Composting has numerous benefits for livestock producers.
"The main reason for using compost in soil is not the nutrients," said Dr. Jonathan Riven, UW-Extension, Stevens Point. "It is to improve soil health, density, water filtration and nutrient uptake. It's a soil enhancer, not just a fertilizer."
According to Riven, composted material improves the soil structure and improves the uptake of nutrient by the plants. Soil that has had compost spread on it has more earthworms and soil microbes.
During a composting demonstration program at a Burnett farm, Riven outlined steps for turning manure into compost, and he also shared ideas for composting farm animal mortalities.
"When composted material is spread on clay land, it will help with soil drainage, and when it is spread on sandy ground it helps to hold moisture," he said. "Composting maximizes the benefits of natural microbes that need air, nutrients and water."
He provided a "recipe" for creating compost but said there are not set rules. Composting will occur naturally over time, but by following the basic principles of creating compost, the process will be faster.
Ideally, a compost pile will be made up of two to three parts carbon and one part nitrogen. Turning it keeps the material fluffy. If it is not turned, it packs tight, forcing out air, an important component in composting.
Moisture is also necessary, but not too much or it, too, will force out air. If it is too dry, the microorganisms cannot function.
"There are tests to determine moisture, but practically speaking, just pick up a handful and squeeze it," he said. "There should only be sheen on your hand. If your hand is wet there is too much water."
The more active the microbes are in a compost pile, the higher the temperature will go.
"We want a high temperature to kill pathogens and weed seeds," Riven said. "If it gets too hot, it will kill the microorganisms."
Ideally, place the material to be composted in a windrow. It should reach 131 F in 15 days, and it needs to be turned five times to accomplish that goal.
"Decide when you will be needed the composting, and that determines how you will manage it," he said.
Riven listed practical indications to determine when the composting process is complete.
· The pile size will decrease to one-third to one-half the size of the original pile.
· Temperature — if it heats when it is turned, it's not done. It means the microbes found more uncomposted nutrients to digest.
· A bag test — put a little material in a bag, and close it. After several days, there should be no odor and it should smell earthy, not like manure.
"There will be some nutrient loss, but there is nutrient loss if you do not compost manure, too," he said. "If you pile manure and do not compost it, there are losses, and if you spread it on the field and it is not immediately used by the plants, there will be losses.
"But you do not compost just for the nutrients. There are many other benefits."
Riven went on to describe how to include farm animal moralities in the compost pile. The process is much the same and varies by the size of the animal.
Small animals like lambs and pigs compost right along with the manure and other material in the pile with little or no evidence of an animal at the end of the process. Larger animals take longer and require a larger pile.
When composting animals, begin with a base of 18 to 24 inches of coarse material (it should be an absorbing material). Then place the carcass on its side, and cover it with a carbon material 18 to 24 inches thick.
The cover insulates the pile and conceals odor. It should be thick enough so predators do not detect the animal and dig in the pile.
The cover material can be things like shredded straw, manure or even finished compost. The problem with using only manure as a cover is the odor, he said.
Corn stalks work well, but Riven suggested chopping them first.
"If you start to smell the pile, you need to have a thicker cover and more coarse material," he said. "If the pieces of material are bigger, you may need a thicker cover."
"All you are trying to do is optimize a naturally occurring process," he emphasized. "All material will compost if you leave it long enough."
Animal carcasses are high in nitrogen, so a carbon material is needed to try to accomplish the ideal composting ratio of carbon and nitrogen.
Riven pointed out that deer that have been hit by cars remain on the sides of roads and begin to decompose on their own eventually. On a farm, however, it is not legal or practical to leave an animal that has died.
In addition, burying animals is not always appropriate and requires special equipment. Composting is a way of dealing with them immediately, rather than waiting for a rendering company to pick them up.
Keep in mind that there are regulations regarding composting, but if the compost is processed on a farm where it will be used, there are no permits required as long as it is located in an appropriate place. The pile should not be near a well, on a hillside or near a river.