AS WE move into spring following a very mild winter that will have encouraged weeds, keeping on top of these yield-robbers will be essential this year.

Apart from anything else, they also have the ability to soak up nutrients and with fertiliser prices as high as they have ever been, a bit of careful planning for their control will pay off.

With that in mind, agro-chemical giant, Bayer, has provided us with key elements to remember for spring stubble and cover crop management

Attentional to detail will be essential when using glyphosate ahead of spring crops this year. It is highly effective against a wide range of weeds and cover crop species, but success cannot be taken for granted.

Here are five tips for best control:

1. Ensure the application reaches the target

“If you don’t get Roundup (glyphosate) application right, there’s the risk of transplanting grass weeds into a crop where they are harder to control,” said Roger Bradbury, Bayer's market development manager for cereals.

Several factors can prevent the active reaching the target or reduce its efficacy in the field. These include physical losses through things like drift, run-off and bounce, and chemical losses caused by hard water, pH and light degradation.

On top of that are field factors, such as the target’s characteristics like shape, structure and size, and weather that all might affect performance. By the time the spray reaches its intended target the final dose could be very different to what it was when put into the sprayer.

2. Take care with overwintered stubbles

Spraying off overwintered stubbles with glyphosate is a job which can be, perhaps, inadvertently rushed in the race to get land prepared for drilling in the spring, added Mr Bradbury.

While grass weed control is the typical driver for stubble sprays, overwintered stubbles are likely to have a range of weed types, potentially also including more challenging broadleaved weeds, such as volunteer oilseed rape and cranesbill.

That all adds up to an application to bigger weeds, including potentially tillering grass weeds and a denser canopy or mat of green material to spray in more challenging conditions.

3. Be reasonable about forward speeds

A sensible forward speed for stubble management is 10-12 km/hr, Mr Bradbury suggested. “It’s not what growers will want to hear – they’ll want to be going 16 km/hr or faster, but it will increase the risk from drift, increase turbulence behind the cab and the boom, so you get uneven spray deposition in the field. It just increases the chances of a poor result.”

Forward speed also depends on the field surface and the quality of the boom suspension system. You need to go at a speed which allows you to maintain constant boom height.

4. Cover crop canopies need careful management

Cover crops tend to be bigger and bulkier compared to stubbles. Spray off needs to be at least four weeks ahead of drilling to give time for the biomass to degrade before planting into it.

Cover crops may need two applications, the first to eliminate the large, bulky species, the second to destroy grassweeds sheltered by the canopy or emerging in spring.

Mr Bradbury suggested that higher water volumes – around 150-200 l/ha and a medium/coarse spray quality to allow bigger droplets to penetrate the canopy for cover crop destruction

5. Keep stewardship in mind

Effective application is vital for the long-term sustainability of glyphosate. “There is no known resistance to glyphosate in the UK, but the risk is there. Application is important to make sure what is put in the tank arrives at the target to do the job,” he added.