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TECHNOLOGIES FOR EFFICIENT MANURE UTILIZATION AND NUTRIENT MANAGEMENT

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Abstract

Manure brokering and Nutrient Best Management Practice (N-BMP) crop insurance provide incentives for animal feeding operators and crop producers to utilize manure efficiently. Efficient use of manure nitrogen can replace synthetic fertilizers and reduce overall N 2 O emissions. Manure brokering matches livestock producers who have excess manure with grain farmers who can utilize the manure as a fertilizer. Manure brokering allows both the livestock and crop producer to experience an economic return, utilize manure nutrients efficiently, and reduce reliance on synthetic fertilizers. N-BMP crop insurance is based on the proven concept that risk is a major reason that farmers are not adopting conservation technologies such as nutrient management and other best management practices (NRC, 1996). Farmers need assurance that the occasional failure of best management practices will not cause significant loss of income. In practice, farmers often get this assurance by applying extra inputs. N-BMP insurance protects crop producers against the risk of insufficient nitrogen and phosphorus and provides technical assistance when crediting manure and legume nutrients. N-BMP Insurance may be used in tandem with manure brokering, in addition to its other applications (e.g., legume crediting).
TECHNOLOGIES FOR EFFICIENT MANURE UTILIZATION
AND NUTRIENT MANAGEMENT
Tom J. Buman, Agren, Inc.1*
Jamie Ridgely, Agren, Inc.1
Margaret K. Walsh, ICF Consulting2
1Agren Inc, 1238 Heires Avenue, Carroll, IA 51301, U.S.A. Telephone: 712.792.6248. Email:
tom@agren-inc.com*, jamie@agren-inc.com. 2ICF Consulting, Inc. 1725 I St. NW Suite 1000,
Washington, DC 20006, U.S.A. Telephone: 202.862.1200. Email: mwalsh@icfconsulting.com.
Manure brokering and Nutrient Best Management Practice (N-BMP) crop
insurance provide incentives for animal feeding operators and crop producers to
utilize manure efficiently. Efficient use of manure nitrogen can replace synthetic
fertilizers and reduce overall N2O emissions.
Manure brokering matches livestock producers who have excess manure with
grain farmers who can utilize the manure as a fertilizer. Manure brokering allows
both the livestock and crop producer to experience an economic return, utilize
manure nutrients efficiently, and reduce reliance on synthetic fertilizers.
N-BMP crop insurance is based on the proven concept that risk is a major reason
that farmers are not adopting conservation technologies such as nutrient
management and other best management practices (NRC, 1996). Farmers need
assurance that the occasional failure of best management practices will not
cause significant loss of income. In practice, farmers often get this assurance by
applying extra inputs. N-BMP insurance protects crop producers against the risk
of insufficient nitrogen and phosphorus and provides technical assistance when
crediting manure and legume nutrients. N-BMP Insurance may be used in
tandem with manure brokering, in addition to its other applications (e.g., legume
crediting).
1.0 INTRODUCTION
Profitable crop production requires significant nutrient inputs from synthetic
fertilizers, animal manures, and legumes. Nitrogen (N) in particular is often
required in considerable quantities, and its application contributes significantly to
the production of N2O, a potent greenhouse gas (GHG), by agricultural soils.
Manure can replace the use of synthetic fertilizer when it is properly tested,
credited, and applied. Manure brokering and Nutrient Best Management Practice
(N-BMP) crop insurance provide incentives for animal feeding operators and crop
producers to utilize manure efficiently. They may be employed separately or
together. While N of manure origin also contributes to N2O production, through
displacement of commercial fertilizers, a marked reduction in N2O emissions may
be achieved.
2.0 MANURE BROKERING
2.1 BACKGROUND AND RATIONALE
Properly applied, manure provides sufficient nutrients for crop production and
can replace the use of synthetic fertilizers (Chase et al., 1991). Furthermore,
manure improves soil structure and increases organic matter content, enhancing
crop production capacity as well as soil quality (Sharpley et al., 1998). Field trials
conducted by the University of Minnesota showed a substantial yield increase on
manured plots relative to those fertilized with commercial N (Randall, 1997).
