the danish agricultural agency runs the system and publishes annual guidelines for individual farms including the maximum total amount of nitrogen that can be used on the farm within a season farmers are responsible for completing their annual fertilisation account by the end of march each year furthermore under the fertiliser accounting system nitrogen standard quotas are calculated annually at the farm level these quotas depend on crop and soil type climatic conditions irrigation precipitation and the precrop the quotas are set at least below the estimated economic optimum for the various crops with the targeted regulation the farmers fertilization and cropping management will be restricted based on the sensitivity of the aquatic environment and local conditions