Article taken from the Agronomist & Arable Farmer
Chemical options for black-grass control are disappearing, so cultural control, including stale seedbeds, is essential. Stale seedbeds are a crucial weapon in the fight against all grass weeds, but in particular black-grass. In order to maximise their effectiveness, it is essential that they are managed correctly.
Dormancy in black-grass varies greatly from year to year, largely due to environmental conditions during seed production. This makes the use of stale seedbeds prior to crop establishment highly unpredictable and varied between years. As part of its overall national black-grass trials programme, on a second wheat site near Doncaster, Agrovista is looking to improve germination of grass weeds in stale seedbeds by manipulating seed dormancy, in a bid to improve the reliability of stale seedbeds. This would allow non-selective controls to be used to eradicate both herbicide-susceptible and herbicide-resistant weeds, reducing the pressure on a limited and dwindling number of in-crop herbicides.
With black-grass dormancy likely to be low this year, given warm and dry conditions during the June maturation period, stale seedbeds could work extremely well if done correctly and any grower with high levels of black-grass should aim to get as many stale seedbeds in as possible before drilling.
Cultivation Depth
While black-grass will naturally germinate in stubbles after harvest given adequate soil moisture, emergence of the first and subsequent flushes can be greatly improved by shallow cultivations and good soil consolidation to improve soil-to-seed contact. Tight control over cultivation depth followed by good seedbed consolidation is vital, whatever equipment is used and whatever the soil type.
At the Doncaster site Agrovista is comparing a range of machines for creating the stale seedbeds, including the Claydon straw rake, Vaderstad Topdown and Amazone Catros.
It is often the case that no matter how many stale seedbeds are carried out, the best flush of black-grass is when the field is drilled, so Agrovista is looking at methods to replicate this level of soil disturbance, while still conserving moisture.
In most situations, effective management centres on shallow cultivations and good seedbed consolidation. By minimising cultivation depth throughout the autumn growers will not disturb seeds deeper down in the soil profile where black-grass seed will naturally decay at around 70% a year.
Moving Soil
The allelopathic effect of black-grass roots exudates, suppressing the germination of other weed seeds, including its own, is well documents. The build-up of black-grass root exudates in the soil can therefore discourage further black-grass germination, so once a good flush of black-grass has germinated it must be controlled quickly with a non-selective glyphosate-based herbicide. This should be done prior to the three-leaf stage, encouraging further black-grass germination, which can be helped by further raking and rolling. Moving soil for subsequent stale seedbeds as soon as the first flush of black-grass has been sprayed off also prevents the build-up of root exudates that could stop further black-grass seeds germinating.
In addition to different cultivations, Agrovista is also looking at novel methods to improve the efficacy of stale seedbeds. Stubble burning, banned in the UK in 1993, was practice that improved grassweed control largely due to the breaking of seed dormancy resulting in weeds germinating before crop planting. Looking to replicate these benefits, in conjunction with Thermoweed, Agrovista is evaluating the technique of infra-red controlled burning.
This involves the killing of weeds and weed seeds with intense infra-red heat produced by a tractor-mounted fuel-burning device which relies on propane gas burners. This intense heat is also likely to break dormancy in more black-grass seeds, improving the stale seedbed flush. Recent evidence has also identified seaweed extracts that very successfully break dormancy in black-grass seeds under laboratory and glasshouse conditions. These products will also be evaluated on the site under field conditions.
Stale seedbeds also have a big role to play with other grassweeds, and similar techniques to black-grass should be employed for ryegrass and sterile brome. For meadow, rye and soft brome however, for maximum germination, they need an ‘after ripening’ period, so stubbles should be left untouched for several weeks following harvest before stale seedbed cultivations are carried out. Perenial weeds such as couch are often best treated with glyphosate before any cultivation.
Top Tips to Improve Reliability of Stale Seedbeds for Black-grass Control
Chemical options for black-grass control are disappearing, so cultural control, including stale seedbeds, is essential. Stale seedbeds are a crucial weapon in the fight against all grass weeds, but in particular black-grass. In order to maximise their effectiveness, it is essential that they are managed correctly.
