Open day explores lessons from autumn’s early drilling26 July 2023
The legacy of last autumn’s early cereal drilling on disease was a hot topic at ProCam’s recent summer open day in Yorkshire.
Although not the case everywhere, a lot of wheat was drilled worryingly early last autumn, after the early harvest, said ProCam head of crop production, Mike Thornton.
Speaking at the company’s trials hub open day at the Stockbridge Technology Centre, Cawood, home to around 1,100 ProCam trial plots, he said once that early drilled scene had been set, the weather conspired to make agronomy in those crops extremely hard.
Mr Thornton said: “To begin with, the dry autumn hindered residual herbicide performance. After that, rain in late October made it difficult to spray post-em herbicides or barley yellow dwarf virus (BYDV) aphicides on time.
“We then had a mild winter and wet spring which fuelled Septoria pressure, followed by hot, dry weather around the flag leaf and ear timings, which favoured yellow rust. For many growers, the season provided a harsh reminder of how early drilling and the weather can join forces to work against you.”
Wheat drilling date and diseasE
Discussing ProCam’s drilling date trial plots at the site – which monitored the performance of winter wheat varieties with different disease resistance profiles when drilled in September, October and December – Mr Thornton said these illustrated clearly how earlier drilling can undermine a variety’s Septoria tritici resistance.
“The Recommended List gives a starting point rating for Septoria tritici resistance. But we know if you drill early, ratings are effectively reduced. A variety rated 6.4, for instance, might fall to equivalent to 5.8 if drilled a fortnight earlier, which has a big impact on how much you need to spend on fungicides.
“In our trial plots, a variety rated mid-5s against Septoria tritici drilled in September struggled to hold off the season’s intense pressure with a standard fungicide programme. Even a highly resistant variety is not immune to the impact of early drilling.”
Conversely, Mr Thornton said industry data shows earlier drilling can reduce yellow rust infection in wheat, but observations in the Cawood plots suggested this was not a hard and fast rule.
“With plenty of soil moisture over winter and spring, early-drilled crops did not have to root deeply. So when the hot, dry weather arrived, they became more easily stressed, and stressed crops are more prone to rust.
“A key lesson is not to rush into drilling early just because you have bought seed and have a weather window; increased Septoria pressure could cost you more than you gain. Equally, never underestimate yellow rust. Once the weather turns drier, especially with a susceptible variety, it is amazing how quickly rust can explode.”
Winter barley drilling date
Comparing plots of conventional winter barley against the hybrid barley SY Canyon, when drilled in September and October and even later, ProCam was also putting winter barley drilling date flexibility to the test.
Mike Thornton said: “You would not purposely plan to drill winter barley too late into autumn, but in the real world delays happen. So it is useful to have some drilling date flexibility. Later drilling also reduces blackgrass burdens.
“On-farm, we have seen that hybrid barley appears to cope better with later drilling than conventional barley. And in these plots, the visual difference between the hybrid when drilled earlier or later has not been that much. However, if you do drill towards the end of the autumn drilling window, it becomes even more important to apply the first nitrogen (N) dose on time, in order to feed the hybrid’s spring growth.”
A timely first N dose will also help with hybrid barley’s grass weed suppression, said Mr Thornton. “Hybrid barley is good at suppressing blackgrass, ryegrass and certain brome species, and although grass weeds do germinate in it, they seem to be outcompeted by its spring vigour.
“If you have a field with these weed problems, maybe consider planting hybrid barley. This has to be balanced against having fewer herbicide options in barley than winter wheat. But compared with winter wheat, hybrid barley is also earlier-maturing, which gives more time for stale seedbeds after harvest.”