Lupin crops (white lupin, narrow-leafed lupin) fix nitrogen, produce protein-rich seeds and can diversify crop rotations, However, the low competitive ability of lupin towards weeds and its high yield variability is a barrier to increase its cultivation with no or reduced herbicide use.
Intercrops often contain around half the weed biomass of lupin sole crops. The crop growth together with lupin provides a complementary grain production that can compensate for low productivity of lupin in some years. The grains of the two species are easy to separate after threshing. An additional benefit is that the protein concentration of the intercropped cereal is often increased compared to a sole-cropped cereal.
Nicolas Carton, SLU
zenodo.org: Practice abstract "Intercropping of lupin for weed control and complementary grain production in organic farming"