Article taken from Crop Production magazine
Article written by Tom Allen-StevensFor the growers’ who’ve gathered for the Syngenta Driving Up Oilseed Rape Yields meeting, the first question to address is whether they’ll be growing the crop at all this autumn. With rapeseed prices hovering around £250/t and the challenges and costs of getting a crop established in the first place, the UK rapeseed area for 2016 harvest is set to dip.
But these growers appear unfazed. “We’ve 300ha of OSR and we’re carrying on – I’m not into knee jerk reactions,” says John Haynes farming on the Essex/Herts border. His crop was badly hit by cabbage stem flea beetle (CSFB) last year and he’s determined to do all he can to ensure the crop pulls away from the pest this autumn.
“We’ll definitely be drilling the crop, but won’t be making too many decisions about how and when until we know what conditions are like – having that moisture there is absolutely crucial.” The OSR area will also stay at roughly the same level for Lincs grower Andrew Ward. “It’s an important part of the rotation,” he says. A long time grower of HOLL varieties on wide row spacing’s, it’s the winter wheat area that’s reduced for him, in favour of spring barely, as part of a plan to eliminate blackgrass.
“We’re getting 95% establishment and that’s key to success with OSR. Minimum surface disturbance and good consolidation bring the moisture up to the seed and thus helps it get away” he says.
Pulses have come into the rotation for Derby grower James Chamberlain, to fit in with greening requirements for the Basic Placement Scheme. But his OSR area on relatively light soils will be staying roughly the same.
“It was the driest September for 100 years and land we took on required remedial cultivations, so wasn’t drilled until 9 Sept. In a normal year, we’d be happy with that, but the dry conditions meant it then suffered a staggered emergence. This put us on the back foot from the start,” he recalls.
“The difficulty with OSR is that there’s such a heavy cost before the crop has even emerged. But the best way to reduce the cost of production is to increase yields, which means doing everything possible through the autumn and spring to achieve that output. SO, whatever the crop needs it will get,”
Working out what that is through the crucial establishment phase is the aim of the meeting – the growers are part of a group that comes together regularly over the year to consider how new and different agronomy techniques can enhance field performance, with a view to achieving an OSRF crop that has the potential to yield more and yield more consistently. Cultivations expert Phillip Wright Resolutions has joined the group to discuss how to keep the soil in good heart.
“When I dig holes and inspect fields around the UK, there are three things I assess which are crucial for getting results from the soil,” he says. “The most important is drainage – a soil that quickly returns to field capacity is what’s best for the biology and the roots. The other two of equal importance are organic matter and weight of the equipment used,”
Drainage is an area that’s seen considerable underinvestment since grant-funding ceased over 30 years ago, he maintains. “It costs around £2400/ha, which includes permeable backfill. That may be a lot more than the £70/ha cost of the 1970s, but if you relate that to land value, the cost has actually gone down in relative terms.”
But where the problem areas are addressed with a proper drainage scheme, you can expect a payback of less than ten years from increased yields, says Phillip Wright. “The backfill is where a lot of the money goes – make sure the contractor uses enough of it and that it’s the right quality. Power station clinker should be avoided as it degrades over time.” John Haynes has around 300ha to drain and has just brought a new trencher. “The drainage work will pay for itself over five years with improvement in soil structure it’ll bring, especially for the OSR. If you haven’t got a drainage system then your yield potential is fundamentally limited,” he points out.
“Axle weight and ground pressure are both important when it comes to the size of equipment you use,” continues Phillip Wright.
“Ideally a soil should be 50% solid material and the rest pores for air and water. As soon as you squeeze that, you reduce the porosity so it becomes flooded – when all the pores are full of water – much faster.” Get as low as 20% porosity and that severely limits yield as roots need the air to space to grow and develop, he explains. “It would be like growing plant roots in a plastic bag.”
The difficulty is that agricultural equipment is getting bigger, and that’s literally putting more pressure on the soil. “You need 50-55kg/hp for a primary operation tractor, so if your main cultivation tractor is 400-500hp, that’s 20-130t. Pulling that weight over soils, particularly if they’re damp, can do a lot of damage. Land is most vulnerable in the spring, which is why these wide rotations could be a worry.”
