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Low disturbance tilth

Shaun Groom is pictured with the Duplex Seed-equipped Aerosem at the Pottinger factory.

single hydraulic ram, which operates across the bank of discs. This ensures equal pressure across all the coulters to maintain uniform working and seeding depth.

Companion crop option The Aerosem’s hopper can be divided to allow fertiliser application during drilling and for maize the two outer sections are used for seed while the centre section holds fertiliser. With IDS, the operator can adjust fertiliser placement so that it is ideally positioned in rows next to the maize seed, but the company has also been involved in companion cropping trials in the UK last year to help tackle soil erosion which can be an issue for maize growers. “The Aerosem IDS allowed planting of companion crops in rows away from the maize seed to cover the bare ground between maize rows without smothering or competing with the crop,” explained Pottinger UK sales manager Shaun Groom. “There was no negative effect on maize yield despite fears the companion crop might take nutrients and the lack of fertiliser didn’t adversely affect yield either, and although further research into this is progressing, it is believed

nitrogen fixing might have been an additional benefit of the companion crops. At harvest the soil supported harvesting trailers better than bare ground. For stock farmers the ground lends itself to grazing immediately after maize harvest while for those producing maize for AD plants, it is easier to get on the field to inject digestate.” Pottinger expects the new Duplex seeding option to prove popular allowing the Aerosem to drill maize solo, with fertiliser or with companion crops, and the drill can be converted from straight cereal drilling to Duplex maize in under one hour. With alternative Suffolk coulters available as well as cultivation options to suit the ground conditions and weather, the drill is extremely versatile. A 3m Aerosem equipped with double-disc coulters, and the Duplex seeding units costs just £39,000, of which the Duplex option accounts for £8,000 and Shaun said the system is aimed at mixed farming operations for which maize is a significant part of the cropping. Although the current range extends only to 4m, bigger folding models are in development and will increase options for larger growers.

The Terrasem has proved very successful providing great seeding performance in a wide range of conditions but a new Wave Disc version promises minimal soil movement during drilling, within a conventional cultivations regime.

A new version of the Terrasem drill allows growers to take advantage of low disturbance crop establishment within a traditional cultivations regime, reducing the power requirement, minimising opportunity for weed growth and keeping available moisture where needed in the seeding area. The new Wave Disc Terrasem is an alternative to the standard model, which has aggressive angled concave-profile leading cultivation discs to move soil across the entire drill width. Working widths are 3–9m, with or without fertiliser and in its standard format 510mm concave discs provide aggressive cultivation and are suitable for all soil types. A key feature is a bank of pneumatic packer wheels across the width, in line with the coulters ensuring land is firmed evenly after the cultivation discs have passed and fertiliser has been applied, but ahead of the drilling coulters.

Demand growing Demand is growing for drills capable of establishing crops in a low disturbance regime, but flat discs can create smearing of heavy or wet soils affecting root penetration, explained Pottinger. The Wave Discs get around this problem with their fluted profile, and are designed for shallow operation, with each front mounted disc lining up with each seeding coulter at the rear, preparing only a band of soil for seeding, and minimising disturbance elsewhere. Disc and coulter spacing is either 12.5cm or 16.7cm and matched to the consolidation wheels so all seeding units plant into identical soil conditions. For high-yield locations 12.5cm is recommended while for damper, heavy soils with higher clay content the wider spacing is advised. Three coulters operate behind each tyre at 12.5cm row spacings and, when applying fertiliser, one row is applied between two rows of seed and placed in the uncultivated zone. Seed coulters are in two rows at the rear and staggered, to provide space for soil and trash flow between each unit. Equal length mounting arms ensure equal operating pressure and seeding depth across the width and the folding wing sections are capable of flexing down as well as upward, for optimal ground contour following. Separate depth control for the cultivation discs behind the tractor wheels allows deeper operation to remove wheelings. Development of the Wave

The 510mm Wave Discs have a fluted profile creating a 45mm band of loosened soil.

Disc started in 2015 and Pottinger explained the design objectives for the new tillage system; 1. Low disturbance during dry seasons would help preserve moisture for plant growth. 2. In wet areas the soil is moved very little for minimum smearing. 3. Low disturbance reduces opportunities for growth of weeds resistant to herbicide applications. 4. Minimal disturbance allows earlier operation in the season while soil is still very wet. 5. Reduced soil erosion risk.

Tilled area The Wave Discs create bands of tilled soil just 45mm wide, leaving the area between the discs untouched. Where 12.5cm spacing is used; 35 per cent of the width is touched by the discs and for 16.7cm spacing the area reduces to just 25 per cent. However, where leading discs create slots for following coulters on most drills, a turn in work means the seeding units can run out of the prepared area; but the 45mm tilled width from the Wave Disc means the seed coulters remain within the tilled bands. Minimising soil movement during drilling helps reduce smearing and sealing of the seed slot edges. Because the Wave Disc doesn’t penetrate the lower soil structure or move soil to the sides, conditions for the plant roots to penetrate are optimised. Pottinger claims that in heavy, wet soils the disc action allows drilling up to a day earlier than with conventional drills.

Black-grass germination Where grass weeds are a problem, the low-disturbance action reduces germination triggering and suppresses vernalisation. For autumn drilling the Wave Disc is ideal to establish crops into stale seedbeds, minimising weed seed disturbance, but creating ideal conditions for crop germination and growth. Fewer cavities and clods within the cultivated area means conditions for weeds to germinate are poor continued over...

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Farmers Guide May 2017  
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