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USDA explores manure’s uses

March 24, 2010 – The U.S. Department of Agriculture’s Economic Research Service recently released a report on manure use for fertilizer and energy production.

The U.S. Department of Agriculture’s Economic Research Service recently released a report on manure use for fertilizer and energy production.

According to the study, based on information collected through the Agricultural Resource Management Survey (ARMS) plus the U.S. census and Environmental Protection Agency (EPA) databases, manure is only used on a small fraction of U.S. cropland – about 15.8 million acres or five percent of all U.S. cropland.

Crop use
Corn accounted for more than half of the land receiving manure in the U.S. and the majority of that applied to the crop was sourced from dairy or hog operations.

“With its high nutrient uptake, particularly for nitrogen, corn is an attractive option for livestock operations seeking to utilize manure,” states the 53-page report.

In contrast, the report says lighter, drier manure from cattle feedlots and poultry operations is more likely to be shipped to regions farther away from the source operation, due to cheaper transportation costs. As a result, manure from these sources is “spread over a wider range of commodities.”

Compliance costs
With the movement toward larger livestock operations, many produce more manure than can be absorbed by the farm’s crops. Federal, state and local government regulations involving the storage, transport and application of manure have also expanded, meaning more planning, filing and administrative work (and expense) by livestock operations to comply with the regulations.

“Estimated costs of compliance vary with the degree to which nearby farmers are willing to accept manure for application to their cropland,” states the report. “A low willingness to accept among nearby farmers means that livestock producers will need to transport manure much farther for crop application.”

According to the report’s authors – James M. MacDonald, Marc O. Ribaudo, Michael J. Livingston, Jayson Beckman, and Wen Huang, all with the ERS of the USDA – production costs for livestock operations would increase by 2.5 to 3.5 percent if there was limited willingness by local farmers (defined as 20 percent or less of nearby farmers) to accept manure.

“Expanded regulation through nutrient management plans will likely lead to wider use of manure on cropland, at higher production costs, with little impact on the size structure of farming operations,” the report says.

Manure-to-energy
The study also investigated what effects increased competition for manure for energy production might have on agriculture. The authors found that while there was widespread interest in using manure as an energy feedstock, manure-to-energy projects are currently not in widespread use within the U.S.

“Digester systems, including those planned or in construction, cover less than three percent of dairy cows and less than one percent of hogs,” the report states. “The single operating combustion plant utilizes litter from 6.6 percent of U.S. turkey production, while an idle plant in California could utilize manure from about three percent of fed cattle.”

It’s expected that the currently envisioned manure-to-energy projects are not likely to lead to constraints on finding manure for use as a fertilizer. “Many of the nutrients that are beneficial to crop growth remain after energy production,” the reports says.

Background
Under the Food, Conservation, and Energy Act of 2008, the USDA was directed to prepare the study, which was to provide:

To view the entire report, visit www.ers.usda.gov/Publications/AP/AP037.