Because legumes usually fix N from the atmosphere, some of their N requirements are met through this process. Inoculate alfalfa with specific host bacteria if alfalfa has not been grown recently in a field. Decrease the seeding rate of the companion crop and do not overapply N to avoid shading of the new alfalfa and grass seedlings. Preplant N fertilizers generally are applied broadcast and incorporated in combination with P fertilizers. Application of N fertilizers in the establishment of alfalfa is not suggested under dryland conditions.
Grasses require annual N applications.
The suggested N rate is related to the NO 3 -N status of the soil. Nitrogen application can increase yields of grass-legume mixtures, but also results in a decline of the legume component. Therefore, application of N to mixtures comprised of more than 50 percent of the legume component is not recommended. Generally, the proportion of legume will decline with time. Suggested N rates in Table 2 are for an expected yield of 4 tons per acre.