By Natalie Wood,

Country Arable Agronomist at Yara UK

Adequate nutrition has always been important for good establishment of oilseed rape and autumn micronutrients have an important part to play.

Typically, there always tends to be a wide variation in the state of oilseed rape crop across the country. Some crops drilled into moist seed beds have faired well are already getting well established, whereas other crops which went into drier conditions are struggling, particularly since OSR roots aren’t able to grow through solid soil well and tend to curl up, rather than penetrate through.

Micronutrients play an important role at either end of this spectrum. Large plants that haven’t had any foliar micronutrients applied may be struggling to get sufficient nutrition from the soil, having depleted the reserves. Small plants will need all the help they can get to overcome pests and grow sufficiently before winter arrives and soil temperatures start to drop.

Several key micronutrients are needed by oilseed rape – but manganese, boron and molybdenum are the main micronutrients for oilseed rape and are important for early plant establishment, plus the maintenance of healthy green leaves.

* Manganese is necessary for photosynthesis and protein synthesis whilst also regulating the activity of nitrate reductase. As such deficiency leads to an accumulation of nitrate in plant tissue which can encourage diseases as well as reducing the plants tolerance to cold temperatures over winter.

* Boron has several key roles in plants and is required for both cell division and cell elongation, boron is particularly important for root development, during stem extension and at flowering.

* Molybdenum is needed by plants to utilise nitrogen and similar to manganese a deficiency can lead to high levels of nitrates in plant tissues.

Consider a specific application of a balanced combination of micronutrients, including manganese, magnesium, boron and molybdenum as a foliar application that are important for oilseed both in the autumn and spring. This is a precaution for potential micronutrient deficiencies before they start to show symptoms – once this occurs, then yield is already being lost.

An autumn application can reduce the susceptibility of oilseed rape to disease and help to increase establishment. Recent Yara trial data from the 2018 harvest has shown an average yield benefit of 0.46t/ha from an application in the autumn and the spring.

At ex-farm prices of £320/tonne this yield benefit would give you an extra £147/ha with a return on investment of about 4:1 from the two applications.