1 Sep 2017
The Clearfield production system for oilseed rape is a unique system that offers unique benefits. Combining vigorous, hybrid varieties with innovative BASF herbicides, effective against a large number of weeds.
Clearfield varieties have been developed using traditional plant breeding techniques and are tolerant to the imidazolinone group of ALS inhibitor herbicides, which includes post-emergence, imazamox-based Cleranda (imazamox + metazachlor) and Cleravo (imazamox+ quinmerac).
This autumn, 11 varieties are available from Monsanto, DSV, Pioneer and Grainseed, providing a range of growth habits, disease resistance, and for many, yields comparable with mainstream varieties.
Why consider Clearfield?
“Clearfield gives a ‘rapid start effect’,” Clare Tucker, BASF Business Development Manager explained, “This early vigour allows fast and even establishment in the autumn, which is so critical to mitigate the effects of challenges such as cabbage stem flea beetle attacks.
In addition to hybrid vigour, varieties are tolerant of possible residues from sulphonyl urea (SU) herbicides used in previous cereal crops, allowing the plants to get off to the best possible start.”
Wide range of weed control
Both Cleravo and Cleranda offer very similar broad-spectrum, weed control and can be used as a one-shot option. However, where high populations of weeds that get big quick are anticipated, such as crane’s-bill, poppy or mayweed, Cleravo allows the option of an early application of metazachlor or Springbok to sensitize them.
- Broad-spectrum, broad-leaf weed control
- Brassica weed & volunteer OSR control, ensuring a pure oil sample and the ‘designed’ crop stand.
- Control of volunteer cereals, wild-oats, bromes & ryegrass present at spraying
Clearfield herbicides are also unaffected by establishment system due to their foliar application.
How to get the most out of Clearfield?
Good agronomy is needed to get the best from the Clearfield system and here, Ms Tucker gives some key pointers which will allow growers to maximise Clearfield’s potential.
Two key things to remember
- Timing – Apply to small, actively growing weeds. Target 1-4 true leaves for broad-leaf weeds and 2-3 true leaves (max. 2 tillers) for volunteer cereals. Typically weeds will be at this stage in September and October.
- Foliar uptake – Ensure good spray cover.
- A water volume of 100 l/ha is OK. If it’s a thick crop use angled nozzles, rather than increasing the volume.
- Apply as a medium spray, using flat fan or small droplet air induction nozzles, not coarse
- Allow a minimum of 2 hours to become rain-fast (if applied to a dry leaf)
- Always add Dash HC 1.0l/ha as it improves leaf cover and uptake
- After application, wash sprayer tank thoroughly, as per label.
- Keeping records is also very important. It may be practical to add the suffix CL to the field name as a reminder and will help to avoid misapplication of Cleranda and Cleravo to non-Clearfield varieties.
- To control Clearfield oilseed rape volunteers in following crops
- Reduce the risk of dormancy by delaying cultivation for 2 weeks, if moisture is available, or 4 weeks if it remains dry. This will encourage an early flush before the next crop and/or within the following one.
- Ensure herbicide programmes in following crops include non-Group B herbicides.
Cleranda contains imazamox and metazachlor; Cleravo contains imazamox and quinmerac. Astrokerb contains aminopyralid + propyzamide. Cleranda and Cleravo are registered trademarks of BASF. All other products are those of other manufacturers where proprietary rights may exist.*Astrokerb is an alternative option here where propyzamide is already planned for blackgrass