Article taken from FarmBusiness MagazineOilseed rape growers will need to do all they can this summer to ensure their crops establish quickly and evenly, advise Chris Martin. Plants that are slow to establish are most prone to cabbage stem flea beetle attack, as shown graphically in some areas last season following the ban on neonicotinoid seen treatments. “Some crops were so badly damaged, they were written off, with areas in Bedfordshire and Hertfordshire particularly badly affected,” says Mr Martin.
DEFRA’s recent decision not to grant emergency use of neonicotinoid seed treatments in areas in need could mean many of the worst affected growers will not risk a repeat this season, says Mr Martin. However, he believes most other growers will stick with the crop, albeit in some cases on a smaller area, especially now the market appears to be staging a much needed recovery.
Encouraging rapid growth will be even more critical this season, as adult flea beetle numbers are higher than usual in some areas due to suboptimal control last autumn.
“Establishing a small-seeded crop at low seed rates during the summer can pose a significant challenge at the best of times, says Mr Martin. “This is demonstrated by the enormous variability we see in plant populations and eventual yields every season.
“Slow-growing crops will be more susceptible to all seeding pests and diseases, but are especially prone to early attack from cabbage stem flea beetle, which can wipe out a backward crop as it struggles to come through the ground.
“However, by following a few simple guidelines, growers can help crops to grow away strongly, tipping the odds very much in their favour. OSR establishment has been at the heart of Agrovista’s Growcrop Gold trials, carried out over a range of sites across the UK over the past six years. These show that the highest yields tend to be achieved with lower seed rates on good seedbeds with adequate moisture, giving evenly establo9shed low plant populations in the autumn” says Mr Martin. “By getting the right plant population from the outset we stand a much better chance of achieving the optimum canopy towards the end of flowering, which is the crucial period when seed is set.”
The first step to successful establishment is to remove compaction, he advises. “OSR is a lazy rooter and needs soils with plenty of cracks and pores so it can put down the deep taproots that underpin high yields. The crop is also very intolerant of water logging.""
Locating the position of any soil pan is important to cure, rather than create problems.
“Use a spade or a penetrometer to ensure remedial cultivations are carried out at the right depth. Going too deep will compress the compaction layer from below and increase wheel slippage.”
A good seedbed is next on the list. Maintaining moisture is critical, so cultivations should be kept to the minimum possible to achieve a seedbed that contains a mix of fine soil and small aggregates.
“We want to encourage good seed to soil contact while minimising capping. It’s a fine balance, but the trick is not to over work soils and roll them straight after drilling to conserve moisture in the surface layer.
Optimum seed depth is 15mm, though growers should check pre-emergence herbicide labels first to ensure this is permitted. The best way to achieve this is by conventional drilling, though sub-casting can achieve good results, or coulters can be fitted to the back of subsoiler legs. Manufacturers are also developing their own systems. Establishing the correct plant population is vital to achieving consistent yields, says Mr Martin. “Several years of Growcrop Gold work has shown the highest yields are typically achieved by sowing 15-20 seeds per metre of row to produce 12-15 plans.”
As a rule of thumb 40-60 seeds/sq metre will achieve an acceptable result at 12.5-25cm spacing, where normal establishment is expected. However, at 50cm spacing this would produce 30 seeds/m of row, so seed rates should be reduced accordingly.
“Establishing more than 12-15 plants creates too much early competition. Plants fight for light, which reduces establishment and tends to produce tall, spindly plants that are more prone to pest attack. Too a high seed rate also wastes money.” Mr Martin adds.
Correct plant spacing also encourages crops to produce open, branches architecture the following spring that makes best use of sunlight and optimises yields.
Where higher levels of flea beetle attack are predicted seed rates can be increased, but narrower row spacing must be used rather than cramming more seed along the row.
“The rule of not exceeding 60 seeds/sq metres should still be observed. If growers remain uneasy they should choose varieties with the best early autumn vigour.”
Companion plants, a relatively recent innovation, have been trialled extensively in Agrovista’a Growcrop Gold programme where they have often improved establishment and ultimately yield. These plants grow alongside the OSR in the autumn before they die off over the winter. Berseem clover has been shown to deliver significant benefits in OSR crops planted at optimum seed rates of 15 seeds/m of row.
“This combination typically increases OSR root mass by 20%,” says Mr Martin. “On average, companion plants provide a 0.3-0.4t/ha benefit and in trickier establishment conditions, can be significantly more with 0.75t/ha yield increases not uncommon.”
Thanks to their erect growth habit they don’t increase competition within the rape crop, he explains. “But they do help suppress weeds, improve soil structure and organic matter and help reduce slug damage.” Says Mr Martin.
“There is evidence from France, where companion plants are used widely, that they also reduce damage caused by cabbage stem flea beetle.""
Phosphate is an important nutrient to aid early crop growth. The nutrient is immobile so accurate placement is important as small rape plants have poorly developed roots.
“Placing soluble phosphate fertiliser alongside and just beneath seeds produces optimum results,” says Mr Martin. Growers who do not have access to specialist kit can achieve good results by incorporating phosphate into the top inch of seedbed, he adds. Mesurol seed dressing has an effect on flea beetle and is legally available on imported seed. “It can help in some situations, though results aren’t overly consistent,” he notes. “In addition, mesurol is not systemic, so well-timed, approved pyrethroid sprays will still be needed to combat flea beetle. Be prepared to spray at the first sign of shot-holling.”
