As growers and millers await new options in the UK Flour Millers Group 1 category the last new addition to the AHDB Recommended List (RL) in this category was KWS Zyatt in 2017 plant breeders are in the meantime exploring additional ways of helping growers manage nitrogen to achieve milling specifications.

With its varieties Skyfall and RGT Illustrious making up two of the four Group 1s on the current AHDB RL, RAGT is investigating the use of companion crops to manipulate grain nitrogen levels in milling wheat (and spring barley) in two new trials at its demonstration field at Ickleton, Cambridgeshire, this season.

Two large blocks of RGT Skyfall and RGT Illustrious have been intercropped with nitrogen-fixing cover crop species to see if the technique might encourage more effective nitrogen uptake by the wheats, perhaps replacing a late nitrogen fertiliser application and improving protein production efficiency.

Each block has been split between standard and low N nitrogen regimes.

The aim is to discover what interactions might exist between variety, companion crop and nitrogen dose, and what further work might be needed, to produce guidelines to help growers manipulate grain nitrogen to suit various end use purposes while reducing reliance on nitrogen fertilisers.

RAGTs Tom Dummett says: We embarked on a major project last autumn to see if cover crops can help reduce the carbon footprint of wheat production, and what varietal differences might exist, to help meet changing support payment criteria and help farming meet its net zero requirements.

Biggest contributor We know that nitrogen fertiliser is the biggest contributor to a farms carbon footprint.

We can also see the day when end users will be paying a lot more attention to carbon footprints of farm commodities, so it makes sense to do the work now, so we can share any positive findings with growers to help them meet their customers requirements.

Meanwhile, Elsoms Seeds is looking for evidence of differences in the way varieties take up nitrogen.

A second year of trials with its Group 2 variety Mayflower and German A wheat Lemmy, plus Group 2 KWS Extase, Gleam, Elsoms coded lines and Group 3 Merit at the companys trials site at Cowlinge, Suffolk, is testing the performance of these varieties at 0kg N/hectare, 85kg N/ha (all applied early), 150kg N/ha (two splits) and 200kg N/ha (three splits).

Elsoms head of agriculture Paul Taylor says: We already knew there were some varieties that were really good at scavenging for nitrogen, but not at what point in the season they did it.

Oakley was one, Robigus was one.

It always used to be ‘dont grow a second wheat after Robigus because there wouldnt be any fertility left in the ground.

Results from last season pointed to a change in the yield ranking of varieties at the different nitrogen rates.

For example, at 85kg N/ha applied early in one dose, Mayflower yielded 10.45 tonnes/ha, compared with Extases 9.2t/ha.

Okay, 85kg N/ha is not what farmers are going to do, but 150kg N/ha is probably what they are going to do, says Mr Taylor.

In this scenario Extase, which has a two point yield advantage over Mayflower in treated trials in the East yielded 10.6t/ha to Mayflowers 10.7t/ha.

This is work we are going to have to develop.

If you look at Gleam, which is higher yielding at the 200kg N/ha rate, it is also efficient at 150kg N/ha and doesnt do too badly at 85kg N/ha.

The next stage is to start drilling down into the timing of N doses, says Mr Taylor.

The advice for Mayflower would be to apply more of its nitrogen earlier, he adds.