Oilseed rape

 

Rapeseed for oil and energy

The oilseed rape crop is of enormous importance for many agricultural producers in the EU. Currently the demand for oilseed rape exceeds the supply and for this reason, stable producer prices are probable. Since rapeseed oil is a highly nutritious cooking oil, demand on the world market is rapidly increasing. Large volumes are required for processing oil into biofuels as a renewable energy source and this had recently added to the demand for the crop.

 

Oilseed rape has great cultural benefits also; the introduction of a combinable broad-leaved crop to break the continuous cycle of cereal growing can increase yields of winter wheat by upto 10%, furthermore a break in the rotation allows pest and disease pressure to be managed more effecticvely. Oilseed rape is a crop which is also particularly suited to minimum tillage farming which represent savings to the grower in time, energy and costs.

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Oilseed rape requires potassium

Rape seed has specific nutrient requirements and, for an optimum yield, it requires besides nitrogen especially potassium. 

• In spring, at the start of the growing season, large amounts of potassium are taken up in a short period of time since potassium uptake precedes biomass production.
• When the canopy is fully developed, a crop of rapeseed can contain up to 400 kg K₂O ha^-1.
• Depending on the development of the plant, by the beginning of winter 100 kg K₂O ha^-1 may have already been taken up.
• A good supply of potassium increases the frost resistance of the crop and, therefore, results in fewer losses during harsh winters.
• Plants are more able to cope with drought stress much more efficiently because of their optimized water balance.
• The synthesis of oil is aided by the activation of enzyme metabolism.

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Magnesium und Sulphur for a high oil content in oilseed rape

Magnesium 

• The majority of magnesium (Mg) required is taken up before pod development.
• The magnesium requirement of an oilseed rape crop is approximately 60 kg MgO ha^-1.
• Following a severe winter with a large loss of foliage, a good supply of magnesium is important for the development of new leaves.
• The improved assimilation by the plant, especially by the pods has a positive effect on the synthesis of oil and overall yield.

 

Sulphur

• With a requirement of 50-70 kg sulphur ha^-1, rapeseed has a very large sulphur demand.
• An optimum supply of sulphur results in a more efficient utilization of nitrogen and, therefore, has a positive effect on yield.
• Oil content is positively affected as sulphur is directly involved in the synthesis of fatty acids.
• Minor temporary sulphur deficiency may be controlled until late budding by means of foliar applications of ESPO products without any yield loss. However, more prolonged deficiency can result in yield losses of up to 75 %.
• The uptake of sulphur in oilseed rape occurs in conjunction with magnesium and, therefore, a combined application of both nutrients is recommended.
• Organic fertilisers and manures are generally insignificant sources of sulphur for this demanding crop. 

 

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Boron fertilisation – standard practice in oilseed rape

• Oilseed rape belongs to the group of boron requiring crop plants.
• During the growing season an oilseed rape crop can take up approximately 350-450 g boron ha^-1.
• Swollen lower parts of stems, compressed growth, development of root cavities, reduced growth of secondary side roots, as well as poor pod set post flowering are possible effects of an insufficient supply of boron which will adversely affect yield.
• Therefore for oilseed rape growing areas it is advisable to include boron content in soil analyses.
• Boron content of lighter soils should not be lower than 0.2-0.5 mg boron per kg soil and for heavy soils no less than 0.25-1.2 mg boron per kg soil using CAT-analysis.

 

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Attention to provision of manganese on high organic matter soils

• Shortages in the supply of manganese occur predominately on soils with high organic matter content and/or high pH values or after applications of lime.
• Manganese, like magnesium, affects synthesis of chloro-phyll and photosynthesis. This ensures a high assimilation rate and affects yield positively.
• The increased growth of secondary side roots improves the uptake of nutrients from the soil.
• Only a well supplied crop can guarantee a high output potential.
• To avoid competition for nutrients, a foliage application of manganese should always be combined with an application of magnesium.

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Fertiliser recommendations

Fertiliser is applied in order to maintain the fertility of the soil so that its natural yield potential can be protected over the long term. This requires the maintenance of an optimal nutrient content in the soil. Nutrients removed with the harvest have to be replaced through an adequate application of fertiliser. Together with the replacement of removed nutrients adjustments have to be added for site specific losses (for example: leaching or erosion).
 
The total removal of a plant results from the nutrient uptake of the main crop (e.g. grain, tubers or beets) and the uptake of harvest residues (e.g. straw, leaves). If the harvest residues remain on the field, only the removed nutrients by the main crops have to be replaced.

 

Recommendations for soil applications

The table shows fertiliser recommendations calculated on the nutrient uptake of the main crops on base of an optimal soil nutrient content. Adjustments for site-specific losses due to leaching, fixation or erosion are not taken into consideration.

• Approx. 400-600kg Korn-Kali^® ha^-1 for potassium requirements and, at the same time the magnesium and sulphur requirements.

   

  Korn-Kali^®

• Approx. 200-300kg Patentkali^® ha^-1 for sulphur and magnesium requirements in spring and at the same time supplementing potassium.

   

  Patentkali^®

• Approx. 200-300kg ESTA^® Kieserit ha^-1 for sulphur and magnesium requirements, 300-400kg ha^-1 for severe sulphur and magnesium deficiencies.

   

  ESTA^® Kieserit gran.

 

Recommendations for foliar applications

• 20-25kg EPSO Top^® ha^-1 or EPSO Microtop^® as a 5% concentration for periods of high demand or for the control of latent deficiency of magnesium and sulphur, as well as for deficiency of trace minerals. Several split applications should be given between rosette and flowering stage.

   

  EPSO Top^®

  EPSO Microtop^®