WOSR Fertiliser requirments using GAI canopy management research by Teagasc with Seedtech
Oilseed Rape in Focus
On January 19th, I hosted our ‘Oilseed Rape in focus’ event in Oakpark, in conjunction with John Spink of Teagasc Oakpark, Liam Wilkinson of Limagrain in a crop of LG Aviron.
The main topic covered was how to save €100 per acre on the average crop of WOSR in the next few weeks (most WOSR crops are 2 Green Area Index (GAI) which can save 100 kg N/ha) using the Teagasc canopy management research.
Why grow winter rape in 2022?
Breeding has ‘moved the dial’ with newer varieties
Workload: Only crop we can drill in August and early September
Soil Fertility: Only crop that can use (low cost/free) slurry/manure in
August Autumn growth: Only crop that can use/store sunshine in August/September and reduce fertilizer N in spring (GAI method) – better than a cover crop!!
Grassweeds: Only crop that can use propyzamide (Kerb) that has no known grass weeds resistance
Break crop benefit > oats
WOSR crop and the effect of radiation on N requirements
Canopy Management Research conducted by Teagasc Oakpark, on how Winter Oilseed Rape can capture and use N.
Canopy N (GAI) remains in the crop.
Each unit of GAI contains 50kg of N
Crop requires 3.5 GAI at flowering
Applied fertiliser efficiency of 60%
Each 1t yield >3.5t/ha needs 60Kg /ha
UK developed system validated
Calculating N requirement
Save Fertiliser N if post-winter crop size allows
WOSR is the only Autumn sown crop that has the ability to harness sunshine and use /store in August, September, October and reduce Fertilizer N in Spring.
Conclusion: Oilseed Rape and N
2021 / 2022 season
Exploit the N in the crop
N cost savings compared to a small 0.5 GAI canopy (CAN at €680/t)
GAI 1.0: 33kg N sparing: €83/ha (potential saving)
GAI 1.5: 67 kg N sparing: €168/ha
GAI 2.0: 100 kg N sparing: €251/ha
Future seasons:
Potential will vary with season: sowing early allows it to be exploited
But you must reduce N if you have it in the crop or soil
Avoid excessive canopy size at flowering: poor pod fill, lodging.
Variety Profile - Yield
Variety Profile - Agronomics
If you would like more information on what to sow this spring, see HERE
If you have any queries, please contact Nigel or me.
