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Keep spring barley standing for yield and grain quality

Agronomy Issues
heavy heads demand PGR programme to stay standing
Heavy heads of high yielding spring barley plants demand PGR programme to stay standing

With the surge in spring barley area expected this season, quality is likely to be more important for growers aiming to hit premium specs for malting and distilling markets.

Many growers have already decided to simply target the barley feed market, where pushing for high yields will deliver greater returns.

In both instances, managing lodging risk will be an essential agronomy objective, advises Syngenta Technical Manager, Georgina Wood. “The challenge is tailoring the PGR programme to the prevailing seasonal conditions.

UK spring weather maps showing seasonal differences

“Over the past three seasons (above) spring barley crops have endured vastly contrasting conditions, from record warmth, to bitterly cold; to heavy rains and saturated soils, or periods of prolonged drought. That all has a significant effect on crop growth patterns and the demand of PGR options and timings,” she said.

“Spring barley has a very short growing, period compared to winter crops which means it doesn’t have the chance to build up any rooting and resilience to spring/summer conditions. That gives the PGR programme a key role to prevent lodging.”

For spring barley grain quality, preventing lodging is essential to maintain consistent Nitrogen uptake and water – essential for managing grain N levels, specific weight and proteins.

“Heads of lodged barley are more susceptible to spoiled grains with moulds and bacteria, along with impurities that will impact on quality assurance,” warned Georgina.

Georgina Wood framed

With heavier heads of spring barley pushed for feed market yields, there is the added risk of brackling and stem lodging.

Georgina advocated that using a PGR is especially important in a wet season, when nutrient uptake and growth is likely to be far more consistent and greater.

In a particularly dry year, however, drought stress can act as a natural PGR, especially on light soils. “In seasons with prolonged dry weather, it is advisable to adjust any planned PGR use and reduce rates, or in some cases avoid altogether,” she advised.

Citing the very dry year in 2018, she reported a trial showed a two-spray programme was extremely effective in reducing crop height, but at a slight expense of crop yield and specific weight.

“In a more normal season, trials have shown reducing height to prevent lodging and retain quality had no adverse impact on spring barley yield.”

Its trials last year, for example, which started extremely dry, but then turned wet, saw over 20% lodging and around 15% brackling in higher seed rate plots. At lower seed rates lodging was reduced, but brackling was the greater issue.

Spring barley lodging trial results 2019

“In both instances, the incidence of lodging and brackling was completely eliminated with a two spray programme of just 0.1 l/ha Moddus at GS30-31, followed by Ethephon + CCC/Mepiquat,” reported Georgina.

Where spring barley crops are actively growing and not stressed, the recommended PGR programme is for Moddus at 0.1-0.2 l/ha at the T0/T1 timing (GS 30-32) to promote stem strength. In situations of high lodging risk, a follow up of ethephon + mepiquat chloride 0.5-0.75 l/ha at the T2 (GS 37) would further help to keep crops standing.

“Even at very low rates Moddus has been shown to be extremely effective in reducing lodging risk in spring barley. The key is to adapt the PGR programme to the season and the situation.”