Recycling is a popular activity these days, especially when it comes to old ideas.  One good idea that's come back to the farm is composting.   Composting today is fairly similar to yesteryear, when families piled table scraps, yard waste and farm debris in a mound at the edge of the yard.  Ingredients were added and mixed and eventually it turned into rich, black composting material to be spread around plants and trees in the yard.

Bob Wackernagle is one of many Michigan farmers realizing the benefits of composting manure on his 110-head dairy farm.  Federal regulations required Wackernagle to have a waste management plan for the large volume of manure his cows produce.  With the help of the Michigan Integrated Food and Farming Systems, the University of Nebraska and local agriculture agents, Wackernagle designed a secondary composting operation on his farm.

The basic science behind composting involves aerobic (oxygen-requiring) decomposition of organic material.  Microorganisms feed on organic matter and consume oxygen.  This causes large amounts of heat, carbon dioxide and water vapor to build up inside the compost piles.  As piles are turned, the material is mixed and the process restarts itself until the organic material is decomposed and nutrient-rich compost remains.  There are variations on composting methods, but the concept is the same.

Bob Wackernagle's
Compost Recipe

To protect the ground from leaching and to build an arched base under the material, Wackernagle starts by spreading a layer of sandy gravel or loose stones on the ground behind his barns.  He overfills the free stalls with sawdust, which is swept together with the manure when the stalls are cleaned.  It's good to have at least 50 percent manure and the rest sawdust - or another carbon source.

Using a box spreader, he transports the manure/sawdust mixture to the field and spreads it into windrows 200-feet long, 4-feet tall and about 8-feet wide.  Size is important because large windrows can trap decomposing bacteria in the center and emit bad odors when turned.  On the other hand, small windrows may not trap enough heat to evaporate moisture and weed seeds.  Then he covers the long piles with a fleece blanket to trap in heat and control the smell.

After 4 or 5 days, he mixes the piles with a compost spreader.  Mixing is important because it adds oxygen and allows heat, water vapor and gases to escape.  Piles decompose faster at the beginning of the composting process, so more turning is required during the first few weeks.

Wackernagle uses a thermometer to check temperatures of the piles.  The average temperature should remain between 120 degrees Fahrenheit and 140 degrees Fahrenheit.  Lower temperatures mean not enough oxygen is passing through the pile and higher temperatures may cause bad odors.  It takes Wackernagle 45 to 65 days for the piles to turn to nutrient-rich compost, which he applies to his fields and sells to local nurseries and homeowners.

Wackernagle still does daily spreading as part of his manure management plan, but said the compost has reduced his dependence on commercial fertilizers and eliminates the need for a slurry store.