User's Guide for Estimating
Carbon Dioxide, Methane, and
Nitrous Oxide Emissions from
Agriculture Using the State
Inventory Tool
January 2022
Prepared by:
ICF
Prepared for:
State Energy and Environment Program,
U.S. Environmental Protection Agency
This section of the User's Guide provides instruction on using the CO2, ChU, and N2O from
Agriculture (Ag) module of the State Inventory Tool (SIT), and describes the methodology
used for estimating greenhouse gas emissions from agriculture at the state level.
-------
Module 7 - Agriculture Module
January 2022
Table of Contents
1.1 Getting Started 2
1.2 Module Overview 3
1.2.1 Data Requirements 5
1.2.2 Tool Layout 6
1.3 Methodology 6
1.4 Uncertainty 30
1.5 References 30
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.1
-------
Module 7 - Agriculture Module
January 2022
1.1 Getting Started
The Agriculture (Ag) module of the State Inventory Tool (SIT) was first developed using
Microsoft® Excel 2000. While the module will operate with older versions of Excel, it
functions best with Excel 2000 or later. Some of the Excel basics are outlined in the
sections below. Before you use the Ag module, make sure your computer meets the system
requirements. In order to install and run the Ag module, you must have:
• IBM-PC compatible computer with the Windows 95 operating system or later;
• Microsoft® Excel 1997 or later, with calculation set to automatic and macros
enabled;
• Hard drive with at least 20MB free; and
• Monitor display setting of 800 x 600 or greater.
Microsoft Excel Settings
Excel 2003 and Earlier: For the SIT modules to function properly, Excel must be set to
automatic calculation. To check this setting, launch Microsoft Excel before opening the Ag
module. Go to the Tools menu and select "Options..." Click on the "Calculations" tab and
make sure that the radio button next to "Automatic" is selected, and then click on "OK" to
close the window. The security settings (discussed next) can also be adjusted at this time.
Excel 2007 and Later: For the SIT modules to function properly, Excel must be set to
automatic calculation. Go to the Formulas ribbon and select "Calculation Options." Make
sure that the box next to the "Automatic" option is checked from the pop-up menu.
Microsoft Excel Security
Excel 2003 and Earlier: Because the SIT employs macros, you must have Excel security
set to medium (recommended) or low (not recommended). To change this setting, launch
Microsoft Excel before opening the Ag module. Once in Excel, go to the Tools menu, click
on the Macro sub-menu, and then select "Security" (see Figure 1). The Security pop-up box
will appear. Click on the "Security Level" tab and select medium. When set to high, macros
are automatically disabled; when set to medium, Excel will give you the choice to enable
macros; when set to low, macros are always enabled.
When Excel security is set to medium, users are asked upon opening the module whether to
enable macros. Macros must be enabled in order for the Ag module to work. Once they are
enabled, the module will open to the control worksheet. A message box will appear
welcoming the user to the module. Clicking on the "x" in the upper-right-hand corner of the
message box will close it.
Excel 2007 and Later: If Excel's security settings are set at the default level a Security
Warning appears above the formula box in Excel when the Ag module is initially opened.
The Security Warning lets the user know that some active content from the spreadsheet has
been disabled, meaning that Excel has prevented the macros in the spreadsheet from
functioning. Because SIT needs macros in order to function properly, the user must click
the "Options" button in the security message and then select, "Enable this content" in the
pop-up box. Enabling the macro content for the SIT in this way only enables macros
temporarily in Excel but does not change the macro security settings. Once macros are
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.2
-------
Module 7 - Agriculture Module
January 2022
enabled, a message box will appear welcoming the user to module. Click on the "x" in the
upper right-hand corner to close the message box.
If the Security Warning does not appear when the module is first opened, it may be
necessary to change the security settings for macros. To change the setting, first exit out
of the Ag module and re-launch Microsoft Excel before opening the Ag module. Next, click
on the Microsoft Excel icon in the top left of the screen. Scroll to the bottom of the menu
and select the "Excel Options" button to the right of the main menu. When the Excel
Options box appears, select "Trust Center" in left hand menu of the box. Next, click the
gray "Trust Center Settings" button. When the Trust Center options box appears, click
"Macro Settings" in the left-hand menu and select "Disable all macros with notification."
Once the security level has been adjusted, open the Stationary Combustion module and
enable macros in the manner described in the preceding paragraph.
Viewing and Printing Data and Results
The Ag module contains some features to allow users to adjust the screen view and the
appearance of the worksheets when they are printed. Once a module has been opened, you
can adjust the zoom by going to the Module Options Menu, and either typing in a zoom
percentage or selecting one from the drop-down menu. In addition, data may not all
appear on a single screen within each worksheet; if not, you may need to scroll up or down
to view additional information.
You may also adjust the print margins of the worksheets to ensure that desired portions of
the Ag module are printed. To do so, go to the File menu, and then select "Print Preview."
Click on "Page Break Preview" and drag the blue lines to the desired positions (see Figure
2). To print this view, go to the File menu, and click "Print." To return to the normal view,
go to the File menu, click "Print Preview," and then click "Normal View."
Figure 1. Changing Security Settings
Figure 2. Adjusting Print Margins
E3 Microsoft Excel - Bookl
P0
File Edit
View Insert
Format
Tools | Data Window Help I
| A1
f*
Spelling.,. F7
1
A |
| B |
c I
a
Research... Alt+Click
~
H I
1 |
J
K
I]
Error Checking...
T]
T]
Speech ~
4
Shared Workspace,,,
in
in
Share Workbook.,,
T]
Track Changes ~
in
Compare and Merge Workbooks...
JM
lol
Protection ~
TT]
Online Collaboration ~
J2j
Goal Seek,,,
33
14
Scenarios...
33
Formula Auditing ~
!eT|
_
33
| Macro ~ |
;>
Macros...
Alt+F8
ill
1
Add-Ins...
Record Me
w Macro...
J9j
cafl
AutoCorrect Options...
Security,,,
1
20
1
L
_l
21
Customize...
£
| Visual Basic Editor
Alt+FU
22J
Options,..
(A
> Microsoft Script Editor
Alt+Shift+Fll
23
24~
:l^J File £dlt Module Options
Jiusting
Reset Worksheet
1.2 Module Overview
This User's Guide accompanies and explains the Agriculture module of the SIT. The SIT was
developed in conjunction with EPA's Emissions Inventory Improvement Program (EIIP).
Prior to the development of the SIT, EPA developed the States Workbook for estimating
greenhouse gas emissions. In 1998, EPA revisited the States Workbook and expanded it to
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module 1.3
-------
Module 7 - Agriculture Module
January 2022
follow the format of EIIP guidance documents for criteria air pollutants. The result was a
comprehensive, stepwise approach to estimating greenhouse gas emissions at the state
level. This detailed methodology was appreciated by states with the capacity to devote
considerable time and resources to the development of emission inventories. For other
states, the EIIP guidance was overwhelming and impractical for them to follow from scratch.
EPA recognized the resource constraints facing the states and developed the SIT. The ten
modules of the SIT corresponded to the EIIP chapters and attempted to automate the steps
states would need to take in developing their own emission estimates in a manner that was
consistent with prevailing national and state guidelines.
Because most state inventories developed today rely heavily on the tools, User's Guides
have been developed for each of the SIT modules. These User's Guides contain the most
up-to-date methodologies that are, for the most part, consistent with the Inventory of U.S.
Greenhouse Gas Emissions and Sinks. Volume VIII of the EIIP guidance is a historical
document that was last updated in August 2004, and while these documents can be a
valuable reference, they contain outdated emissions factors and, in some cases, outdated
methodologies. States can refer to Volume VIII of the EIIP guidance documents if they are
interested in obtaining additional information not found in the SIT or the companion User's
Guide.
The Ag module calculates carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)
emissions from the agricultural sectors shown in Table 1. The Ag module now estimates
CO2 emissions from Liming of Soils and Urea Fertilization for consistency with the Inventory
of U.S. Greenhouse Gas Emissions and Sinks. These categories were previously estimated in
the Land Use, Land-Use Change, and Forestry module.
While the module provides default data for each sector (depending on availability), users
are encouraged to use state-specific data, where available. If using outside data sources, or
for a more thorough understanding of the tool, please refer to the following discussion for
data requirements and methodology.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.4
-------
Module 7 - Agriculture Module
January 2022
1.2.1 Data Requirements
To calculate CO2, CH4, and N2O emissions from agriculture, general animal and crop
production and emission characteristics are required. A complete list of the activity data
and emission factors necessary to run the Ag module is provided in Table 1.
