Active Management key to oilseed rape yield

Article taken from the FarmBusiness

This season’s big OSR crops need active management if they are to yield well, Agrovista's Mark Hemmant warns. Speaking at a joint event with BASF at Stoughton in Leicestershire, he said the building blocks for good yields were in place. "Establishment was good, crops have come through the winter well, and for crops drilled using deeper min-till, rooting looks like it's been strong,” he said.

“But, we still have some way to go with many crops certainly lodging-prone. Also, the excess biomass present in many crops will create shaded canopies with limited branching potential, shown in Growcrop Gold trials to limit seed set and pod fill.”


Mr Hemmant said there were three types of crops this spring: quickly-established ones that were running out of steam and declining rapidly; low seed rate crops with good structure and biomass; and high seed rate crops that were going to be vulnerable to lodging and shaded canopy issues.

"The main agronomic attention needs to be to minimise pigeon damage, delay nitrogen applications, but ensure well-timed sulphur applications and the application of a robust growth regulating fungicide programme,” he said.

He saw Caryx, "the only plant growth regulator for oilseed rape, as an important ally this spring. “ADAS work has shown it's very good at reducing lodging risk as well as managing canopies. It can only be applied once in a season, so if the target's lodging prevention, applications should be made stem extension. For canopy manipulation to improve light penetration, applications should be at yellow bud stage, along with strobilurin for sclerotinia management."

Caryx contains metconazole and mepiquat chloride, active ingredients with complementary modes of action and consistent performance, even in low temperatures. Trials delivered positive rooting effects and good crop height reduction, says maker BASF.

Mr Hemmant suggested 1.0 l/ha was likely to do a similar job to full rate metconazole, but on high-risk, high-fertility sites, a full rate 1.4l/ha was his recommendation.

BASF's Will Reyer saw Caryx and the assessment of green area index (GAI) as crucial this spring. “A plant's seed numbers are set in the two to three weeks after the end of flowering; the challenge thereafter is to ensure seeds fill well, by keeping plants healthy to maximise photosynthesis, which can be achieved by having a green area index (GAI) of 3.5-4.0 at flowering,” he said.

BASF and Agrovista launched an updated GAI app for iPhone at the event. "The app gives you an accurate assessment of an OSR crop's GAI from a digital photograph taken with your phone. The size of the rape crop's canopy is a critical indicator for growth regulation application decisions on both conventional and wide-row crops,” Mr Reyer said.

Growers and advisers can also upload photos from any digital I camera or smartphone to a GAI tool at to assess GAI.

Mr Reyer said growth stage was king in managing oilseed rape: "You should measure GAI in March even if you intend to apply fungicides in April. Our trials suggest that just prior to onset of stem extension is the right time to measure canopy size.”

  • The Caryx app can be downloaded from the iTunes App store.


21 February 2014

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