Pulse crops are particularly well suited to take advantage of novel nitrogen-fixing bacteria biofertilisers, since they are already adept at utilising naturally fixated nitrogen, according to Syngenta Technical Manager, Simon Jackson.

Speaking at the PGRO Pulse Potential Roadshow in January, he reported research and growers’ field trials with new Nuello iN seed treatment in peas and the foliar applied Vixeran in beans that added consistency and certainty to performance in both pulse crops.

“Both products fix atmospheric nitrogen and convert it to ammonium in the plant, to support development at key points in the growing season. It ensures the availability of nutrients at a time when plant vigour and yield could otherwise be limited,” he advises.

“Nitrogen availability is such a vital component of protein production for a pulse crop,” says Simon.

He advocates it could be especially important this season, after the wet autumn and winter will have depleted soil nitrogen reserves. Pulse crops are also typically grown as a break after successive nutrient-depleting cereal crops, when reserves in the soil are at a low point in the rotation.

“In some instances, soils simply don’t have sufficient background bacteria to initiate productive root nodule formation in pulse crops, or where the existing nodules have been damaged by pea and bean weevil activity,” he adds. “Dry soil conditions can also affect conventional nutrient uptake by plants.

“Pulse crops are particularly greedy for nitrogen at certain points in the growing cycle, especially seed development as pods fill. If they draw on the green leaf area to fulfill that demand, the photosynthetic activity of the plant, and consequentially its yield, will be adversely affected.

“Nitrogen fixation from applied nitrogen-fixing bacteria can help to fill the gap and keep plants actively growing to increase yield.”

Nuello iN seed treatment supplies two bacteria capable of atmospheric nitrogen fixation, one of which also helps to release phosphate from the soil to enhance plant establishment. The bacteria get into the root during germination and colonise the plant, to source nitrogen in a form that can be used by the seedling long before root nodulation. Furthermore, it is available during dry spring conditions when soil nutrient uptake can be limited. 

Launched in cereal crops in 2023, research has indicated Nuello iN seed treatment supplies an equivalent of around 30 kg/ha of artificial N, as well as enhancing crop biomass and root development.

Trials in vining peas in 2024 saw the same rooting advantages and stronger early growth . Five trials across the eastern counties and Scotland all recorded a positive increase in yield from the treatment, with an average 0.95 t/ha improvement. That included one field with a 2.3 t/ha increase, at 8.99 t/ha, where some of the same seed lot had been treated with Nuello iN, to give a direct comparison.

“Tenderometer readings (TR) also showed there was no effect on maturity and no difference in the colour or taste,” he reported. Nuello iN can be conveniently applied to seed prior to delivery, which can be stored normally before use.

Simon advocates pulse crops can get the same atmospheric nutrient boost for more consistent performance from foliar application of Vixeran fixating bacteria later in spring.

“The technology is now well proven in a range of crops and gives confidence for what it can deliver in pulses, particularly beans and good results seen in growers’ field trials of combining peas,” he says.

Timing recommendation for both crops is around six true leaves – at which time there is good growth to get the bacteria taken up into the plant, but whilst there is still sufficient bare soil, so some bacteria reach the ground and fix nitrogen in the biosphere around the roots.

“The action of fixing nitrogen in the plant and in the soil ensures an important continuity of nutrient supply in varied conditions and ongoing through the plant’s development,” Simon adds.

Application typically in early to mid-May means soils are sufficiently warm to initiate strong bacteria activity, ideally consistently above 10⁰C. It’s also a timing that enables tank mixing with other products, such as foliar feeds, or possibly to coincide with first fungicide timings.

He reported field bean trials in 2024 that were badly hit by the widespread onset of rust achieved a 0.9 t/ha yield increase from the fungicide programme, and an additional 0.26 t/ha where that was combined with the Vixeran treatment – achieving 4.82 t/ha. There was also an increase in the Thousand Seed Weight with the Vixeran application.

In combining peas last year, a grower’s field scale trial, with Vixeran at the six true leaf stage in May, produced a 1.47 t/ha increase at 6.9 t/ha, compared to 5.4 t/ha in the farm standard control.

“Biofertiliser technology is now being recognised as a significant step for growers looking to improve the consistency and reliability of pulse crops as a break in the rotation,” says Simon.

All video presentations from the PGRO/Syngenta Pulse Potential Roadshow are available to view on the Syngenta website: www.syngenta.co.uk/pulses/pgro-syngenta-2025