Surface ground pressure can be mitigated through lower ground pressure tyres, he notes. In a recent demonstration, using a Fendt 936, if tyre pressure was dropped by just 0.4bar (5.5psi), if the infiltration rate of the soil improved by six times. “But a greater axle weight just puts the compaction deeper, to a point where it’s below your deepest cultivations.”
Compacted layers
There’s no better way to check soils for compaction than with a spade and OSR roots in particular are vulnerable to compacted layers. “The best time to inspect is in the spring, but you want to come back in summer to see how roots have managed through any suspect areas,” Philip Wright advises.
Any subsoiling should be carried out when the soil is neither too dry nor too soft, aiming to lift and drop back the soil over the wing, putting vertical fissures into the structure. “Don’t boil the soil – you’ll lose the support,” he says.
“But loosening isn’t sorting – that’s only part of the journey. Nature does the rest. Much of a soil’s ability to maintain its structure is related to soil organic matter (SOM) content.” SOM builds resilience into the soil, helping it withstand the pressures put upon it. Most arable soils lie in the 2-5% band, he says, and the higher the better. Tests have shown it would take 2.4bar (35psi) to compress a soil with 6% SOM to 10% air filled porosity – below the critical level for yield. But the same soil with just 1.5% SOM would compress the same porosity under a pressure of just 0.8bar (12psi)
“SOM makes a huge difference, particularly on heavy soils, to the ease with which they can be worked and the width of the cultivation window,” points out Philip Wright.
Andrew Ward has used sewage cake and incorporated straw to build SOM levels in his heavier soils from where they were as low as 2% to 3.5-4.6% currently. It has also been a focus for James Chamberlain. “We’ve always incorporated the straw, but have moved recently from biosolids to compost. Both help the SOM levels, but while biosolids built up the phosphate, compost brings in some potash.”
Compost can lock up N in the short term, notes Philip Wright, although it’s a good long term choice. “Watch for diesel use when chopping straw, especially if it’s a bit green – it can be better to leave the stubble long and top it,” he notes. All agree that getting an even chop of straw is an essential start to OSR seedbed. While Andrew Ward establishes his crop in just one pass (see panel), John Haynes has a dilemma. “Most OSR last year was established with a Vaderstad TopDown and Biodrill, but we drilled 90ha with the Vaderstad Rapid. The Rapid-drilled crop came through together and withstood the CSFB better. But in the spring, we found the rooting in the TopDown established crop was better. Either way, consolidation afterwards was essential. “This year we’ll aim to start drilling around 10 Aug, but that depends on moisture. If there’s enough, we’ll probably go with the Rapid as that’s the best for CSFB. We’ll be drilling conventional varieties, keeping the seed rate high at about 80 seeds/m”.
James Chamberlain prefers the early vigour he feels he gets from hybrids, aiming for a rate of about 35 seeds/m2 up to 40 seeds/m2 on stronger land. “Our land doesn’t self structure, so we’ll be using the plough and power harrow in front of the drill, aiming for the end of August or first week of September.”
Former Long Ashton scientist and slug specialist Dr David Glen of Styloma stresses that the risk of crop damage from the pests should always be assessed. But the minimum cultivation advocated for blackgrass control may not help, he admits. “There’s some conflict in the soil disturbance does reduce slug numbers.” Agrovista’s Chris Martin believes cropping patterns haven’t changed dramatically. “Ploughing is a good tool for burying or desiccating slug eggs and so helps reduce populations,” he says. “But it often leads to cloddy seedbeds which means populations can increase very rapidly. “So as long as soils are well consolidated and where direct drills are used the seed slots are suitably covered, minimum soil disturbance can still achieve good slug control.” As always, the threat to autumn crops is weather driven, both experts agree.
