Aim: to elucidate if it is possible to detect variations in the source of nitrogen (organic vs. inorganic) measuring nitrogen isotope ratio (δ15N) in berries and to examine the degree of variation occurring for this parameter naturally within a vineyard.
Methods and Results: two nitrogen fertilization strategies based on the use of organic and inorganic nitrogen sources were compared through four consecutive seasons in a vineyard, and berry δ15N was measured at harvest. The source of nitrogen affected remarkably nitrogen isotope ratio, as samples from organically fertilized vines always showed higher δ15N values. Additionally, variations in berry δ15N were measured during two seasons in a 60-node sampling grid in a 4.2 ha vineyard, showing that a wide range of variation existed for δ15N within the vineyard, and that its values followed a structured pattern that was in accordance with variations in altitude, being lower in the highest parts of the field.
Conclusions: the source of nitrogen (organic vs. inorganic) affects berry δ15N. Nevertheless, the degree of variation observed naturally within a single field is very relevant, and associated to variations in altitude.
Significance and Impact of the Study: this is the first study that, to our knowledge, demonstrates a direct relationship between nitrogen source and nitrogen isotope ratio in grapevines, and opens the door to its use in grapevine nutrition and terroir studies.
Authors: Luis G. Santesteban1*, Maite Loidi1, Inés Urretavizcaya2, Oihane Oneka1, Diana Marín1, Ana Villa1, Blanca Mayor1, Sara Crespo1, Jorge Urrestarazu1, Carlos Miranda1, F. Javier Abad1, 2, José B. Royo1
1Dept. of Agronomy, Biotechnology and Food Science, Univ. Pública de Navarra- UPNA, Campus Arrosadia, 31006 Pamplona, Spain
2Instituto de Agrobiotecnología (IdAB-CSIC), Avenida Pamplona 123, 31192, Mutilva Baja, Spain
3INTIA, Edificio de Peritos Avda. Serapio Huici nº 22, 31610, Villava, Spain
Keywords: Nitrogen, fertilization, organic, inorganic, Vitis vinifera L.