30 October 2001
Should I plough in my heavy blackgrass burden?
I am a farmer in Kent. My land is a mixture of light land on one side of the farm, and heavy clay on the other. Last year, with the wet autumn, the sprayer would not go near the field. As a result, weeds, especially blackgrass, have really got going.
How can I get rid of these weeds without using too many sprays, and should I definitely plough, for at least this year (at the moment the field is in untouched stubble).
If you are just starting with lo-till then I would plough, on the understanding that what you are about to bury is less than what you could potentially bring up.
If you are already in lo-till I would plough as well, BUT with hindsight I would advise you do things differently in future as a routine.
If you have a high seed return in any year then you need to adopt a strategy to lower the seed bank at every opportunity.
From what you have said I am assuming that this field is going into a spring crop (stubble untouched).
I would look to cultivate as soon as possible after harvest to allow germination of these weeds and spray them off repeatedly with low rates of glyphosate (which is very cheap now) to lower the seed bank.
This would then allow you to plant your spring crop confident that you have reduced the weed problem.
My advice would be to avoid lo-till if you have a grass weed problem unless you are prepared to work at the system.
Conventional tillage will keep the lid on the problem, but in my opinion will never get rid of it. But a well managed min-till system, using effective stale seed beds, rotating cereals with broadleaved crops and the occasional spring sown crop, can go a long way to getting the problem back to manageable levels again.
It takes time and patience. Further information on the subject is available from the Soil Management Initiative (SMI).
Ask for A Guide to Managing Crop Establishment. It covers weed control and gives detailed case studies of farms where lo-till has been used to overcome grass weed problems.
You could also try Revised Guidelines for Preventing and Managing Herbicide-Resistant Grass Weeds on the Home Grown Cereals Authority website.
Spray off with glyphosate & plough. Its too late to start min-tilling and waiting for a greening up.