Natural abundance analysis of the role played by N as indicator for the certification of organic-system deriving food.

Background: The natural abundance of stable isotope N (δ N) in production systems has emerged as an alternative to distinguish organic products from conventional ones. This study evaluated the use of δ N values recorded for nitrogen fertilizers, soil and plant tissue in order to set the differences between organic and conventional agricultural production systems applied to rice, potatoes, apple and banana crops.

Results: Values of δ N recorded for N sources ranged from +5.