Special Feature: Aeration and Turf

publication date: Apr 30, 2008

 | 

author/source: David Harris

Aeration of turf helps to provide the optimum growing environment, as well as improving drainage. After such a wet year, many groundsmen will be focused on getting water away from the surface, but iif our topsy turvy climate brings a drought similar to that of 2006, well aerated turf can also make best use of irrigation water. Planning turf renovation work such as aeration becomes increasingly difficult as the pressure to keep surfaces in play grows – cricket outfields being utilised for winter sports on municipal playing fields and few golf courses have any kind of closed season. A quick return to play has thus become a priority, but can this be achieved without compromising the effectiveness of the aeration?

Austin Jarrett of Turfmech suggests that it can, if the right equipment is chosen. “The Earthquake Tremor can loosen and aerate compacted soil to depths of 350mm whole causing minimal surface disturbance, due to the action and design of its rotating wedge-shaped knives which pass cleanly down through the surface before moving the rootzone and subsoil sideways to full working depth. As the knives reemergefrom ground, a full-width skid below the machine prevents the turf from lifting, ensuring that the surface is left level and virtually ready for use.”

Campey Turfcare’s sales director Simon Gumbrill agrees that choosing the appropriate system is key. “A recent addition to our range, the Carrier Turf uses angled discs with knives to slit the turf and penetrate the thatch layer, and due to its inbuilt pressure weight transfer system, can work well in hard conditions,” he explains. “This machine can be used frequently, and it incorporates a brush system to stand the sward up plus a roller to level the surface, so the pitch or fairway can be quickly back in play.”

Slitting can be a good choice for areas that are dry and compacted, particularly if they contain stones, agrees Ruston’s Engineering Co, which now complements its SGG Airone tractor mount range with a heavy duty attachment for its Grasshopper zero turn mower.

The pto-driven Aeravator uses solid forged steel tines which vibrate
as they penetrate the ground, fracturing the surrounding soil. With a
1.5m working width for generous output, the Aeravator can be quickly
switched with the mower deck.

Tine action is another important aspect, suggest Sisis, which has
introduced a new pedestrian aerator, the Arrow.

Aimed at contractors and others with a high workload on cricket
pitches and bowling greens, the Arrow uses components proven on the
tractor-mounted Aer-Aid Javelin.

“Tines enter and are withdrawn vertically ensuring minimal surface
disturbance, while variable spacing and a choice of tines allows
groundsmen to choose the optimum combination for the conditions,”
says the company’s Lynn Hilton.

Using the Verti-Drain’s parallel action, the tines can be set up to go in and come out straight for minimal disturbance, explains Charterhouse Turf Machinery’s Philip Treadgold. “The Verti-Drain also has adjustable heave to suit the conditions,” he says, “But tine selection is also crucial – in the summer when groundsmen want to aerate midseason they would need to use a mini tine of 5mm. It is better to use many smaller tines than fewer larger ones.”

Choosing the right tine for the ground conditions is key, suggests Joedy Ibbotson of John Deere. “We offer a wide range of tine types and we would recommend that greenkeepers use mini or needle tines in the playing season, aerating little and often for minimal surface disturbance and greatest effect,” he says. “Our star tine has also proved popular – it makes a cross-shaped hole which has a large surface area for effective aeration with little disruption.”

Ransomes Jacobsen comments that the design of its new Jacobsen Performaire deep aerator allows for rotational adjustment of the tine holders to preserve the correct angle of exit and entry into the turf.

The smaller Performaire 60 can be operated in close spacing mode on golf greens as well as its primary use on fairways and sports pitches.

By using alternative tine settings and tine lengths, working depths from 25 to 400mm can be selected – depth can also be altered from the tractor cab via a hydraulic top link.

Adding a new design to the well-proven Soil Reliever range, JSM Distribution says that the Super 54 and Super 70 are supported on a triple roller system to follow ground contours and ensure that the tine holders do not contact and damage the surface. Two piece tine heads allow varied tine patterns to be used, matching conditions and aeration requirements.

The angled frame of the established Soil Reliever models allows weight transfer to the top of the working area, increasing penetration which gives a smoother exit from the hole and a cleaner finish.