Plenty of activity
Long dry spells until July held slugs back, but rain thereafter triggered plenty of activity, notes David Glen. “The weather going into the autumn will be of key importance,”
The wet weather certainly increased slug numbers in this season’s crops, but it’s future conditions which will determine the risk to next season’s, says Chris Martin. “Mild damp weather particularly favours slugs.” Both advocate trapping to assess that risk and guide control measures, but it must be done correctly to be informative, they stress.
It involves putting a small amount of chicken layers’ mash under pieces of slate or tile placed in fields due to be sown. They’re left overnight and the numbers of slugs present beneath each counted early the next morning. AHDB Cereals and Oilseeds advises laying nine traps (13 in fields larger than 20ha) in a “W” pattern, but also concentrating on areas known to suffer damage.
“Growers should set the traps in representative areas of the field, avoiding compacted parts such as headlands and target the usual suspect areas,” says Chris Martin.
Never use slug pellets under the traps, he warns. “The main reason for not doing so is that they can attract non-target organisms – insects, birds and even mammals – which can eat the cluster of pellets and be severely harmed or killed. Just a few spoonfuls of a metaldehyde-based pellet could kill a dog.” Trap timing is important, he adds. “To get a true picture, its best to start trapping before cultivation. Soil disturbance disrupts slug surface in activity, resulting in low catches even when they’re abundant in the soil.”
Trapping soon after cultivation and drilling can give a misleading impression that slug numbers are low, agrees David Glen. “It takes time for slugs to resume normal surface activity after the disruption caused by cultivations. “Trap in stubble after harvest of cereals or oilseed rape when the soil surface is visibly moist,” he advises. Trapping after drilling is one of the commonest mistakes growers make, he believes. “Another is not trapping because the risk in a particular field or farm is usually low yet slug numbers have risen due to favourable weather.”
The trap count thresholds triggering pellet treatments are:
- For fields going into winter wheat: four or more slugs per trap in preceding stubble.
- For fields going into winter OSR: Four or more slugs per trap in the previous standing crop or one per trap in preceding cereal stubble. Winter wheat is the most vulnerable cereal, notes David Glen. “Generally slugs are less of a problem in the spring OSR than the winter crop. But it’s worth trapping just before cultivation in the same way”. Effective control of slugs needs to combine cultural and chemical control measures, says Chris Martin.
Crop Residues
Removing trash from the previous crop as soon as possible after harvest and killing weeds and volunteers in the run up to drilling denies slugs food and shelter and helps prevent populations building. Baling crop residues helps, as does an application of glyphosate, notes David Glen. “Creating a fine, well consolidated seedbed so that slug movement is restricted reduces crop damage,” says Chris Martin. “Seed rates should be increased in high risk sites and seed dressings such as Deter (clothiandin) can reduce grain hollowing in cereals. Drilling highest risk sites early, into a good seedbed to a depth of 4-5cm will help prevent hollowing. Rolling after drilling to consolidate the seedbed will also reduce slug damage.” David Glen suggests drilling slightly deeper in cloddy seedbeds and rolling as soon as possible after drilling. For reducing slug pressure in OSR, Chris Martin believes that it’s important to sow high vigour varieties to help the crop grow away from slug activity. “Seed to soil contact and adequate consolidation are also essential to ensure rapid emergence. There’s also increasing evidence to suggest that growing companion mixtures based on berseem clover and vetches amongst OSR crops can significantly reduce slug activity on the emerging plants.” When it comes to chemical control he says Ferrex (based on ferric phosphate) will continue to be his first choice. “I’ve been very happy with its performance over the past few seasons including the very difficult wet autumn of 2012 when it clearly outperformed metaldehyde based pellets.”
Know your slug
The Greyt Field Slug (Derocerus reticulatum) is the most important of several species attacking cerals and oilseed rape, according to Chris Martin. In cereals, initial damage is grain hollowing, followed by shredding of the leaves of young seedlings. Adults are 30-50mm long and vary from cream to deep grey in colour. Each slug can lay up to 300 eggs, usually in batches of 10-50 and they’ll reproduce throughout the year if conditions are favourable. Warm and damp weather is ideal for a rapid build up in slug populations.
