Oilseed rape looking good
Early yield results are reasonably consistent at 3.7 – 4.5 t/ha. Given favourable weather conditions, it is likely that the area planted will increase as margins look promising for 2013.
Winter oilseed rape is suitable for both food and feed use. The crop is usually sown before mid September, to get good establishment.
OSR is an excellent break crop in a cereal rotation resulting in increased yields of the following wheat of 1.5t/ha approx. OSR plants also improve the soil structure. Grass weeds (e.g. Sterile Brome) that are difficult and costly to control in cereals can be controlled conveniently in OSR.
Free draining, medium to heavy soils are best suited to oilseed rape production. OSR should not be grown on land where brassicas have been grown during the previous four years.
Prepare a fine, firm, level seedbed. Sow to a depth of 1.5cm (0.5 inch). Ploughing followed by one-pass drilling technique is still popular but min till is also satisfactory.
Ideally cultivation should be done when soil conditions are dry as rape does not like
compaction. The seedbed should be rolled as rape requires a consolidated
seedbed and also to retain moisture.
Research work by Teagasc Oak Park (‘05-‘07) work has shown that under good conditions, seeding rates should be 60-80 seeds/m2 (lower rates are for hybrids).
Yield, disease resistance, standing power and earliness of maturity are the most
important factors in variety selection. The HCCA recommended list is our best guide to the most promising varieties and the DAFF 3 year yield data.
ADAS trials show that 150 volunteer cereals/m2 can half the yield and just 20 cereals per m2 can knock yield by 0.15t/ha while 150 broad leaved weeds will reduce yield by 8%. Scutch should be controlled in the previous crop but graminisides may be used in the growing crop.
The stale seedbed technique can be used in a minimum tillage rotation e.g. shallow cultivate and roll and then use glyphosate products to dessicate emerged weed before sowing.
Post Emergence
Graminicides can be used from the one true leaf stage of the OSR up to early flower bud stage. However, application is recommended early at the 2-3 leaf stage of the grass weeds before they are sheltered beneath the OSR canopy. A second application may be required, to control later germinating weeds or on thin crops.
Two-spray sequential programmes are very effective in min-till systems. If early weed competition is not too heavy, particularly in ploughed seedbeds, a single graminiside application later in the autumn may suffice.
A fungicide programme for the control of the main diseases Phoma and Light Leaf Spot will involve 1-2 applications. Monitor crops closely in October-December to identify symptoms.
Slugs and pigeons can attack rape. Control slugs where anticipated by the application of metaldehyde pellets eg. Matarex or methiocarb pellets eg. Draza. Pigeons are usually only a problem on late sown crops.
