The role of isotopic profiling in identifying organic and biodynamic practices in Vitis labrusca grape cultivation

This study investigated nitrogen, carbon, and oxygen isotopes to differentiate fertilizers used in grape cultivation. The hypothesis posited that organic and biodynamic practices produce distinct signatures compared to conventional. It represents the first study of nitrogen isotope in Vitis labrusca grapes. One hundred twenty grape samples, from organic, biodynamic and conventional practices, were analysed. The results revealed that organic and biodynamic exhibited similar nitrogen isotopic values, both significantly higher than those of conventional grapes. Carbon also differed significantly, with organic and biodynamic showing less negative values than conventional. An intermediate group suggested cross-contamination or transitional farming practices. Oxygen was less efficient in identifying cultivation practices. These findings underscore the effectiveness of isotopic profiling in verifying organic and biodynamic certifications, providing insights into agricultural systems, and supporting the authenticity of organic and biodynamic labels. Nitrogen, in particular, proved valuable for ensuring the integrity of grape cultivation.