Table 1. Agricultural Sectors, Data Requirements, and Gases Emitted
Module Worksheet
Data Required
Gas(es)
Enteric Fermentation
Emission Factors by Animal Type
Animal Population Numbers
ch4
Manure Management-ChU
Manure Management-IN^O
Typical Animal Mass (TAM)
Volatile Solids (VS) Production
Maximum Potential CH4 Emissions (B0)
Kjeldahl (K) Nitrogen Excreted*
Animal Population Numbers
ch4, n2o
Ag Soils-Plant-Residues & Legumes
Ag Soils-Plant-Fertilizers
Ag Soils- Animals
Residue Dry Matter Fraction
Fraction Residue Applied
Nitrogen Content of Residue
Kjeldahl (K) Nitrogen Excreted
Crop Production
Fertilizer Utilization
TAM*
N20
Rice Cultivation
Seasonal Emission Factor
Area Harvested
ch4
Liming of Soils
Emission factors for CO2 emitted from
use of crushed limestone and dolomite
(ton C/ton limestone)
Total limestone and dolomite applied to
soils (metric tons)
co2
Urea Fertilization
Emission factors for CO2 emitted from
the use of urea as a fertilizer (tons C/ton
urea)
Total urea applied to soils (metric tons)
co2
Ag. Residue Burning-ChU
Ag. Residue Burning-IN^O
Residue/Crop Ratio
Fraction of Residue Burned
Dry Matter Fraction*
Burning Efficiency
Combustion Efficiency
Carbon Content
Nitrogen Content*
cm, n2o
* For consistency in calculations, data that overlaps between sectors are pulled through from the
original input into subsequent uses.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.5
-------
Module 7 - Agriculture Module
January 2022
1.2.2 Tool Layout
Because there are multiple steps to complete within the Ag module, it is important to have
an understanding of the module's overall design. The layout of the Ag module and the
purpose of its worksheets are presented in Figure 3.
Figure 3. Flow of Information in the Ag Module*
Control Worksheet
Individual Sector Worksheets
1. Choose a State
2. to 6. Enter Emission Factors and Activity Data for:
2. Enteric Fermentation
Enteric Fermentation
Enter animal population data for each year
Manure Management
3a. CH4 from Manure Management
Ag Soils
Enter animal population data for each year
Rice Cultivation
3b. N20 from Manure Management
Liming of Soils
Review data imported from Manure CH4 worksheet
Urea Fertilization
4a. Ag Soils-Plant-Residues & Legumes
Ag Residue Burning x
Enter crop production data for each year
X.
4b. Ag Soils-Plant-Fertilizers
x
Enter fertilizer use by calendar year or growing year
<
4c. Ag Soils-Animals
Review data imported from Manure CH4 worksheet
5. Rice Cultivation
Enter data harvested for each year
6. Liming of Soils
Enter data on amount of limestone and dolomite applied to soils
7. Urea Fertilization
Enter data on amount of urea applied to soils
8a. Ag. Reside Burning-CH4
Enter crop data and activity data for non-default crops
8b. Ag Residue Burning-N20
Enter nitrogen content for non-default crops
9. View Summary Data ¦*
—Summary Data
Presented in both table and graphical formats in MMTC02E.
10. Export Data ¦*
—*¦ Uncertainty
Review information on uncertainty associated with default data.
* These worksheets are the primary worksheets used in the Ag module; subsequent worksheets are used to
populate the default data and are provided for informational purposes only.
1.3 Methodology
This section provides a guide to using the Ag module of the SIT to estimate CO2, ChU, and
N2O emissions from livestock and crop production. Within the Ag module the sectors
included are enteric fermentation, manure management, agricultural soils, rice cultivation,
liming of soils, urea fertilization, and agricultural residue burning. Because the methodology
differs for each sector, they are discussed separately and specific examples for each sector
are provided.
The Ag module automatically calculates emissions after you enter or choose default data for
the factors on the control worksheet and the activity data within each sector worksheet.
The tool provides default data for most required information; however, other more state-
specific data may be used if available. Additionally, for some states data may not be
available for all crop or livestock types, so users should check each worksheet to determine
if additional information may be available.
The Ag module follows the general methodology outlined in Chapters VII through XI of the
Emissions Inventory Improvement Program (EIIP) guidance, however because of the
automation of the calculations within the tool, the order of steps discussed in this User's
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.6
-------
Module 7 - Agriculture Module
January 2022
Guide do not always follow the order of steps discussed within the EIIP guidance document.
This User's Guide provides an overview of the estimation methodology used in the Ag
module by walking through the following steps: (1) select a state; (2) enter emission
factors and activity data for enteric fermentation; (3) enter emission factors and activity
data for manure management; (4) enter emission factors and activity data for agricultural
soils; (5) enter emission factors and activity data for rice cultivation; (6) enter emission
factors and activity data for liming of soils; (7) enter emission factors and activity data for
urea fertilization; (8) enter emission factors and activity data for agricultural residue
burning; (9) review summary information; and (10) export data. The general equations
used to calculate CO2, ChU, and N2O emissions from agriculture are shown in the discussion
of each specific sector.
Step (1) Select a State
To begin, select the state you are interested in evaluating. By selecting a state, the rest of
the tool will automatically reset to reflect the appropriate state default data and
assumptions for use in subsequent steps of the tool.
Step (2) Enter Emission Factors and Activity Data for Enteric Fermentation
Control Worksheet
On the control worksheet, either select the default data provided or enter user-specified,
animal or crop-specific data that will be used throughout the tool. To proceed with the
default data, select the "Check/Uncheck AN" button for each sector or check the individual
default box directly to the right of specific yellow input cells. Note that this number can be
overwritten if you later discover that the data for your state differ from the default data
provided by the tool. To enter user-specified inputs, enter data directly into the yellow
input cells. If the user-specific inputs do not match the default data in the control
worksheet (i.e., the default value is overwritten), the text will appear red. See Figure 4 for
locations of the "Check/Uncheck AN" buttons, individual default check boxes, and yellow
input cells. Information requirements on the control worksheet for each sector are
discussed separately below.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.7
-------
Module 7 - Agriculture Module
January 2022
Figure 4. Control Worksheet for the Ag Module
I
UT.
e a
State Inventory Tool - Methane and Nitrous Oxide from Agriculture Module
1. Choose a state. I California I T I
This is very important - it selects the correct default variables for your state.
2. Fill In the Variables that are used in this Tool and Click to proceed to the respective worksheets.
Either Type in the Value or Click the Default Box
Enteric Fermentation Emission Factors | Consult 6uidance~|
Reset Worksheet
Animal Group
Dairy Cattle
Dairy Cows
Dairy Replacement Heifers
Replacements 0-12 mos.
Replacements 12-24 mos.
Beef Cattle
Beef Cows
Beef Replacement Heifers
Replacements 0-12 mos.
Replacements 12-24 mos.
Heifer Stockers
Steer Stockers
Feedlot Heifers
Feed lot Steer
Bulls
Other
Sheep
Goats
Swine
Default Factor
(kg/animal/Yr) Factor Used Use Default? (Check for Yes)
Manure Management Animal Calculation Values | Consult guidance |
Animal
Dairy Cattle
Typical Animal Mass (TAM1
(kg)
Use
Default Factor Default?
Volatile Solids
-------
Module 7 - Agriculture Module
January 2022
Figure 5. Example of Activity Data Applied in the Enteric Fermentation Worksheet
I
TFT
I
2 Enteric Fermentation Emissions in California
Emissions from Enteric Fermentation are calculated by multiplying each animal
population by an animal- and region-specific emission factor. Those resulting
values, in kg CHtl are then converted to million metric tons (MMTCHJ, MMT carbon
equivalent (MMTCE), MMT carbon dioxide equivalent (MMTCCuE), and then summed.
For more information, please refer to the Agriculture Chapter of the User's Guide.
< Return to
Control Sheet
Enteric Fermentation
Dairg Cattle
Dairy Cows
Dairy Replacement Heifers
Replacements 0-12 mos.
Replacements 12-24 mos.
Beef Cattle
Beef Cows
Beef Replacement Heifers
Replacements 0-12 mos.
Replacements 12-24 mos.
Heifer Stockers
Steer Stockers
Feedlot Heifers
Feedlot Steer
Bulls
Other
Sheep
Goats
Swine
TOTAL
1990
Emission Factor
(kg CH.fhead)
R Default Anrnal Data?