Additionally, soils with improved soil tilth and higher organic matter content retain
more water and make it more available to plants (Hudson, 1994).
Manure currently supplements or replaces the use of synthetic fertilizers on 17
percent of corn acreage and 2 to 9 percent of soybean acreage in the United
States (U.S. Department of Agriculture Economic Research Service(USDA
ERS), 2000). However, Ribaudo et al. (2003) estimate that less than half of
swine farms are following the nitrogen best management practice (BMP)
recommendation, resulting in over application of N to cropland. Additionally,
most hog farms do not operate enough land to apply all of the manure they have
available at the BMP recommended rate. These farms are applying manure at
greater than the recommended rate and are not fully utilizing the nutrients in their
manure.
This widespread over application of agricultural N has measurable consequences
to atmospheric N2O concentrations, as agricultural N2O emissions represent a
key source of U.S. GHG emissions (U.S. Environmental Protection Agency,
2003). Therefore, meeting comprehensive GHG management and emission
reduction targets will require the judicious application of agricultural N, including
manure. Manure brokering and N-BMP insurance are potential means for
improving the efficiency of necessary agricultural N inputs, allowing for the
simultaneous mitigation of production costs and reduction in GHG emissions.
2.2 THE MANURE BROKERING PROCESS
Manure brokering matches livestock producers (exporters) who have excess
manure with grain farmers (importers) who can utilize the manure as a fertilizer.
Manure brokering allows both the livestock and crop producer to experience an
economic return, utilize manure nutrients efficiently, and reduce reliance on
synthetic fertilizers.
Key steps in Agren’s manure brokering process include communicating the value
of the manure to both the exporter and importer, negotiating a fair price for the
product, and providing technical assistance on nutrient crediting. A survey
administered to central Iowa landowners and animal feeding operators
documented that the manure broker must take an active role in bringing together
exporters and importers for the service to be successful. Furthermore, the broker
must provide technical assistance in order to ensure proper nutrient crediting and
manure application methods (Agren, Inc., 1997).
Distance to available cropland and competition for available land
Willingness of cropland operators to accept manure
o Deterrents include uncertain nutrient content and availability, soi
l compaction
due to heavy application equipment, weed pressure, odor, social issues
Moisture content of manure
Manure type (species)
Manure handling system
Nutrient content of manure
Nutrient requirements of crop
Price volatility of synthetic fertilizers
Size of animal feeding operation (regulated vs. unregulated)
Local/state land application regulations
Conservation compliance requirements
Method and timing of application
Seasonal land availability vs. storage capacity
2.3 FACTORS INFLUENCING THE FEASIBILITY OF MANURE
BROKERING
2.3.1 REGIONAL ASSESSMENT
On a regional basis, the economic feasibility of manure brokering is primarily
based on three factors: extent to which animal feeding operations are integrated
with grain production; land use in the region; and recommended nutrient
application rates (a factor of crops produced and yield potential).
Manure brokering in the U.S. is clearly most feasible in the Corn Belt. Net costs
for manure transportation and application are consistently lower in the Corn Belt
than any other region in the United States. Animal feeding operations in the
Corn Belt region tend to be more integrated with grain production, so there is
generally more land available for application of manure per animal unit.
Secondly, more land is used for grain production in the Corn Belt than other
regions of the U.S. Therefore, the availability of suitable land off farm is higher
than other regions, reducing the distance manure must be transported. Finally, a
large portion of the crops grown in the Corn Belt region utilize significant rates of
nitrogen (particularly corn), and crop yields in the region tend to be higher when
compared to other regions (Ribaudo et al., 2003).
2.3.2 FARM LEVEL ASSESSMENT
Figure 1 summarizes a number of factors that may affect the feasibility of manure
brokering on a farm level.
