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Trends and Developments in Hog Manure Management: 1998-2009
By Nigel Key, William D. McBride, Marc Ribaudo, and Stacy Sneeringer
Economic Information Bulletin No. (EIB-81) 39 pp, September 2011
What Is the Issue?
Over the last decade, U.S. hog industry production has shifted to fewer and larger operations that
specialize in a single phase of hog production and the use of production contracts. Consolidation
of operations has meant that an increasing volume of manure is often produced on farms with less
cropland per animal for spreading the manure. A higher manure-to-cropland ratio has magnified
the risk that manure nutrients (nitrogen, phosphorous, and potassium) and pathogens might flow
into ground and surface water due to overapplication of manure on crops or leakage from manure
storage facilities. These runoff contaminants can harm aquatic life and livestock and affect
human drinking water. In addition, increased concentration of hogs per farm has led to conflicts
with nearby residents or communities over odor and air quality. Legislative initiatives, such as
the Clean Water Act and various State regulations, have implemented environmental policies to
mitigate the risk of water pollution and reduce conflicts. Despite the pronounced shifts in hog
industry structure and regulation, little information exists for assessing how these changes have
affected manure management practices and environmental quality. Using data from three surveys
of hog farmers, the authors shed light on these issues by examining how hog manure management
practices vary with the scale of production and how practices have changed since 1998.
What Are the Study Findings?
• Hog farm operators altered their practices between 1998 and 2009 in ways that suggest intent
to manage manure in a more environmentally sound manner. In 2009, operators were more
likely to have comprehensive nutrient management plans and, accordingly, to have increased
their efforts to apply manure at rates not exceeding the nutrient needs of the crop. They were
more likely to have applied manure over a larger share of their cropland and to have increased
their use of feed additives that reduce phosphorus in hog manure, increased the nutrient
testing of manure, and removed excess manure from their premises. They were less likely to
have added commercial fertilizer to crops receiving manure.
• Changes in manure management practices and outcomes from 1998 to 2009 are related to
structural changes in hog production, particularly the increase in farm size and regional shifts of production. The changes include more use of pit/tanks and less of lagoons for manure storage; a decline
in spreading solid manure, as well as in spreading liquid manure without incorporating it into the soil; and less
intensive manure application by the largest farms.
• Environmental policies are likely behind some of the observed patterns of change in hog manure management
between 1998 and 2009. For example, the relatively slow growth in production in the Southeast compared
with the Heartland may be partly attributable to State regulations in North Carolina designed to reduce risks
associated with manure lagoons. Nationally, greater use of comprehensive nutrient management plans, as well
as a decline in intensity of manure applications by the largest operations, may be in response to Federal and
State policies designed to reduce overapplication of manure nutrients. These changes suggest that larger hog
operations are altering their manure management decisions in response to legal nutrient application constraints
and that environmental policy is contributing to the adoption of conservation-compatible manure management
practices.
How Was the Study Conducted?
This study uses information from surveys of U.S. hog producers conducted in 1998, 2004, and 2009 as part of
USDA’s annual Agricultural Resource Management Survey (ARMS). The detailed surveys cover a cross-section
of U.S. hog operations and collect information on production costs, business arrangements, production facilities
and practices, and farm operator and financial characteristics. The surveys also provide information about manure
storage and handling, fertilizer use, manure application techniques, Environmental Quality Incentives Program
(EQIP) payments, the use of comprehensive nutrient management plans, and manure application rates. The data
allow the authors to document the current state of manure management and track producers’ manure management
practices during a period of rapid change in the hog industry. Data from the surveys are disaggregated by farm size
according to the number of animal units produced (by 1,000 pounds of live animal weight). Because larger hogs
produce more manure, animal units provide a consistent measure for comparing manure handling trends among
farms with different levels of manure output.
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