“…Regarding nutrient management regime, natural 15 N abundance (δ 15 N value) has received attention as an indicator to discriminate organically grown crops from conventionally grown crops. The δ 15 N values of organically grown crops without synthetic fertilizer tend to be higher than those of conventionally grown crops with synthetic fertilizer, as observed in some vegetables (Nakano et al, 2002(Nakano et al, , 2003b(Nakano et al, , 2010Bateman et al, 2005Uehara, 2005, 2006a;Yun et al, 2006;Camin et al, 2007Camin et al, , 2011Amor et al, 2008;Rogers, 2008;, fruits (Camin et al, 2011), and tea (Morita et al, 1999;Hayashi et al, 2011). δ 15 N values have also been reported to be higher in organic rice than in conventional rice (Fujita et al, 2003;Suzuki et al, 2009), and a threshold value of 3‰ has been proposed (Fujita et al, 2003).…”