Article taken from the Farmers Guide
Yields in flattened oilseed rape crops can tumble by 50 per cent and even crops considered to be gently leaning can lose a quarter of their yield, recent ADAS work funded by BASF shows.
The problem is more widespread than most people think, says Dr Sarah Kendall, who led the research. An aerial survey of 2,000ha (4,900 acres) of East Anglian OSR crops carried out in 2012 showed lodging affected 99 per cent of fields, with an average of 35 per cent of crop area lodged. A follow-up survey in 2014 of 1,000 ha (2,400 acres) across North Yorkshire, Lincolnshire and Cambridgeshire showed all fields contained lodging, with an average 27 per cent of crop area affected.
“Lodging often occurred in the middle of the fields where it can go unnoticed until harvest,” says Dr Kendall.
To assess how much this was hitting profits, artificial lodging experiments were carried out last year at ADAS Rosemaud on the variety Kite, with lodging induced at four growth stages and three lodging angles, from a slight lean to flat.
Not surprisingly, flat crops suffered the most damage. Yields of the 4.5t ha crop were slashed to under 2t/ha when extreme lodging occurred at the latest mid-seed fill timing, and only by slightly less during flowering and early seed fill. Seed oil content fell by 5-8 per cent.
Crops lodged to 45 degrees suffered losses of 0.75-1.5t/ha, the latter at mid-seed fill. Oil contents were hit by up to 6 per cent.
Even crops that were leaning to just 22.5 degrees suffered significant yield losses. “Some growers would consider this degree of leaning as beneficial, helping to avoid shattering and making combining easier,” says Dr Kendall. “However, yield can be cut by 25 per cent when leaning occurs during seed filling.”
Based on an OSR price of £250/t ad 31 per cent lodging (the average found in the two surveys) losses in a flat crop could reach £170/ha from lost yield and oil content alone, regardless of addition combining and drying costs, says Dr Kendall. That equates to about £110m nationally.
“However, even late leaning can have dramatic effects, leading to a potential loss of £70/ha. The cost of lodging can be significant and should not be ignored.”
That is especially true in a season like this, says ADAS colleague Dr Pete Berry. “Green area indices generally range from 1-3, not dissimilar to 2014, and present a big challenge. We need to avoid lodging and the production of an over–thick canopy at flowering that reflects a lot of light, reducing yield potential.”
Yield is all about maximising seed set, Dr Berry explains. “High yielding crops may not always have heavy seeds but they have lots of them. Seed number is determined by the two- to three-week period after mid flowering, so lots of flowers are bad news.
“Having a more open canopy is much more helpful – ideally we want thinner crops than we are used to. You should be able to see about 10 per cent soil when looking down from above during flowering.”
This represents a green area index (GAI) of about 3.5. Such a canopy lets sunlight penetrate down to the leaves, the biggest contributors to yield, producing optimum numbers of seed.
To achieve the optimum canopy at flowering, GAI must be estimated just before stem extension to determine nitrogen and PGR management, says Dr Berry.
Assessing the amount of additional nitrogen required based on this information is straightforward. Timing is also critical – forward crops should be starved of nitrogen, Dr Berry advises. ADAS work has shown splitting a 240kg/ha seasonal application between green bud (140kg) and yellow bud/early flowering (100kg) shortened the crop by about 30cm and increased yield by 0.3t/ha compared with equal splits at conventional timings of pre-stem extension and green bud.
Growth regulation
Agrovista technical manager Mark Hemmant says any crop with a GAI above 0.8 will need a growth regulator. “Most crops look like they will need active intervention in 2015 to prevent disappointing yields,” he advises.
Caryx (mepiquat chloride + metconazole) delivers additional yield even in the absence of lodging, he maintains. “Its growth manipulation effects ensure you end up with the optimum canopy, producing lots of seed rather than lots of pods. This delivers very useful yield benefits, even the absence of lodging – you could say you get lodging control for free.”