FIGURE 1. FACTORS IMPACTING THE FARM LEVEL FEASIBILITY OF BROKERING
2.4 EVALUATING N2O REDUCTIONS
Potential N2O reductions from the use of manure brokering to offset synthetic N
fertilizer use have been calculated according to the methods of the Inventory of
U.S. Greenhouse Gas Emissions and Sinks and are consistent with IPCC
Guidelines (IPCC/UNEP/OECD/IEA, 1997). Although this method is intended for
application to national-scale greenhouse gas inventories and not at the project-
level, we apply it here simply to demonstrate in a gross way the potential
mitigative capacity for this technology, rather than as a true-to-life emission
estimate. Should a more detailed analysis prove worthwhile, we recommend a
more site-specific approach to emissions evaluation. Incorporating location-
specific environmental and management factors into a dynamic simulation
modeling scenario (e.g., DAYCENT, as described by DelGrosso et al., 2001) is
one approach. It should also be noted that no attempt was made here to perform
a comprehensive GHG life-cycle analysis. For example, the energetic costs of
synthetic fertilizer manufacturing and the resulting CO2 emissions are substantial.
Their displacements by the methods described here, when those fertilizers are
never manufactured, are not accounted for in the GHG analysis. Similarly, GHG
differences involved in the transportation and distribution of manure versus
synthetic fertilizers are likely to be noteworthy, but are not evaluated here. Also,
differences in emissions for GHGs other than N2O (e.g., CH4), whose emissions
patterns may be altered based on the fertilizer source, are not considered.
Nitrogen from synthetic fertilizer in this scenario was replaced with equal
amounts of manure N, as is consistent with Iowa’s BMP recommendation (Iowa
State University, 1999). The fate of the N depends on its original source.
Synthetic fertilizers, according to the IPCC Guidelines, volatilize 10 percent of the
total N application; 20 percent of manure N is volatilized. Of the volatilized N, 1
percent becomes N2O indirectly following off-site deposition. Of the N remaining
in the soil, 1.25 percent becomes N2O directly through soil microbial processes
for both synthetic fertilizer and manure nitrogen. However, as the amount of
nitrogen remaining in the soil differs following volatilization, these direct
emissions from manure are smaller than those of synthetic fertilizer. Finally, 30
percent of the total application is assumed to leach or run off, of which 2.5
percent of the total N is converted to N2O. Because the total N application is
identical in either case, the leaching and runoff contributions to N2O production
are the same. This is documented in Figure 2.
In addition to differences in emissions from direct applications, the displacement
of synthetic fertilizers is explicitly accounted for here, as well, because manure
nitrogen will emit N2O whether it is applied at BMP (crop utilization) rates or over
applied. For ease of calculation, we assume here that emissions of unused
manure would be the same if the manure were applied to these soils or not,
though it should be noted that many environmental or management situations
could in reality alter that condition substantially. For the purposes of these
calculations, manure management related emissions (e.g., lagooning) will be
equivalent whether the manure is eventually over applied or not. Application
rates do not affect past management. Manure that is treated as waste and does
not enter a management system, is likely to be land applied eventually, and
therefore the application of soil emission calculations is more valid than any
other. While actual emissions are sensitive to a variety of specific conditions, the
assumption of emission parity is both necessary and valid in this application.
Tom Allen contacted Agren about brokering all of the manure from his 6000 head swine
finishing units in central Iowa. The operation generated about 9.8 million L of liquid manure
annually and Allen did not own or operate any cropland. When Allen contacted Agren, he was
paying for the full cost of manure application. Agren located three landowners near the facility
willing to pay a portion of the application costs to have the manure properly applied to their
land. Currently, Allen is recouping all of the application costs of his manure and is unable to
fully accommodate the demand from his neighbors. The following table summarizes cost
savings realized by Allen and his neighbors.
