Growing Winter Oilseed Rape

Fertilisation and nutrient deficiencies

Many mineral elements are essential to successfully growing winter oilseed rape (WOSR). A deficiency in any one of these elements can have a significant impact on final performance.

Nitrogen

Rapeseed needs 7kg of nitrogen per hundredweight produced. Nitrogen requirements are weighted more to the end of winter. The nitrogen supply for WOSR must not exceed 100kg/ha over a single period, otherwise the nitrogen supply can be susceptible to leaching and will be washed away and your investment lost.

Be careful in some regions, as there are restrictions on the application of nitrogen after August 31. To deliver the right amount of nitrogen to the winter application, it is important to weigh the biomass. It is possible to use a conversion table, available as a mobile app, as a decision support tool or a drone to estimate the biomass and the amount of nitrogen recommended to be supplied.

Nitrogen Loss

Nitrogen is easily lost to leaching via water. The key to success is to provide the right amount at the right time, allowing the WOSR to use the maximum amount of nitrogen supplied.

• It is recommended to split up the applications made after the winter and not to exceed 100kg/ha per application.
• By observing these rules, you maximise the efficiency of your fertilisation investments while reducing your environmental impact by limiting losses through:
  • • Volatilisation in the form of NH3
    • Pollution of groundwater in the form of NO3 nitrates through washing out and leaching

Phosphorus and Potash

Rapeseed is a very demanding plant in terms of phosphorus use, however, it is less so with potash. If no fertiliser was applied in the year before the WOSR was planted, it is recommended to apply both components before sowing. To estimate the amount of phosphorus and potash required, you can refer to the table below.

Phosphorus and Potash Fertilisation Recommendations by Soil Type

Sulphur

Winter oilseed rape is a demanding crop in terms of sulphur requirements. A sulphur deficiency can have serious consequences on the final yields. WOSR requires sulphur inputs in the form of sulphate. Timing wise, it is important to bring 75kg/ha of sulphate (S03) at the beginning of bolting. If organic fertiliser has been spread on the field, take into account the amount of sulphur from this as you calculate your sulphate application.

To get agronomic advice or find seed, contact find your local MAS Seeds representative.