Latest cultivator air seeder sees shortcomings go
By Peter Hill
GERMAN drill maker Horsch believes it has ironed out most of the shortcomings of wide-working cultivator air seeders with the development of its latest model.
Although this type of implement provided many growers with their first chance to go to wide drilling widths, the lack of depth control and high cost has seen them lose favour.
"One of the reasons users complained of poor seeding depth is that these machines have their hoppers on the main frame," says Michael Horsch. "You can imagine the effect of putting 2t of seed in the hopper and then progressively losing that weight in work."
The Horsch "CO" Airseeder gets round that by carrying its 2500-litre tank on the drawbar, and using flotation tyres at the front and back of the cultivator section to control working depth.
"Most implements of this type have wheels located within the centre of the frame. That is also a mistake, as any vertical movement is directly transmitted to the cultivator tines," claims Mr Horsch.
"But support the frame on a long wheelbase and field irregularities are ironed-out much more effectively."
The Horsch Airseeder comes in sizes from 6m to 12m (20ft to 40ft), with three rows of heavy duty "C" tines positioned to give 25cm (10in) row spacing. A straight-tine covering harrow follows with a staggered row of wheels, and softly-inflated tyres bring up the rear to consolidate the seed-bed along each row.
The frame is formed in 2m (6ft 6in) sections to follow ground contours, while pivoting balloon tyres at the front and the centre sections roller tyres support the implement during turns and transport.
Single unit used
Despite the width of the implement, only one Accord seed metering unit and distribution head is used which, Mr Horsch points out, makes a significant cost saving. This is achieved by pressurising the tank to the same level as the seed delivery tubes and allowing seed to fall into the airstream instead of creating a venturi.
"This way the air-flow can carry four times as much seed and we can use just one distribution system for drills up to 12m wide."
The one drawback of this arrangement is that only a small filling hatch can be provided in the tank, as it must remain airtight. That means it is practical only to fill by auger rather than from bags.
Seed is conveyed by the air system to the "C" tine coulters, which can be fitted with a choice of arrow-head sweep points to enable the implement to work on ploughed, disced, tined or untouched stubble.
The Horsch Airseeder is fitted with a pressurised seed hopper. This enables just one metering and distribution system to take seed to a full 12m (40ft) working width. Price of a 6m drill starts from about £31,000.