Emissions
(kg CH«]
Check All Boxes
Emissions
(MMTCE)
Emissions
(MMTCOjE)
0.000
0.000
0.000
0.000
73.8
¦
70.962.340
56.1
Animal
Populations
62.9
54.2
18,672,435
44.0
3,982,442
44.9
16,678,080
53.0
3,744,079
0.0000
0.0000
0.0040
0.0187
0.0040
0.0167
0.0037
0.406
0.048
0.000
0.000
0.023
0.107
0.023
0.0%
0.021
1.490
0.178
0.350
0.079
0.0002
0.0003
0.0056
0.3135
0.046
0.001
0.002
0.032
1.795
0.004
0.006
0.117
6.583
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.9
-------
Module 7 - Agriculture Module
January 2022
Box 1: Caution When Providing Animal Population Data
If you decide to use animal population data that is different from the default data, please be
aware of the following possible data issues:
Animal populations fluctuate during the year, in some cases by large amounts. For example, a
census done before calving will give a much smaller number than a census done after calving.
Thus, the average animal population over the course of the inventory year should be used in the
estimates (termed here the "annual average population"). For some animals, a specific state's
population may only be given for one month, while the national population is given at other
points during the year. In this case a state's annual average animal population may be
estimated based on the animal population in the state in a given month, and an adjustment
factor developed with (2) the national population of the animal in the same month, and (2) the
national population of the animal either six months before or after. Therefore, to obtain an
average annual animal population it may be necessary to use animal census data from multiple
points throughout each year.
Note that for enteric fermentation the tool gives users the option of providing heifer
replacement data in aggregate or by age class (0 - 12 months and 12 - 24 months); default
populations are provided in aggregate although default emission factors are provided for both
options. If users provide data by age class, it is important to make sure that the total heifer
replacement data are deleted to avoid double counting.
Finally, emissions estimates for enteric fermentation and manure management rely on the same
underlying livestock population data and livestock characteristic data. Therefore, if not using
default data it is important to use the same population data to estimate emissions from these
two source categories. Note that although the specific sub-categories of livestock types may
vary between the two sources, they should rely on the same underlying population data. For
example, total swine populations are used for enteric fermentation, while swine are split into
breeding and market, and further divided by weight class in the manure management source
category. Additionally, calves are omitted in the enteric fermentation estimates; this is because
emissions are assumed to be zero through six months of age. Emissions from calves are
included in the manure management estimates; therefore, the calf populations are required in
that worksheet.
The Ag module calculates emissions for enteric fermentation by multiplying animal
populations by the annual emission factor to obtain the total Chk emitted. Then, the total
CH4 emitted is converted into carbon dioxide (CO2) equivalents by multiplying by the GWP
of CH4 (25). Finally, emissions are divided by 109 to express emissions in MMTCO2E.
Equation 1 demonstrates the emission calculation for enteric fermentation.
Equation 1. Emission Equation for Enteric Fermentation
Emissions (MMTCO2E) =
Animal Population ('000 head) x Emission Factor (kg ChU/head) x 25 (GWP)
-r 1,000,000,000 (kg/MMTC02E)
Once this sector worksheet is complete, use the gray navigational arrow to return to the
control worksheet and proceed to the next sector.
Step (3) Enter Emission Factors and Activity Data for Manure Management
Emissions from animal waste during storage in a management system are accounted for in
this sector. Following storage in a management system it is then assumed that the manure
is ultimately applied to soils, where further emissions take place. These subsequent
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.10
-------
Module 7 - Agriculture Module
January 2022
emissions, as well as a third emission type, manure managed through daily spread, are
considered to be emissions from agricultural soils, and are discussed in Step 4.
Control Worksheet
Both CH4 and N2O are produced during the manure decomposition process. The data
required for manure management sector within the control worksheet are the typical animal
mass (TAM), volatile solids (VS) production, and maximum ChU producing capacity (B0),
which are pulled into manure ChU worksheet. Each data requirement is discussed in more
detail below:
• Typical animal mass is the average mass of the entire animal population sub-category,
expressed in kg.
• Volatile solids are defined as the organic fraction of the total solids in manure that will
oxidize and be driven off as gas at a temperature of 1,112°F. Total solids are defined as
the material that remains after evaporation of water at a temperature between 217° and
221°F. CH4 emissions from livestock are directly related to the amount of VS produced.
Production of VS is reported in the tool as kg VS per head per year for cattle (excluding
calves), and as kg VS per 1,000 kg of animal mass per day for calves and all other
livestock (i.e., swine, poultry, sheep, goats, and horses).
• The ChU-producing capacity of livestock manure is generally expressed in terms of the
quantity of ChU that can be produced per kilogram of VS in the manure. This quantity is
determined by animal type and diet and is commonly referred to as Bo with units of
cubic meters of ChU per kilogram VS (m3 ChU/kg VS).
After completing the control worksheet for this sector, use the gray arrows to navigate to
the sector worksheets.
Step (3a) CH4 from Manure Management Sector Worksheet
To estimate ChU emissions from manure, information is input into the blue cells in Figure 6
on annual average animal populations (in number of head) for the following animal types:
cattle (by type), swine (by type), poultry (by type), sheep (by type), goats, and horses.
The red arrows in Figure 6 indicate the areas where the required data are entered or pulled
through to the manure management worksheet from the control worksheet. If users plan
on providing their own animal population data, please review the notes in Box 1. When
decomposition occurs without oxygen (i.e., anaerobic decomposition) ChU is produced. The
CH4-producing capacity of livestock manure depends on the specific composition of the
manure, which in turn depends on the composition and digestibility of the animal diet. In
general, the greater the energy content of the feed, the greater the ChU-producing capacity
of the resulting manure.
The Ag module calculates ChU emissions for manure management by first calculating total
VS produced by the state's livestock. To do so, each animal type population is multiplied by
the VS production rate, provided in kg/head/year for cattle (excluding calves), and kg/1,000
kg animal mass/day for calves and all other livestock (i.e., swine, poultry, sheep, goats, and
horses). For cattle (excluding calves), animal population is multiplied by the VS rate
(kg/head/year) for total VS produced. For calves and all other livestock, animal population
is multiplied by the TAM (kg), VS rate (kg/1,000 kg animal mass/day), and number of days
per year to obtain the total annual VS produced.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.11
-------
Module 7 - Agriculture Module
January 2022
This value is multiplied by B0, and the weighted ChU conversion factor (MCF),1 resulting in
m3 ChU. The total m3 ChU emitted is converted into CO2 equivalents by multiplying by
density of ChU (0.678 kg/m3 ChU) the GWP of ChU (25). Finally, emissions are divided by
109 to express emissions in MMTCO2E. Equation 2 demonstrates the calculation ChU
emissions for manure management.
Equation 2. Emission Equation for ChU Manure Management
VS Producedcattie, excluding calves = Animal Population ('000 head) x 1,000 x VS
(kg/head/yr)
VS Producedcaives and aii other livestock = Animal Population ('000 head) x TAM x
VS (kg/1,000 kg animal mass/day) x 365 (days/yr)
Emissions (MMTCO2E) =
VS Produced (kg) x B0 (m3 CH4/kg VS) x MCF x 0.678 kg/m3 x 25 (GWP)
-r 1,000,000,000 (MMTCO2E)
1 MCF represents the extent to which the B0 is realized for a given livestock manure management
system environmental conditions. The weighted MCF for each animal type is based on default data for
the percent of each animal type's manure handled in manure management systems and the MCF for
each system.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.12
-------
Module 7 - Agriculture Module
January 2022
Figure 6. Example of Activity Data Applied in the Manure Management ChU
Worksheet
INSERT
C
PAGE LAYOUT
D
FORMULAS
E F
DATA REVIEW
G H I
VIEW
J
DEVELOPER
K L
ADD-INS
M
3a. CH4 from Manure Management in California
Methane emissions from Manure Management are calculated by multiplying each animal population by the volatile solids (VS) production rate for the total amount of
VS produced. For cattle, total VS produced is calculated by multiplying the animal population by the amount of VS produced per animal head per year. For calves and
other livestock, total VS produced is calculated by multiplying the animal population by the typical animal mass (TAM) and by the amount of VS produced per kilogram
of animal mass per year. For each animal, this VS total is multiplied by the maximum potential emissions factor and by the methane conversion factor (MCF) of the
manure system by the percentage manure managed in that system. This yields methane emissions in cubic meters which are then converted to MMTCE, MMT carbon
dioxide equivalent (MMTCO2E), and then summed. Note that default emission factors are available through 2015. To facilitate emission calculations for later years, the
tool utilizes 2015 emission factors as proxies for emission factors in subsequent years (2016 through 2020). Emission factors for 2016 and beyond will be updated
soon as new data become available. For more information, please refer to the Agriculture Chapter of the User's Guide.
Check All Boxes
Clear All Data
I"- CH4 from Manure Management
1990
P" Default Animal Data?
