Agronomy Advice

Planning for Successful Oilseed Establishment

By: Mark Tucker

Oilseed rape can be a tricky crop to establish, so attention to detail is critical to overcome various obstacles that can affect early growth and development.

Oilseed Rape field
Oilseed Rape field

With current crop and input prices the stakes are high, so time spent planning your early crop management will be very rewarding.

Fitter, Faster, Stronger a phrase as applicable to oilseed establishment as it is to elite sport performance. Crop Nutrition has a vital part to play in achieving a fitter, faster, stronger crop.


A fit crop is much more able to overcome the stresses that can affect early crop growth right from germination. Phosphate and potassium, in particular, are key for this early phase of growth. We want to promote maximum root and shoot growth so that the crop is able to access water and other nutrients from the soil. Managing the crop towards building a large root mass also builds in resilience for the rest of the crop’s life, minimising the impact of spring drought and maximising spring nitrogen uptake, therefore improving nitrogen use efficiency.


Having adequate levels of potassium in leaves helps to lower the cell sap’s freezing point (a natural anti-freeze) preventing frost damage, and increasing winter survival. Good water regulation is important in dry autumns and in freezing conditions. Potassium helps limit water loss when the plant struggles to access sufficient from the roots.


It is well understood that speed of crop development is a vital ingredient for successful oilseed establishment. There are two elements to consider here. Firstly, there is the application (timing and method) of the fertilizer and secondly there is the nutrient itself (rate and availability). The application timing is simple: nutrients should be applied at the time of drilling, or immediately post drilling. Do NOT wait and see, as by then soils are cooling down, growth rates will be slowing and the return on investment will be poor. This seedbed application of fertilizer will ensure leaves and plants are bigger, and growth rates are faster.

The method of application is more complex. If the equipment / technology is available then placing the fertilizer, whether liquid or solid, adds further to the speed of emergence and early growth and vigour. Placing fertilizer also allows application rates to be reduced by up to 1/3rd e.g. from 30 kg N/ha down to 20-25.

OSC Crops

If placing fertilizer is not an option then broadcasting is still very effective and will give that all important speed of establishment, keeping the growth momentum going, and minimising the impact of pests such as CSFB.

With regard to the nutrients themselves then speed of growth is especially influenced by Nitrogen, with a 30kgN/ha application rate allowed in the autumn if you’re in an NVZ. This rate can be reduced however if you’re placing your fertiliser, down to 20-25kgN/ha due to the application being more precise. In order for the plant to get maximum benefit from this nitrogen application, then it is important to have some sulphur available to the crop. If sulphur is limiting, then the early growth will be restricted as it is the building block for nitrogen use in a crop’s growth and development. Phosphate, in particular, doesn’t travel very far in the soil (less than 1mm) therefore placing the fertiliser at drilling will ensure that the nutrients are close to the seeds so that they can access them quickly upon germination.

When considering the fertilizer product of choice then pay attention to the ingredients. Time is of the essence with immediate crop availability being essential. With that in mind, choose a fertilizer that delivers available nutrient for an immediate crop response. Available nutrients are the ‘ates’ – nitrate, phosphate and sulphate. Regarding phosphate also look to products that give season long supply through containing a mix of ‘ortho’ and ‘poly’ phosphate. These are least at risk of ‘fixation’ rendering them unavailable. Products that fit well are YaraMila ACTYVA S (16-15-15 +6.5% SO3) as a solid product. If using liquids then CHAFER 18-27-0 is also a good fit for autumn placement.

A new innovation, and still in trials, is a broadcast application of the organo-mineral fertiliser Yara NATURE (8-3-3) applied at 375kg/ha. With its 45% organic matter base you can expect additional soil health benefits from applications. First year trials look very encouraging when compared to conventional, mineral fertilisers.


Stronger plants come from a having a balanced crop nutrition program in place. Bigger is not always better. By way of an example, big plants achieved through applications of straight nitrogen can be very weak if they do not have the potassium to maintain the turgor of cells in leaves and stems, resulting in wilting and floppy growth. Furthermore, if the plants are well supplied with nitrogen, but molybdenum is in short supply, nitrogen metabolism will be poor resulting in small leaves, rich in nitrate nitrogen that can encourage and increase disease levels, therefore weakening the plant. Increasing crop shoot and root development with the NPKS seedbed / starter fertilizer generates an increased demand for micro and macronutrients as cell multiplication is rapid. Two to highlight for the stem and leaf cell strength would be calcium and boron as these both create strong cell walls. This strength will help mitigate the impact of CSFB feeding as they invade petioles and stems. Research trials have shown that the placed application of YaraMila ACTYVA S reduced CSFB larvae count/plant.

OSR Trial

When looking for a starter fertiliser for OSR then an NPKS compound product is ideal. A compound means that all the nutrients are in the same prill/granule, so wherever it lands gets the correct analysis that’s on the bag, in a good even application.

Once the crop has established then we can turn our attention towards applying foliar micronutrients. When the crop has enough biomass, 4-6 true leaves, YaraVita BRASSITREL PRO can be applied. BRASSITREL PRO is a crop-specific foliar micronutrient mix which contains the key micronutrients (calcium, boron, magnesium, molybdenum, manganese) that are required for brassica crops, in one handy can. The idea of the crop-specific mixtures is to supply the crop with all that it needs to prevent deficiencies occurring in the first place, as once symptoms become visible they are already affecting the crop’s yield potential. Long-term trials data shows you can achieve a 0.27t/ha yield increase from using YaraVita BRASSITREL PRO in the autumn and spring at 2-3 l/ha.

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Recommended fertilisers

The following fertilisers are recommended for early season application to all crops and will supply nitrogen, phosphate, potash and sulphur (NPKS) ideal for early season applications to cereals together with a recommended foliar phosphate to give crops a boost of energy

Read about improving nutrient efficiency

Wheat agronomy and fertiliser advice
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