Oilseed rape offers wide range of benefits
This week presents the last opportunity to sow oilseed rape this year. There is a huge resurgence of interest in the crop for a number of reasons.
For a start, it achieved a better gross margin than any of the cereal crops this year. It also provides a take-all break and leaves high levels of residual nitrogen for subsequent crops of winter wheat. It can also help control annual and perennial grass weeds. Finally, it spreads the harvest workload, since it will normally be cut before winter wheat.
Heavy to medium soils, similar to those required for wheat, will give good yield potential. However, rape will not tolerate water-logging. Crop rotation is important to minimise disease risk so rape should not be sown more often than one year in 4-5.
Crops isolated from other crops will also have less disease risk from wind-borne diseases. Hybrid varieties have extra vigour and should do better than conventional varieties when sown late. Seeding rate is dependent on variety, seed size and required plant stand but will range from 3kg/ha (60-70 seeds/m2) for hybrids to 6kg/ha (100-120 seeds/m2) for conventional.
Larger seeds will normally give better plant establishment and produce more vigorous plants. If this is your first year growing rape, it is particularly important to read all pesticide labels carefully so as to avoid risk to this year's crop either from chemicals you are applying now or indeed herbicides that were applied last spring to the previous cereal crop.
Plough or thoroughly cultivate before sowing if products such as Hussar were used during the past year. Sowing depth should be shallow at 20-30mm, but make sure there is at least 15mm soil covering if you are using pre-emergence weed control with either Butisan S or Katamaran.
Do not use pre-emergence herbicides if heavy rain is forecast. Pre-emergence weed control is best for both poppy and cleavers.