Year
Cost of
manure
application
paid by
Exporter
Cost of
synthetic
fertilizer paid
by Importers
Savings
realized by
Exporter as a
result of
brokering
Savings realized
by Importers
based on
replacement of
synthetic fertilizer
1997 (Prior to
Manure
Brokering) $38,740 $74,180 0 0
2003 0 0 $38,740 $35,110
($100.3 ha-1)
Application of 9.8 million liters of manure with a N-content of 6.1 g l-1 would emit 1.83 t N2O.
The equivalent amount of synthetic N emits 1.86 t N2O. Because the manure is going to emit
N2O whether it is applied at the BMP rate or not, however, the actual “business as usual”
emissions would be 3.69 t N2O, indicating a real greenhouse gas savings in this case of 1.86 t
N2O.
FIGURE 2. N2O EMISSION CALCULATIONS
2.5 COST SAVINGS POTENTIALLY REALIZED BY CROP AND
LIVESTOCK PRODUCERS
A successful manure brokering agreement allows both the crop and livestock
producer to realize a profit by avoiding costs. The crop producer replaces the
cost of synthetic fertilizers with the lower expense of transporting and applying
the manure. As implied in this example, the livestock producer can reduce or
eliminate the cost of manure disposal through manure brokering. See figure 3.
FIGURE 3. MANURE BROKERING COST & N20 EMISSION SAVINGS: A CASE STUDY
Commercial Fertilizer N2O Emission Calculation
N
COMMERCIAL is the total nitrogen applied as commercial synthetic fertilizer.
Direct N2O-N Emissions from Applied Fertilizer = (0.9 * NCOMMERCIAL) * 0.0125
Indirect N2O-N Emissions from Volatilized Fertilizer = (0.1 * NCOMMERCIAL) * 0.01
Indirect N2O-N Emissions from Leached/Runoff Fertilizer = (0.3 * NCOMMERCIAL) * 0.025
Total Commercial N2O Emissions = (Direct N2O-N + Indirect Volatilization N2O-N +
Indirect Leaching/Runoff N2O-N) * 44/28
Manure N2O Emission Calculation
N
MANURE is the total manure nitrogen applied.
Direct N2O-N Emissions from Applied Manure = (0.8 * NMANURE) * 0.0125
Indirect N2O-N Emissions from Volatilized Manure = (0.2 * NMANURE ) * 0.01
Indirect N2O-N Emissions from Leached/Runoff Manure=(0.3 * NMANURE) * 0.025
Total Manure N2O Emissions = (Direct N2O-N+ Indirect Volatilization N2O-N +
Indirect Leaching/Runoff N2O-N) * 44/28
2.6 POTENTIAL N2O SAVINGS FROM MANURE BROKERING
Gollehon et al. (2001) used U.S. Census of Agriculture data to estimate manure
nutrient production and the capacity of cropland and pastureland to assimilate
nutrients. Their report concludes that, nationally, 60 percent of manure nitrogen
cannot be properly utilized on the farm where it was produced. In the Heartland
Region (similar in size and location to the Corn Belt region discussed above),
recoverable nitrogen exceeds the level of crop uptake on the farm where it was
produced by 81,278 t or about 40 percent. The same report contends that each
county in the Heartland Region produces 25 percent or less of the county’s
assimilative capacity of manure nitrogen. Therefore, it is reasonable to assume
that excess manure nitrogen in a particular county could be exported by livestock
producers and properly applied within that same county. This estimate does not
account for farm level variables such as the importer’s willingness to accept the
manure, nor the costs or benefits associated with its use on operations where it
is not now used. In the assessment shown as Table A, we will use a factor of 50
percent to account for variables in farm level feasibility.
TABLE A. POTENTIAL NITROGEN AND GHG SAVINGS IN THE HEARTLAND REGION
USING MANURE BROKERING
Excess N
(t)
Percent
available for
within county
transfer
Farm-
level
feasibility
factor
Potential N
Savings
(t N)
Potential N2O
Reduction
(t N2O)
81,278 100% 50% 40,639 1261
TABLE B. N2O EMISSIONS FOR U.S. MANURE BROKERING.
