AHDB Cost Benefit Calculator
AHDB have published a Cost benefit calculator for nitrogen fertiliser use on grassland
From the AHDB website: The tool can be used to work out the cost versus the benefit of applying nitrogen fertiliser to grassland. Accounting for fertiliser and feed prices, it calculates the cost of nitrogen application and then compares with the feed value of grass. This will help with the decision on whether it is more cost effective to apply nitrogen fertiliser to grassland or purchase feed instead