Dairy Cattle
Dairy Cows
Dairy Replacement Heifers
BeeF Cattle
Feedlot Heifers
Feedlot Steer
Bulls
Beef Cows
Beef Replacement Heifers
Steer Stackers
Heifer Stockers
Breeding Swine
Market Under 60 lbs
Market 60-113 lbs
Market 120-179 lbs
Market over 180 lbs
Poultry
Layers
Typical
Animal Volatile
Mass Solids (VS)
(TAM) (kg)
[kg VSfheacVyear]
(Metric
Tons CH J
0.020
=
=
0.000
=
0.000
0.000
0.020
=
0.000
=
0.000
=
0.000
0.012
=
=
=
0.000
=
0.000
=
0.000
0.012
=
=
0.000
=
0.000
=
0.000
0.012
=
=
0.000
=
0.000
=
0.000
0.012
=
=
0.000
=
0.000
=
0.000
0.012
0.000
0.000
=
0.000
0.000
=
0.000
=
0.000
0.000
=
0.000
0.000
0.442
=
0.000
=
0.000
=
0.000
=
=
0.000
=
0.000
=
0.000
> 0.442
=
=
0.000
=
0.000
=
0.000
0.442
=
=
0.000
=
0.000
0.000
o unci
D Q00
Step (3b) N2O from Manure Management Sector Worksheet
Once the K-Nitrogen is entered onto the control worksheet under the agricultural soils step
and the animal population data are entered into the manure management Chk worksheet,
no additional data are required to produce emission estimates of N2O from manure
management. Figure 7 shows an example of the worksheet for N2O from manure
management.
Production of N2O during the storage and treatment of animal wastes occurs by combined
nitrification-denitrification of nitrogen contained in ammonia that is present in the wastes.
In order for N2O to be produced, the manure must first be in an aerobic system, in which
the nitrogen in ammonia is converted to nitrites (nitrification). Following this the manure
must go through an anaerobic decomposition period, in which the nitrates are converted to
N2O (denitrification). These types of conditions are most likely to occur in dry manure
management systems that generally have aerobic conditions, but that can undergo periods
of saturation to create the anaerobic conditions necessary for N2O emissions to occur. The
amount of N2O released depends on the system and the duration of waste management.
To estimate N2O emissions from manure management, the Ag module first calculates the
total K-nitrogen excreted by the state's livestock. To do so, each animal type population is
multiplied by the K-nitrogen excretion rate, provided in kg/head/year for cattle (excluding
calves), and kg/1,000 kg animal mass/day for calves and all other livestock (i.e., swine,
poultry, sheep, goats, and horses). For cattle (excluding calves), animal population is
multiplied by the K-nitrogen excretion rate (kg/head/year) for total K-nitrogen excreted. For
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.13
-------
Module 7 - Agriculture Module
January 2022
calves and all other livestock, animal population is multiplied by the TAM (kg), the K-
nitrogen excretion rate (kg/1,000 kg animal mass/day), and 365 days per year for total K-
nitrogen excreted.
Next the tool separates the total K-nitrogen into the amount in liquid systems (lagoons and
liquid/slurry) and dry systems (drylot and solid storage), and multiplies by the emission
factor specific to these types of systems (0.001 kg N20-N/kg N for liquid systems and 0.2
kg N20-N/kg N for dry systems). Finally, total kg N2O emissions are converted to MMTCO2E
by multiplying by the GWP of N2O (298) and dividing by 109 to convert from kg to
MMTCO2E. Equation 3 demonstrates the calculation N2O emissions for manure
management.
Equation 3. Emission Equation for N2O Manure Management
K-Nitrogen Excretedcattie, excluding calves = Animal Population ('000 head) x 1,000 x
K-Nitrogen (kg/head/day)
K-Nitrogen ExcretedCaives and aii other livestock = Animal Population (*000 head) x TAM
x K-Nitrogen (kg/1,000 kg animal mass/day) x 365 (days/yr)
Emissions (MMTCO2E) =
K-Nitrogen Excreted x Emission Factor (liquid or dry) x
298 (GWP) -r 1,000,000,000 (kg/MMTCQ2E)
Once this sector worksheet is complete, use the gray navigational arrow to return to the
control worksheet and proceed to the next sector.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.14
-------
Module 7 - Agriculture Module
January 2022
Figure 7. Example of the Manure Management N2O Worksheet
A
HI
|G|
ImT
ToT
ToT
3b N20 from
Manure Management in California
N;P emissions from Manure Management are calculated by multiplying each animal population by the typical animal mass (TAM) by the
amount of Kjejdahl nitrogen produced per kilogram of animal mass per year. This value is then multiplied by a non-volatization factor
and the proportion of waste processed in liquid and solid management systems to give two totals of unvolatized N. Each of these are
multiplied by an emission factor specific to the management system to give two totals of nitrogen emissions. These totals are then
summed and converted to N^O. This amount is then converted to MMTCE, MMT carbon dioxide equivalent (MMTCO^E), and then
summed. For more information, please refer to the Agriculture Chapter of the User's Guide.
N2O from Manure Management
Number of
Animals
[•000 head)
Dairg Cattle
Dairy Cows
Dairy Replacement Heifers
Beef Cattle
Feedlot Heifers
Feedlot Steer
Swine
Breeding Swine
Market Under 60 lbs
Market 60-119 lbs
Market 120-179 lbs
Market over 180 lbs
Poultrg
Layers
Hens > 1 yr
Pullets
Chickens
Broilers
Turkeys
Other
Sheep on Feed
Sheep Mot on Feed
Total K-Nitrogen
Excreted (kg)
1990
Unuolatilized N
from Manure in
Anaerobic
Lagoons and
Liquid Sgstems
(fcg)
Unuolatilized N
from Manure in
Solid Storage.
Drglot & Other
Sgstems (kg)
Emissions from
Anaerobic
Lagoons and
Liquid Sgstems
(kg N,O N)
EE
Animal Population Data
475,537
400.159 I I 15.871 1
400
208,663
K-Nitrogen and TAM
are applied here
176
304,975
257
322.301
271
316
Emissions from
Solid Storage.
Drglot. & Other
Sgstems
(kg N,O N)
< Return to
Control Sheet
Total N,0
Emissions
(kg NzO)
!<<~~! \ fnntrnl / Fnfprir Fprmpntatinn I CH4 frnm Manurp Mananpmpnt N7fl frnm Maniirn Mananpmpnt An Snik-Plant-Rpciriupcfel pnump<; 1 <
Emission:
(MTCE)
38,47
64,34
295,670
24,99
38,433
3,24
2,042
17
477.188
40,34
757.631
64,05
Step (4) Enter Emission Factors and Activity Data for Agricultural Soils
Emissions from agricultural soils are divided into three worksheets in the SIT, 1) residues,
legumes, and histosols; 2) fertilizers; and 3) animals. In addition, emissions can be either
direct through cropping and animal management practices or indirect through either
volatilization into the atmosphere as NOx and NH3 or from agricultural leaching and runoff.
Both direct and indirect emissions are estimated in the worksheets described below.
Control Worksheet
N2O is produced naturally in soils through the microbial processes of denitrification and
nitrification.2 A number of anthropogenic activities add nitrogen to soils, thereby increasing
the amount of nitrogen available for nitrification and denitrification, and ultimately the
amount of N2O emitted. These activities include application of fertilizers, animal production,
cultivation of nitrogen-fixing crops, incorporation of crop residues, and cultivation of
histosols (highly organic soils). The sources of N2O described here are divided into three
categories: (1) direct emissions from agricultural soils due to cropping practices; (2) direct
and indirect emissions from soils from fertilizer application; and (3) direct and indirect
emissions from agricultural soils due to animal production. Each of these is discussed in
more detail in Step 4. Within the control worksheet data must be entered by crop type for
2 Denitrification, the process by which nitrates or nitrites are reduced by bacteria, results in the
release of nitrogen into the air. Nitrification is the process by which bacteria and other
microorganisms oxidize ammonium salts to nitrites, and further oxidize nitrites to nitrates.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.15
-------
Module 7 - Agriculture Module
January 2022
residue dry matter fraction, fraction residue applied, and nitrogen (N) content of residue.
Crop types utilized include alfalfa, corn for grain, all wheat, barley, sorghum, oats, rye,
millet, rice, soybeans, peanuts, dry edible beans, dry edible peas, austrian winter peas,
lentils, and wrinkled seed peas. Additionally, K-nitrogen is entered by animal type for dairy
and beef cattle (by type), swine (by type), poultry (by type), sheep, goats, and horses.
Data on the residue dry matter fraction, fraction residue applied, and N content of residue
are pulled into the agricultural soils emissions from residues, legumes, and histosols
worksheet. K-nitrogen is pulled into the agricultural soils-animals worksheet along with
animal population data and TAM from the manure management sector. After completing
the control worksheet for this sector, use the gray arrows to navigate to the sector
worksheets.
