STERLING, Ill. — Composting is one option for managing animal mortalities.
“Composting is not just putting stuff in a pile,” said Jay Solomon, University of Illinois Extension educator, energy and environmental stewardship. “Decomposition is a natural process that occurs anytime there is organic matter and a carbon source.”
However, composting is the act of managing that decomposition of the organic matter so the volume of the material is reduced in a timely way, explained Solomon during an Animal Mortality Composting Workshop, hosted by the University of Illinois Extension.
Hot or active composting maintains the conditions for dynamic biological activity. “This requires turning the pile or moving it,” Solomon said. “You need to have the correct carbon-to-nitrogen ratio of 30 units of carbon to one unit of nitrogen.”
The carbon source can be provided by a variety of items such as leaves, straw, paper, sawdust or animal bedding with manure. “Small wood chips or coarse sawdust works really great,” Solomon said.
Mulch is an option if it does not contain a lot of big chunks. “I don’t recommend biosolids compost because it doesn’t have structure so it tends to pack down,” Solomon explained. “Straw has so much structure that too much air moves through it and it dries out.”
The energy source for the microbes in the compost pile can include cow manure, grass clippings and mortalities, Solomon said. “Microbes can handle a pretty good range of moisture.”
One of the most important practices to make the mortality composting process work is to move or stir the pile to keep the oxygen going to the microbes.
“Moving the pile adds oxygen, removes carbon dioxide and remixes the carbon and nitrogen,” Solomon noted. “Since the microbes don’t move around very much, you feed the microbes by moving the pile.”
A steaming compost pile is an indication there’s enough carbon and nitrogen for the microbes to be eating and turning it into organic matter, he said.
The size of the bin for the composting process should allow for a pile that is at the minimum of 3-feet wide by 3-feet deep by 3-feet tall. “That will allow for enough heat down inside the pile,” Solomon said.
Active composting occurs when the temperature of the pile is from 55 to 160 degrees. “You need to use a 36-inch thermometer and the pile should get to 140 degrees for at least three days during a cycle to kill the bad bacteria,” Solomon said.
“The composting process is finished when there is no recognizable feedstock in the pile,” Solomon said. “The compost should have an earthy smell and it should shrink to about one-third of the original volume.”
When determining the size of the bins for the composting process it is important to make them wide enough for the bucket on the machine that is going to move the pile from one bin to the next. “Also make the roof tall enough for raising the bucket,” Solomon noted. “Sized properly, composting bins are good for any mortality rate.”
A composting facility needs at least three bins and four is better, the speaker said. “You need one bin that is in process, one for loading and one you’re moving to,” he explained. “A concrete apron is a good idea or the ground needs to be packed in front of the bin so you don’t create soft spots with your loader.”
It is important for livestock producers to manage the composting system. “People tend to not use enough cover, so don’t skimp on that,” Solomon stated. “The biggest thing is to keep the mortalities covered.”