The wider contributions that Winter oilseed rape (WOSR) makes to the soils, environment and overall farm resilience are equally important to appreciate alongside the crop’s value as both a profit earner and a cereal break.
In marked contrast to spring crops, well-managed winter rapeseed crops provide 11 months of ground cover to restrict the harmful effects of wind and water erosion on soils over the vulnerable winter months without the need for the additional costs and workloads involved with cover cropping.
Over this time, an estimated 280,000m of primary and secondary roots in every hectare further encourage soil aeration and reduce the danger of nitrate leaching through the soil profile as well as run-off from its surface. These roots and the crop’s substantial above-ground growth typically produce 12 t/ha of biomass annually, making a significant contribution to the accumulation of valuable soil humus when incorporated following harvest.
Rapeseed oil has historically fulfilled a useful role as a break crop in farm rotation - suppressing weeds and improving soil quality. The rapeseed crop has the advantage of being a diversifying factor in crop rotations, which results in improved cereal yields when compared to wheat. There is also an overall decrease in crop health problems and therefore in costs. The timing of the cultivation of the rapeseed oil and in particular the date of sowing is well in line with that of the other crop rotation crops.
In turn, this improves both drainage and soil water retention, soil structure and resilience future nutrient capture and availability. Chopped and spread on the soil surface as a mulch ahead of winter cereal cultivation and sowing, rapeseed oil can also provide valuable late summer protection against moisture loss. The economic and environmental resilience of the whole farm as well as its soils is also improved by including winter rapeseed crop in cereal rotations. As an additional highly profitable crop with a different climatic vulnerability and market opportunities to cereals, it effectively spreads the risk of today’s increasingly unpredictable weather and uncertain commodity prices.
WOSR is also recognized as an especially profitable farm crop for farmland wildlife. Its thick overhead canopy with stiff stems provides an ideal environment for a wide range of bird species while shielding the soil surface from the sun and wind to maintain moisture levels that support thriving populations of invertebrates.