Step (4a) N2O from Agricultural Soils Sector Worksheet - Residues,
Legumes, and Histosols
This worksheet covers N2O emitted from agricultural soils due to biological nitrogen fixation
by certain crops, crop residues remaining on agricultural fields, and histosol cultivation.
Figure 8 presents an example of the data, as used in the calculations on this worksheet.
Figure 8. Example of Activity Data Applied in the Agricultural Soils Residues and
Legumes Worksheet
TgT
ur
TEL
_Lp L
4a. Ag Soils- Plant Residues & Legumes in California
Emissions from Plant Residues are calculated by first converting the crop production to metric tons. This value is
multiplied by the ratio of plant residue to crop mass, the fraction of dry matter in the residue, the fraction of residue
applied, and the N content of the residue. These values are summed to yield total N returned to soils, multiplied by an
emission factor (EF), and converted to N^O. For Legumes, the crop production is multiplied by the residue to crop mass
ratio, the dry matter fraction, and the N content of above-ground biomass. These values are then summed to yield total
N-fixed by crops, multiplied by an EF, and converted to NjO. Emissions from histosols are calculated by converting
acres cultivated into hectares, multiplying by an EF, and then converting to N2O. This amount is also converted to
MMTCE, MMT carbon dioxide equivalent (MMTCO^). For more information, please refer to the Agriculture Chapter of the
User's Guide.
< Return to
Control
Check All Boxes
Agriculture Soils - Emissions from Residues, Legumes, & Histosols
1990 BP Default Crop Data?
Legumes and Crop Residue Calculations
Production
(metric tons)
N Returned to
Soils (kg)
Alfalfa
Corn for Grain
All Wheat
Barley
Sorghum for Grain
Oats
Rye
Millet
Rice
Soybeans
Peanuts
Dry Edible Beans
Dry Edible Peas
Austrian Winter Peas
Lentils
Wrinkled Seed Peas
Red Clover
White Clover
Direct NzO
Emissions
(metric tons NzO)
Emissions
(MMTCE)
•000 tons
'000 bushels
'000 bushels
'000 bushels
'000 bushels
'000 bushels
"000 bushels
'000 bushels
'000 hundredweight
'000 bushels
'000 lbs
'000 hundredweight
'000 hundredweight
'000 hundredweight
'000 hundredweight
Residues
Legumes
Dry Matter Fraction
Fraction Residue Applied
Nitrogen Content
H / Fntnrir Fnim.-.nt-|-inn / t~H4 frnm Mjni irs MamnnmRr / M"'n frnm Manure I'-faronRmmt \ An Rnik-Plant-RRBlriiiR^KI
i / An R I <
N2O is emitted from the cultivation of N-fixing crops, also known as legumes. To estimate
state emissions of N2O from N-fixing crops, data on the amount of beans (by type), pulses
(by type), and alfalfa produced in the state is input into the dark green cells in Figure 8. In
addition, data on production of non-alfalfa forage crops, such as red clover, white clover,
birdsfoot trefoil, arrowleaf clover, and crimson clover are desirable. In order to calculate
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.16
-------
Module 7 - Agriculture Module
January 2022
the total N input from N-fixing crops, the SIT multiplies the production of each type of N
fixing crop by the residue to crop mass ratio for each crop, the residue dry matter fraction,
and the nitrogen content in each crop. For forage crops total N input is simply calculated as
the production of N-fixing forage crops multiplied by the nitrogen content of the crop. The
total N input for all N-fixing crops is multiplied by the emission factor for direct emissions of
N2O (1.0 percent) to obtain the amount of emissions in N20-N/yr. The result is converted
from kg N2O-N to MMTCO2E by multiplying the emissions from crop residues by 44/28 (the
molecular weight ratio of N2O/N2O-N) and by the GWP of N2O (298) and dividing by 106 to
convert from metric tons to MMTCO2E. Equation 4 shows emission calculations from N-
fixing crops.
Equation 4. Emission Equation for N-fixing Crops
Emissions (MMTCO2E) =
Crop Production (MT) x Mass ratio (residue/crop) x Dry Matter Fraction x N content
x Emission Factor (1.0%) x 44/28 (Ratio of N20 to N20-N) x 298 (GWP)
-r 1,000,000 (MT/MMTCO2E)
N2O is also emitted from crop residue that is incorporated into the soil (i.e., the portion of
the crop that has been neither removed from the field as crop nor burned). To estimate the
total N in crop residues returned to the soil for each crop, the SIT multiplies the production
of each crop by the crop residue to crop mass ratio, the dry matter fraction for residue, the
fraction of residue applied (accounting for removal of crop and the fraction burned), and the
N content of the residue. Next, the total N in all crop residues is multiplied by the emission
factor for direct emissions of N2O (1.0 percent) to obtain the amount of emissions in N2O-
N/yr. The result is converted from kg N2O-N to MMTCO2E by multiplying the amount of
emissions from crop residues by 44/28 (the molecular weight ratio of N2O/N2O-N) and by
the GWP of N2O (298) and dividing by 109 to convert from kg to MMTCO2E. Equation 5
shows emission calculations from N-fixing crops.
Equation 5. Emission Equation for Residues
Emissions (MMTCO2E) =
Crop Production (MT) x Mass ratio (residue/crop) x Dry Matter Fraction x Fraction
Residue Applied x N content x Emission Factor (1.0%) x 44/28 (Ratio of N2O to N20-N)
x 298 (GWP) -r 1,000,000,000 (kg/MMTC02E)
N2O is also emitted from the cultivation of high organic content soils, or histosols. To
estimate state emissions of N2O from the cultivation of histosols, the SIT requires data on
histosol cultivation acreage by temperate and sub-tropical climate types. To calculate the
direct emissions from histosols, the acreage of cultivated soils is converted into hectares
and multiplied by the appropriate emission factor for the climate type (8 for temperate or
12 for sub-tropical) in kg N2O-N per hectare per year. The result is converted from kg N2O-
N to MMTCO2E by multiplying the emissions by 44/28 (the molecular weight ratio of
N2O/N2O-N) and by the GWP of N2O (298) and dividing by 109 to convert from kg to
MMTCO2E. Equation 6 shows emission calculations from N-fixing crops.
Equation 6. Emission Equation for Histosols
Emissions (MMTCO2E) =
Area Cultivated (acres) x 1/2.471 (ha/ac) x Emission Factor (kg N20-N/ha/yr)
x 44/28 (Ratio of N20 to N20-N) x 298 (GWP) -r 1,000,000,000 (kg/MMTC02E)
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.17
-------
Module 7 - Agriculture Module
January 2022
Step (4b) N2O from Agricultural Soils Sector Worksheet - Fertilizers
This worksheet estimates both direct and indirect emissions from agricultural soils due to
synthetic fertilizer use and organic fertilizer use, including dried blood, compost, tankage,
and land application of sewage sludge3, as shown in Figure 9.
Figure 9. Example of Required Data in the Agricultural Soils Fertilizers Worksheet
1
TmT
0
MI
I
4b. Ag Soils Plant Fertilizer Emissions in California
< Return to
ontrol Sheet
Check All Boxes
Emissions of N^O from Fertilizers are calculated by first adjusting synthetic and organic fertilizer use data (in kg
N) to calendar year. The amount of N in synthetic fertilizer is multiplied by a synthetic volatilization rate to
estimate volatilized N. According to the IPCC Good Practice Guidance, the manure portion of organic fertilizers is
subtracted from the total of organic fertilizers. Then, the amount of N in non-manure organic fertilizer is multiplied
by the fraction N in other organics and by an organic volatilization rate to estimate organic volatilized N.
Unvolatilized N for synthetic and organic fertilizer is calculated using the remaining fraction of the volatilization
rates. These categories are summed, multiplied by an EF, and converted to metric tons of N2O emitted. This
amount is also converted to MMTCE, MMT carbon dioxide equivalent (MMTCO^). For more information, please
refer to the Agriculture Chapter of the User's Guide.
Clear All Data
Please choose between either
calendar year or growing year
inputs. When using default
data only growing year may be
used.
f Calendar Year
Growing Year
Agriculture Soils - Emissions from Fertilizers
1990
IE
Default Fertileer Data?
Fertiliser Calculations
Growing Year Entry
Organic
Dried Blood
Compost
Dried Manure
Activated Sewage Sludge
Other Sewage Sludge
Tankage
Other
Dried Manure'i
Non-Manure Cvpanics
Manure OrtjantaF
Total
1
Total N in
Fertilizer Use
Fertilizers
(kg N)
(Calendar Year)
499,916,501
498,499,543
2,951,717
3,048,452
32,460
31,506
2,533,633
2,566,637
-
385,624
450,310
\V.
