Winter Oilseed Rape
• The location of the farm is an important factor as different disease pressures will influence certain criteria that the variety will need to display. For example, light leaf spot pressure is far more of a consideration in the North and Scotland. Temperature also plays a part as some colder regions will need a variety with greater winter hardiness.
• Different varieties will suit different situations and heavy or light soils can influence factors such as establishment or vigour, so crops need to be chosen accordingly. Soil diseases like clubroot will also be a key factor in selecting the right variety. For example, Crocodile CR, a variety resistant to common strains of clubroot, offers a high yielding option for sites affected by this disease.
• The aim is to achieve good seed to soil contact to ensure rapid seed germination and good conditions forresidual herbicides to work effectively.
• Short OSR rotations can result in higher pressure from soil borne diseases such as stem canker and verticilium wilt. Consideration should be given to rotation length and disease resistance scores when making variety choices. For example, a variety like DK Expansion offers excellent resistance to stem canker, whilst the conventional variety Flamingo has shown strong resistance in verticilium trials.
• Early vigour and speed of development will influence decisions on drilling date and therefore help to manage the workload at the busiest time of year. Maturity windows can also be chosen to ensure that the optimum OSR harvest doesn’t clash with other crops that might be on farm. Varieties that can be drilled later tend to be hybrids, but Ballad and Flamingo have excellent vigour and could be an option for later drilling.
• With chemistry restrictions making weed control difficult, different input options might need to be considered, for example in Clearfield, where brassica weeds are problematic. DK Impression CL yields very closely to the top varieties with the added benefit of good broad leaf weed control from the Imazamox herbicide.
• OSR has a more limited market than that of cereals; however, there are still options to consider, such as growing a specialist oil profile like HEAR or HOLL, to attract a premium. This does have some practical considerations, including isolation from other OSR crops, but offers options beyond the one market that double low OSR trades into.