With harvest well underway, Hutchinsons technical support manager Neil Watson says that several lessons are emerging as to why wheat yields are so variable, beyond the obvious reasoning of the variable establishment.
“What is most evident so far this harvest is the significant variability in yield with some crops performing well considering the circumstances, whilst others barely reaching half this potential – and occasionally within the same field,” he says.
“The trend seems to be better or freer draining soils have maintained their yield capabilities, albeit with no record yields. Conversely the heavier and the poorly structured soils have seen their potential plummet.”
He adds that root development goes a long way in explaining why yields may have suffered, highlighting the ratio of 20:1 for final biomass production and below-ground root development.
“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 on in the season just as the crop approached ripening, caused premature senescence.”
This lack of biomass was evident in the early spring, and wet soils also impacted the uptake of nitrogen in the crop. Adding to this, the lack of sunshine further hindered biomass production at the critical growth stages.
“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.”
Reduced stress
It isn’t all bad news. The lower temperatures through the growing stages did reduce stress on the crops, he believes, however, this was also true for grassweeds.
“Blackgrass control, or lack of it will have impacted yield, not because of poor residual control in the autumn, quite the contrary, because of the wet spring surviving plants were able to negate the effects of the autumn residuals.”
Disease pressure was also a major hurdle for growers, he notes. “Septoria pressure was high in the early part of the season, continuing through the critical months of April and May. The early drilled crops as expected were at the greatest risk with many growers struggling to keep leaf two clean.”
“Rust was a major risk this season, both yellow and brown in susceptible varieties, once in the crop in the base of the crop fungicide programmes struggled to hold the disease beyond three weeks,” he says.
“Fusarium and ergot are more prevalent this year than most, primarily because of a wet flowering period.”
Due to operations being delayed, BYDV was also more prevalent in winter crops. “The wet winter did not help with take-all in cereals this year either, it has even shown through in first cereals.”