THE NATURAL N-15 ABUNDANCE OF SUGARCANE AND NEIGHBORING 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 natu ral N-15 abundance (delta(15)N) in the leaves of sugarcane compared to those of neighbouring plants. The sugarcane plants from Tres Poutas o f 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 indic ated significant contribution of N-2 fixation. In other sites examined in Brazil and in the Philippines, the contribution of N-2 fixation wa s not clear.