The natural N-15 abundance of sugarcane and neighbouring plants in Brazil, the Philippines and Miyako (Japan)

The contribution of nitrogen fixation by sugarcane plants grown in the fields at various sites in Brazil, at a few sites in the Philippines and in Miyako Island (Japan) was examined using the difference in natural N-15 abundance (delta(15)N) in the leaves of sugarcane compared to those of neighbouring plants. The sugarcane plants from Tres Poutas of Minas Gerais State, Cerquilho, Novo Horizonte, Igarapava, Itapolis, Assis of Sao Paulo State in Brazil showed lower delta(15)N values than the neighbouring plants with an average contribution of N-2 fixation to total plant N of 30% (ranging from zero to 72%). The sugarcane from Gerona in the Philippines and from three sites in Miyako Island indicated significant contribution of N-2 fixation. In other sites examined in Brazil and in the Philippines, the contribution of N-2 fixation was not clear.