EMISSION TYPE Synthetic Fertilizer
(t N2O) Manure Nitrogen
(t N2O)
Direct N2O 718 639
N2O from Volatilization 64 128
N2O from Leaching and Runoff 479 479
Total N2O Emissions 1261 1245
Note: Totals may not sum exactly due to independent rounding.
Table B provides an estimate of potential N2O savings calculated for manure
brokering in the U.S. Manure N emissions are approximately 16 t N2O smaller
than those from synthetic fertilizers. As explained in Section 2.5, however, the
total emissions associated with the use of synthetic fertilizers are the sum of the
commercial fertilizer plus the manure emissions, or 2,507 t N2O. If, however, we
are replacing synthetic fertilizer with manure, the synthetic fertilizer need never
be applied, and total emissions are those resulting from the applied manure
alone, or 1245 t N2O, indicating a potential real N2O reduction of 1261 t N2O, or
0.39 Tg CO2-Eq. This value is similar to the amount of N2O produced though
agricultural burning in the U.S. in 2001 (0.46 Tg CO2-Eq.) (U.S. Environmental
Protection Agency, 2003).
3.0 NUTRIENT BMP INSURANCE
3.1 BACKGROUND AND RATIONALE
The growing concern over the affect of agriculture on air, water, and soils has
increased the interest of researchers in developing nutrient BMPs. In theory,
farmers will increase management efficiency and decrease negative
environmental impacts by implementing BMPs. Although nutrient BMPs have
been developed and are widely recognized, the adoption of many of these
practices remains slow (Nowak et al., 1998).
A number of studies highlight the reluctance of producers to implement BMPs for
crediting manure nutrients. A recent survey of 1,928 farms in Wisconsin found
that two out of three farmers apply nitrogen for corn production in excess of the
University of Wisconsin’s BMP recommendation. Data collected between 1990
and 1998 indicated only 36 percent of all the producers applying animal manure
made an effort to credit or account for the value of manure nitrogen. Of those
attempting to credit manure, 83 percent underestimated manure nitrogen by
greater than 10 percent. Only 3 percent of the farmers who credited manure did
so within 10 percent of University of Wisconsin recommendations. Researchers
concluded that less than 2 percent of producers applying manure on cornfields
do so with any degree of accuracy (Shepard, 2000).
Similarly, the 1995 Iowa Farm and Rural Life Poll found that greater than one-half
of producers applying manure to their land did not adjust the synthetic fertilizer
rate to account for the nutrients in the manure. Only one percent of livestock
producers used manure nutrient analysis as a major factor in determining the
manure application rate. Sixty percent of producers relied on their own judgment
as the major factor in determining the correct application rate (Lasley, 1995).
United States Department of Agriculture (USDA) Economic Research Service
(ERS) states that one of the most important barriers to nutrient BMP adoption by
farmers is risk of failure (Feather, 1995). Farmers’ perception of the risk prevents
adoption of BMPs, even when farmers believe they may be profitable (NRC,
1996). Feather (1995) further concludes that although farmers may understand
the practices and believe they are economical, they still do not adopt them.
Farmers rely on fertilizers and other agricultural inputs to protect and increase
crop yields. In practice, farmers over apply nutrients as a form of “product
insurance”, rather than testing and evaluating actual input needs. Farmers
believe that in order to calculate nutrient availability from animal manure it entails
greater risk and requires more time and knowledge than simply over applying
manure or synthetic fertilizer. In order for appropriate manure crediting to take
place a farmer must have a comprehensive understanding of nutrient
management and manure crediting, as well as trust measured manure nutrient
values and the opinion of an expert.
The risk of following nitrogen BMPs is not merely perception. One of the most
difficult challenges facing agriculture is determining the optimal rate of nitrogen
fertilizer application (Schepers et al., 1992). The problem is one of synchronizing
soil nitrogen availability (from all sources) with crop needs. Even within a single
field, variation such as changes in soil type, soil moisture, landscape position,
and weed pressure can confound the effects that nitrogen alone would have on
crop production (Englehardt et al., 2001). These unknowns translate to real
economic risk. Bock (1991) has demonstrated that when the optimal nitrogen
application rate is underestimated, the resulting nutrient deficiency can
significantly reduce a farm’s profit margin.
