May 31, 2023
Regenerative trials show key advantages for most robust wheats
Regenerative regimes allowing earlier autumn drilling benefit robust wheat varieties, as shown in trials comparing two high-yielding wheats. The trials revealed that early October drilling resulted in a yield advantage of nearly 2t/ha compared to drilling a month later. Fitzroy, a disease-resistant variety, outperformed Gleam in terms of yield and fungicide response, especially under higher Septoria pressure. Managed fungicide programs reduced disease levels and improved yields by over 1t/ha. Earlier drilling provides value in coping with spraying conditions and grass weed competitiveness. However, delaying drilling remains important in areas with significant black-grass risks.
- Regenerative regimes allowing earlier autumn drilling benefit robust wheat varieties.
- Trials comparing two high-yielding hard feed wheats showed little yield difference between them.
- Early October drilling resulted in a yield advantage of almost 2t/ha compared to drilling a month later.
- Fitzroy, a disease-resistant variety, showed a greater advantage in early sowing than Gleam, a less disease-resistant variety.
- Septoria tritici levels were higher in earlier-sown crops compared to later-sown ones.
- A managed fungicide program reduced Septoria levels and improved average variety yields by over 1t/ha.
- Fitzroy performed better than Gleam in terms of yield and fungicide response, especially under higher Septoria pressure.
- Gleam may be a better choice for later drilling slots with lower disease pressure, given robust spraying programs.
- Earlier drilling provides extra value in terms of performance and coping with less-than-ideal spraying conditions.
- Fitzroy’s grass weed competitiveness is an additional advantage.
- Delaying drilling is crucial in areas with significant black-grass risks.
Regenerative regimes allowing earlier autumn drilling can give particular advantages to the most robust wheat varieties, reveal the latest trials undertaken as part of Agrii’s Green Horizons sustainability-improving initiative.
The fully-replicated trials comparing the performance of two similarly high yielding hard feed wheats grown side-by-side under contrasting cultivation regimes on heavy but relatively black-grass free ground in Dorset last season showed little, if any, yield differences between them; both delivering just under 12.75t/ha.
Unsurprisingly, they also showed early October drilling giving a yield advantage of almost 2t/ha over drilling almost exactly a month later.
Averaged across the broad range of disease treatment programmes employed, the 2.7t/ha early sowing advantage shown by especially-robust Fitzroy was more than twice that of the 1.1 t/ha of much less disease-resistant, Gleam.
Figure: Dorset Regenerative Trials 2021/22
“We did not originally intend to have a such a disparity in drilling dates,” explains trials co-ordinator, John Miles. “While we were able to direct drill the ground under the well-established regenerative regime at the end of the first week in October, we couldn’t sow the nearby land under the plough for a further month. This gave us a golden opportunity to explore how the different varieties responded to Septoria pressures, in particular.
“Altogether in our untreated plots, just over 36% of the area of the top three leaves were suffering from Septoria tritici in the earlier-sown crops by mid-June against around 26% in the later sown ones. Reflecting their different levels of Septoria resistance, this varied from 28% and 22% respectively with Fiztroy (RL score 7.5) to 45% and 30% with Gleam (RL score 5.8).”
Applying a robust managed fungicide programme reduced Septoria levels in the trials to an average of 10% and 3% for the earlier and later sowings, improving average variety yields by over 1t/ha.
The difference in both yield and fungicide response between the two varieties was especially marked in the earlier drilling, higher Septoria pressure slot.
Under the robust programme, Fitzroy averaged 14.18t/ha – just over 0.5t/ha up on its untreated performance. At 13.35t/ha, Gleam, on the other hand gave a response of fully 1.9t/ha.
“This really underlines the value of a variety like Fitzroy with its Septoria – not to mention yellow and brown rust – resistance superiority,” stresses Mr Miles. “This robustness allowed it to take much greater advantage of the extra performance opportunity offered by earlier drilling than Gleam.
“In the later drilling slot where disease pressures tend to be less, Gleam may be a better choice providing spraying programmes are sufficiently robust. Indeed, across all treatment programmes from early November drilling on the ploughed ground in our Dorset trials it averaged 12.1t/ha against Fitzroy’s 11.36t/ha.
“Where ground conditions allow earlier drilling, though, there can be little doubt about the extra value of the likes of Fitzroy – not least in providing as much leeway as possible to cope with anything that may get in the way of less-than-ideal spraying conditions.
“Its additional grass weed competitiveness can be very valuable here too. Having said that, as our work at Stow Longa continues to show, delaying drilling remains crucial wherever black-grass risks are significant.”