17 November 1995

Dutch beet tests show twist lifter works best

NO tail losses and 2.3% soil tare are being achieved in a Dutch research project which twists beet out of the ground, rather than forcing them out with shares.

Although no more than a feasibility study for now, the project shows root breakages can be eliminated and soil tares slashed, says Bert Vermeulen of the Dutch Institute for Agricultural Machinery Research.

The test rig locates a three-pronged "grab" into the shoulders of each beet and rotates to pull the beet out of the ground. A 5 bar (72psi) air stream then removes loose soil.

The main advantage is that soil is not smeared on to beet, making removal of loose dirt easier, explains Mr Vermeulen. "The wetter the soil the better it works.

"But to match current equipment in the field a machine would need to lift six beet a second. The electronics are quick enough to sense the beet, it is just the mechanics that we need to work on."

Co-worker Jos Swinkels of Eindhoven University is looking at automated beet recognition so individual beet-pulling robots can locate and lift beet. "It should not be difficult. We are dealing with a white-topped beet against a dark background," says Mr Vermeulen.

East German researchers have also considered the approach and proposed a system which uses multiple "grabbers" carried on a working belt to achieve the necessary work rate. &#42

This test rig shows low soil tares are possible by twisting beet out of the ground and blasting with air. Trials have achieved 2.3% soil tare.