3.2 NUTRIENT BMP INSURANCE AS A RISK MANAGEMENT TOOL
Farmers need assurance that the occasional failure of BMPs will not cause a
significant loss of income. Nutrient BMP (N-BMP) insurance is a form of financial
insurance that protects farmers against the risk of insufficient nitrogen and
phosphorus for crop growth and provides technical assistance for crediting
manure and legume nutrients. The policy permits farmers to lower their inputs
and operating costs by avoiding application of excess fertilizer. Farmers apply
the amount of nitrogen recommended by their local expert institution, such as the
state University and Extension system. Depending on the state, this BMP
recommendation is calculated from field specific information such as soil test
data, yield goals, and previous manure or legume history.
To determine whether insufficient fertilization actually diminished yield, the yield
of an over-fertilized area or “check strip” is compared to that of directly adjacent
BMP-managed land. If the yield of the check strip is greater than the yield on the
adjacent BMP-managed land, the diminished yield is declared to have resulted
from inadequate nutrition due to BMP management, and the insurance policy
compensates the farmer for the loss, excluding a 5 percent deductible.
In many cases, applying recommended rates of manure and purchasing BMP
insurance is the least costly alternative for farmers that are unsure of manure
crediting recommendations. Figure 4 demonstrates how Nutrient BMP Insurance
can provide significant cost savings to farmers. Nutrient BMP coverage will be
offered as an endorsement to federal crop insurance through the U.S. Federal
Crop Insurance Corporation and participating companies on a pilot basis in the
states of Iowa, Wisconsin, Minnesota, and Pennsylvania for the 2004 crop year.
FIGURE 4. N-BMP INSURANCE COST AND N2O-EMISSION SAVINGS: A CASE STUDY
The Ridgely family farms 535 hectares in north central Iowa in a corn/soybean rotation. They
currently fertilize their crops exclusively with synthetic fertilizer, but may purchase liquid swine
manure for 176 ha of their farm (nutrient requirements for meeting the farm’s yield goals are
171 kg N ha-1, 123 kg P2O5 ha-1, and 95 kg K20 ha-1). The Ridgelys are interested in taking the
manure, but do not trust that the BMP recommended rate of manure will provide adequate
nitrogen to the crop. The Ridgelys are considering three options:
Option 1) Commercial Fertilizer
§ Continue historic application rates of synthetic fertilizers at 171 kg N ha-1 ($0.55 kg-1),
123 kg P2O5 ha-1 ($0.59 kg-1), and 95 kg K20 ha-1 ($0.31 kg-1) for a total cost, including
application, of $211 ha-1.
Option 2) Manure + Extra Commercial Fertilizer
§ Nutrient analysis of the liquid swine manure is 6.1 g N L-1, 5.8 g P2O5 L-1 , and 3.59 g
K20 L-1 .
§ Apply 28,050 L ha-1 by subsurface injection, as per Iowa State University BMP
recommendation for an application cost of $111 ha-1.
§ Apply an additional 112 kg ha-1 (100 lbs. ac.-1) synthetic N to ensure sufficient nitrogen
at a cost, including application, of $77 ha-1.
Option 3) Manure + N-BMP insurance
§ Apply 28,050 L ha-1 by subsurface injection, as per Iowa State University BMP
recommendation, for an application cost of $111 ha-1.
§ Purchase N-BMP insurance for $22 ha-1.
FERTILIZER OPTIONS
(COST FOR A TWO-YEAR CORN/SOYBEAN ROTATION)
$0 $50 $100 $150 $200 $250
Option # 3
Option # 2
Option # 1
$/ha
Synthetic Fertilizer
Manure
Insurance
Result: By selecting Option 3, the Ridgely family can save $78 ha-1, (the cost of Option 1
minus the cost of Option 3) amounting to an annual savings of nearly $14,000.
