Postheading biomass distribution for monocrops and mixtures of small graincereals

Biomass distribution during the harvest period ran affect the yield and qua lity of silage produced from cereal crops. Our objectives were to determine the changes in biomass distribution among morphological structures and how management practices could affect those changes. Three field studies were conducted to evaluate the productivity of barley (Hordeum vulgare L.), oat (Avena sativa L.), triticale (x Triticosecale rimpaui Wittm.), and rye (Sec ale cereale L.) grown as monocrops and mixtures. Seeding rates ranging from 250 to 750 seeds m(-2) were evaluated to determine their effects on biomas s distribution from heading to the soft-dough growth stages. While seeding rate had a profound effect on per plant biomass, it had little effect on bi omass per unit land area or the distribution of the biomass between leaves, stems, and spikes. During the postheading period for all tests, the leaf c omponent declined and the spike component increased, The stem component dec lined for all tests, but variation was found for the tests harvested on the basis of the oat and triticale components. Composition biomass Heights fro m our spring cereal tests averaged across the three sampling times (heading to soft dough) were 18% leaf, 50% stem, and 31% head for 'Noble' barley: 1 8% leaf. 44% stem, and 37% head for 'AC Mustang' oat; and 22% leaf, 43% ste m, and 35% head for 'Wapiti' triticale. Plant populations and total, leaf, stem, and spike biomass per plant for mixtures were found to be intermediat e to the monocrops. Total biomass quantity and distribution among leaves, s tems, and spikes were affected by genotype, production practices, and time of harvest, with the latter having the greatest effect. Understanding culti var, species, and management effects is important for optimum feed quantity and quality.