KUHN APEX 6000 RC and 8000 RC: New Seed Drills for Direct Drilling

In direct drilling, the seeding unit works through both soil and crop residue. The disc must cut through the surface layer, the coulter must place the seed at the required depth, and the closing wheel must seal the furrow. The result depends on how well these operations work together: accurate metering alone cannot ensure uniform emergence if seeds end up at different depths or alongside straw pushed into the furrow.

KUHN has focused on this sequence in its new APEX range. These trailed pneumatic seed drills feature ISOFLEX seeding units with parallelogram linkages and hydraulic downforce adjustment, together with the OPTISEED metering system. The machines are designed for direct drilling and sowing into minimally cultivated soil.

Two Models Built on the Same Design Principles

At launch, the range comprises the APEX 6000 RC, with a working width of 6 m, and the 8 m APEX 8000 RC. Both models have a pressurised main hopper with two compartments and a total capacity of 5,600 litres. The stated operating speed is up to 12 km/h.

The choice of working width allows operators to select a machine according to their cropping area, field layout and available tractors. Both models use the same core technologies: the wider APEX follows the same principles of furrow formation and product metering.

KUHN APEX Specification Summary

The operating speed is stated by the manufacturer. The appropriate speed in the field depends on soil conditions, crop residue and the quality of work achieved by the seeding units. Downforce is expressed in kilogram-force: KUHN’s “250 kg” designation refers to the force applied to each unit, rather than its mass.

The range offers row spacings of 16.7 and 20 cm. Row spacing determines plant distribution and should suit the farm’s crop production system.

ISOFLEX: Depth Control Starts Beside the Disc

The ISOFLEX seeding unit uses a single-disc coulter assembly with a narrow attack angle. Its narrow working component confines soil disturbance to the seeding row. This geometry supports the purpose of direct drilling: to create a seed furrow while leaving a substantial proportion of the field surface covered by plant material.

A side-mounted depth-control wheel sits beside the opening disc. It also holds crop residue against the ground, helping the disc cut through it. This is intended to reduce the risk of uncut straw being pushed into the seed furrow, where it can impair direct seed-to-soil contact.

The seeding unit is mounted on a parallelogram linkage with 330 mm of travel. The linkage allows the unit to move vertically over uneven ground while maintaining the coulter’s working angle. Seeding depth is adjusted manually on each unit using a T-shaped lever.

Downforce is set from the cab through the hydraulic system and can reach 250 kgf per seeding unit. The system maintains the selected force as the units move. Depth and downforce adjustment serve different purposes: the former sets the seed’s position relative to the surface, while the latter helps the working component maintain that position against soil resistance.

Guiding the Seed and Closing the Furrow

After metering, seed travels through the pneumatic system to the coulter. In the APEX design, it is delivered beneath the opening disc’s axis and guided towards the bottom of the furrow. According to KUHN, this trajectory limits seed bounce.

A large-diameter, notched closing wheel completes the unit’s work. Its working angle can be adjusted to change its action on the soil when closing the furrow. This adjustment matters because soil condition affects how readily the soil crumbles, consolidates and closes the seed slot.

The machine has 460 mm of front clearance. This space accommodates plant material when drilling through crop residue and cover crops. Actual residue flow also depends on the amount, moisture content and distribution of material in the field.

OPTISEED and Multiple Sowing Configurations

The OPTISEED system uses cassette-type metering units designed for a range of seeds and fertilisers. The units are accessible from ground level, and the cassettes can be changed without tools. This simplifies switching between crops and servicing the metering system.

The two-compartment hopper, four distribution heads and two seeding lines support several product placement configurations. APEX can sow two products in alternate rows, deliver two products as a mixture, or establish a crop at wider row spacing. An optional additional hopper accommodates a third product.

This arrangement is suitable for sowing with localised fertiliser application, intercropping and establishing cover crops. The specific placement configuration should be selected according to the agronomic compatibility of the components and the requirements for fertiliser application.

Half-width shut-off is standard. It helps reduce overlaps in wedge-shaped areas and along field boundaries. A side platform provides access for filling, while an integrated emptying system allows remaining material to be discharged from the hopper into a bulk bag.

KUHN Seed Drill Parts from Bas-Agro

Bas-Agro LLC manufactures aftermarket replacement parts for agricultural machinery. Parts for KUHN seed drills can be selected and purchased through the KUHN seed drill parts section. When choosing a part, the machine model, assembly configuration and part number must be taken into account. Compatibility with the new APEX range should be checked separately: machines sharing the same brand do not necessarily use interchangeable working components.

The APEX range received recognition from the EIMA 2026 jury in the Technical Evolution category. The main technical interest lies in the seeding unit’s design: the side wheel controls depth beside the disc, the parallelogram follows ground contours, the hydraulic system maintains downforce, and the adjustable closing wheel completes the seed row. The performance of these components together under specific soil conditions determines the quality of seed placement.