An Agriculture Canada Lethbridge Research Centre study indicates composting manure might be an affordable and effective method to distribute the benefits over a wide area.
“We believe the reduction in resource requirements for hauling compost rather than fresh manure could be up to 75 percent,” said Frank Larney, soil conservationist with the Lethbridge Research Centre and lead researcher on the project.
“Hopefully, what should happen is the costs of composting will be offset by the savings in haulage costs.”
The scientists will try to verify these results in further study this June.
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Composting has long been seen as a sustainable option for handling cattle manure produced by the livestock industry. But equipment costs and amount of land needed are the two factors that have limited the widespread use of the technique.
During composting, manure is formed into long windrows. The windrows are turned regularly to allow the flow of air into the piles.
Composting usually takes between three and six months, depending on the season. The process occurs more rapidly during warmer weather and slows in cool weather. The finished product is an odorless, dark, nutrient-rich material similar to humus.
Fresh manure is normally hauled from feedlot pens directly to the field, Larney said. Because of trucking costs, it is normally carried only short distances.
The downside is that farmland close to feedlots receives too much manure, while land located farther away can be nutrient deficient.
British Columbia’s Fraser Valley has a particular problem in this regard because it has large livestock herds but little land to apply the manure to. The waste must be trucked to the province’s interior.
For the study, started in May 1996, fresh manure from straw-bedded pens was formed into windrows. To allow for good air circulation, the windrows were turned seven times during the composting process.
For physical and chemical analysis, samples were taken from the windrows during composting and after the curing process, which finished in November 1997.
During composting, the carbon mass was reduced by about 65 percent, while the mass of nitrogen was reduced by roughly 33 percent, Larney said.
These nitrogen losses are comparable to those that would occur during the traditional method of handling, transporting and spreading of fresh manure, he said.
