand, a different approach is required. Aerators equipped with “needle tines” (ranging in size from
inch to ⅝ inch) can make millions of tiny aeration channels in the soil profile to help reduce or relieve long-term compaction problems. These slim-profile tines permit grounds professionals to continue their aeration regimen while keeping the turf ready for immediate play. 3 / 16
What's more, since regular aeration treatments help provide passageways through which water can move, both drainage and irrigation are aided tremendously, eliminating the added time and costs associated with irrigation.
Another benefit is that increased root growth means that turf plants require less surface fertilization, as the longer root structures can draw on water and nutrients located deeper within the soil.
- Hollow core
The fall — along with spring — is traditionally one of the times to use hollow-tine aeration (pulling cores). One of the most common reasons for hollow-tine aeration during this season is conducting a soil-exchange program; that is, altering the soil profile by removing soil cores and replacing them with a suitable topdressing.
This approach permits pulling plugs ranging from 3 inches (for routine maintenance and thatch control) down to 10 inches (soil-replacement purposes).
Also useful in the fall is deep-tine aeration, down to a depth of 16 inches. Solid tines tend to penetrate native soils more effectively, breaking more easily through the hardpan layer and helping to shatter compaction, particularly if the turf has suffered heavy summer use.
Contrary to popular opinion, aeration may also be effectively employed in the winter, depending, of course, on whether the ground is frozen. This is an often-overlooked opportunity to tackle compaction problems; a near-deserted field is an inviting target for the grounds professional armed with the right aeration equipment.
Deep or solid tines are useful at this time to help reduce or eliminate pending conditions, helping improve the ability of the soil to irrigate itself.
Depending on the location of the field, the type of turf and the usage its put to, wintertime aeration can mean your turf is in playable condition — when most of your competitors' fields or courses won't be.
Philip Threadgold is executive vice president of Redexim Charterhouse (Pittston Township, Pa.). For more information, visit the Redexim Charterhouse web site at www.redexim.com.
PREMIER GOLF RESORT IS HOOKED ON AERATING YEAR-ROUND
Year-round aeration is a fact of life for many turf professionals. In the case of Tom Alex, director of Golf Course Maintenance at Grand Cypress Golf Club, part of the Grand Cypress Resort in Orlando, Florida, it's a practice he swears by.
A 48-hole, Jack Nicklaus-designed course, Grand Cypress was awarded the Golf Magazine Gold Medal as one of the finest golf resorts in America. The layout is impressive.
Several holes on the North, South and East nines create the overall effect of a Scottish glen. A recurring feature on the North and South fairways is a contained or “ledged” effect, where certain fairways are constructed on differing levels. This gives definition to the fairways and improves the players' sense of perspective. Par threes 8 and par fours 9 on the North/South courses are double greens. Grand Cypress' new course is a beauty as well. Inspired by the Old Course at St. Andrews, the new course challenges golfers with deep pot bunkers, double greens, a snaking burn and even the old stone bridge.
Clearly, these are grounds that require a certain level of upkeep and Alex takes his role at Grand Cypress very seriously.
Alex uses a Verti-Drain (model 7212) with a four-foot-wide span, which the course purchased in 1997. The unit gets so much use, that Grand Cypress is preparing to buy a second to keep up with its four-season aeration schedule.
According to Alex, the first major aerification of the year is typically in mid-May, a couple of weeks before a major June event that takes place each year on the course. “We use
Alex used to use coring tines each May and then fill in the resulting holes with sand, but now prefers to use the really narrow tines. “They are much gentler on our USGA greens and we get better transition zones; you can't tell where the bermuda ends and the Poa trivialis begins,” he said.
After the big event in June, they do a thorough aeration using the Verti-Drain's ½-inch coring tines, which penetrate down to 8 inches. August brings the summer's second aeration, again with the ½-inch coring tines.
In February and again in April it's time for Alex's crew to devote some time and attention to the two driving range tees, which are then solid tined to keep them in shape. Then in May, he uses coring tines on the ranges to permit maximum access by turf plant roots to air and water.
“The one aerator we have now covers 48 holes worth of greens, about 8 acres,” says Alex. “By using it at various times throughout the year, we've noticed an improvement in the health of our turf and we get much deeper rooting. We're really looking forward to adding another machine so we can intensify our aeration efforts even more.”
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