Scottish Nitrogen Balance Sheet 2020

The Scottish Nitrogen Balance Sheet brings together evidence on flows of nitrogen in Scotland from across the whole economy to understand and keep track of the use of nitrogen.


Nitrogen Use Efficiency (NUE) is a summary indicator which can be calculated from the nitrogen flows in the Scottish Nitrogen Balance Sheet (SNBS). NUE is the ratio (expressed as a percentage) of useful nitrogen-containing output to all nitrogen inputs.

Table 1: Summary measures of Nitrogen Use Efficiency
Nitrogen input (kt N / yr) Useful nitrogen output (kt N / yr) Nitrogen use efficiency
Arable 93.1 58.2 62.5%
Livestock 197.3 20.0 10.1%
All Agriculture 187.7 55.4 29.5%
Aquaculture 23.1 6.9 29.9%
All Food 210.8 62.3 29.6%
Forestry 28.2 7.7 27.3%
Whole Economy 290.6 78.1 26.9%

Note: Sectors of the economy not included in the above table have no significant useful outputs, and so if their Nitrogen Use Efficiencies were to be calculated they would be 0%.

In 2020, the whole economy NUE figure was 26.9%. Although the whole economy figure is dominated by food production, this figure is lower than the NUE for food production due to the inclusion of sources such as transport which produce no useful nitrogen outputs. The NUE for all food production is 29.6%, with the figures for aquaculture (29.9%) and agriculture (29.5%) being very similar. The 29.5% figure for all of agriculture comprises two extremely different values for arable agriculture (62.5%) and livestock based agriculture (10.1%). Livestock based agriculture is inherently less nitrogen efficient than arable agriculture because only a small proportion of the ingested nitrogen by livestock ends up in useful nitrogen-containing produce.



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