Winter wheat harvest is proving to be extremely variable this season.

Some crops are performing well considering the battle they endured throughout the wet winter, while others barely reached half of their yield potential.

Several lessons are starting to emerge to explain the reasoning behind such variability in yield, beyond the obvious reason of establishment, explains Neil Watson, Hutchinsons technical support manager.

“The trend seems to be that freer-draining soils have maintained their yield capabilities, albeit with no record yields.

“Conversely, the heavier and poorer structured soils have seen their potential plummet,” he says.

More significantly, it has all been about soil drainage and root development.

“The ratio of 20:1, which refers to the final above ground biomass production to below ground root production, tells you everything.

“If you hinder root development, the knock-on effect on biomass will be all too evident.”

The effects of temporary root drowning were not only limited to the winter.

In some parts of the country, heavy rain late in the season, just as the crop approached ripening, caused premature senescence.

This lack of biomass was all too evident from early spring onwards, where wet and waterlogged soils hindered uptake of nitrogen at key growth and developmental stages.

What’s more, the lack of sunshine significantly hindered biomass production, particularly early in the season during the construction phase.

Neil notes that this was not made up for throughout the critical growth stages of the growing season that followed.

“In the latter stages, it has not helped with grain fill either, subsequently bushel weights have suffered.

“Elevated temperatures towards the end of the growing season also led to accelerated leaf aging, leading to negative effects in the grain filling phase,” he says.

However, lower temperatures during most of the critical spring/summer growth period helped reduce the stress on crops.

Weeds and disease

Blackgrass control has also been a major issue, with the lack of opportunities to get on to the land with timely spray applications

“Yields were no doubt impacted, not because of poor residual control in the autumn, but because the wet spring surviving plants were able to negate the effects of the autumn residuals,” explains Neil.

Disease pressure played a key part in yield loss areas.

Septoria pressure was particularly high in the early part of the season, continuing through the critical months of April and May.

As expected, the early drilled crops were at the greatest risk, where many growers struggled to keep leaf two clean.

Fusarium and ergot are more prevalent this year than most, primarily because of a wet flowering period.

“Rust was also a major risk this season, both yellow and brown in susceptible varieties.

“Once in the base of the crop, fungicide programmes struggled to hold the disease beyond three weeks,” he says.

Neil believes that because the wet soils delayed applications, barley yellow dwarf virus was more common among winter than spring crops this season.

“The wet winter did not help with take-all in cereals this year either – it has even shown through in first cereals.”

“When you consider all of these issues that the season has thrown at crops, it’s no wonder we are seeing a range of yields across farms and even fields.”