Nitrogen use efficiency (NUE) will be the theme of the 2022/23 FACTS assessment for advisers in agriculture and field vegetables.

With high input prices, the assessment is timely as by optimising NUE, farmers will optimise yield for a given input and at the same time reduce emissions of greenhouse gases and ammonia, and minimise nitrate leaching.

The online assessment must be completed by May 31, 2023, in order for FACTS qualified advisers to retain their status.

Ian Richards, who manages the FACTS Information Service, says: There are several ways to calculate NUE.

For the annual assessment, we chose a method which gives useful management information while being straightforward for farmers and advisers to use.

NUE is the ratio of nitrogen output contained in a harvested crop to the total nitrogen input, from all sources as a percentage.

It offers the best measure of how well nitrogen is being used, but it is not that simple to calculate, especially when it comes to livestock production.

For cereal crops, the yield and grain N content provides a measure of output which can be calculated down to field level.

For livestock, the measure will require estimates of milk, wool, meat and cull stock for a whole farm.

The measure of nitrogen inputs needs to take into account purchased fertiliser as well as any organic manures, plus the level of soil nitrogen determined by soil analysis.

Over time, NUE can provide a benchmark to monitor and seek to improve farm performance.

Factors that can be managed to improve NUE include improving soil structure and quality, adjusting soil pH through liming, managing other nutrients and choice of fertiliser type, as well as paying attention to timing and application methods.

For instance, applying manures through rapid incorporation, injection or use of trailing shoes can improve availability and reduce losses to the atmosphere.

However, some factors affecting NUE cannot be controlled by farmers and growers.

Such factors include soil texture, local climate and topography.

Advisers There are several options to help advisers prepare for the online assessment.

BASIS is currently developing a module for the BASIS Classroom virtual learning option.

BASIS approved trainers will be offering courses of one to two days in length.

Full information will also be published by the FACTS Information Service for those who wish to study for themselves.

Jane Salter, head of environmental policy at the Agricultural Industries Confederation, says: Paying attention to nitrogen use efficiency has become increasingly important as the farming industry looks to address its economic and environmental challenges.

By being able to demonstrate improvements in NUE, farmers can show a sustainable practice is being implemented.

For advisers working in horticulture, amenity and turf industries where NUE is less relevant, there are alternative FACTS online assessments.