In recent years the area of winter oilseed rape has stabilised at around 8,500 hectares. Target yield is 5t/ha, which many growers achieved in 2020, but there has been some variability in recent years – see table 1. Late sowing and pigeon grazing have been factors in low yielding years. Typically winter oilseed rape is sown after winter barley which increases the chances of getting the crop sown in August.
Area and yield of winter oilseed rape
Source Teagasc harvest report & cso.ie
Oilseed rape is a member of the Bracassia family and is grown for its oil content.
There are a number of types of oilseed rape, both winter and spring, which can be grown.
Oilseed rape can be further segregated into “Double low” varieties, HEAR varieties and HO, LL varieties. Oilseed rape naturally produces contain some unwanted compounds, erucic acid and glucosinolates. These compounds were found to be harmful (immunotoxic) to both humans and animals.
- 'Double low' varieties (low erucic acid, less than 2% of measured fatty acid, and low glucosinolates, less than 35mmol/kg in the meal) are the most commonly grown in Ireland and typically have oil content of 43-44%.
- HEAR (high erucic acid rape) varieties are more specialised and are generally grown for specialist markets (including bio-fuels) and are regarded as non-food crops.
- HO, LL (high oleic, low linolenic fatty acid profile) varieties are healthier for human consumption and have high stable oil for the food processing industry.
Oilseed rape acts as a break crop from the take-all fungus which adversely affects wheat. Yield of wheat sown after sowing rape can increase by 0.5-1.5 t/ha depending on the incidence of take all during the growing season.
The returns from oilseed rape often compare less favourably with cereals, however the rotational benefits from first cereals after oilseed rape can result in extra profitability from the cereal crop and so the return over two years are usually similar to two cereals crops.
Link to “Winter Oilseed Rape Profit Monitor analysis 2017”
Link to “Spring Oilseed rape Profit Monitor analysis 2017”