Current: Optimizing nitrogen application to sugar beet using placement and banding of fertiliser

Timescale: 2024 - 2028
Project Lead: Dr Georgina Barratt
Project Sponsor: BBRO

Project Summary

Nitrogen fertiliser is the one of the biggest sources of greenhouse gas (GHG) emissions on farm from the sugar beet crop. Calculations from a report commissioned by British Sugar and undertaken by ADAS shows that fertilisers are the second biggest source of GHG emission on farm at 17%, after machinery which accounts for 24%. The emissions from fertiliser are high because of the fossil fuels burnt to drive the energy intensive process required in their manufacture and from nitrous oxide (N2O) emissions when fertiliser breaks down in the field. N2O is 298 times more potent than CO2 so even a small amount has a significant impact on the total GHG emissions from the sugar beet crop. This is an issue that affects all sugar beet growers, and therefore has relevance to the whole beet growing area.

Main Objectives

Clearly there is a need to reduce GHG emissions to reach the industry target for Net Zero in 2040 as well as the increasing pressures from British Sugar customers to show the industry is making advances on reducing GHG emissions. Placing or banding fertiliser has been shown to increase N uptake and reduce overall N application (Wu et al., 2020). This is an instant win for the industry as it results in reduced GHG emissions from the sugar beet crop as well as reducing the cost of inputs for the grower. However, there is limited research in the UK on optimising placement and banding of fertiliser to reduce N application rates. There is a need to generate more robust guidance on best practice to give those in control of fertiliser regimes in sugar beet the confidence to adopt a different method of N application, moving away from broadcasting and to reduce overall N application rates.
Wu, P., Liu, F., Li, H., Cai, T., Zhang, P. and Jia, Z., 2021. Suitable fertilizer application depth can increase nitrogen use efficiency and maize yield by reducing gaseous nitrogen losses. Science of The Total Environment, 781, p.146787.

BRO undertook limited placement fertiliser trials in 2018, with some split fields comparing placement to broadcast in 2019 and 2020. However, the work in 2018 did not show any significant differences between broadcast or placed fertiliser, likely due to the warm and wet weather being favourable for high levels of soil N mineralisation. The split field comparison did show some benefits of placed fertiliser with canopies growing faster and a suggestion this drove higher yields, but this now needs to be advanced through undertaking robust replicated tramline trials. Some of this work also looked at the benefit of placing phosphorus at drilling which can help drive faster canopy growth alongside N. This is something that could be explored further in the future but for now the focus on N should be the first step to keep the trials manageable to start. Phosphorus can always be looked at in years 2 or 3 if assessed to be worthwhile.
Evidence from Nordic Beet Research (NBR) supports the observations made in these early BBRO trials and split field observations. NBR support the full N rate being applied at drilling which is much greater than the 30-40kg/N suggested by BBRO currently and is worth exploring as this would also require less passes with machinery reducing fuel burn and the associated GHG emissions.
Although not a key driver for undertaking this work, reducing the amount of N applied as well as applying it closer to the plant for better uptake can reducing N leaching. This is a key concern for many catchments in the beet growing area and therefore this work can help support the water companies in reducing nitrate levels in drinking water.


Investment in machinery may be a limitation to those not currently using placement or banding. This is why the banding option is being assessed as adding a banding kit to existing drills can be more affordable.
These treatments would need to be replicated at least once -totalling 10 strips down the field. Three replications would be ideal but will depend on field size.
All fertiliser will be liquid to keep the trial consistent and also facilitate accurate application to the strips that would not be possible with broadcast AN.
Two fields will be used on the farm to replicate the trial, one will have a lighter soil type than the other. This spreads risk in the event there is an error in applying the fertiliser but more importantly enables a comparison of the observations to assess if they are consistent between two fields with different cropping histories, and therefore soil nitrogen levels. Fields will be extensively tested to ensure they are suitable for a fertiliser trial as previous experience has shown that fields with higher N levels will fail to show significant differences between treatments.

Outcomes / Key Message For Growers And Industry

Under review
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BBRO is a not for profit making company.
We are set up jointly by British Sugar plc and the National Farmers' Union.

British Sugar
National Farmers' Union