Harvest 2022: Light levels lifted yields despite drought

Despite record-breaking summer temperatures and a lack of rain, winter wheat yields recorded from harvest 2022 were higher than many had anticipated.

Crops made the most of the good growing conditions earlier in the season and benefited from lower disease pressure than the previous year, say commentators. Final figures showed the drought and intense heatwave combination was not as damaging as feared. 

The AHDB’s Recommended List results, taken from 28 sites around the country, show an average treated yield of 11.5t/ha in 2022 – some 0.64t/ha ahead of the five-year average – with untreated yields of 9.67t/ha being 0.91t/ha higher than normal.

See also: Harvest 2022: The 5 top-yielding winter wheat varieties map

The Ceres Rural review of 2022 yields, taken from 137 wheat crops in the South and the Midlands, gives a more realistic guide to on-farm yields, with the first wheat average coming out at 9.2t/ha and the second wheat figure at 8t/ha, giving an average wheat yield for harvest 2022 of 8.7t/ha.

That’s slightly above the Adas estimation of 8.4-8.6t/ha for this year’s wheat yields, which again is higher than the five-year average of 7.9t/ha.

Sunshine

Yields were good, even though grain size was small, as there was plenty of sunlight to fill the grains, says Chris Bean, technical director of Zantra. He likens the harvest 2022 results to those of 2018, which was another high-performing year.

“In years where sunlight levels are down, so are yields,” he says. “In 2021, we had 20% less sunlight compared with 2018, with yields dropping by a corresponding amount. Sunshine is important if crops are to fulfil their potential.”

Harvest results were “punchier” than many thought they would be, acknowledges Jock Willmott, agronomist and partner at Ceres Rural, even after the drought and some reining back on nitrogen fertiliser totals.

“Yields were better than quality,” he reports. “Grain proteins were down, possibly because nitrogen rates were reduced and uptake was limited, which is why there is further scrutiny of the place for milling wheats in rotations in 2023.”

Specific weight

One feature of the 2022 harvest was grain specific weight, which was good across the board, helped by high ultra-violet light levels, thinner crops and no harvest holdups.

“In our trials, every variety came in at 76-82kg/hl,” says Mr Bean. “Last year, that figure was 55-74kg/hl, so growers shouldn’t assume they’ll get the same results next year.”

The average for specific weight was 78-80kg/hl, while protein levels for Group 1 wheats ranged from 12.2-12.8%, according to the AHDB harvest report.

Other observations from Zantra trials and clients’ farms are that crops drilled in September performed better than those with later drilling dates, especially on heavy soils. 

“After rain arrived in October last autumn, soil conditions were compromised in some circumstances. The dry spring that followed meant that the root systems of some later-drilled crops couldn’t penetrate to any great depth,” says Mr Bean.

His other general point is that second wheats finished early, which is usually a sign of take-all, but may have been caused by a lack of root development. “It didn’t take much to pull up these plants – they weren’t anchored in as well as first wheats.”

Disease effects

Disease pressure was lower, but wheat varieties with Cougar in their parentage did show more septoria than others.

“Septoria never really got going in the way that it can,” says Mr Willmott. “Even so, the Cougar strain remains a concern, especially given the higher risks associated with wheat growing this year.”

According to Mr Bean, growers should ask how many hectares of varieties with Cougar in their background they want to grow, as the stakes are higher. “It mainly affects the Group 3 sector, which didn’t do as well as other market groups this year.”

Varieties such as Astronomer and Rashid are three-way crosses rather than two-way ones, he accepts, but the reluctance of the biscuit market to pay for these varieties, and their lower yields, mean they are struggling to find a place.

Yellow rust was a hot topic again in 2022, with varieties such as Zyatt and Skyfall being affected and needing careful management.

“This is where the right drilling slot has a place,” advises Mr Bean. “Drill Zyatt in September and you are far less likely to be troubled by yellow rust.” He also stresses the importance of growing a diverse mix of varieties on farm, using those with different parent lines to reduce disease risk.

Variety winners

The hard Group 4 feed varieties did very well and the shift to growing more of them also reflects their lower growing costs and wide market acceptance.

In the Recommended List trials, Champion, Insitor and Dawsum all shone, with Graham, Gleam and Cranium also delivering. The overall winner was Champion, which just edged out the others with a yield of 106%.

“It was pleasing to see that older stalwarts such as Gleam and Graham didn’t fall away,” says Mr Willmott. “That’s good news for growers – consistency is what they are after. It’s always a relief when nothing bombs, while nothing is outstanding.”

In Zantra work, Champion, Dawsum and Costello were put through their paces, with Dawsum producing the highest yields and a specific weight of 80kg/hl.

Of the soft Group 4s, Skyscraper and Bairstow were the top performers on 103%, with Skyscraper again giving good results on farm.

The Group 2 sector also did well, with Extase leading the pack on 103% and not suffering a repeat of the sterility issue that affected some crops in 2021. Where growers got nitrogen levels right, it produced a grain protein of 12-12.5%, making it saleable.

“Drill it in October, or it gets too bold and tall,” recommends Mr Bean. “Given the dry springs trend and its dislike of developing new tillers in the spring, we’ve found it worth using higher seed rates with Extase.”

He also suggests paying closer attention to fungicide inputs – despite Extase’s reputation, it gave a 2.5t/ha response to a four-spray programme again this year.

Newcomer Palladium produced good results in Zantra trials, being one of the highest-yielding varieties, while Mayflower was slightly off the pace for yield, but gave the highest grain protein from a lower nitrogen rate.

Variety losers

In general, the Group 1 and Group 3 varieties were less impressive and more variable in 2022, with a couple of exceptions.

Apart from its yellow rust susceptibility, Zyatt had a very good year for yield and quality, coming in well ahead of the others in this bread-making group. This result was similar to that of 2018, another high sunlight season.

Otherwise, Skyfall was affected by yellow rust and Crusoe saw brown rust come back with a vengeance. However, Crusoe has the advantage that it will produce 13% protein from 250-260kg/ha of nitrogen, stresses Mr Bean, while both Zyatt and Skyfall need closer to 300kg/ha.

Many of the Group 3 varieties underperformed, most likely due to higher septoria levels, and support for this sector is waning. Merit did very well in the Recommended List trials, but it’s less clear if this was repeated on farm.