2018 – What went wrong with black-grass control? - Dick Neale - Agronomist & Arable Farmer

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For many it is no more or less than expected, but for others it is a shocking realisation of what a few surviving plants seen in February can morph into come June – very frustrating when all the variable expenditure is in place and the prospect of spraying off is too much to bear.

Those who have implemented many of the learnings that have come out of Hutchinsons’s Black-grass Centre of Excellence at Brampton may be somewhat frustrated by a spike in surviving black-grass plants this year, but, in the main, continue to see significant progress being made in black-grass control across their farms.

What is important, however, is for individual growers to conduct an immediate post-mortem and recognise what went wrong and why.

Technical manager Dick Neale says: “Ask yourself, was the wrong choice of cultivation made? Was the field returned to winter wheat too soon?  Was it drilling a bit too early or missing out the pre-drilling glyphosate? Was there a delay in pre-em application?”

Mr Neale urges growers to consider some key messages that were learnt from Brampton when approaching the next season.

As a starting point, he suggests zoning fields red for heavily infested fields or green where black-grass is minimal amber is a ‘red in denial’.

In doing this, it is possible to identify the fields that require the most severe measures.

Have patience, he says: “While growers will be keen to sow ex-oilseed rape (OSR) seedbeds first, it has been regularly observed these are among the last to see dormancy break.

“An OSR or bean crop with significant black-grass seed return will almost inevitably lead to poor control following first wheat.

“Balanced rotations have to be shelved in the short term in order to focus on the long term need for good black-grass control, and with this in mind, spring barley is the new winter wheat.

“For the very worst of infected fields, a plan of two spring barleys or a 3-4-year grass ley are, in reality, the only viable options.  Our work at Brampton has established that while a spring wheat may be a viable crop with far less black-grass return than in winter wheat.  It sill returns seven times more seed that a spring barley crop – making it unviable as a long-term control solution.”

Mr Neale points out that other spring cropping options such as spring beans, sugar beet, linseed and peas are uncompetitive and limited with regards to chemical black-grass control options.