Research by the Grains Research and Development Corporation (GRDC) in New South Wales has identified that removing weeds shortly after they begin to emerge can preserve 50 to 75 millimetres of soil moisture.

Steve Simpfendorfer, senior plant pathologist with Industry and Investment NSW, says growers need to be aware that one control treatment may not be enough.

“A lot of growers will be out there now, spraying to conserve soil moisture,” Dr Simpfendorfer said.

“What they also need to do is make sure their paddocks are clean three weeks before sowing – which means monitoring and possibly even another herbicide application if there’s more rain and subsequent weed or volunteer germination between now and then.

“It’s a bit of extra time and cost, but will save money in the long term by reducing the need for in-crop treatments.”

Control of the green bridge gives crops a better chance to reach their potential by reducing the risk of pests and diseases surviving between seasons, while preserving valuable soil moisture and nutrients. Ultimately this will reduce the early pressure from a range of diseases in crops when they are considerably more susceptible.

A fact sheet put together by the GRDC outlines some of the issues created by allowing weeds and crop volunteers to grow on paddocks, roadsides and non-crop land..