8 March 2002

SUSTAINABLE FARMING: 2

WEED CONTROLSTRATEGIES

Consider weed management in a rotational context and exploit cultivations and crop rotation to reduce plant numbers in a more sustainable way, advises James Clarke of ADAS.

"Winter-sown rotations are here to stay," he says. "So leaving beneficial plant species while controlling those which reduce profitability will be a major challenge."

Understanding a weeds biology will help growers exploit its life cycle for control opportunities. "Knowing germination characteristics, how to break dormancy and seed decline rate are all essential.

"But control decisions also need to reflect implications on yield – both in current and future crops – crop quality, ease of harvest and the spread of pests and diseases."

Maximise the control of aggressive weeds before crop establishment, he says. "That gives more flexibility within a crop and may allow beneficial spring plant species to be encouraged into autumn dominated cropping."

Reducing herbicide use is not sustainable, says Mr Clarke. "So maximise what can be done outside the crop. Set-aside helps, but only to a restricted area and it wont be around forever."

He reminds growers that cultural control is non-selective in terms of biodiversity.

"The other key issue is that different plant species have different ecological requirements, which can be conflicting. Preserving one species may be at the expense of another."