At one time, agriculture was a self-sustaining cycle. Farmers grew crops, which they used to feed their livestock, and they fertilized their cropland with the nutrients in the animal manure. But with the advent of large-scale animal feedlots, the cycle was broken, says Colorado State University soil and crop sciences Associate Professor Jessica Davis.
"Today, livestock producers bring in feed from other places," Davis explains. "Some nutrients leave the operation as meat or milk, but a large portion of the nitrogen and phosphorous stays right on the feedlot as manure."
Some livestock producers are increasing the number of animals on their feedlots without increasing their acreage. In northeast Colorado's feedlot-intensive South Platte River Basin, the groundwater is becoming critically contaminated with nitrogen due in part to the concentration of animal manure in localized areas.
The U.S. Department of Agriculture and Environmental Protection Agency recently developed a new strategy encouraging all animal feeding operations to develop and implement voluntary, comprehensive nutrient management plans. So, when livestock producers make plans to expand their operations, they need to plan not just for where the cattle are penned and fed but for what to do with the extra manure, as well.
"Producers with an inadequate land base need to develop a marketing strategy for getting the manure off their land," Davis says, "and this represents a new and different approach. The problem the industry is facing is that people are willing to pay to ship corn to cattle, but not to ship manure to corn."
Davis, working in cooperation with Mike Lacy, associate professor from the Department of Sociology, and Dana Hoag, professor from the Department of Agricultural and Resource Economics, recently surveyed more than 250 farmers and ranchers in Weld County, which has the heaviest concentration of livestock in the state. They learned that manure is being valued primarily not as fertilizer for its nitrogen content but as a soil amendment that improves soil quality. Since manure is often not valued highly by farmers, feedlots generally can't afford to haul it more than five miles from its source.
Davis suspects that if manure were more widely used for high-value uses, like soil remediation, the industry could afford to haul it farther, resulting in improved soil quality in one place and reduced contamination at the source site.
"Many farmers already know that if they have poor or eroded land with low crop yield, application of manure would be a great way to remediate the soil," she says. "But there is often not enough manure close by to make it affordable. So we need to figure out what we can do to increase the value and therefore the transport distance of manure."
Davis currently is working with Cooperative Extension and Natural Resource Conservation Service field staff in six states to provide a series of workshops designed to help livestock producers and farmers make better decisions about manure management. Each participant will develop a comprehensive nutrient management plan specific to his or her operation, including strategies for the collection, storage, utilization, and marketing of manure. The workshop materials also will be placed on a Web page so that livestock managers with operations of all sizes can benefit from the information.
"Manure accumulation is a problem not just for feedlots but also for small-acreage horse owners," Davis warns. "Some people are hauling manure to the landfill and actually paying to get rid of it. Manure is too good for this."
According to Davis, a good option for manure disposal is through a composting co-op. Under such an arrangement, a group of animal owners would bring all their manure together for composting, resulting in a product they could sell rather than one they need to pay to get rid of.
"Composted manure is great for landscaping and could be of value to an increasing Front Range population trying to garden on poor soils," says Davis. "Another potential market for composted manure is organic farmers, who don't have many environmentally acceptable or locally effective options for adding nutrients to the soil. Mine spoils also could benefit from manure, as could soils burned by wildfire. We shouldn't be wasting this valuable resource on the landfill."