Changes in 15 N natural abundance of biologically fixed N 2 in soybean due to shading, rhizobium strain and plant growth stage

Aims The evaluation of 15N abundance of N derived from biological N2 fixation (BNF) in legume shoots (‘B S ’ value) is essential for quantifying BNF inputs to field-grown legumes. The aim of this study was to investigate the impact of shading, development stage of soybean (Glycine max) and rhizobium strain on the ‘B S ’ value.