28 June 2002

Flames benefit specialist crop

By Peter Grimshaw

WEED control without herbicides is difficult at the best of times, so keeping weeds at bay when harvesting a specialist crop five or six times a year requires something a little special.

For Valley Produce of Springals Farm, near Reading, weed burning before each regrowth of its commercial mint crops is the solution. The technique has been so successful it may now be extended to some of the businesss other 240ha (600 acres) of herb and salad crops.

Best control had traditionally been achieved with a single application of lenacil (Venzar). But the company is keen to reduce chemical use in short-cycle crops.

There is also a fear that more chemical approvals will be lost for specialist crops. "We decided to start looking at alternative weed-control methods as a pre-emptive move, in case the regulations are lost," says manager Colin Hill.

Consumer concern over chemicals and demand from leading retailers for improved traceability also influenced the decision.

After talking to other growers, an £8500 HOAF Twinsprite gas burner was bought in March and set up to span the mint beds.

Although the Calor Gas used is relatively cheap, about £40/ha (£16/acre), operating cost looks like being more than herbicide, mainly due to the slow workrate and repeated gas cost.

No effect on the mints flavour or quality is expected. First indications are that crop recovery is delayed by about a week.

Unlike the single lenacil herbicide application, which allowed a steady ingress of weeds during the season, burning promises weed and fungal spore control throughout the season.

Valley Produce farm technician Paul Stephens says the main benefits are easy use and refuelling, and more effective weed control than mechanical weeding. "Initially it was just the solution to our mint problems, but we can see a number of other uses for it and are definitely planning to use it more next year."

The Twinsprite can also work down individual rows, burners operating independently. &#42