Article written by Tom Allen-StevensFor the growers’ who’ve gathered for the Syngenta Driving Up Oilseed Rape Yields meeting, the first question to address is whether they’ll be growing the crop at all this autumn. With rapeseed prices hovering around £250/t and the challenges and costs of getting a crop established in the first place, the UK rapeseed area for 2016 harvest is set to dip.
But these growers appear unfazed. “We’ve 300ha of OSR and we’re carrying on – I’m not into knee jerk reactions,” says John Haynes farming on the Essex/Herts border. His crop was badly hit by cabbage stem flea beetle (CSFB) last year and he’s determined to do all he can to ensure the crop pulls away from the pest this autumn.
“We’ll definitely be drilling the crop, but won’t be making too many decisions about how and when until we know what conditions are like – having that moisture there is absolutely crucial.” The OSR area will also stay at roughly the same level for Lincs grower Andrew Ward. “It’s an important part of the rotation,” he says. A long time grower of HOLL varieties on wide row spacing’s, it’s the winter wheat area that’s reduced for him, in favour of spring barely, as part of a plan to eliminate blackgrass.
“We’re getting 95% establishment and that’s key to success with OSR. Minimum surface disturbance and good consolidation bring the moisture up to the seed and thus helps it get away” he says.
Pulses have come into the rotation for Derby grower James Chamberlain, to fit in with greening requirements for the Basic Placement Scheme. But his OSR area on relatively light soils will be staying roughly the same.
“It was the driest September for 100 years and land we took on required remedial cultivations, so wasn’t drilled until 9 Sept. In a normal year, we’d be happy with that, but the dry conditions meant it then suffered a staggered emergence. This put us on the back foot from the start,” he recalls.
“The difficulty with OSR is that there’s such a heavy cost before the crop has even emerged. But the best way to reduce the cost of production is to increase yields, which means doing everything possible through the autumn and spring to achieve that output. SO, whatever the crop needs it will get,”
Working out what that is through the crucial establishment phase is the aim of the meeting – the growers are part of a group that comes together regularly over the year to consider how new and different agronomy techniques can enhance field performance, with a view to achieving an OSRF crop that has the potential to yield more and yield more consistently. Cultivations expert Phillip Wright Resolutions has joined the group to discuss how to keep the soil in good heart.
“When I dig holes and inspect fields around the UK, there are three things I assess which are crucial for getting results from the soil,” he says. “The most important is drainage – a soil that quickly returns to field capacity is what’s best for the biology and the roots. The other two of equal importance are organic matter and weight of the equipment used,”
Drainage is an area that’s seen considerable underinvestment since grant-funding ceased over 30 years ago, he maintains. “It costs around £2400/ha, which includes permeable backfill. That may be a lot more than the £70/ha cost of the 1970s, but if you relate that to land value, the cost has actually gone down in relative terms.”
But where the problem areas are addressed with a proper drainage scheme, you can expect a payback of less than ten years from increased yields, says Phillip Wright. “The backfill is where a lot of the money goes – make sure the contractor uses enough of it and that it’s the right quality. Power station clinker should be avoided as it degrades over time.” John Haynes has around 300ha to drain and has just brought a new trencher. “The drainage work will pay for itself over five years with improvement in soil structure it’ll bring, especially for the OSR. If you haven’t got a drainage system then your yield potential is fundamentally limited,” he points out.
“Axle weight and ground pressure are both important when it comes to the size of equipment you use,” continues Phillip Wright.
“Ideally a soil should be 50% solid material and the rest pores for air and water. As soon as you squeeze that, you reduce the porosity so it becomes flooded – when all the pores are full of water – much faster.” Get as low as 20% porosity and that severely limits yield as roots need the air to space to grow and develop, he explains. “It would be like growing plant roots in a plastic bag.”
The difficulty is that agricultural equipment is getting bigger, and that’s literally putting more pressure on the soil. “You need 50-55kg/hp for a primary operation tractor, so if your main cultivation tractor is 400-500hp, that’s 20-130t. Pulling that weight over soils, particularly if they’re damp, can do a lot of damage. Land is most vulnerable in the spring, which is why these wide rotations could be a worry.”
