Article taken from FarmBusiness
A new study assessing the impact of lodging on oilseed rape yields high-lights the importance of early canopy management in this season’s forward crops.
Dr Sarah Kendall of ADAS says OSR lodging is widespread and could be costing growers much more than previously thought. New research shows losses can top £500/ha current market values in severely lodged areas, and almost half that even where crops are leaning.
Artificial lodging experiments funded by BASF were carried out by ADAS last season in the variety Kite at four growth stages – early and mid-flowering and early and mid-seed fill – and three lodging angles - 90°, 45° and 22.5°.
Flat crops suffered the most damage. Yields of the 4.5t/ha crop dropped below 2t/ha when lodging was induced at mid-seed fill, and nearly as much at earlier timings. Seed oil content fell by 5-8%.
Crops lodged to 45° also suffered heavy yield losses of 0.75-1.5t/ha, the latter at mid-seed fill. Oil contents were hit too, by up to 6%.
Interestingly, crops that only leant during seed fill (22.5°) were also hit hard. “Such leaning is sometimes regarded as beneficial by helping to avoid shattering and making combining easier,” says Dr Kendall. “However, our findings show that yield can be cut by 25%.”
Two aerial surveys, one carried out in 2012 in East Anglia and the other last year in North Yorkshire, Lincolnshire and Cambridgeshire, reveal the extent of the problem. They showed respectively that 99% and 100% of fields were affected by lodging, and that on average 31% of crop was lodged. “Often this occurred in the middle of fields, where it can go unnoticed until harvest,” says Dr Kendall.
“Based on an OSR price of £250/t and 31% lodging, losses on a flat crop can reach £170/ha from lost yield and oil content alone, regardless of additional combining and drying costs. Even late leaning can have dramatic effects, leading to a potential loss of £70/ha.”
This season’s forward crops need careful management, says ADAS colleague Dr Pete Berry. “This year green area indices generally range from 1-3, presenting a big challenge. We need to avoid lodging and the production of an over-thick canopy that reflects a lot of light, reducing yield potential. Ideally we want thinner crops that we are used to. You should be able to see about 10% soil when looking down from above during flowering.”
That equates to a Green Area Index (GAI) of about 3.5, which allows sunlight to penetrate down to the leaves, the biggest contributors to yield. To achieve this GAI needs to be estimated just before stem extension so nitrogen applications and plant growth regulators can be managed to manipulate crop growth. Crops with a GAI above 0.8 will require a growth regulator such as Caryx or Sunorg Pro/Caramba, he advises.
Agrovista technical manager Mark Hemmant favours Caryx at stem extension, not only on thick, forward crops but also those sown in wide rows at low seed rates to optimise canopy architecture. “Most crops look like they will need active intervention in 2015 to prevent disappointing yields, and Caryx delivers additional yield even in the absence of lodging,” he maintains.
Work at Agrovista’s Morley Growcrop Gold site in 2013 showed a crop of low seed rate/wide row Quartz treated with one litre/ha of Caryx produced an additional 0.3t/ha over untreated, reflecting similar results on other sites.
Increased branching was a key driver. “Secondary branches can contribute over 1t/ha, and we know that Caryx encourages their production. A population of 25-30 plants/m² in spring will help produce the ideal canopy, but Caryx still helps to produce the optimum structure to maximise sunlight capture and photosynthesis,” says Mr Hemmant.
Metconazole also improves rooting. Work at ADAS Boxworth produced an extra 0.3t/ha from a one litre/ha application and a margin over input costs of £63/ha.
“Caryx can increase rooting by about 25%, says Dr Berry. “This can increase water uptake by 9-10mm over the season, producing an extra 0.25-0.3t/ha of yield in a dry year.”
Estimating GAI
Aim for GAI 3.5 at flowering.
Caryx
A new study assessing the impact of lodging on oilseed rape yields high-lights the importance of early canopy management in this season’s forward crops.
Dr Sarah Kendall of ADAS says OSR lodging is widespread and could be costing growers much more than previously thought. New research shows losses can top £500/ha current market values in severely lodged areas, and almost half that even where crops are leaning.
Artificial lodging experiments funded by BASF were carried out by ADAS last season in the variety Kite at four growth stages – early and mid-flowering and early and mid-seed fill – and three lodging angles - 90°, 45° and 22.5°.
