Make Space For Weed Control in Cereal Drilling Rush

September, 2003 - Don't rush ahead with cereal drilling as soon as you get sufficient soil moisture without making space for effective out-of-crop grass weed control this autumn, advises Monsanto technical specialist, Manda Sansom. Otherwise you could easily lose all the benefits of earlier drilling in additional herbicide costs or seriously compromised yields.

In particular, she stresses this season's variable soil moisture levels and uncertainty put the onus on a flexible approach to seedbed preparation and drilling to take maximum advantage of every pre-planting and pre-emergence spraying opportunity.

"Warm soils and minimal black-grass dormancy mean we'll see a rapid flush of weed seed germination following rain," she explained. "Large numbers of annual grass weed seedlings will come through in a few days. To avoid the bulk emerging into the newly sown crop it will pay to hold-off on drilling for a short while to hit them with a timely glyphosate spray. This will do much to take the pressure off pre-em and post-em programmes heavily dependent on both weather and seedbed conditions.

"To minimise the delay as well as the risk of failure in catchy conditions, use one of the modern Roundup formulations. Rainfast in as little as an hour and allowing cultivations just six hours after application, they are ideal for high pressure autumn systems with limited spraying and drilling windows.

"Alternatively, if you really can't wait why not go in with Roundup pre-em - alone or tank-mixed with a residual herbicide," suggested Mrs Sansom. "As well as being approved for post-planting use, modern Roundups are compatible with a wide range of commonly used agrochemicals. So they can be used very effectively to knock-out rapidly emerging weed seedlings or those transplanted by cultivations - weeds which often escape residuals in less-than-ideal seedbeds."

Mrs Sansom stresses that failing to make space for adequate grass weed control outside the growing crop is likely to be a recipe for disaster in a season in which seedbed weed populations are set to be so high; especially so with ever-increasing resistance problems.

"Tackling weeds effectively with a combination of cultivations and Roundup in the autumn has allowed savings of up to £30/ha to be made in in-crop herbicide bills," she reported. "It has also prevented yield losses of as much as 1t/ha from early season weed competition. And it is playing an increasingly vital role in tackling resistant weed populations.