\V.
2,919,257
3,016,946
32,460
31.506
Unuolatized
Volatized N
(kg)
Direct NzO
Emissions
(metric tons)
Indirect NzO
Emissions
(metric tons)
Direct
Emissions
(MMTCE)
Indirect
Emissions
(MMTCE)
b!q1 I Q.7303o1 I 0.06493! [
Fertilizer
Application Data
Agriculture Soils - Emissions from Fertilizers
1991
E
Default Fertileer Data?
~1 / l~H4 frnmi Manure MaronpmRnt / M7Q finm Manum Mamnpmpnt / An Snik-Plant-Rpqrii ip^BI pnninp^ \ An finils-Plant-FRrtilij-Rrs / fli l<
To complete this worksheet fertilizer deposition data are required in the dark green cells in
Figure 9 for either a standard calendar year or the growing season year, however if the
default data are used the SIT automatically is based on the growing year. If fertilizer use
data are entered on a growing year basis, the first step of the calculation is to convert it to
calendar years by taking 65 percent of fertilizer use from the year being calculated and the
remaining 35 percent from use the subsequent year.
Emission calculations begin by multiplying total non-manure organic fertilizer use by the
percent of N in organic fertilizer to calculate total N present. Next volatilized and
unvolatilized N are disaggregated to separate calculations for direct emissions from fertilizer
application and indirect emissions through volatilization as ammonia (Nhb) and nitrogen
oxides (NOx). The fraction of volatilized N is assumed to be 10 percent of synthetic fertilizer
and 20 percent of organic fertilizer. Thus, direct emissions are calculated by multiplying
3 in accordance with the IPCC Good Practice Guidelines, manure used as commercial fertilizer is
subtracted from total organic fertilizer use to avoid double-counting with the Agricultural Soils from
Animals.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.18
-------
Module 7 - Agriculture Module
January 2022
total N by 0.9 for synthetic fertilizer and 0.8 for organic fertilizer to obtain the amount of
unvolatilized N. This value is multiplied by the emission factor for direct emissions of N2O
(1.0 percent) to obtain the amount of emissions in INhO-N/yr and converted from kg N2O-N
to kg N2O by multiplying by the ratio of N2O/N2O-N (44/28). Indirect emissions are
calculated by multiplying the total fertilizer N that volatilizes by the volatilization emission
factor (0.001 kg INhO-N/kg N) and converting from kg N2O-N to kg N2O by multiplying by the
ratio of N2O/N2O-N (44/28). Note that indirect emissions from leaching are accounted for in
the agricultural soils-animals worksheet, which is discussed below in Step 3c.
Finally, both direct and indirect emissions are converted from kg N2O to MMTCO2E by
multiplying by the GWP of N2O (298) and dividing by 109 to convert from kg to MMTCO2E.
Equation 7 demonstrates the calculation for direct emissions and indirect emissions are
shown in Equation 8.
Equation 7. Emission Equation for Direct N2O Emissions from Agricultural Soils
Step (4c) N2O from Agricultural Soils Sector Worksheet - Animals
To calculate N2O emissions for this worksheet, no additional data are required. Figure 10
shows an example of the agricultural soils-animals worksheet. Nitrogen flux from animal
production is dependent on the waste management system employed (if any) and the
amount of waste excreted. The methodology presented in this section does not account for
site-specific conditions that could affect either the amount of nitrogen excreted or the
resulting emission factor for N2O emissions. These conditions could include temperature,
humidity, and others. Estimates include direct emissions from application of animal waste
through daily spread operations, eventual application of managed animal wastes, and
animal wastes that are deposited directly on soils by animals in pastures, ranges, and
paddocks. In addition, indirect emissions from volatilization, leaching, and run-off are also
estimated. This method reflects the assumption that all manure is eventually applied to
agricultural soils as a mode of disposal.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.19
-------
Module 7 - Agriculture Module
January 2022
Figure 10. Example of the Agricultural Soils Animals Worksheet
A
I
HE
TgT
IkT
4c. Agriculture Soils- Animal Emissions in California
Emissions from Animals are calculated by multiplying each animal population by the typical animal mass (TAM) by the amount of K-Nitrogen (K-N) produced per kilogram
of animal mass per year for total K-N excreted. Indirect emissions are estimated by multiplying K-N by a volatization rate and EF to give emissions of N. Direct
emissions from pasture, range, and paddock are calculated by multiplying K-N by the percent of manure in pastures and an EF for that system. Direct emissions from
manure applied to soils are calculated by multiplying K-N for daily spread and managed systems by the percent of manure in these systems and an EF for each
system, excluding a small percent of managed manure used as feed. These totals are then summed and converted to N-O. Unvolatized N from fertilizers, calculated
on the previous worksheet, and K-N from manure are multiplied by a leaching EF to give emissions from leaching and runoff. The emissions summary for each year
converts the total direct and indirect estimates for livestock and runoff/leaching to MTNjD, MMTCE, and then MMT carbon dioxide equivalent (MMTCO^E). For more
information, please refer to the Agriculture Chapter of the User's Guide.
Agriculture Soils - Emissions from Animals & Runoff
1990
Number of Indirect Animal
Animals Total K-Nitrogen N,0 Emissions
('000 head) Excreted (kg) (metric tons N)
Unmanaged
Pasture. Range,
and Paddock
Unmanaged
Sfstems -
~ail) Spread
Dairg Cattle
Dairy Cows
Dairy Replacement I-
Reef Cattle
Feedlot Heifers
Feedlot Steer
Bulls
I Calves
Beef Cows
Steer Stockers
Total Beef Heifers
Breeding Swine
Market Under 60 lbs
Market 60-119 lbs
Market 120-179 lbs
Market over 180 lbs
Poultrj
Layers
I 1,114.2 |
ersj| 520.6 1
_L
71 r
7i r
Animal Population Data
K-Nitrogen and TAM
are applied here
r
3 r
3_r
^ r
7i r
i r
< Return to
Control Sheet
K-NITROGEN EXCRETED RY MANAGEMENT SYSTEM (kg)
DIRECT EMISSIONS (MT N)
Manure
Applied to Pasture. Rang
Soils and Paddock
i r
^. r
i / N2Q from Manure Management / Aq SQils-Plant-Residues&Leaurnes / Aa Soils-Plant-Fertilizers \ Aq Soils-Animals I Rice Cultivation / I <
1
The SIT calculates emissions by multiplying each animal population (entered in the manure
management worksheet) by the rate of N excreted by animal type, provided in
kg/head/year for cattle (excluding calves), and kg/1,000 kg animal mass/day for calves and
all other livestock (i.e., swine, poultry, sheep, goats, and horses). For cattle (excluding
calves), animal population is multiplied by the K-nitrogen excretion rate (kg/head/year) for
total K-nitrogen excreted. For calves and all other livestock, animal population is multiplied
by the TAM (kg), the K-nitrogen excretion rate (kg/1,000 kg animal mass/day), and 365
days per year for total K-nitrogen excreted. Next, the total K-nitrogen is disaggregated into
manure handled in managed systems, manure applied as daily spread, and manure
deposited directly into pastures, ranges, or paddocks, based on default percentages
obtained from the U.S. Inventory (EPA 2021).
Direct emissions from manure handled in management systems and applied as daily spread
is multiplied by the volatilization factor (0.8) to obtain the total unvolatilized N.
Additionally, for poultry an adjustment must be made for the small portion of waste used as
animal feed. For all poultry categories (i.e., layers (hens, pullets, and chickens), broilers,
and turkeys), the total K-nitrogen in managed systems is multiplied by 0.958, as it is
assumed that 4.2 percent of all poultry manure is used as animal feed and not applied to
agricultural soils (Carpenter 1992). The total unvolatilized N is multiplied by the emission
factor for direct emissions of N2O (1.0 percent) to obtain the amount of emissions in N2O-
N/yr.
For animal waste deposited directly onto pasture, range, and paddock the total K-nitrogen is
multiplied by the percent of manure deposited on pasture, range, and paddocks and the
IPCC default emission factor for direct emissions (0.02 kg INhO-N/kg N excreted) (IPCC
1997, EPA 2021) to obtain the amount of emissions in INhO-N/yr.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module 1.20
-------
Module 7 - Agriculture Module
January 2022
Indirect emissions from volatilization to Nhh and NOx are estimated as 20 percent of the
total K-nitrogen excreted per year multiplied by the emission factor of 0.001 kg INhO-N/kg N,
following the methodology of organic fertilizers, shown in Equation 8.