Agrovista trials in 2013 at Stoughton showed Caryx at 1-litre/ha produced an extra 0.3t/ha of yield even where leaning was only slight. A slightly bigger return was obtained in the dry spring of 2014, again in a crop with little leaning.
Increased branching was a key driver. “Secondary branches can contribute over 1t/ha, and we know that Caryx encourages their production.”
Further work was carried out to assess whether crops sown at wide row widths and low seed rates (500mm and 20 seed/m²) would respond in the absence of lodging. This is now Agrovista’s standard sowing recommendation after six years of trials that clearly demonstrate how this spatial arrangement helps crops produce the right branch architecture.
Work at the Morley Growcrop Gold site shows the same positive benefits – a l-litre/ha application of Caryx on a cop of Quartz sown at low seed rate in wide rows produced the same result as at Stoughton.
“A population of 25-30 plants/m² in spring will help produce the optimum structure to maximise sunlight capture and photosynthesis,” says Mr Hemmant.
“Even where you already have a lot of branches and lodging is absent, you still see better yields as treated plants redirect energy from the main raceme to the branches, maximising seed number.”
Caryx also improves rooting, helping to explain the additional yield obtained in Agrovista’s 2014 trial. Work at ADAS Boxworth that year produced an extra 0.3t/ha from a 1-litre/ha application and a margin over input cost of £63/ha.
“Metconazole, as in Caryx, can increase rooting between depths of 40 and 100cm by about 25 per cent, says Dr Berry. “This can increase water uptake by 9-10mm over the season, producing an extra 0.25-03t/ha of yield in a dry year.”
Estimating GAI
Aim of GAI 3.5 at flowering
GAI 2
- 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
Using GAI for N
the Fertiliser Manual (RB209), but this may vary by season
or
- Measure crop N by assessing crop GAI just before stem extension and multiplying by 50kg. Assess
using digital photographs uploaded onto www.totaloilseedcare.co.uk or using BASF’s Caryx App
Yields in flattened oilseed rape crops can tumble by 50 per cent and even crops considered to be gently leaning can lose a quarter of their yield, recent ADAS work funded by BASF shows.
The problem is more widespread than most people think, says Dr Sarah Kendall, who led the research. An aerial survey of 2,000ha (4,900 acres) of East Anglian OSR crops carried out in 2012 showed lodging affected 99 per cent of fields, with an average of 35 per cent of crop area lodged. A follow-up survey in 2014 of 1,000 ha (2,400 acres) across North Yorkshire, Lincolnshire and Cambridgeshire showed all fields contained lodging, with an average 27 per cent of crop area affected.
“Lodging often occurred in the middle of the fields where it can go unnoticed until harvest,” says Dr Kendall.
To assess how much this was hitting profits, artificial lodging experiments were carried out last year at ADAS Rosemaud on the variety Kite, with lodging induced at four growth stages and three lodging angles, from a slight lean to flat.
Not surprisingly, flat crops suffered the most damage. Yields of the 4.5t ha crop were slashed to under 2t/ha when extreme lodging occurred at the latest mid-seed fill timing, and only by slightly less during flowering and early seed fill. Seed oil content fell by 5-8 per cent.
Crops lodged to 45 degrees suffered losses of 0.75-1.5t/ha, the latter at mid-seed fill. Oil contents were hit by up to 6 per cent.
Even crops that were leaning to just 22.5 degrees suffered significant yield losses. “Some growers would consider this degree of leaning as beneficial, helping to avoid shattering and making combining easier,” says Dr Kendall. “However, yield can be cut by 25 per cent when leaning occurs during seed filling.”
Based on an OSR price of £250/t ad 31 per cent lodging (the average found in the two surveys) losses in a flat crop could reach £170/ha from lost yield and oil content alone, regardless of addition combining and drying costs, says Dr Kendall. That equates to about £110m nationally.
“However, even late leaning can have dramatic effects, leading to a potential loss of £70/ha. The cost of lodging can be significant and should not be ignored.”
That is especially true in a season like this, says ADAS colleague Dr Pete Berry. “Green area indices generally range from 1-3, not dissimilar to 2014, and present a big challenge. We need to avoid lodging and the production of an over–thick canopy at flowering that reflects a lot of light, reducing yield potential.”