Surface ground pressure can be mitigated through lower ground pressure tyres, he notes. In a recent demonstration, using a Fendt 936, if tyre pressure was dropped by just 0.4bar (5.5psi), if the infiltration rate of the soil improved by six times. “But a greater axle weight just puts the compaction deeper, to a point where it’s below your deepest cultivations.”
Compacted layers
There’s no better way to check soils for compaction than with a spade and OSR roots in particular are vulnerable to compacted layers. “The best time to inspect is in the spring, but you want to come back in summer to see how roots have managed through any suspect areas,” Philip Wright advises.
Any subsoiling should be carried out when the soil is neither too dry nor too soft, aiming to lift and drop back the soil over the wing, putting vertical fissures into the structure. “Don’t boil the soil – you’ll lose the support,” he says.
“But loosening isn’t sorting – that’s only part of the journey. Nature does the rest. Much of a soil’s ability to maintain its structure is related to soil organic matter (SOM) content.” SOM builds resilience into the soil, helping it withstand the pressures put upon it. Most arable soils lie in the 2-5% band, he says, and the higher the better. Tests have shown it would take 2.4bar (35psi) to compress a soil with 6% SOM to 10% air filled porosity – below the critical level for yield. But the same soil with just 1.5% SOM would compress the same porosity under a pressure of just 0.8bar (12psi)
“SOM makes a huge difference, particularly on heavy soils, to the ease with which they can be worked and the width of the cultivation window,” points out Philip Wright.
Andrew Ward has used sewage cake and incorporated straw to build SOM levels in his heavier soils from where they were as low as 2% to 3.5-4.6% currently. It has also been a focus for James Chamberlain. “We’ve always incorporated the straw, but have moved recently from biosolids to compost. Both help the SOM levels, but while biosolids built up the phosphate, compost brings in some potash.”
Compost can lock up N in the short term, notes Philip Wright, although it’s a good long term choice. “Watch for diesel use when chopping straw, especially if it’s a bit green – it can be better to leave the stubble long and top it,” he notes. All agree that getting an even chop of straw is an essential start to OSR seedbed. While Andrew Ward establishes his crop in just one pass (see panel), John Haynes has a dilemma. “Most OSR last year was established with a Vaderstad TopDown and Biodrill, but we drilled 90ha with the Vaderstad Rapid. The Rapid-drilled crop came through together and withstood the CSFB better. But in the spring, we found the rooting in the TopDown established crop was better. Either way, consolidation afterwards was essential. “This year we’ll aim to start drilling around 10 Aug, but that depends on moisture. If there’s enough, we’ll probably go with the Rapid as that’s the best for CSFB. We’ll be drilling conventional varieties, keeping the seed rate high at about 80 seeds/m”.
James Chamberlain prefers the early vigour he feels he gets from hybrids, aiming for a rate of about 35 seeds/m2 up to 40 seeds/m2 on stronger land. “Our land doesn’t self structure, so we’ll be using the plough and power harrow in front of the drill, aiming for the end of August or first week of September.”
Former Long Ashton scientist and slug specialist Dr David Glen of Styloma stresses that the risk of crop damage from the pests should always be assessed. But the minimum cultivation advocated for blackgrass control may not help, he admits. “There’s some conflict in the soil disturbance does reduce slug numbers.” Agrovista’s Chris Martin believes cropping patterns haven’t changed dramatically. “Ploughing is a good tool for burying or desiccating slug eggs and so helps reduce populations,” he says. “But it often leads to cloddy seedbeds which means populations can increase very rapidly. “So as long as soils are well consolidated and where direct drills are used the seed slots are suitably covered, minimum soil disturbance can still achieve good slug control.” As always, the threat to autumn crops is weather driven, both experts agree.
