This Arable Extra discusses optimal nitrogen rates for crops based on 2024-25 fertiliser and crop prices.
- Nitrogen (N) fertiliser is the biggest single variable cost within cropping.
- Nitrogen helps to drive crop growth, but is also the largest contributor to greenhouse gas emissions from arable systems and can leach to freshwater.
- The economic optimum applied N fertiliser rate is less than the biological maximum N rate.
- Economic optimum N rates, for wheat, perennial ryegrass and autumn and spring barley, based on September 2024 prices, are provided in Figures 1, 2 and 3.