Organic, conventional and hydroponic vegetables: Can 15N natural abundance of farm N inputs differentiate mode of production?

Natural abundance analysis of the role played by 15N as indicator for the certification of organic‐system deriving food

“…The use of mixed fertilization (synthetic + organic fertilizers) in a conventional system, and organic N sources (vermicompost and mulching) with low ⊐ 15 N values in organic systems, provides evidence for the non-differentiation between organic and conventional tomatoes, in which the organic tomatoes presented low ⊐ 15 N values and the conventional tomatoes presented high ⊐ 15 N values. 5 Besides, Inácio et al also suggested that the greatest influence of N inputs on the ⊐ 15 N value of plants was presented when the total soil N pool was low. 5…”

“…5 Besides, Inácio et al also suggested that the greatest influence of N inputs on the ⊐ 15 N value of plants was presented when the total soil N pool was low. 5…”

“…In the conventional production system, the use of synthetic nitrogen fertilizers prevails, such as urea, nitrates and ammonium forms. 5 The demand for organic foodfood produced without the use of synthetic fertilizers and pesticides 6,7 and, consequently, its production, have been growing on a yearly basis, mainly due to consumers' search for safer, healthier and tastier products. 8,9 Moreover, consumers' perceptions regarding this agricultural production system type have a great impact on the environment.…”

“…8,12,13 Accordingly, the natural abundance of 15 N (⊐ 15 N) can contribute to separate conventional production system products from those deriving from organic production systems in relation to fertilization, mainly due to the association between ⊐ 15 N value and the source of nitrogen fertilizers used in production systems. 5,14 According to the literature, ⊐ 15 N values of organic and synthetic fertilizers range from +5‰ to +20‰ and from −5‰ to +5‰, respectivelysuch values can reflect on plants. [15][16][17] Studies focused on identifying production systems through ⊐ 15 N values have been conducted in some countries, including Italy, Spain, Japan and Brazil.…”

“…However, it is known that organic fertilizers such as animal waste and compounds have been widely used in organic production systems. In the conventional production system, the use of synthetic nitrogen fertilizers prevails, such as urea, nitrates and ammonium forms 5 …”