A new endophytic bacteria which captures atmospheric nitrogen and converts it to a plant-available form has the potential to improve the productivity of beans, claim experts.

Vixeran biostimulant aims to kick-start a bean crop’s natural fertility cycle at an early stage. And while beans are often referred to as ‘nitrogen fixers’, it’s not the plants themselves that do anything, but the microscopic soil rhizobium bacteria that they host on roots.

Syngenta’s Simon Jackson explains that where the natural rhizobium bacteria can be supplemented at an early stage with Vixeran endophytic bacteria, Azotobacter salinestris, the process can be more efficient and productive.

This’ll also be the message shared at the PGRO Pulse Roadshows 2024 during January. “We’ve see outstanding results with applications of Vixeran on beans. There’s a clear yield benefit in trials from supplementing the crops’ natural processes,” says Simon.

“A bean plants’ nodules that contain the nitrogen-fixing rhizobium will be formed on the roots three to five weeks after emergence and straight away start to fix nitrogen. However, the nodules will gradually senesce and stop fixing nitrogen around the time of pod filling.”

Nitrogen demand

Because pulse seeds are a great source protein, this is exactly when the demand for nitrogen is at its highest, says Simon, which means the plant will rob the required nitrogen from the leaves, sapping the plant of its photosynthetic yield building potential.

“The addition of Vixeran complements the plants’ nitrogen requirement for structural growth, while also reducing the burden on the leaves to supply nitrogen to fill the seeds in the pod. This allows the leaves to stay greener and continue photosynthesising for longer, that in turn increases yield,” he explains.

“Importantly, the Vixeran bacteria is capable of converting atmospheric nitrogen to its plant available form (NH3) in the leaves, roots and soil surrounding the plant. By going straight into the plant, the nitrogen isn’t leached or volatilised, which is highly efficient and avoids environmental losses from soil.”

Trial results

By applying Vixeran during periods of active crop growth, trial results have shown, on average, a 0.53t/ha improvement in yield. Assessments on a Vixeran-treated crop showed a 12% uplift in pod numbers along with a corresponding 12% increase in seed weight in each of the pods.

Simon advises Vixeran should be applied in spring when beans are actively growing at a rate of 50g/ha after the six-leaf stage (GS16), through to the start of flowering. A single application is required to inoculate the crop with the beneficial endophyte.


He says the product is physically and biologically compatible with Elatus Era and Amistar where the application timing coincides with the crop’s fungicide strategy, along with many other crop protection products, fertilisers and biostimulants.

Vixeran is effective across a wide range of crops and includes recommendations for cereals, maize, potatoes, grassland and now beans.