How fermentation gases are produced
During ensiling, substrates such as grass or maize are stored under vacuum and thus preserved. This produces lactic acid in particular, which lowers the pH value of the silage. In addition, gaseous compounds are formed during the ensiling process - fermentation gases. These include CO₂ and nitrous gases (nitrogen monoxide and nitrogen dioxide). These respiration and fermentation processes create the so-called fermentation gas bonnets at the start of Silierung.
Especially in hot and dry years, farmers observe fermentation gas bonnets at the beginning of Silierung. Due to the prolonged drought before harvest, the nitrogen absorbed by the plant is not converted and is stored in the plant as nitrate. During Silierung, this nitrate is first reduced to nitrite and then nitrous gases are produced.
Risk due to moist food
However, if the feed is too moist and is stored in this way, the risk of nitrous gases developing also increases. This is due to the faster and more intensive conversions that occur during Silierung. This causes the film over the silo to expand and sometimes yellowish to rust-coloured vapours escape. These nitrous gases are produced right at the start of ensiling - because the nitrate contained in the plants is broken down.
Fermentation gases are dangerous and toxic, but are also part of the Silierung process. If they are produced, farmers must take special care.