MITIGATED GREENHOUSE GAS EMISSIONS
Potential N
2O reduction for the Ridgely farm was calculated based on those methods
described under Section 2.5.
N2O EMISSIONS FOR THE RIDGELYS
SCENARIO Emissions
(t N2O)
Option 1: Synthetic Fertilizer 1.86
Option 2: Manure + Synthetic Fertilizer 2.14
Option 3: Manure + N-BMP Insurance 0.92
Note: Totals may not sum exactly due to independent rounding.
The use of Option 3 rather than Options 1 or 2 results in an overall N2O-savings of 0.94 and
1.22 t N2O, respectively. N-BMP insurance allows the Ridgelys to adopt this practice and
simultaneously mitigate the risk of insufficient N and any resulting loss of yield.
3.3 POTENTIAL N2O SAVINGS FROM N-BMP INSURANCE
Farmers may decide to change their fertilization practices and follow a BMP for
many reasons, including regulatory pressure, environmental stewardship,
improved operating efficiency, and improved net return.
The USDA ERS annually computes nutrient mass balances for major U.S. crops.
A nutrient mass balance indicates how closely the nutrient inputs (synthetic
fertilizer, legumes, manure) compare with crop nutrient removal. A positive
nitrogen mass balance implies that nitrogen remains in the soil after the crop has
used what it needs for growth. Using nitrogen mass balance estimates for the
Corn Belt Region, USDA ERS reviewers of the N-BMP policy estimate the land
potentially benefiting from the policy to be 27 percent of corn-cropped area, or
6.1 million hectares. We include this as an estimated land area for N-BMP
insurance implementation.
Shepard (2000) documented in his survey of Wisconsin farmers that two of three
farmers apply excess nitrogen for corn production, and on average, farmers used
an excess of 42.6 kg N ha-1. Furthermore, in nearly 7 percent of the cases,
nitrogen application rates exceeded 448 kg N ha-1 or nearly 280 kg N ha-1 more
than the recommended rate. Similarly, a confidential and unpublished survey in
Illinois indicated that 13 percent of farmers apply an excess of 44.8 kg N ha-1 or
more beyond the state BMP recommendation (Greene, 2001). We include 44.8
kg N ha-1 as an estimate of average over-application rate based on these studies
and an appreciation that farmers over applying to the greatest extent will be
those with the greatest financial incentive to purchase N-BMP insurance. Table
C provides a national gross assessment of the nitrogen that could be potentially
saved with the N-BMP insurance, along with resulting N2O reductions.
TABLE C. POTENTIAL NITROGEN AND GHG SAVINGS USING N-BMP INSURANCE
Hectares targeted for
Insurance policy sales
(millions of hectares)
Average nitrogen
over- applied
(kg ha-1)
Potential nitrogen
savings
(t N)
Potential N2O
Reduction
(t N2O)
6.07 44.8 271,936 8440
Potential N2O reduction for implementation of N-BMP Insurance was calculated
based on those methods described under Section 2.4 and is documented in
Table D.
TABLE D. N2O EMISSIONS FOR N-BMP INSURANCE
EMISSION TYPE Synthetic Fertilizer
(t N2O) Manure Nitrogen
(t N2O)
Direct N2O 4807 4273
N2O from Volatilization 472 855
N2O from Leaching and
Runoff 3205 3205
Total N2O Emissions 8440 8333
Note: Totals may not sum exactly due to independent rounding.
Manure emissions are approximately 107 t N2O less than those of emissions
associated with synthetic fertilizers. The total business as usual emissions,
however, accounting for both the synthetic and the manure N2O emissions, totals
16,773 t N2O, indicating an overall emission reduction of 8440 t N2O, or 2.6 Tg
CO2-Eq. This is most comparable in magnitude to SF6 emissions from
magnesium production in the U.S. in 2001 (2.53 Tg CO2-Eq.) (U.S.
Environmental Protection Agency, 2003).
