Bayer Crop Science
@bayer4cropsukPublished on 18th September 2020
Weed Management
Roundup Use In Spring
Spring cropping provides a huge window of opportunity to control difficult weeds such as black-grass and Italian ryegrass before sowing the crop. But attention to detail is all important to avoid infestations in the crop, especially because there are limited selective herbicide options available for spring crops.
Cultivation is one option, but it is unlikely to achieve 100% weed control. Furthermore, ploughing and cultivation need to be carried out when soil and weather conditions are correct in order to avoid over-cultivation and to protect the soil structure while minimising soil moisture loss. An alternative is to control emerged weeds with Roundup to ensure a clean start.
Overwintered Stubbles
Uncultivated land can harbour plants with large variations in size which must be treated with the appropriate dose of Roundup.
Stale Seedbeds
The technique of creating stale seedbeds is a vital tool in out-of-crop control of difficult annual grasses. Stale seedbeds are an integral part of reduced tillage systems.
To encourage the maximum amount of weed germination before drilling and to create a stale seedbed prior to planting spring crops:
Create a medium quality, 5cm clod size, seedbed using a tined cultivator on light soils and heavy disc harrows on medium/heavy soil
Work top down to conserve moisture. Consolidate with a disc ring press, Cambridge Roll or double disc ring press, depending on soil type
Wait for weed germination, 10-20 days
Spray weeds with Roundup
Drill as early as 6 - 48 hours later depending on the formulation used
The use of stale seedbeds in conjunction with reduced tillage techniques means that savings in time, labour and cost can be achieved compared to conventional ploughing techniques. Yield increases can be common following the reduced tillage, stale seedbed technique.
Caution: Carrying out reduced tillage techniques without the use of stale seedbeds can result in an increase in annual weed seeds and problems for weed control throughout the rotation.
Post plant, pre-emergence
Where spring crops are established under time constraints, there are often situations where the crop is drilled, but some green material is left on the surface. This can grow away again and present a real challenge for post-emergence herbicides.
All Roundup formulations have recommendations to spray before crop emergence. This allows residual herbicides to be tank-mixed with Roundup in order to combine residual weed control programmes with the removal of any weeds surviving the cultivation and drilling operations.
Modern Roundup formulations have been developed with improved physical properties, leading to increasingly good compatibility with other herbicides, easier use and quicker cleaning of packaging and equipment.
Caution: Always check tank-mix sheets and the product label for post-planting Roundup applications.
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