Quantification of biological N2 fixation of hedgerow trees in Northern Lampung

The contribution of the leguminous hedgerow trees Flemingia congesta and mixed Gliricidia sepium — Peltophorum dasyrrachis established on an Ultisol (Grossarenic Kandiudult) in Northern Lampung, Sumatra to the N economy of the hedgerow intercropping system was assessed. N2 fixation estimates of hedgerow trees over a two year period after establishment were obtained by the 15N dilution method using Peltophorum dasyrrachis as the non-fixing reference plant.