As growers continue to rethink their rotations this season, there is still opportunity to get winter seed out of the shed, but attention to detail will be key.
Do not be too quick to abandon drilling winter wheat in favour of planting a spring crop this season, says ProCam seed manager, Lee Harker.
While at some point a spring crop will become the better option, a decent number of modern winter wheat varieties can still be drilled until the end of January, or even mid-February in some cases, if conditions are suitable, he says.
Winter wheat could also be financially more attractive than planting a spring crop for some growers in these situations, he believes.
“Spring barley is the usual go-to crop in place of winter cereals in these types of seasons,” says Mr Harker.
“But we could end up with a million hectares of spring barley if lots of growers jump into it this season, compared with circa 600,000ha normally. That may not be great for barley prices at harvest. We might end up at £120/tonne for barley and £150/t for wheat.”
Although winter wheat yield does decline with later drilling, Mr Harker says findings from 19 years of ProCam 4Cast, the company’s annual big data analysis of thousands of hectares of cropping, have shown winter wheat planted into the new year can still yield remarkably well, reaching 8 or 9 t/ha.
Yields can be similar to or above those of a spring variety, he says.
However, a big watch point with later winter wheat drilling highlighted by the ProCam 4Cast data was increased yield variability.
The lowest yields in the early part of the new year were down to 5-6t/ha. Delaying drilling even later pushed the worst yields down to almost 4t/ha.
“What this variability indicates is the increased importance of attention to detail with later drilling,” says Mr Harker. “You can’t just leave things to chance. You have to know what you are doing, especially with varieties.
“The crucial factor to be aware of with later drilling is vernalisation requirement – the period of cold weather starting at germination that winter varieties need in order to initiate ear formation at the growing point.
“Consult industry resources for information on individual variety latest drilling dates, then work with your agronomist to fine tune agronomy to local conditions.”
Yield potential initially declines with later drilling due to a shorter tillering period over winter, says Mr Harker. Late-sown crops might only produce a couple of tillers per plant, compared with more than four tillers if sown earlier, he notes.
Vigorous-tillering varieties help with this, he says, as do higher seed rates. Increasing the seed rate also helps against the reduced emergence that inevitably occurs when drilling later into poorer seedbed conditions, where plant establishment could fall by as much as half, he adds.
"If drilling has been delayed from early October, you may need to work on the basis of increasing seed rates by at least 10 seeds/sq.m for every week that drilling has been delayed after this date. If seed availability is limited, you will need to plant a smaller area, for example by leaving out headlands.
“Seed rates need matching to the variety, but other factors to also take into account when finalising seed rates include things such as seed viability, risks from slugs and weeds, temperature, soil fertility, field altitude and aspect, and potential for waterlogging. In clay soils, consider seed rates at the top of any given seed range,” says Mr Harker.
“Further into the season, late drilling also shortens the period that determines the number of grains set per ear and shortens the grain-filling period. Fast-developing winter wheat varieties help here. Early flowering varieties tend to lose less yield when drilled late.”