Utilization of nitrogen (15N) from urea and green manures by rice as affected by nitrogen fertilizer rate - Contreras Espinal, Freddy Sinencio; Silva, Edson Cabral da; Muraoka, Takashi; Franzini, Vinícius Ide; Trivelin, Paulo Cesar Ocheuze; Teixeira, Marconi Batista; Sakadevan, Karuppan (African Journal of Agricultural Research, 2016)