•Nitrogen or phosphorus
based systems
–N based systems as in the Nitrate Directive, (170 kg
N/ha) are most common
–P based systems e.g. Sweden, the allowed level of P is
defined as livestock density corresponding to 22 kg P in
manure/ha, - no problems with
requirements of 170 kg N/ha returned in animal excreta (Nitrate Directive).
Another advantage is that information on P content in manure is
more reliable, as losses in animal houses and during storage are
almost non-existent and therefore easier for the farmer to
calculate.
–N and P-based systems