However, there is zero tolerance of contamination of product by weeds and weed seeds, particularly for bagged salads, necessitating increased use of unsustainable hand-weeding. The majority of salad crops are hand-weeded once and sometimes twice at a cost of up to £1,000/ha, depending on weed levels. The task leads to back problems.
Brassica production is affected by weed contamination and losses of effective herbicides have increased the requirement for hand-weeding. A HortLink project of which HDC was a funder, FV 266, commissioned Tillett & Hague Technology, with its expertise in precision guidance technology, to come up with a suitable in-row and inter-row vision-guidance system to work with rotary hoe machinery.
A prototype was successfully tested commercially in 2007. Costings proved use of the machine for organics halves the need for hand-weeding, saving £150/ha to £250/ha depending on crop, and that the payback period for a machine would be between one year and 1.6 years. For conventional production, costs were also halved and there was a payback period of 1.6 years on the machinery.
Garford Farm Machinery has developed its Robocrop 2 rotary hoe vision-guided system for accurate, fast inter-row weed control. This utilises a digital video camera to view the crop ahead of the hoe toolbar. Comparing the data with a grid gives a best match scenario used to steer the hoe mechanically, reducing operator fatigue.