Therefore, add fresh inoculum to seed to help insure adequate nodule formation and nitrogen fixation. Pure alfalfa vs alfalfa-grass mixtures. Pure stands of alfalfa usually produce the highest protein yield and often the highest tonnage on soils well suited for alfalfa. Grasses are sown with alfalfa for a number of reasons. Grass fills in gaps in alfalfa stands caused by poor alfalfa establishment or winter-killing.
Grasses reduce weed invasion and soil erosion.
Alfalfa-grass mixtures cure more rapidly and ensile more easily than pure alfalfa. However, most grass yield is at first cutting, so there is little advantage of grass at later harvests. Seed at proper rates and dates. I assume that proper seeding practices will be followed. Sowing additional seed does not improve a stand when poor seeding management is used.