No easy answer to secondary growth in spring barley

Secondary growth – it’s the conversation starter among tillage farmers these days. “What are we going to do with all this secondary growth?”

Well there is no easy answer.

Secondary tillers are visible across fields and tramlines of spring barley crops and will cause rejections on quality and high moisture levels for some farmers.

Pre-harvest glyphosate cannot be applied to a crop destined for the human food chain, for malting barley or for seed and can only be used in other crops where there is a weed problem.

As crops are thin this year there are plenty of weed problems out there where plants made their way up through the thin crops.

However, the other side of the problem this year is yields are back and price is low. So adding more cost is not helpful either.

Assess the crop

AgriLand spoke to Michael Hennessy who is head of crops knowledge transfer at Teagasc.

“Not every crop in the country needs or should get a crop dessicant,” Michael stated.

“There’s a good bit [of second growth] coming back in relatively thin crops and then you have all these green tramlines, but what we’re saying is people should try and assess crops on a field-by-field basis.”

He added that this assessment should take place around the time that the main crop is ready for glyphosate – when the grain is at approximately 30% moisture content and will take a thumbnail.

If the green shoots around the main crop are late grain fill scenarios, and they’re pretty full, the crop that’s ripening around them will help these green shoots to ripen faster. However, it will delay harvest by a week or so.

Where there is a weed problem that needs to be controlled, and there is a lot of secondary growth, growers should time the application for the harvest date of the main bulk of crop.

For example, where there is a weed problem and the the secondary shoots are just starting to flower or starting grain fill when the rest of the crop is at 30% moisture content then glyphosate could be used on those parts of fields or entire fields.

Other alternatives include whole cropping the crop for animal feed or leaving these very green areas unharvested for a few weeks and harvesting later in the year, if this is worthwhile.

Green tramlines

Many people driving the roads will have noticed a lot of green tramlines in most crops and as Michael said “there’s no easy answer to that”.

He added: “If the grain in the tramlines is bulking up reasonably well it could just be a scenario where farmers, especially on the malting barley side, just leave the tramlines until the end to harvest and not wreck every load of grain.”

Where tramlines are very green some growers are considering driving through the tramlines to beat down the green shoots underneath the head of the combine.

However, if the problem was only in the tramlines, that amount of green grains wouldn’t be a big issue. It’s the green grains throughout the field that are going to cause problems.

Michael advised farmers to take samples near to harvest time and decide if the barley is destined for feed or not.

Glyphosate is only used as a last resort to control weeds and cannot be applied to seed, malting or feed crops for human consumption.

Michael recommended anyone with a weed problem to consult with their advisor.

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