8 September 2001
Making best use of glyphosate

I have been really pleased with the results of glyphosate as a pre-harvest treatment. It has enabled me to get on and harvest a lot quicker. Are there any further benefits to demand its use specifically in a lo-till situation?

The key to successful weed management with Lo-till is the preparation of stale seedbeds. Creating a seedbed where grass weeds can germinate after harvest allows the use of a non-selective herbicide (glyphosate) to remove the weed prior to crop establishment.

This reduces the burden of weeds in the crop itself, thereby reducing the pressure on the selective herbicide used in the crop. This is particularly important for blackgrass management.

It is important to produce a consolidated “stale” seedbed, and to allow time for the weeds to germinate in order for the technique to be successful. Given adequate moisture, it may be possible to remove several flushes of grass weeds before drilling the crop itself.

It is better to use sequential applications of glyphosate to subsequent weed flushes of small weeds (1-2 leaves), than to wait and apply to large established, tillered weeds, which will require a higher dose of glyphosate, and leave a greater residue of dead plant matter which can compromise final seedbed preparation.

For annual weeds, cultivation may take place 6 hours after glyphosate application, though ideally, 24hours would be preferable. Where weather conditions are very catchy, paraquat is an alternative option (rainfast in 10 minutes, and cultivation after 4 hours possible.)

From:Iain Hamilton