Farm nitrogen balance

Nitrogen is an essential nutrient for plant growth. Nitrogen supplied by fertiliser, soil and other sources are consumed in harvested crops and animal products. However, excess nitrogen can also be lost to the wider environment. Losses of nitrogen to the environment can have harmful effects on, for example, climate change, biodiversity, air quality and water quality.

Nitrogen balance measures the difference between nitrogen input and nitrogen output, accounting for land area. A large nitrogen balance can indicate a higher risk of nitrogen being lost to the environment.

Nitrogen balance increases slightly in 2024-25

The average farm nitrogen balance increased by 3% to 46.1 kg N surplus/ha in 2024-25. This average increase across all farm types was mostly driven by increased fertiliser input on general cropping farms.

Figure 6: Median farm nitrogen balance for the average farm, 2019-20 to 2024-25.

Estimates of the average nitrogen balance vary by farm type. Nitrogen from fertiliser makes the largest contribution to nitrogen input for general cropping and cereal farm types. Nitrogen balance on arable farm types stayed at high levels in 2024-25.

For the average cereal farm, nitrogen balance fell by 1% to 35 kg N surplus/ha compared with the previous year. Nitrogen inputs from fertilisers fell, which was offset by falling outputs from wheat and barley.

Nitrogen balance on the average general cropping farm rose by 26% to 25.6 kg N surplus/ha in 2024-25. This was driven by increased fertiliser inputs and decreased wheat and barley outputs. Lower cereal yield results in higher estimates of nitrogen accumulation in the soil, driving an increase in nitrogen balance.  

Dairy farms, where the primary output is milk, have the highest average nitrogen balance of the farm types, estimated at 262.8 kg N surplus/ha in 2024-25. Nitrogen balance for the average dairy farm decreased by 6% from the previous year. The fall in nitrogen balance was driven primarily by decreases in medium energy concentrate feed inputs.   

Average nitrogen balance decreased for all livestock farm types in 2024-25. Across all LFA farm types, increases in cattle output contributed to the fall in nitrogen balance. In LFA cattle farms, fertiliser inputs also fell. Lowland cattle and sheep farms also saw falls in fertiliser input, driving the decrease in nitrogen balance despite falls in sheep output.

Mixed farms have a nitrogen balance comparable to livestock farms, with an estimated average of 47.9 kg N surplus/ha in 2024-25, an increase of 38% from the previous year, which was the lowest figure in our time series.

Average farm nitrogen use estimates are based on results from the Farm Business Survey (FBS) and weighted to represent all commercial sized farms in Scotland. Charts by farm type are available to explore on the Agriculture Statistics Hub.

Table 7: Median farm nitrogen balance by farm type, 2023-24 and 2024-25.