4.0 CONCLUSIONS
Manure brokering and N-BMP insurance used independently or in combination
form a valuable tool for animal feeding operators with a limited land-base to apply
manure nutrients. Livestock and poultry producers can, in effect, sell the
nutrients along with a warranty on the nutrient content and performance of the
manure.
Given that manure brokering and N-BMP Insurance may be used in tandem, it
would be inappropriate to treat their overall N2O emissions savings additively.
Either, however, is comparable in magnitude to some of the smaller component
sources of the U.S. Greenhouse Gas Inventory. While the emission savings
estimates arrived at are preliminary and based on national-level information, we
believe they highlight the importance of further analysis and consideration of
these programs under a comprehensive greenhouse gas emission reduction
plan.
Project level benefits to individual farm operations are measurable both from an
environmental viewpoint and with respect to cost of production. We believe this
preliminary examination provides evidence of sufficient potential to encourage
further inquiries into the applications of manure brokering and N-BMP insurance
in meeting agronomic needs and environmental agreements, reducing
greenhouse gas emissions and exploring benefits to farmers such as risk
mitigation.
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Agren, Inc. 1997. Manure Brokering Business Plan.
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Chase, C., M. Duffy, W. Lotz. 1991. Economic Impact of Varying Swine Manure
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Article
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Census of agriculture data were used to estimate manure nutrient production and the capacity of cropland and pastureland to assimilate nutrients. Most farms (78 percent for nitrogen and 69 percent for phosphorus) have adequate land on which it is physically feasible to apply the manure produced onfarm at agronomic rates. (The costs of applying manure at these rates have not been assessed). Even so, manure that is produced on operations that cannot fully apply it to their own land at agronomic rates accounts for 60 percent of the Nation's manure nitrogen and 70 percent of the manure phosphorus. In these cases, most counties with farms that produce "excess" nutrients have adequate crop acres not associated with animal operations, but within the county, on which it is feasible to spread the manure at agronomic rates. However, barriers to moving manure to other farms need to be studied. About 20 percent of the Nation's onfarm excess manure nitrogen is produced in counties that have insufficient cropland for its application at agronomic rates (23 percent for phosphorus). For areas without adequate land, alternatives to local land application-such as energy production-will need to be developed.
Article
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Agricultural chemicals and sediment from cropland may reduce the quality of America's surface and ground water resources. The Clean Water Act stipulates that individual States are responsible for controlling agricultural nonpoint source pollution. Most State plans rely chiefly on education and technical assistance to promote the adoption of less polluting practices. Because profitability drives production decisions, these programs tend to be most successful when they promote inexpensive changes in existing practices. This report presents research findings on the success of incentive programs to control agricultural nonpoint source pollution.
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Farming systems that combine animals, forage, and cash grain production have the opportunity to augment commercial fertilizers with nutrients generated on a farm. To do this, the farmer must weigh the economic benefits associated with a low-risk option of relying on commercial nutrients against technological and managerial uncertainties associated with using on-farm nutrient sources. This decision by the farmer must be made in the context of maintaining a financially-viable farm while reducing the probability of environmental degradation caused by over-application of crop nutrients. Supposedly, best management practices (BMPs) promoted by water quality programs help the farmer achieve this objective. A survey was conducted among Wisconsin livestock farmers to assess the application of all sources of nitrogen (N), and phosphorus (P2O5) in the production of corn. Nitrogen and phosphorus inputs were selected because they have been shown to negatively effect the surface and ground water resources when used in excess or in sensitive ecological areas. This research differed from more common attitudinal surveys of farmers by focusing on the actual agronomic behaviors associated with the management of crop nutrients in mixed farming systems. Data from 1,928 farms in Wisconsin was used in this analysis to determine the overall nutrient application rates and use of BMPs. Results indicate that two out of three farmers apply excess nitrogen (N), while four out of five apply excess phosphorus (P2O5) for corn production. Few use the recommended BMPs in an appropriate fashion. These results indicate that farmers' actual behavior patterns must be brought into the design of both best management practices and implementation strategies for water quality programs.