Oilseed rape cannot be grown too regularly in the same field for the risk of a serious disease build up, so it is usually used as a break between cereal crops. Other important break crops include, potatoes, sugar beet, grass leys, peas and beans all of which allow insects and fungal pests to die out between cereal crops.

In the UK the oilseed rape crop was barely known until the 1970's when the explosion in commodity prices and targeted support from the CAP raised the price to a sufficiently high level that farmers chose to grow it. Now, around 400,000 hectares of oil seed rape is grown annually, roughly one eighth of the area of wheat and barley. Most of this is autumn sown and known as winter oilseed rape.

Oilseed rape is not a very high yielding crop by comparison with cereals. Typically winter rape yields around 3 tonnes per hectare compared with 8 tonnes per hectare for wheat. However, with a higher price and the "break crop" benefit to the following wheat crop, oilseed rape remains an important crop in the arable rotation and currently the UK is about 90% self sufficient

How we start the crop off

Once the previous spring barley crop has been removed, planting takes place in the third week of August using our specially adapted cultivator drill. This is illustrated below.

 

The rape plant produces a tap root and therefore we have to provide ideal conditions for this to develop and store enough food to get the plant through the winter. Our drill provides a 300mm slit in the soil so that the roots can easily grow down to find moisture and nutrients.Once the crop has been planted we have to roll the soil to preserve moisture and to protect the seedlings from slugs.

Fertilizer

The key to growing a successful rape crop is good establishment. We help the plants get off to the best start by placing nitrogen fertilizer around the seed so that it quickly develops. If we can produce a strong plant before the winter period it is less likely to be attacked by pigeons and slugs. Rape requires high levels of nitrogen to produce a good yield of seed and we apply this fertilizer in 3 doses during the spring months. Like wheat and barley, oilseed rape also receives the correct amounts of potash, phosphates, sulphur and lime that it needs to successfully grow.

Crop protection

Oilseed rape is very vulnerable to insect attack and we need to control pests using insecticides at certain times of the year. Also, fungicides are applied to the crop in both the autumn and spring periods to protect the stems and leaves from damaging fungal attacks. Nutrient hungry grass weeds are easily removed from the rape crop and this helps reduce their numbers for the following cereal crops. Broadleaved leaves, however are not as easily controlled due to their similarity to the oilseed rape plant.

What happens to the harvested crop

Today's varieties of oilseed rape have been bred to provide an oil that is suitable for use in cooking and food processing. Known as vegetable oil, the oil is widely used by the food industry and is now being increasingly processed for use as bio diesel