Abstract
Fall-sown cereal crops; six-row barley, two-row barley, naked barley, wheat, oat and rye, were cultivated for silage. One cultivar was used for each crop. These crops were sown on the same date, and were harvested at seven stages successively during April and May. Heading occured in the order mentioned above. Dry matter yields (DM) and dry matter digestibility (DMD) in vitro were measured. (1) On the same harvesting day, early-heading crops were superior in DM yield to late-heading crops. (2) Before heading, DMD of leaf and stem was 80-90% and just before heading it began to decrease. DMD of leaf decreased to 70-60% and that of stem did to 50-40%. DMD of ear increased to 90%. Total DMD decreased towards heading, but slightly increased. thereafter. Total DMD of crops was influenced by the proportion of DM weight of leaf, stem and ear to total DM weight and DMD of these organs. On the early harvesting day, the late-heading crops were higher in DMD than early-heading crops and on the late harvesting day the early-heading crops were higher in DMD than late-heading crops. (3) On the same harvesting day, early-heading crops were superior in digestible dry matter (DDM) yield to late-heading crops. Because DDM yield is the product of DM yield and DMD, it can be influenced by both the factors, and so were data in this experiment. For example, 'Wasebozu', six-row barley, was higher in DM yield than 'Kikaihadaka', naked barley, and in DMD the former was lower than the latter. In DDM at seven harvestings, the yields of them were as follows. They were of even yield in one harvesting and the former was of higher yield in two harvestings and the latter was of higher yield in four harvestings. In heading date there was little difference between them, and they were also alike in the progress of maturity of their ears after heading.
