Secondary tillers in cereal crops are likely to require careful management in the run-up to harvest.
Light-land winter barley crops appear to have been particularly badly affected, but both wheat and oilseed rape have also responded to renewed moisture in May and June with a resurgence in growth.
Crops struggled to take up nitrogen that was applied during the dry spell, said Ben Freer, development agronomist for The Arable Group. Instead, crops bolted through growth stages to heading. “Then we had the sudden surge of moisture in May, and the crops thought, hang on, we’re not doomed yet, grabbed hold of the nitrogen, and put down some more tillers.”
The impact was likely to be higher grain nitrogens and screenings, he said. “But even if everything is over 2% nitrogen the maltsters still need malt.”
Some varieties are more affected than others. At TAG’s Morley open day last week, Saffron and new malting contender, Wintmalt, had noticeably thrown more tillers. “In the variety trials the later-maturing varieties look worse at the moment, while the six-row varieties seem to be less affected.”
In some fields the ratio between maturing crop and green tillers was as much as 50:50, said Dick Neale, Hutchinson’s technical manager. “It is pretty horrendous.”
Where fields only had a small percentage of green tillers he advised spraying glyphosate as soon as grain was at 30% moisture. But deciding on what to do with the 50:50 fields was much trickier. “The green tillers are all carrying full ears, some almost as good as the crop they are in. Growers are in a difficult position – you can leave them and get a bigger crop, and potentially have quality issues, or spray and lose 50% of the crop.”
Combining capacity would have to play some part in the decision, he said. “Waiting for the green tillers to mature will delay combining. Most growers want to get barley out of the way before oilseed rape and wheat harvest.”
If growers chose to spray glyphosate, rates might need to be higher than the typical pre-harvest rate of 1 litre (360g)/ha, Mr Neale said. “Normally you’re only desiccating the odd green leaf and the stems, but this year you’re trying to stop it as quickly as possible. Doses will probably need 720-1000g/ha depending on how green it is.”
Growers should also check with their buyer for any problems in applying glyphosate to malting crops, Mr Freer said. He believed the best plan was to attempt to make the difference between bold and secondary grains as big as possible. “It will make it easier to screen them out.”
There was also some secondary growth in wheat, Mr Neale noted. “But it’s nowhere near the problem in barley.”
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