Silage Season Safety – Processing and Packing

When you’re processing and putting up silage in any type of structure, it’s a complicated job, and potentially dangerous.  

Silo Gas

a graphic of an upright forage silo showing how silo gas would disperse

Silo gas is created in ANY type of silage storage system, but is a particular problem in tower silos.

  •  Silo gas also known as nitrogen dioxide.  It’s a normal part of the silage making process.  We start to see this gas a few hours to a day or so after a silo is filled. Then it’s produced for about 2-2.5 weeks.
  • Depending on conditions – Silo gas is produced in ALL kinds of silos – tower or upright silos, bunkers, piles, bags.  The biggest issue is when it’s in a confined space, such as, a tower silo, an adjoining room, silo chute or in the space between silo bags or bunker walls.
  • In the air, nitrogen dioxide has a faint yellowish color though in low light conditions, you probably won’t see it. It smells a bit like bleach and is very irritating — even a few breaths can cause serious health problems.
  • Avoid silo gas, especially during that initial three-week post-harvest window. Treat a tower silo and areas surrounding stored silage as a confined space.  Ventilate thoroughly – generally with the blower.  Get more information – entering any confined space incorrectly has deadly consequences.

Bunker Silo Rollovers & Other Issues

Color image of a straight truck unloading corn silage on a pile with a pushing and packing tractor on the sides of it.

Photo from Flickr – See credits below

  • There are special hazards with packing a bunker silo.  Some great detailed information can be found in this article from Penn State Extension on horizontal silo safety.
  • Tractor rollovers occur every season while people are packing bunkers and piles – It’s critical that you select the right tractor – it MUST have a ROPS (rollover protective structure) and a seatbelt.
  • A wide front-end is also an absolute must. Front-wheel and front wheel-assist tractors provide extra traction and stability for packing. Duals usually increase stability as well as appropriately-placed weights.
  • Backing a tractor up ANY slope is preferred – you achieve better stability AND CONTROL.  
  • On a slope – as you fill a bunker, make sure your packed, wedge-shaped surfaces are not too steep – We generally talk about a safe slope being 3 to 1 or something even less steep. On a pile or bunker that’s 20 feet high, you need a wedged surface to drive up that’s at least 60 feet long in the horizontal direction.  Anything less, and you run a great chance of rolling a tractor.
  • There are many other precautions to take with your employees and family members who are working at this time…Like these:
    • Only experienced people should be permitted to operate equipment.
    • Require all equipment operators to remain in their vehicles to avoid being run over.
    • Keep visitors and children out of ANY farm work zone.  A packing operation seems cool and fun to watch – but operators have a lot to pay attention to, and the chaos associated with visitors and bystanders can be very distracting.
    • Have workers wear brightly colored safety vests or t-shirts to increase visibility.

This post was originally developed to support a series of silage harvest-related podcasts posted by colleague Liz Binversie , Agriculture Extension Educator, UW Madison, Division of Extension Brown County.  This one is written to connect to the podcast covering processing and packing.

Photo Credits:

Silage packing pictures — Creative Commons — to license –

Silo gas photo from John Shutske personal collection.

September 11, 2020

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