Core collection is a time consuming task and one that must be done soon after hollow coring to prevent the cores getting wet, points out Groundsman Industries’ Billy Warke. For a truly efficient clear up which also avoids the risk of damage to freshly cored greens by following collection machinery, Groundsman Industries offers the Flexblade Core Collector which attaches to its aerators, picking up cores as they are produced.

To allow greenkeepers to aerate in the most advantageous conditions of the peak growing season (which is also usually the peak playing season, making it imperative that the turf is left in a good enough condition for play) without the risk of surface lifting in shallow areas, Groundsman Industries now fits a segmented and independently suspended turf retainer system to its aerators. The system follows surface contours and allows even greens with delicate roots to be aerated.

But Billy Warke says that greenkeepers should not shy away from aeration: “We highly recommend needle tining all the greens in a three week cycle, covering six greens a week. This has huge benefits as it allows moisture and nutrients to seep down, encouraging the roots to grow downwards for much more durable grass. After a cut with a greens mower, the green can be back in play.”

Another approach is to use air injection, which provides effective aeration with minimal surface disturbance, suggests Terrain Aeration. Terralift machines introduce compressed air from 10 to 20bar, creating fissures down to 1m while a steel holding plate protects the surface area immediately around the probe. Slight surface movement indicates that the air blast has done its job, before the turf settles and can be brought back into play.

The HydroJect 3010 from Toro Products, meanwhile, uses pulses of highly pressurised water to alleviate compaction and flush harmful minerals through the compaction layer without disrupting the surface. It is said to increase percolation, improve gas exchange and enhance turf health. Toro suggests that the technique can be used to supplement aeration with its Pro-Core machines during the summer months or heavy play.

As aeration is a relatively costly operation, with high value equipment and often a significant power requirement, high workrates are expected. But these need to be achieved without compromising on quality.

Turfmech points out that the major constraint on performance is soil conditions, and that the optimum is a dryish soil when the knives can penetrate the surface comfortably and create cracks and fissures within the subsoil. But Austin Jarrett says: “There is no compromise between quality of work and output with the EarthQuake Tremor due to the smooth and progressive passage of the knives through the soil at all working depths.”

Wiedenmann suggests that its latest Terraspike GXi offers the best of both worlds by operating as a deep aerator, but at the speed of machines working at shallower depths.

UK Sales manager Chas Ayres says: “The GXi can cope with depths to 250mm but has the speed of shallower machines. It does away with the need to have two machines so is more cost effective.”

The GXi has dual belt drive with a balanced crank shaft plus a sprung-loaded headstock to soak up the stresses of working at high speed, protecting itself and the tractor as well as the operator. Tool-free adjustment of working depth and loosening angle along with just four greasing points minimise downtime.

Ryetec Equipment imports the Aero King range, designed to be simple to operate and robust enough for a long life in the hands of a contractor, but on the issue of speed, Mark Harrison states: “For maximum output you need a lighter machine which can get the tines in and out quickly. There is inevitably a compromise in terms of durability.” He comments that while a quick, shallow aeration operation can work well in the summer months, more intensive treatment is needed from time to time.

“For best results, deeper aeration should be considered at least every two years if not annually, otherwise the ground becomes compacted and rain water can’t disperse. But to work at 30cm deep, the operation has to be slower to avoid damage.” A contractors or local authority looking for time savings could find the Imants Rotoknife useful, suggests Simon Gumbrill of new importer Campey.

“The Imants Rotoknife gives effective surface aeration at any time of year and can be done on a regular basis,” he says. “Using a combination of discs mounted on rotors within its frame, the Rotoknife can work on anything from golf greens and tees to sports pitches to break down thatch and get rid of surface water.” Using the material removed during aeration as a topdressing, the Koro Recycling Dresser from Campey Turfcare offers considerable time savings during renovation – the surface is ready for overseeding, and the 1.3m RD1300 version even incorporates a brush to take the dressing into greens

Breaking through thatch

Combining aeration and scarification improves efficiency, minimises traffic on sensitive turf and boosts the effectiveness of the aeration process by removing thatch.

John Deere’s Aercore 800 can aerate or verticut or perform the two operations in tandem, and the company’s Joedy Ibbotson comments: “This minimises disruption to play and reduces passes, protecting the turf. It has proved a popular solution.”