DEFRA’s recent decision not to grant emergency use of neonicotinoid seed treatments in areas in need could mean many of the worst affected growers will not risk a repeat this season, says Mr Martin. However, he believes most other growers will stick with the crop, albeit in some cases on a smaller area, especially now the market appears to be staging a much needed recovery.
Encouraging rapid growth will be even more critical this season, as adult flea beetle numbers are higher than usual in some areas due to suboptimal control last autumn.
“Establishing a small-seeded crop at low seed rates during the summer can pose a significant challenge at the best of times, says Mr Martin. “This is demonstrated by the enormous variability we see in plant populations and eventual yields every season.
“Slow-growing crops will be more susceptible to all seeding pests and diseases, but are especially prone to early attack from cabbage stem flea beetle, which can wipe out a backward crop as it struggles to come through the ground.
“However, by following a few simple guidelines, growers can help crops to grow away strongly, tipping the odds very much in their favour. OSR establishment has been at the heart of Agrovista’s Growcrop Gold trials, carried out over a range of sites across the UK over the past six years. These show that the highest yields tend to be achieved with lower seed rates on good seedbeds with adequate moisture, giving evenly establo9shed low plant populations in the autumn” says Mr Martin. “By getting the right plant population from the outset we stand a much better chance of achieving the optimum canopy towards the end of flowering, which is the crucial period when seed is set.”
The first step to successful establishment is to remove compaction, he advises. “OSR is a lazy rooter and needs soils with plenty of cracks and pores so it can put down the deep taproots that underpin high yields. The crop is also very intolerant of water logging.""
Locating the position of any soil pan is important to cure, rather than create problems.
“Use a spade or a penetrometer to ensure remedial cultivations are carried out at the right depth. Going too deep will compress the compaction layer from below and increase wheel slippage.”
A good seedbed is next on the list. Maintaining moisture is critical, so cultivations should be kept to the minimum possible to achieve a seedbed that contains a mix of fine soil and small aggregates.
“We want to encourage good seed to soil contact while minimising capping. It’s a fine balance, but the trick is not to over work soils and roll them straight after drilling to conserve moisture in the surface layer.
Optimum seed depth is 15mm, though growers should check pre-emergence herbicide labels first to ensure this is permitted. The best way to achieve this is by conventional drilling, though sub-casting can achieve good results, or coulters can be fitted to the back of subsoiler legs. Manufacturers are also developing their own systems. Establishing the correct plant population is vital to achieving consistent yields, says Mr Martin. “Several years of Growcrop Gold work has shown the highest yields are typically achieved by sowing 15-20 seeds per metre of row to produce 12-15 plans.”
As a rule of thumb 40-60 seeds/sq metre will achieve an acceptable result at 12.5-25cm spacing, where normal establishment is expected. However, at 50cm spacing this would produce 30 seeds/m of row, so seed rates should be reduced accordingly.
“Establishing more than 12-15 plants creates too much early competition. Plants fight for light, which reduces establishment and tends to produce tall, spindly plants that are more prone to pest attack. Too a high seed rate also wastes money.” Mr Martin adds.
Correct plant spacing also encourages crops to produce open, branches architecture the following spring that makes best use of sunlight and optimises yields.
Where higher levels of flea beetle attack are predicted seed rates can be increased, but narrower row spacing must be used rather than cramming more seed along the row.
“The rule of not exceeding 60 seeds/sq metres should still be observed. If growers remain uneasy they should choose varieties with the best early autumn vigour.”
Companion plants, a relatively recent innovation, have been trialled extensively in Agrovista’a Growcrop Gold programme where they have often improved establishment and ultimately yield. These plants grow alongside the OSR in the autumn before they die off over the winter. Berseem clover has been shown to deliver significant benefits in OSR crops planted at optimum seed rates of 15 seeds/m of row.
“This combination typically increases OSR root mass by 20%,” says Mr Martin. “On average, companion plants provide a 0.3-0.4t/ha benefit and in trickier establishment conditions, can be significantly more with 0.75t/ha yield increases not uncommon.”
Thanks to their erect growth habit they don’t increase competition within the rape crop, he explains. “But they do help suppress weeds, improve soil structure and organic matter and help reduce slug damage.” Says Mr Martin.
“There is evidence from France, where companion plants are used widely, that they also reduce damage caused by cabbage stem flea beetle.""
Phosphate is an important nutrient to aid early crop growth. The nutrient is immobile so accurate placement is important as small rape plants have poorly developed roots.
“Placing soluble phosphate fertiliser alongside and just beneath seeds produces optimum results,” says Mr Martin. Growers who do not have access to specialist kit can achieve good results by incorporating phosphate into the top inch of seedbed, he adds. Mesurol seed dressing has an effect on flea beetle and is legally available on imported seed. “It can help in some situations, though results aren’t overly consistent,” he notes. “In addition, mesurol is not systemic, so well-timed, approved pyrethroid sprays will still be needed to combat flea beetle. Be prepared to spray at the first sign of shot-holling.”