A major problem in organic grass seed production on arable farms is to provide for a sufficient nitrogen supply. A nitrogen-fixing crop may be able to cover the nitrogen requirement - wholly or partly. However mixed cropping of a grass seed and a nitrogen-fixing crop is expected to reduce the establishment of the seed crop, especially for species that require a long establishment period. One way to achieve a satisfactory establishment of the seed crop can be to introduce an intervening year for cutting forage between cover crop harvest and seed harvest. This will enhance tillering, since the light supply for the undersown grass is increased after each cut. However excessive biomass will hinder drying of the crop at maturity and therefore the growth of the nitrogen-fixing crop must be terminated or reduced in the seed production year. One of the first organic seed experiments at Research Centre Flakkebjerg focused on the above-mentioned factors