Yield is all about maximising seed set, Dr Berry explains. “High yielding crops may not always have heavy seeds but they have lots of them. Seed number is determined by the two- to three-week period after mid flowering, so lots of flowers are bad news.
“Having a more open canopy is much more helpful – ideally we want thinner crops than we are used to. You should be able to see about 10 per cent soil when looking down from above during flowering.”
This represents a green area index (GAI) of about 3.5. Such a canopy lets sunlight penetrate down to the leaves, the biggest contributors to yield, producing optimum numbers of seed.
To achieve the optimum canopy at flowering, GAI must be estimated just before stem extension to determine nitrogen and PGR management, says Dr Berry.
Assessing the amount of additional nitrogen required based on this information is straightforward. Timing is also critical – forward crops should be starved of nitrogen, Dr Berry advises. ADAS work has shown splitting a 240kg/ha seasonal application between green bud (140kg) and yellow bud/early flowering (100kg) shortened the crop by about 30cm and increased yield by 0.3t/ha compared with equal splits at conventional timings of pre-stem extension and green bud.
Growth regulation
Agrovista technical manager Mark Hemmant says any crop with a GAI above 0.8 will need a growth regulator. “Most crops look like they will need active intervention in 2015 to prevent disappointing yields,” he advises.
Caryx (mepiquat chloride + metconazole) delivers additional yield even in the absence of lodging, he maintains. “Its growth manipulation effects ensure you end up with the optimum canopy, producing lots of seed rather than lots of pods. This delivers very useful yield benefits, even the absence of lodging – you could say you get lodging control for free.”
Agrovista trials in 2013 at Stoughton showed Caryx at 1-litre/ha produced an extra 0.3t/ha of yield even where leaning was only slight. A slightly bigger return was obtained in the dry spring of 2014, again in a crop with little leaning.
Increased branching was a key driver. “Secondary branches can contribute over 1t/ha, and we know that Caryx encourages their production.”
Further work was carried out to assess whether crops sown at wide row widths and low seed rates (500mm and 20 seed/m²) would respond in the absence of lodging. This is now Agrovista’s standard sowing recommendation after six years of trials that clearly demonstrate how this spatial arrangement helps crops produce the right branch architecture.
Work at the Morley Growcrop Gold site shows the same positive benefits – a l-litre/ha application of Caryx on a cop of Quartz sown at low seed rate in wide rows produced the same result as at Stoughton.
“A population of 25-30 plants/m² in spring will help produce the optimum structure to maximise sunlight capture and photosynthesis,” says Mr Hemmant.
“Even where you already have a lot of branches and lodging is absent, you still see better yields as treated plants redirect energy from the main raceme to the branches, maximising seed number.”
Caryx also improves rooting, helping to explain the additional yield obtained in Agrovista’s 2014 trial. Work at ADAS Boxworth that year produced an extra 0.3t/ha from a 1-litre/ha application and a margin over input cost of £63/ha.
“Metconazole, as in Caryx, can increase rooting between depths of 40 and 100cm by about 25 per cent, says Dr Berry. “This can increase water uptake by 9-10mm over the season, producing an extra 0.25-03t/ha of yield in a dry year.”
Estimating GAI
Aim of GAI 3.5 at flowering
Estimate GAI just before stem extension
GAI 2
- 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 N for large canopy crops
Using GAI for N
Each unit of GAI requires 50kg/ha of N
Optimum GAI at beginning of flowering (3.5) needs 175kg/ha
Plants and soil both contain available N – estimate how much and deduct from the 175kgN/ha target
the Fertiliser Manual (RB209), but this may vary by season
or
- Measure crop N by assessing crop GAI just before stem extension and multiplying by 50kg. Assess
using digital photographs uploaded onto www.totaloilseedcare.co.uk or using BASF’s Caryx App
Measure resulting figure by 0.6 for amount of applied N (fertiliser is 60 per cent efficient).