The vigour and traits Clearfield varieties offer combine to produce a high gross output, according to arable manager Jon Fountain, and have therefore become an integral part of the rotation for the past four years.
Managing the 1,000-hectare Sentry managed joint venture in Hampshire, Agrii grower Mr Fountain said BASF’s InVigor (InV1266) Clearfield (CL) variety, in particular, had proved to be instrumental to his integrated approach to growing the crop.
“This year is our first harvest using the high vigour InV1266 OSR over 40 hectares.
“CL opens up the option to make more use of companion crops in the rotation and serves as a vital tool in tackling problematic brassica weeds, such as Charlock,” he said.
The Clearfield system also helped to reduce the potential contamination coming from volunteer HEAR oilseed rape and brassica weeds high in eurucic acid, he said.
BASF business development manager Clare Tucker echoed this: “Clearfield herbicides allow for timely weed removal and have the widest spectrum of any herbicide, including brassica weeds mentioned.
“In early drilled crops, weeds, such as charlock and chickweed, get big quickly and need timely removal.
“Volunteer rape can also be a problem, causing over thick plant populations and not achieving the strong plant in the spring we are after.
Clearfield herbicides help us to achieve this,” she said.
The ability to control such weeds early on without the added front-loading costs of pre-emergence herbicides earlier in the programme also made the CL variety a ‘flexible’ option.
“This is our third harvest using buckwheat as a companion crop; we will grow CL oilseed rape followed by winter barley.
We will then apply manure and direct drill the buckwheat in early August, a week before the oilseed rape.
“The InV1266 variety has got away well and gives us confidence to implement companion cropping, which is sometimes the difference between failure and a profitable crop,” Mr Fountain added.
Once the buckwheat has provided the early benefits it is removed by the herbicide before it causes excessive crop competition.
Addressing the link between drill date and disease pressure, Mr Fountain highlighted the fast autumn growth of InV1266 as a trait which had made the variety particularly attractive when looking to mitigate the risks posed by cabbage stem flea beetle (CSFB).
“The variety can be drilled any time from August up until the second or third week in September, which allows us to adopt a flexible approach to pest management,” he said.
Ms Tucker added the battle against CSFB was not only about reducing the damage from adult feeding but also about improving the resilience of the plant to tolerate the larvae in the spring.
“We’ve a fighting chance of doing this if we aim for a moderate seed rate, fast and even emergence, and good autumn vigour to establish strong individual plants in the spring.