Abstract :
Cereals are an important substrate for silage production in the short growing season of the northern Prairies. Our objectives were to determine the effects of seeding rate, species, and harvest date on the forage yield and quality of cereals. Three field studies were conducted to evaluate the productivity of barley (Hordeum vulgate L.), oat (Arena sativa L.), triticale (x Triticosecale rimpaui Wittm.), and rye (Secale cereale L.) grown as monocrops or in various mixtures. Seeding rates ranged from 250 to 750 seeds [m.sup.-2]. Harvest times were based on the maturity of the principal cereal in each mixture. Few effects of seeding rate on yield or quality were found, but when effects were found, higher seeding rates were associated with higher yields, lower moisture content, and higher fiber content. All treatments produced high quality forage as measured by neutral detergent fiber (NDF), from 515 g [kg.sup.-1] for early-harvested tests to 656 g [kg.sup.-1] for late-harvested tests, and acid detergent fiber (ADF) contents, from 310 g [kg.sup.-1] for early-harvested tests to 387 g [kg.sup.-1] for late-harvested tests. Protein was low, ranging from 61.5 to 101.0 g [kg.sup.-1]. Biomass yields ranged from 10.1 to 16.5 Mg [ha.sup.-1] in the barley cultivar tests, 7.0 to 18.5 Mg [ha.sup.-1] in the spring cereal tests, and 10.8 to 12.2 Mg ha-1 in the winter cereal tests. Although, some exceptions occurred, forage yield and quality of cereal mixtures were generally intermediate to monocrop production, especially for moisture and fiber content, suggesting that planting species mixtures could extend the harvest period and result in higher-quality silage.