15 May 1998

Patch sprays pay off

PATCH spraying herbicides in cereals has proved its worth in trials, cutting spray costs by £5-15/ha (£2-6/acre). Field studies of commercial equipment are now underway.

The results come from a four-year study jointly funded by the HGCA through its grower levy and MAFF.

Weeds mapped

By using computers and satellite positioning technology weeds were mapped and herbicide rates adjusted on the move accordingly.

The work mapped blackgrass and barren brome in mid-summer and wild-oats and couch just before harvest. The resulting digital maps were used to control spray applications in the autumn using Silsoe Research Institutes prototype patch sprayer.

Herbicide savings should cover equipment costs, provided mapping is only carried out every three years, the HGCA says. Current work suggests blackgrass patches remain stable between years.

A commercial patch sprayer is now being developed by Micron Sprayers and SRI. Such equipment could help a lot if herbicides face more environmental restrictions, says the HGCA.