The sliding or fixed trench cover greatly reduces secondary fermentation of silage. It also limits overheating due to solar radiation and maintains a stable level of humidity and protects the withdrawal area from rain. It is therefore an important barrier that reduces food for birds (that deplete the product) and avoids the toxicity and possible infection caused by their excrement. Tecnoengineering also manufactures and installs fixed covers for trenches, bio-gas, horizontal silos and storage tanks for animal manure.