7 June 2002

SPRAY TIPS: 8

SPRAYINGDRILL

Drilling can make the sprayer operators job easy, difficult or nigh impossible. Planning is the name of the game, especially if the operator doesnt do the drilling.

Efficient overall spray cover depends on matching drilling widths accurately to the boom spray cover. "Its very important to drill or plant accurately between each pass and the wider the boom the more important it is," says Syngenta application specialist Tom Robinson.

Minimise risk by drilling cereals slightly wide of the headland, because the drill widths tend to close up to less than the boom width, which could lead to the sprayer clipping the hedge, he advises. Conversely, bed plantings tend to move apart, resulting in a swath width wider than the sprayer, therefore risking unsprayed crop, a potential disaster with potato blight.

Start drill plans with the need for a LERAP near vulnerable water. Margins can be put down to set-aside, Countryside Stewardship or other forms of barrier strip. But they must match the combination of drill and boom width, along with the boom isolation possibilities and be related to the star rating of the nozzles.

If the products to be used are effective with a three-star nozzle spray quality this simplifies the planning and limits barrier size.

Anything that encourages deep wheelings should be avoided. They can make it very difficult to keep a constant boom height.

Where possible, crops are best drilled or planted across the contour to minimise soil wash down the tractor wheeling.

The tramline setting on the drill is also important. It needs to match the tyre sizes likely to be used when spraying. "Too much damage along the wheelings may give secondary tillers on cereals and green grains at harvest," says Mr Robinson.