Comparison of regulatory approaches for determining application limits for mineral nitrogen fertilizer use

This study investigates the impact of three agricultural regulatory approaches based on soil
surface balances, farm-gate balances or fertilization planning on the maximum permitted
input rates of nitrogen (N) fertilizer and their suitability for agricultural regulation. Using data
of about 10,000 farms representing the agricultural sector in Germany, groups of the different
farm-types were generated for a comparative study and the design and reliability of the
approaches were examined.

Results show that design and purpose differ, but data
requirements are similar, the parameters involved differ in certainty and reliability, and the N
application limits at farm-level vary farm-type specific. However, the design of each
approach could be adjusted to trigger equivalent application limits.