CHANGES IN GAS-COMPOSITION IN CORN SILAGES IN BUNKER SILOS DURING STORAGE AND FEEDOUT

The objective of this project was to study gas composition within sila ges during storage and unloading. For that purpose, changes in CO2, N2 , and O2 within four commercial corn silages in bunker silos were moni tored during storage and unloading. On the day of filling, five plasti c net bags containing the same chopped crop as the remainder of the si lage, pipes for gas sampling, and thermocouples were buried in the cen ter of each silo. In two bunkers, two such sets were installed 10 m ap art. Gas samples and temperature measurements were taken routinely at two-week intervals during storage and more frequently as the unloading face approached the bags. When the face reached the bags, the bags we re retrieved and the contents analyzed in the laboratory. The results include chemical analyses of the various silages, dry matter losses, a nd the percentages of CO2, N2 and O2 during storage of the silages and feedout. Low CO2 and high N2 levels might indicate air penetration in to the silage. In general, CO2 levels in the center of the sealed sila ges were 60-90% and these were higher than the CO2 levels in the top l ayer (20-40%) reported in a previous study. In two bunkers they remain ed at a high level (>70%) until the unloading face was only 1 m away. The data presented here could be useful in further studies of aerobic deterioration of silages.