Successful drilling under new Boss A brand new zero-till drill is helping a group of Essex heavy land farmers tackle black-grass and make time and diesel savings. David Williams saw it in action. The Boss was developed by Sly Europe Ltd; its name taken from the Australian drill manufacturer which developed the coulter. Now Sly Europe is manufacturing the coulter under licence in France, and a key to the successful design is a double-angled or undercut disc. Travelling at a slight angle to direction of travel, and slightly off vertical, it penetrates hard ground more easily than a vertical 90-degree disc and lifts soil to create a seed slot, reducing seed area compaction.

Preventing soil splash The angled disc creates a clean cut and handles trash well, but an issue with the angled disc design can be soil thrown sideways at higher speeds. The Boss coulter gets around this problem using a flexible rubber side wheel, gently holding the raised soil wedge section in position, and trapping any thrown soil. The rubber wheel is a similar diameter to the disc, and mounted slightly to

the rear but rubs against it preventing mud build up. On a sprung trailing arm mount, it moves over undulating ground and trash without affecting disc or seeding depth. Furrow closing is by an angled rubber-rimmed wheel at the rear. This runs along the raised wedge firming it down and sealing the slot while also controlling coulter depth. A second depth control option can be used for level or pre-cultivated ground. In this case the rubber wheel beside the disc can control coulter movement instead of the furrowclosing wheel, offering precision drill quality depth of seeding. A hydraulic-driven fan propels seed from carousel distributors to delivery tubes above the seedboots. Exhaust ports above each vertical coulter tube allow air to escape so that seed is gravity fed to the seedboots. This avoids seed bounce and uneven spacing that can result from delivery at high speed under pressure.

The seedboot is protected, running behind the angled disc which reduces soil contact and wear and helps prevent blocking.

Protected seedboots The seedboots are mounted in the ‘shadow’ of the angled disc, so avoid contact with soil. An advantage to the layout, suggests Sly, is that there is less risk of blockage through plugging and the drill can be run in the same direction as the previous year rather than needing to run at an angle, making it easier to adopt practises such as controlled traffic farming. Other advantages include accuracy of seed spacing and depth as the coulter travels smoothly through consistent ground conditions. Coulters are individually mounted on parallelogram frames, which prevents interference from neighbouring seeding units. Individual adjustment allows optimised seed placement and compensation for factors such as following tractor wheels. Coulter pressure up to 200kg/unit can be applied for effective penetration in hard, dry conditions.

“With neighbours, we farm approximately 400ha of mostly heavy land in Essex,” he explained. “We decided last year that we needed to find an effective zero-till drill to reduce establishment costs and help us tackle the increasing black-grass problem. We share machinery and labour and were all of the view that our previous strip-tillage drill should be replaced, but for our acreage it is a big investment for us, so we needed to be sure we made the right choice.” Cropping is typically two wheats, followed by winter barley but the oilseed rape break crop; grown in previous years, has been replaced by spring beans and vetch as flea beetle damage made it uneconomic. Soils are mainly heavy clay but there are areas of lighter land with high stone content too. The three farms are 160, 130 and 115 hectares and the loose co-operative farming arrangement has served the landowners well for several years. With black-grass an issue, recent cultivation priorities have been to move soil as little as possible although light post-harvest cultivations are carried out to encourage a weed chit prior to spraying, and subsoiling is carried out every four years. Strip tillage was adopted five years ago as part of a strategy to reduce soil movement for weed control, but offered little improvement in terms of weed populations on the heavy land.

Zero-till drills trialled Three zero-till drills were trialled during autumn 2016, and all proved satisfactory, successfully establishing winter crops. “There were aspects of each that we liked but none was ideal. Then we saw the Sly drill coulter and it seemed to answer all the issues,” explained Swithin. “The angled disc was a feature we really liked and we felt individual supply of hydraulic pressure to each coulter was an advantage, especially for our stony ground. The rubber side wheel to keep the disc clean and prevent soil being thrown was another aspect we continued over...

Making the right choice

The undercut or double-angle disc coulter design is well-proven in Australia.

Sly first displayed the new drill at Lamma earlier this year, and even then it was only able to show a sample coulter as no drills had been constructed. It was on the company’s stand when Swithin Waterer, a farmer from Essex, first heard about the new drill.

Farmers Guide saw the drill working on heavy clay soil in mid-October. Shallow post-harvest cultivation had been carried out to encourage a grass-chit leaving a loose surface, but the Boss coulters created minimal disturbance.

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