For the most effective long-term black-grass control, growers and their advisers need to apply the most effective control tools in five main areas - cultivations, sowing date, crop competition, herbicides and seeding prevention, recommends Dr Stephen Moss. “And they need to keep up their efforts for at least five years.
Dr Moss has long been an advocate of rotational ploughing to bury black-grass seeds below the zone from which they will germinate. Following this, he recommends several seasons of minimum tillage, strip tillage or direct drilling to deal with weed seeds near the surface and avoid bringing those ploughed-down back up while still viable.
The most appropriate cultivation strategies should, he insists, be integrated with delayed autumn drilling, spring cropping, grass ley breaks, fallowing or other rotational devices, variously designed to restrict the emergence of grassweeds by delaying the sowing date of the main wheat crop – for several years in extreme cases.
Everything possible should be done to maximise the competitive pressures placed on those weeds that do emerge, using techniques like the most competitive crops and varieties, higher seed rates and narrower rows, improved drainage and cover cropping.
In parallel to these strategies, glyphosate should be employed to eliminate weed seedlings ahead of planting; pre-em and post-em cereal herbicide programmes should be used with care and in ways which minimise resistance development; and effective use should be made of alterative herbicide modes of action in non-cereal crops.
Finally, Dr Moss advises hand-rogueing, patch spraying or complete crop destruction (or silaging for livestock or AD) as necessary before mid-June to stop any weeds that have escaped shedding seed; together with effective crop seed, equipment, straw and manure management to restrict weed seed spread.
“Just like dieting, it’s discipline that really counts,” he stressed. “At the end of the day, losing weight is all about consuming fewer calories and taking more exercise. The best approach depends on the individual. But persistence and commitment will always pay dividends.
“We know that even the most intractable and costly grassweed problems can be overcome with the right management, the necessary determination and sufficient time. However, one size most definitely does not fit all in grassweed control either. Individual growers and their advisers need to choose and use the tools that best suit their individual field and farm conditions. And, above all, they need the discipline to keep at it.”