Plenty of activity
Long dry spells until July held slugs back, but rain thereafter triggered plenty of activity, notes David Glen. “The weather going into the autumn will be of key importance,”
The wet weather certainly increased slug numbers in this season’s crops, but it’s future conditions which will determine the risk to next season’s, says Chris Martin. “Mild damp weather particularly favours slugs.” Both advocate trapping to assess that risk and guide control measures, but it must be done correctly to be informative, they stress.
It involves putting a small amount of chicken layers’ mash under pieces of slate or tile placed in fields due to be sown. They’re left overnight and the numbers of slugs present beneath each counted early the next morning. AHDB Cereals and Oilseeds advises laying nine traps (13 in fields larger than 20ha) in a “W” pattern, but also concentrating on areas known to suffer damage.
“Growers should set the traps in representative areas of the field, avoiding compacted parts such as headlands and target the usual suspect areas,” says Chris Martin.
Never use slug pellets under the traps, he warns. “The main reason for not doing so is that they can attract non-target organisms – insects, birds and even mammals – which can eat the cluster of pellets and be severely harmed or killed. Just a few spoonfuls of a metaldehyde-based pellet could kill a dog.” Trap timing is important, he adds. “To get a true picture, its best to start trapping before cultivation. Soil disturbance disrupts slug surface in activity, resulting in low catches even when they’re abundant in the soil.”
Trapping soon after cultivation and drilling can give a misleading impression that slug numbers are low, agrees David Glen. “It takes time for slugs to resume normal surface activity after the disruption caused by cultivations. “Trap in stubble after harvest of cereals or oilseed rape when the soil surface is visibly moist,” he advises. Trapping after drilling is one of the commonest mistakes growers make, he believes. “Another is not trapping because the risk in a particular field or farm is usually low yet slug numbers have risen due to favourable weather.”
The trap count thresholds triggering pellet treatments are:
- For fields going into winter wheat: four or more slugs per trap in preceding stubble.
- For fields going into winter OSR: Four or more slugs per trap in the previous standing crop or one per trap in preceding cereal stubble. Winter wheat is the most vulnerable cereal, notes David Glen. “Generally slugs are less of a problem in the spring OSR than the winter crop. But it’s worth trapping just before cultivation in the same way”. Effective control of slugs needs to combine cultural and chemical control measures, says Chris Martin.
Crop Residues
Removing trash from the previous crop as soon as possible after harvest and killing weeds and volunteers in the run up to drilling denies slugs food and shelter and helps prevent populations building. Baling crop residues helps, as does an application of glyphosate, notes David Glen. “Creating a fine, well consolidated seedbed so that slug movement is restricted reduces crop damage,” says Chris Martin. “Seed rates should be increased in high risk sites and seed dressings such as Deter (clothiandin) can reduce grain hollowing in cereals. Drilling highest risk sites early, into a good seedbed to a depth of 4-5cm will help prevent hollowing. Rolling after drilling to consolidate the seedbed will also reduce slug damage.” David Glen suggests drilling slightly deeper in cloddy seedbeds and rolling as soon as possible after drilling. For reducing slug pressure in OSR, Chris Martin believes that it’s important to sow high vigour varieties to help the crop grow away from slug activity. “Seed to soil contact and adequate consolidation are also essential to ensure rapid emergence. There’s also increasing evidence to suggest that growing companion mixtures based on berseem clover and vetches amongst OSR crops can significantly reduce slug activity on the emerging plants.” When it comes to chemical control he says Ferrex (based on ferric phosphate) will continue to be his first choice. “I’ve been very happy with its performance over the past few seasons including the very difficult wet autumn of 2012 when it clearly outperformed metaldehyde based pellets.”
Know your slug
The Greyt Field Slug (Derocerus reticulatum) is the most important of several species attacking cerals and oilseed rape, according to Chris Martin. In cereals, initial damage is grain hollowing, followed by shredding of the leaves of young seedlings. Adults are 30-50mm long and vary from cream to deep grey in colour. Each slug can lay up to 300 eggs, usually in batches of 10-50 and they’ll reproduce throughout the year if conditions are favourable. Warm and damp weather is ideal for a rapid build up in slug populations.