Indirect emissions from leaching and runoff are assumed to occur from 30 percent of the
total unvolatilized N. Therefore, indirect emissions from leaching and runoff are calculated
by multiplying the total unvolatilized N by 0.30 and the emission factor (0.0075 kg N2O-
N/kg N). The result is converted to MMTCO2E using the methodology described below.
Finally, both direct and indirect emissions are converted from kg N2O-N to MMTCO2E by
multiplying emissions by the molecular weight ratio of N2O/N2O-N (44/28) and by the GWP
of N2O (298) and dividing by 109 to convert from kg to MMTCO2E. Equation 7 shows the
general equation for the calculation for direct emissions (adjustment for poultry is not
shown) and indirect emissions are shown in Equation 8. Once this sector worksheet is
complete, use the gray navigational arrow to return to the control worksheet and proceed to
the next sector.
Step (5) Enter Emission Factors and Activity Data for Rice Cultivation
Control Worksheet
For the rice cultivation sector, seasonal emission factors are required in the control
worksheet. Mean seasonal emission factors are used to calculate ChU emissions from the
primary and ratoon4 crops. Rice fields for the ratoon crop typically remain flooded for a
shorter period of time than for the first crop. Studies indicate, however, that the ChU
emission rate of the ratoon crop may be significantly higher than that of the primary crop.
The rice straw produced during the first harvest has been shown to dramatically increase
ChU emissions during the ratoon cropping season (Lindau & Bollich, 1993). The higher
emission rate of the ratoon crop supports the use of separate emission factors for the
primary and ratoon rice crops. Seasonal emission factors for rice cultivation are pulled into
the sector worksheet. After completing the control worksheet for this sector, use the gray
arrow to navigate to the sector worksheet.
Rice Cultivation Sector Worksheet
The rice cultivation worksheet in the Ag Module requires data input in the purple cells on the
total acreage of rice grown during both the primary and the ratoon growing seasons.
Figure 11 demonstrates where the acreage data and emission factors are used in the rice
cultivation worksheet.
4 A ratoon rice crop is a second crop of rice grown from the stubble after harvest of the primary crop.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module 1.21
-------
Module 7 - Agriculture Module
January 2022
Figure 11. Example of Activity Data Applied in the Rice Cultivation Worksheet
I
G
M
0
5 Rice Cultivation in California
Emissions from Rice Cultivation are calculated by multiplying the area harvested for the primary and
ratoon crops by a seasonal emission factor. Those resulting values, in kg CH„ are then converted to
million metric tons (MMTCH J, MMT carbon equivalent (MMTCE), MMT carbon dioxide equivalent
(MMTCOjf), and then summed. Rice is cultivated in seven states: Arkansas, California, Florida,
Louisiana, Mississippi, Missouri, and Texas. The default data for all other states is zero for each year.
For more information, please refer to the Agriculture Chapter of the User's Guide.
-------
Module 7 - Agriculture Module
January 2022
Once this sector worksheet is complete, use the gray navigational arrow to return to the
control worksheet and proceed to the next sector.
Step (6) Enter Emission Factors and Activity Data for Liming of Soils
Control Worksheet
The data entered in the control worksheet for this sector are emission factors for limestone
and dolomite used in liming of soils. These emission factors should be in metric tons of
carbon per metric ton of limestone (or dolomite). The default values are based on West &
McBride (2005); if emission factors other than module defaults are available for limestone
and dolomite, you should document their source carefully. If the user-specific inputs do not
match the default data in the control worksheet (i.e., the default value is overwritten), the
text will appear red.
Limestone (CaCCb) and dolomite (CaMg(CC>3)2) are added to soils by land managers to
remedy acidification. When these compounds come in contact with acidic soils, they
degrade, thereby generating CO2. This section presents the methodology for calculating the
CO2 emissions from the application of limestone and dolomite to soils.
After entering the appropriate emission factors, use the gray arrows to navigate to the
Liming of Soils worksheet.
Liming of Soils Worksheet
Within the Liming of Soils worksheet, enter the total limestone and dolomite applied to soil
in the light blue cells, in thousands of metric tons. An example of this worksheet is shown
in Figure 12. Equation 10 shows the method used to calculate CO2 emissions from liming of
soils.
Default data are provided for most states if you wish to use them; however, states are
encouraged to use more detailed data if it is available and well documented. The default
data are from the United States Geological Survey (USGS 2021). Once this worksheet is
complete, use the gray navigational arrow to return to the control worksheet and proceed to
the next source category.
Equation 10. Emission Equation for Liming of Soils
Emissions (MMTCO2E) =
Total Limestone or Dolomite Applied to Soil (1,000 metric tons) x Emission Factor (tons
C/ton limestone or dolomite) x 44/12 (ratio of CO2 to C) -r 1,000,000 (to yield
MMTCO2E)
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module 1.23
-------
Module 7 - Agriculture Module
January 2022
Figure 12. Example of Data Applied in the Liming of Soils Worksheet
A
6.
B i C i D | E i
Liming of Soils in California
< Return to
Control Sheet
Click here to \
find possible ]
data sources. S
Emissions from Liming of Soils are calculated by summing carbon emissions from the application of both
limestone and dolomite to soil. The masses of limestone and dolomite are multiplied by their carbon emission
factors, converted to million metric tons carbon dioxide equivalent, and then summed. For more information
please consult the Land Use, Land-Use Change, and Forestry chapter of the User's Guide.
Required Consumption Data
Check All
6
7
8
Year
\
Total Applied to Soil
('000 Metric Tons)
9
1990
Limestone^
10
Dolomite
12
1991
Limestone
13
Dolomite
15
1992
Limestone
16
Dolomite
18
1993
Limestone
19
Dolomite
21
1994
Limestone
22
Dolomite
24
1995
Limestone
25
Dolomite
27
1996
Limestone
28
Dolomite
30
1997
Limestone
31
Dolomite
33
1998
Limestone
34
Dolomite
36
1999
Limestone
37
Dolomite
39
2000
Limestone
40
Dolomite
41
(Ton C/Ton limestone)
Liming Emission
Factors (from Control)
I Default Activity Data?
I Default Activity Data?
| Default Activity Data?
I Default Activity Data?
| Default Activity Data?
| Default Activity Data?
| Default Activity Data?
I Default Activity Data?
I Default Activity Data?
I Default Activity Data?
Step (7) Enter Emission Factors and Activity Data for Urea Fertilization
Control Worksheet
The data entered in the control worksheet for this sector is an emission factor for urea
application as a fertilizer to soils. The emission factor should be in metric tons of carbon per
metric ton of urea. The default emission factor is based on IPCC (2006); if emission factors
other than module defaults are available for urea fertilization, you should document their
source carefully. If the user-specific inputs do not match the default data in the control
worksheet (i.e., the default value is overwritten), the text will appear red.
Urea is used as a fertilizer that results in CO2 emissions that were fixed during the industrial
production process. According to U.S. EPA (2021), urea in the presence of water and
urease enzymes is converted into ammonium (NH4+), hydroxyl ion (OH ), and bicarbonate
(HCO3 ). The bicarbonate then evolves into CO2 and water. This section presents the
methodology for calculating the CO2 emissions from the application of urea to soils.
After entering the appropriate emission factors, use the gray arrows to navigate to the Urea
Fertilization worksheet.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.24
-------
Module 7 - Agriculture Module
January 2022
Urea Fertilization Worksheet
Within the Urea Fertilization worksheet, enter the total urea applied to soil in the orange
cells, in metric tons. An example of this worksheet is shown in Figure 13. Equation 11
shows the method used to calculate CO2 emissions from the application of urea to soils.
Default data are provided for most states if you wish to use them; however, states are
encouraged to use more detailed data if it is available and well documented. The default
data on the amount of fertilizer applied were derived from state-level fertilizer sales data
provided in TVA (1991 through 1994) and AAPFCO (2017). Once this worksheet is
complete, use the gray navigational arrow to return to the control worksheet and proceed to
the next source category.
