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.
|Manure is applied to about five percent of U.S. cropland. Pig and dairy cow manure are the most common forms of manure to be used on corn crops.
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.
|Litter from chickens and turkeys is applied to a greater range of commodities due to its light weight and ease of transport.
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
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
“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
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.
Under the Food, Conservation, and Energy Act of 2008, the USDA was directed to prepare the study, which was to provide:
A determination of the extent to which animal manure is utilized as
fertilizer in agricultural operations by type (including species and
agronomic practices employed) and size;
|An evaluation of the potential impact on consumers and on agricultural
operations (by size) resulting from limitations being placed on the
utilization of animal manure as fertilizer; and
|An evaluation of the effects on agriculture production contributable to
the increased competition for animal manure due to bioenergy
production, including as a feedstock or a replacement for fossil fuels.
To view the entire report, visit www.ers.usda.gov/Publications/AP/AP037.