Flat crops suffered the most damage. Yields of the 4.5t/ha crop dropped below 2t/ha when lodging was induced at mid-seed fill, and nearly as much at earlier timings. Seed oil content fell by 5-8%.
Crops lodged to 45° also suffered heavy yield losses of 0.75-1.5t/ha, the latter at mid-seed fill. Oil contents were hit too, by up to 6%.
Interestingly, crops that only leant during seed fill (22.5°) were also hit hard. “Such leaning is sometimes regarded as beneficial by helping to avoid shattering and making combining easier,” says Dr Kendall. “However, our findings show that yield can be cut by 25%.”
Two aerial surveys, one carried out in 2012 in East Anglia and the other last year in North Yorkshire, Lincolnshire and Cambridgeshire, reveal the extent of the problem. They showed respectively that 99% and 100% of fields were affected by lodging, and that on average 31% of crop was lodged. “Often this occurred in the middle of fields, where it can go unnoticed until harvest,” says Dr Kendall.
“Based on an OSR price of £250/t and 31% lodging, losses on a flat crop can reach £170/ha from lost yield and oil content alone, regardless of additional combining and drying costs. Even late leaning can have dramatic effects, leading to a potential loss of £70/ha.”
This season’s forward crops need careful management, says ADAS colleague Dr Pete Berry. “This year green area indices generally range from 1-3, presenting a big challenge. We need to avoid lodging and the production of an over-thick canopy that reflects a lot of light, reducing yield potential. Ideally we want thinner crops that we are used to. You should be able to see about 10% soil when looking down from above during flowering.”
That equates to a Green Area Index (GAI) of about 3.5, which allows sunlight to penetrate down to the leaves, the biggest contributors to yield. To achieve this GAI needs to be estimated just before stem extension so nitrogen applications and plant growth regulators can be managed to manipulate crop growth. Crops with a GAI above 0.8 will require a growth regulator such as Caryx or Sunorg Pro/Caramba, he advises.
Agrovista technical manager Mark Hemmant favours Caryx at stem extension, not only on thick, forward crops but also those sown in wide rows at low seed rates to optimise canopy architecture. “Most crops look like they will need active intervention in 2015 to prevent disappointing yields, and Caryx delivers additional yield even in the absence of lodging,” he maintains.
Work at Agrovista’s Morley Growcrop Gold site in 2013 showed a crop of low seed rate/wide row Quartz treated with one litre/ha of Caryx produced an additional 0.3t/ha over untreated, reflecting similar results on other sites.
Increased branching was a key driver. “Secondary branches can contribute over 1t/ha, and we know that Caryx encourages their production. A population of 25-30 plants/m² in spring will help produce the ideal canopy, but Caryx still helps to produce the optimum structure to maximise sunlight capture and photosynthesis,” says Mr Hemmant.
Metconazole also improves rooting. Work at ADAS Boxworth produced an extra 0.3t/ha from a one litre/ha application and a margin over input costs of £63/ha.
“Caryx can increase rooting by about 25%, says Dr Berry. “This can increase water uptake by 9-10mm over the season, producing an extra 0.25-0.3t/ha of yield in a dry year.”
Estimating GAI
Aim for GAI 3.5 at flowering.
Estimate GAI just before stem extension;
- Visual estimate (fraction of soil covered by crop): one-third = GAI 0.5, half = GAI 1, three-quarters = GAI2;
- Upload photo onto www.totaloilseedcare.co.uk or use Caryx app.
If GAI >3 cut 1m² of crop, weigh and multiply result by 0.8.
Reduce and delay nitrogen for large canopy crops;
Optimum PGR timing is late green bud to mid flowering
Caryx
Specifically developed for use in oilseed rape;
Metconazole (30g/litre) + mepiquat chloride (210g/litre)
Timing – from start of stem extension to yellow bud
Rate – GAI > 0.8 = 0.7 – 1 litre/ha GAI > 2 = 1-1.4 litres/ha
Activity –r educes height, strengthens stem, lengthens lower branches, increases secondary branching;
Average yield increase = 0.44t/ha over untreated; margin over input cost = £98/ha @£270/t inc premiums (BASF development trials).