Summary of Operation
■ 100-cow dairy free-stall operation, with an additional 100 heifers and dry cows
■ Alfalfa, corn, oats and wheat on 725 of800 acres
■ Dairy manure compost sold to area nurseries Problem Addressed
Manure management. Bob Wackernagel confronted a manure storage problem at his 725-acre dairy farm near Montague, Mich. His property sits on a high water table, making it difficult to store manure in a traditional lagoon. Once he figured that out, he decided to scrap a lagoon manure storage system that had been in the planning stages for several years. "In years when it is very wet, a lined lagoon would have been partially below the water table," says Wackernagel.
Wackernagel and his wife, Kim, took over the fourth-generation family farm in 1992 from his father, Robert. They have three children who help on the farm.
Greg Mund, resource conservationist for USDA's Natural Resources Conservation Service in Muskegon County, offered Wackernagel the option to join a composting program through the Muskegon Conservation District in 1995. The program, which offers grants to farmers who want to try composting systems, was funded through the Michigan Integrated Food and Farming System project, a W. K. Kellogg Foundation initiative. Mund helped Wackernagel obtain more funding from SARE's farmer grant program in the North Central Region.
It was one of the first operations in Michigan to receive Environmental Quality Incentives Program (EQIP) cost-share funds for a compost manure management system.
Focal Point of Operation — Composting
Wackernagel began composting dairy manure, using a 60-by-120 foot concrete holding pad and a one-half acre composting site. Wackernagel handles the manure with a compost turner he shares with four neighboring farmers. By turning his manure into compost, Wackernagel produces a highly marketable product that was previously a manure management problem. Every spring, he sells this "natural fertilizer" to area nurseries.
Producing good quality compost from manure involves several steps and close management. The process begins in Wackernagel's free-stall dairy barn and heifer barn, where he adds bedding material to put carbon in the manure.
"You just can't take manure and start running a turner through it and make compost," Wackernagel says. "You have to add some carbon first."
In the free-stall barn, he overfills the stalls with sawdust. When the cows back out of the stalls, they rake some of the sawdust into the alleyway, which in turn mixes with the manure. The cows help make a material that can be stored and won't run off like liquid manure. He uses about 40 yards of sawdust per week in the free-stall barn. He adds oat straw to beds in the heifer barn. Composting manure and straw separately from the sawdust mixture allows Wackernagel to spread a straw-based mix as a foundation for his compost windrows.
Wackernagel sometimes adds extra sawdust to the manure if it has more moisture. He also is able to dispose of spoiled or moldy feed or bad haylage, from bunker silos, which are high in carbon, by adding them to the manure mixture.
Wackernagel hauls manure and bedding to one of three places. About 30 percent is directly spread on the fields. The rest is either taken to his concrete holding area or immediately made into windrows on a specially designed composting site. The system gives Wackernagel the flexibility to spread manure on the fields on days when he doesn't have more pressing activities such as making silage and baling hay. He uses the concrete holding area mostly in the winter, when the snow is too deep to make windrows or spread.
Wackernagel builds most of the windrows in the winter, weather permitting, and in early spring. The windrows are built on a composting site that sits on eight inches of crushed and compacted limestone and has runoff ditches on either side to drain off rainwater into a vegetative filter strip system. The windrows start out at 10 feet wide by 4 feet high by 160 feet long. The site will hold eight windrows with room to operate the manure turner.
Wackernagel keeps the windrows covered with large fleece blankets. The breathable fabric sheds water and keeps the compost dry until it is time to begin turning.
Wackernagel begins turning the manure in March to have compost ready to sell to nurs eries and tree farms by May. The peak marketing time for his compost is from April to the first week in June.
Wackernagel works the pile when the temperature dictates, about every seven days. When the internal temperature, checked with a probe, reaches 140 to 145 degrees, the manure is ready to be turned. The carbon/nitrogen (C:N ratio) content must be at least 30 to 1 for the mixture to heat up to the desired temperature. Usually a 1 to 1 carbon (sawdust, straw, etc.) to manure volume is a good starting recipe.
"When you turn it, you are exhausting the carbon dioxide and water, and replenishing the oxygen," says Wackernagel. "The bacteria in the compost can breathe again and continues to break down the carbon."
