12 May 2000

Auto-guidance hoe cuts down pesticides use

A STEERAGE hoe with an automatic guidance system has cut herbicide use by 80% without affecting yields in winter wheat trials, and similar results have been achieved with the control system fitted to a sugar beet hoe.

The guidance system for inter-row hoeing was developed at Silsoe Research Institute near Bedford, and the first commercial version could be ready for use next year. It is designed to fit on a standard steerage hoe, and tests show that it can match or exceed the steering accuracy of most human operators.

The SRI research team, working with ADAS and the Arable Crops Research Institute, based the guidance system on computer analysis of pictures from a video camera mounted on the frame of the tractor-mounted hoe. The camera is a standard mass-produced unit producing black and white pictures which are scanned at the rate of 25 images a second using an ordinary Pentium processor-based computer.

Picture analysis identifies the position of the rows ahead of the hoe, and this provides data to the control system to adjust the steerage mechanism and keep the hoe blades correctly positioned between the rows.

Typical working speeds in winter wheat trials on a wide range of soils are 6km/hr, which was the limit for the type of hoe blades and not for the guidance system, says Nick Tillett, research scientist at the SRI. &#42

Silsoes hoe guidance system uses images produced by a camera mounted on a frame.