Dormancy in black-grass varies greatly from year to year, largely due to environmental conditions during seed production. This makes the use of stale seedbeds prior to crop establishment highly unpredictable and varied between years. As part of its overall national black-grass trials programme, on a second wheat site near Doncaster, Agrovista is looking to improve germination of grass weeds in stale seedbeds by manipulating seed dormancy, in a bid to improve the reliability of stale seedbeds. This would allow non-selective controls to be used to eradicate both herbicide-susceptible and herbicide-resistant weeds, reducing the pressure on a limited and dwindling number of in-crop herbicides.
With black-grass dormancy likely to be low this year, given warm and dry conditions during the June maturation period, stale seedbeds could work extremely well if done correctly and any grower with high levels of black-grass should aim to get as many stale seedbeds in as possible before drilling.
Cultivation Depth
While black-grass will naturally germinate in stubbles after harvest given adequate soil moisture, emergence of the first and subsequent flushes can be greatly improved by shallow cultivations and good soil consolidation to improve soil-to-seed contact. Tight control over cultivation depth followed by good seedbed consolidation is vital, whatever equipment is used and whatever the soil type.
At the Doncaster site Agrovista is comparing a range of machines for creating the stale seedbeds, including the Claydon straw rake, Vaderstad Topdown and Amazone Catros.
It is often the case that no matter how many stale seedbeds are carried out, the best flush of black-grass is when the field is drilled, so Agrovista is looking at methods to replicate this level of soil disturbance, while still conserving moisture.
In most situations, effective management centres on shallow cultivations and good seedbed consolidation. By minimising cultivation depth throughout the autumn growers will not disturb seeds deeper down in the soil profile where black-grass seed will naturally decay at around 70% a year.
Moving Soil
The allelopathic effect of black-grass roots exudates, suppressing the germination of other weed seeds, including its own, is well documents. The build-up of black-grass root exudates in the soil can therefore discourage further black-grass germination, so once a good flush of black-grass has germinated it must be controlled quickly with a non-selective glyphosate-based herbicide. This should be done prior to the three-leaf stage, encouraging further black-grass germination, which can be helped by further raking and rolling. Moving soil for subsequent stale seedbeds as soon as the first flush of black-grass has been sprayed off also prevents the build-up of root exudates that could stop further black-grass seeds germinating.
In addition to different cultivations, Agrovista is also looking at novel methods to improve the efficacy of stale seedbeds. Stubble burning, banned in the UK in 1993, was practice that improved grassweed control largely due to the breaking of seed dormancy resulting in weeds germinating before crop planting. Looking to replicate these benefits, in conjunction with Thermoweed, Agrovista is evaluating the technique of infra-red controlled burning.
This involves the killing of weeds and weed seeds with intense infra-red heat produced by a tractor-mounted fuel-burning device which relies on propane gas burners. This intense heat is also likely to break dormancy in more black-grass seeds, improving the stale seedbed flush. Recent evidence has also identified seaweed extracts that very successfully break dormancy in black-grass seeds under laboratory and glasshouse conditions. These products will also be evaluated on the site under field conditions.
Stale seedbeds also have a big role to play with other grassweeds, and similar techniques to black-grass should be employed for ryegrass and sterile brome. For meadow, rye and soft brome however, for maximum germination, they need an ‘after ripening’ period, so stubbles should be left untouched for several weeks following harvest before stale seedbed cultivations are carried out. Perenial weeds such as couch are often best treated with glyphosate before any cultivation.
Top Tips to Improve Reliability of Stale Seedbeds for Black-grass Control
Keep cultivations shallow- maximum depth of 500mm.
Ensure good consolidation – roll after cultivations for improved seed to soil contact.
Remove black-grass with glyphosate before black-grass at three-leaf stage.
Encourage further strikes with raking / shallow cultivations followed by rolling.