[en] Quantifying below-ground nitrogen (N) of legumes is fundamental to understanding their effects on soil mineral N fertility and on the N economies of following or companion crops in legume-based rotations. Methodologies based on ¹⁵N-labelling of whole plants with subsequent measurement of ¹⁵N in recovered plant parts and in the root-zone soil have proved promising. We report four glasshouse experiments with objectives to develop appropriate protocols for in situ ¹⁵N labelling of four pulses, faba bean (Vicia faba), chickpea (Cicer arietinum), mung bean (Vigna radiata) and pigeon pea (Cajanus cajan). Treatments included ¹⁵N-urea concentration, feeding technique, leaflet/petiole position, and frequency of feeding. Nitrogen-¹⁵-labelling via the leaf-flap was best for faba bean, mung and pigeon pea, whilst petiole feeding was best for chickpea, in all cases using 0.2-mL volumes of 0.5% urea (98 atom% ¹⁵N excess). The implications of uneven enrichment of the nodulated roots because of effects of the ¹⁵N-depleted nodules when calculating root-derived N in soil are discussed. (author)