Forage production and distribution of alfalfa (Medicago sativa L.) interseeded with winter forage cereals

Joint sowing of annual forage species and perennials can yield economic benefits, making land use more efficient, and contributing to ecological sustainability. This experiment was conducted in a typical Hapludol soil in Cordoba, Argentina. In a stand of alfalfa (Medicago sativa L.) seeded in autumn of 2000, interseeding of two short-cycle and two medium to long-cycle winter forage cereals was carried out in 2001 at three different dates (2702, 31/03, and 06/05). A completely randomized experimental design with two replicates was used, in which the treatments consisted of eight interseeding situations, of different cereals combined with different seeding dates, plus a pure alfalfa control. Sampling for biomass determination (at a 10-cm cutting height) was done using a 0.25 m2 quadrant, frequency of sampling being determined by the phonological condition of the forages. Annual biomass yield (kg/MS/ha) of pure alfalfa (5500) was surpassed (P ≤ 0.05) by interseeding of alfalfa with short-cycle cereals, Avena sativa and Hordeum vulgare (6540 and 6720 with early seeding; 6420 and 6230 with the intermediate seeding date, respectively). Interseeding of the intermediate to long-cycle cereals, Triticosecale and Avena bizantina, gave annual productions (5610 and 5810, respectively) not significantly superior (P > 0.05) to the control, while interseeding of cereals at a late date was completely ineffectual. Interseeding at the early and intermediate dates also improved forage distribution due to an increased number of cuttings and greater biomass production, relative to pure alfalfa, at most of the cuttings. (Sp