Effect of Density, Cover, Depth, and Storage Time on Dry Matter Loss of Corn Silage

摘要

Whole-plant corn was harvested at 37% dry matter (DM), finely chopped (10 mm geometric mean length) and ensiled in 54 mini-silos of 100 mm diameter by 600 mm height. Silos were filled at three controlled densities (160, 240, and 320 kg DM/m~3), eithercovered with a nearly perfect seal or left uncovered, opened after 1, 2, and 6 months and replicated three times. Within each silo, two 100-mm diameter nylon screens were placed at 200 and 400 mm from the bottom while filling to analyze DM loss for three separate 200 mm vertical segments. The well-sealed silos did not exhibit any difference in DM loss as a function of density, depth or time (overall average of 0.9% DM loss). The uncovered silos exhibited very sharp differences (overall average of 17.0%DM loss); DM loss was 25.9, 15.9, and 9.1% for densities of 160, 240, and 320 kg DM/m~3, respectively. In the uncovered silos, DM loss was 8.9, 15.5, and 26.4% after 1, 2, and 6 months, respectively. DM loss was 36.1, 12.8, and 2.0% in the first segment(0-200 mm from surface), the second segment (200 to 400 mm), and the third segment (400 to 600 mm), respectively. These results imply that intense compaction of bunker silos (e.g. increasing density from 160 to 320 kg DM/m~3) will reduce DM loss especially in uncovered silos and in the top 0.4 m layer. A well sealed bunker silo is expected to have minimal DM loss, independently of density, at a rate of about 0.5% per month.