Nitrogen (N) surplus is the balance between Nitrogen inputs and Nitrogen outputs. It calculates the nitrogen brought onto the farm (eg fertiliser, imported feed) and subtracts the total nitrogen that is removed from the farm as products (eg meat, wool, milk, crops, exported effluent).
N surplus is an indicator of how efficiently the farming system is using nitrogen. The lower the N surplus number, the more efficiently N is being used in the system.
N Surplus does not account for the environmental conditions of a farm which are important factors in understanding N-leaching risks.
N surplus is reported in OverseerFM in Farm details.