Nitrogen fixing Vixeran^® could provide crops with an equivalent of 30-40 kg/ha conventional N fertiliser this spring, and create a more resilient nutrient strategy to cope with increasingly challenging seasonal conditions. 

The endophytic bacteria in Vixeran convert atmospheric nitrogen into a form that is readily accessible to all crop plants. It is a new opportunity for farmers looking reduce the reliance on high levels of conventional fertilisers to achieve profitable yields, whilst supporting soil health, advocates Syngenta Biologicals Market Development Manager, Neil Procter.

Speaking at a Syngenta Technical Webinar earlier this month (Feb 2024), he pointed out drivers for change in nitrogen use include societal and legislative demands, the cost of fertilisers, climate change requiring reduced energy consumption and the potential for crops to perform better in improved soil microbial conditions with regenerative farming practices, including min till and cover crops.

“Creating conventional N consumes a huge amount of energy in its production. Crop plants then expend further energy to convert nitrates taken up through the root into ammonium - and then into amino acids and proteins to build biomass,” Neil pointed out. “That energy that could be better utilised in driving growth if the N is supplied in a more readily useable form by Vixeran.”

He further believes the continuous supply of N by Vixeran within the plant can help to mitigate the physical constraints of conventional fertiliser application timing and weather conditions for its utilisation – be that too dry for uptake or too wet and leached away.

“Vixeran gives the opportunity to make better use of the resource, for more efficient and sustainable crop production.”

Reporting the development of the Vixeran bacterial strain, Mónica Perdices Hoyo, Technical Director at Ceres Biotics, highlighted that while many bacteria do have the capability to fix atmospheric N - including healthy soil microbial activity - there is huge variability in the efficiency with which they can achieve it.

“The potential of Azotobacter salinestris species has long being recognised, but it was only through huge investment in R&D time and technology that the specific CECT 9690 strain in Syngenta’s Vixeran has been identified and optimised.

“What sets the Vixeran bacterial strain apart - and makes it so applicable for field applications - is the speed at which it gets to work and its resilience to climatic conditions, which means it will provide reliable results more consistently, in a wider range of crops,” she added.

The Vixeran bacterial strain, CECT 9690, is unique in its high nitrogen fixation activity and its triple mode of action – working as a foliar and root endophyte inside the plant, as well as in the soil rhizosphere. The N is supplied exactly where required and not subject to any losses. 

Over 220 arable crop trials undertaken in wheat, barley, maize, oilseed rape and potatoes, had proven yield benefits averaging over 10%, with additional vegetable crop trials showing both yield and produce quality benefits, she added. 

Syngenta UK Technical Manager and biologicals specialist, Andy Cunningham, recommends that to get the optimum performance with Vixeran crops should be actively growing at the time of application, ideally with temperatures reaching 10-12⁰C on the day of treatment to ensure rapid colonisation of the bacteria.

He suggested most growers and agronomists are likely to utilise Vixeran alongside existing nutrition inputs and to benefit from an uplift in yield from its use. “However, it is acknowledged that there is potential in a nitrogen reduction regime to compensate with Vixeran, typically up to 30 kgN/ha and still retain the same yields as a full fertiliser programme, although trials across the UK and Europe have shown that it could compensate more.”

Andy’s recommendations for use in cereals would be a single application between the beginning of tillering through to stem elongation – which would typically coincide with T0 fungicide and early PGR treatments. Trials have shown that for simplicity of application, Vixeran is compatible with most crop protection products and liquid fertilisers.

Results of winter wheat trials in Lincolnshire last season showed an average 0.3 t/ha yield uplift with Vixeran. Used in addition to the crop’s calculated optimum N rate of 220 kg/ha, the treatment improved yield by 0.49 t/ha. And when used to compensate for a 50 kg/ha reduction in conventional nitrogen, produced an extra 0.64 t/ha to bring yield back up to a similar standard.

“The ease of use and convenience of Vixeran means it can be readily incorporated into most spring agronomy regimes. There are great benefits in delivering more sustainable utilisation of nitrogen across a range of crops,” Andy enthused.

“It could also be especially useful this season, to help crops that were slow to establish in the autumn, or where soil conditions have compromised root structures.”