Besides breaking down the manure and carbon into compost, the process reduces the water in the manure, which cuts the volume to be hauled by 50 to 60 percent. The high temperature also kills many weed seeds; Wackernagel has seen his compost kill velvet leaf and ragweed seed.
The farmers sharing the compost turner, provided as part of the conservation district grant, worked out an informal schedule to transport the turner from farm to farm when needed. The turner requires at least an 80 horsepower tractor to operate effectively. The tractor's power takeoff runs the turning rotor, and the hydraulic system runs a rear axle that creeps the compost turner forward while the tractor is in neutral.
The initial turning of a new compost windrow is done at a rate of less than 0.2 miles per hour, says Wackernagel. As the compost breaks down, it becomes easier to turn and the speed can be increased slightly. On average, it takes Wackernagel about half an hour to do four windrows.
The carbon content in the manure will determine the length of time to produce finished compost. Compost made with sawdust will take from 55 to 60 days to finish and compost made with straw, which has a lower carbon content, will take about 70 days to finish. The sawdust compost also has a more even particle size and consistency than the straw compost. The windrow is done when compost temperatures reach ambient temperature, with an additional 20- to 23-day curing period for off-farm uses.
Marketing the compost has never been a problem. Wackernagel put an ad in the local newspaper the first year and has not advertised since. Sometimes, he runs out of compost and has to refer his customers elsewhere.
"I sell so much compost I hardly have a chance to use it on our farm," he says. "I use some on the fields before I plant soybeans and oats and use a little to topdress alfalfa."
Economics and Profitability Wackernagel sells compost in bulk for $15 per cubic yard. The compost can vary in moisture from nearly powdery dry to 25 to 35 percent moisture, with a cubic yard averaging from 1,200 to 1,500 pounds. He sells anywhere from 300 to 500 tons each year.
The compost sales provide a supplement in the spring that covers parts for machinery, oil and other supplies. The compost Wackernagel uses on his own fields also has reduced his fertilizer costs.
He ran a test on a 40-acre field of soybeans, comparing compost to synthetic fertilizers. On 20 acres, he used only compost and a small amount of potash; on the other half, he added 150 pounds of potash and about 20 pounds of nitrogen per acre. When the results were in, Wackernagel found that the composted field out-yielded the "traditional fertilizer" field by about 15 bushels to the acre. Wackernagel notes that oats also respond well to compost, yielding about 100 bushels per acre of high test weight oats.
Wackernagel also saved money by not building a more costly lagoon manure storage system, even considering a government cost-share program that would have helped pay for pumps and liners. The composting management system cost about $23,000, of which Wackernagel paid about $7,500 to match the government cost-share.
Compost turners cost between $18,500 and $26,000. "It wouldn't be cost effective for someone with a 30- to 50-cow farm," Wackernagel says. "But it could work for someone with a large operation. It just depends on how serious you are about composting, or if a few farms can share a turner."
Environmental Benefits Wackernagel became involved in composting manure more for the economic boost than to lessen the dairy's impact on the environment. Nevertheless, he says that manure disposal needs to be handled carefully through such environmentally friendly systems as composting. He is pleased to eliminate odors and water and provide greater opportunities for spreading. It also adds the benefit of producing an organic fertilizer.
Community and Quality of Life Benefits Wackernagel says his area, like much of the country, is being developed for housing. "These people want to live in the country," he says. "But they don't want it to smell like the country. And the compost doesn't have the odor that raw manure does."
What smells in manure is the urine — which is basically nitrogen, says Wackernagel. During the composting process, the carbon absorbs the urine, which microbes break down into humus, with some methane gas lost into the air.
"So you can spread right along side a neighbor's house and it looks like you are spreading black dirt and there's no odor," he says. "There are also hardly any flies, either when spreading or when making the compost."
Wackernagel recommends composting as a positive way to deal with manure disposal. He says anyone interested in setting up a system should call their Natural Resources Conservation Service or Conservation District office.
He has learned one valuable lesson that would cause him to do things differently from the start. "I wouldn't recommend a limestone base for the composting site," he says. "We found out that when you start turning the compost, some of the limestone peels up and gets mixed in." He recommends either black top or concrete.
Wackernagel plans to pave over the limestone composting site with concrete. Wackernagel and his neighbors may eventually jointly buy the compost turner, which they currently lease. And finally, when Wackernagel decides to expand his dairy operation, the composting system will be flexible enough to accommodate the additional manure, unlike a lagoon system.
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