Equation 11. Emission Equation for Urea Fertilization
Emissions (MMTCO2E) =
Total Urea Applied to Soil (metric tons) x Emission Factor (tons C/ton urea) x 44/12
(ratio of C02 to C) -r 1,000,000 (to yield MMTCO2E)
Figure 13. Example of Data Applied in the Urea Fertilization Worksheet
A | B I C I D | E I F |G
10
11J
12
13
14
15
16
17]
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.25
-------
Module 7 - Agriculture Module
January 2022
Step (8) Enter Emission Factors and Activity Data for Agricultural Residue
Burning
Control Worksheet
Agricultural production results in large quantities of crop wastes. In some parts of the
United States, these residues are burned in the field to clear remaining straw and stubble
after harvest, and to prepare the field for the next cropping cycle. This process releases
CO2, CH4, and N2O. In accordance with international greenhouse gas (GHG) accounting
guidelines, the Ag module does not include CO2 emissions from crop residue burning. This
is because the carbon released as carbon dioxide during burning had been taken up from
carbon dioxide in the atmosphere during the growing season, thus resulting in no net
emissions. This sector addresses emissions from burning residues of seven crops for which
burning of crop wastes is significant in the United States—barley, corn, peanuts, rice,
soybeans, sugarcane, and wheat. The data for agricultural residue burning is required by
crop type in the control worksheet and includes:
• residue to crop ratio;
• fraction of residue burned, defined as the proportion of the total crop produced in fields
where residue is burned;
• burning efficiency, defined as the fraction of dry biomass exposed to burning that
actually burns;
• combustion efficiency, defined as the fraction of carbon in the fire that is released to the
atmosphere; and
• carbon (C) content of the crops.
In addition, the dry matter fraction and the N content data from the agricultural soils sector
are used for all crops except sugarcane, which is required here, if applicable. These data
are pulled into the ChU and N2O agricultural residue burning worksheets. After completing
the control worksheet for this sector, use the gray arrows to navigate to the sector
worksheets.
Agricultural Residue Burning Sector Worksheets
The information needed to estimate GHG emissions from burning of agricultural wastes is
the annual production of barley, corn, peanuts, rice, soybeans, sugarcane, and wheat. In
addition, the user has the option of entering the required data in the orange input cells for
up to two additional unspecified crops per year. The SIT provides a conversion to metric
tons from pounds of peanuts, hundred count of rice, tons of sugarcane, and bushels of
barley, corn, soybeans, and wheat. The red arrows in Figure 14 and Figure 15 demonstrate
the use of activity data to calculate agricultural residue burning emissions from ChU and
N2O, respectively.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.26
-------
Module 7 - Agriculture Module
January 2022
Figure 14. Example of Activity Data Applied in the Agricultural Residue Burning
CH4 Worksheet
8a. Ag Residue Burning CH4 Emissions in Kentucky
Emissions from Agricultural Residue Burning are calculated by multiplying the amount of crop produced by a series of factors to calculate the amount of crop
residue produced and burned, the resultant dry matter, and the carbon/nitrogen content of this dry matter. From these, the amount of carbon and nitrogen
released can be determined, and thus methane and nitrous oxide emissions quantified. Those resulting values, in metric tons of gas, are converted to million
metric tons carbon equivalent (MMTCE), then to million metric tons carbon dioxide equivalent MMTCO,E. and then summed. Note that default emission factors
are available through 2016. To facilitate emission calculations for later years, the tool utilizes 2016 emission factors as proxies for emission factors in
subsequent years (2017 through 2020). Emission factors for 2017 and beyond will be updated as soon as new data become available. For more information,
please refer to the Agriculture Chapter of the User's Guide.
Check All Boxes
CH4 from /Agricultural Residue Burning
Burning Efficiency Combustion Efficiency Carbon Content
Crop Production Residue/crop Ratio Fraction Residue Burned Dry Matter Fraction
Totcl C Released
(metric tons C)
Figure 15. Example of the Agricultural Residue Burning N2O Worksheet
AC D EFGHIJ
8b. Agricultural Residue Burning N20 Emissions in Kentucky
Nitrous oxide emissions are calculated using the methodology explained on the Ag. Residue Burning—CH4 sheet. Crop production data for this category will be pulled in from the
methane Ag. Residue Burning sheet; they do not need to be entered again here. Note that default emission factors are available through 2016. To facilitate emission calculations for
later years, the tool utilizes 2016 emission factors as proxies for emission factors in subsequent years (2017 through 2020). Emission factors for 2017 and beyond will be updated as
soon as new data become available. For more information, please refer to the Agriculture Chapter of the User's Guide.
N20 from Agricultural Residue Burning
Crop
Units
Barley
'000 bushels
Corn
'000 bushels
Peanuts
'000 pounds
Rice
'000 cwt
Soybeans
'000 bushelp
Sugarcane
'000 taj^
Wheat
'Qjfl^ushels
Other
Crop Production Residue/crop Ratio Fraction Residue Burned Dry Matter Fraction
Return to
Control Sheet
The first step in estimating emissions from both ChU and N2O from agricultural residue
burning is to multiply crop production by the residue/crop ratio, proportion of residue
burned, proportion of dry matter, burning efficiency, and combustion efficiency. This
determines the total mass of dry matter combusted.
To then estimate ChU emissions, the dry matter combusted is multiplied by the fraction of C
in the residue to estimate the total amount of C released, which is multiplied by the
emission ratio of ChU relative to total C (0.005) to determine emissions of ChU in units of
carbon (ChU-C). Finally, emissions of ChU-C are converted to full molecular weights for ChU
emissions by multiplying by the mass ratio of ChU to C (16/12).
Similarly for N2O emissions, the total dry matter combusted is multiplied by the ratio of N to
dry matter in the crop residues to estimate total N released, which is multiplied by the N2O-
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.27
-------
Module 7 - Agriculture Module
January 2022
N emission ratio (0.007) and converted to full molecular weight of N2O by multiplying by
(44/28), the mass ratio of N2O to N.
Finally, for both ChU and N2O emissions, the results are converted to MMTCO2E by
multiplying by the GWP of ChU (25) or N2O (298) and dividing by 106 to convert from metric
tons to million metric tons, as shown in Equation 12.
Equation 12. General Emission Equation for Agricultural Residue Burning
Emissions ((MMTCO2E) =
Crop Production (metric tons) x Residue/Crop Ratio x Fraction Residue
Burned Dry Matter Fraction x Burning Efficiency x Combustion Efficiency
x C or N Content x Emission Ratio (CH4-C or N2O-N) x Mass Ratio (CH4/C or
N2O/N) X GWP -r 1,000,000 (MT/(MMTC02E)
Once this sector worksheet is complete, use the gray navigational arrow to return to the
control worksheet and proceed to the next sector.
Step (9) Review Summary Information
The steps above provide estimates of total CO2, ChU, and N2O emissions from each
agricultural sector. Total emissions are equal to sum of emissions from each livestock or
crop type, for each year. The information is collected by sector on the summary
worksheets. There are two summary worksheets in the Ag module, one that displays
results in both MMTCO2E and MMTCE, and a second that displays the results in graphical
format. Additionally, the summary worksheet provides an overview of sources excluded
from the current emission estimates. Users should check this list to see if they wish to go
back and enter data for any of the omitted crop or livestock types. Figure 16 shows the
summary worksheet that sums the emissions from all sectors in the Ag module. In the
summary worksheet, users can choose to apply the "National Adjustment Factor," which
helps reconcile differences between the methodologies for estimating N2O emissions from
agricultural soils of the National Inventory of Greenhouse Gas Emissions and the SIT.
Specifically, the method used in the SIT underestimates indirect emissions from fertilizers
while overestimating indirect emissions from livestock and all direct sources of agricultural
soils emissions, relative to the National Inventory. Using the adjustment factor will only
affect estimates of agricultural soils.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.28
-------
Module 7 - Agriculture Module
January 2022
Figure 16. Example of the Emissions Summary Worksheet in the Ag Module
9. California Emissions Summary
Return to
Control Sheet
So to the
Summary Figures
Review discussion of uncertainty
associated with these results
This Worksheet Provides a Summary of Agriculture Emissions for CA Once All Prior Worksheets Have Been Completed.
Note: Totals below do not account for emissions from the following animals, fertilizers, crops, or harvested areas:
Enteric Fermentation:
Manure Management
and Ag Soils-Animal:
Ag Soils-Plant -Residues, Legumes, Red Clover. White Clover, Birdsfoot Trefoil, Arrowleaf Clover, Crimson Clover,
Histosols:
Ag 5o\\s-P\ar\t-Fertilizers:
Rice Cultivation:
Ag Residue Burning:
Liming and Urea:
Adjustment Factor
HrneTie: ana
Dolomite, Urea Fertilizi
post. Dried Manure, Activated Sewage Sludge, Other Sewage Sludge, Tankage
The "National Adjustment Factor"j»opplied to reconcile differences betwaen the methodologies for estimating nitrous oxide emissions from agricultural soils of the National
Inventory of Greenhouse Gte Emissions and the State Inventory Tool. The memoc^ised in the SIT underestimates indirect emissions from fertilizers and overestimates indirect
emissions from livestock ar^j^lirect sources of agricultural soils emissions rqjgraw to the National Inventory. Other sources will not be affected.
O Apply National Adjustment Factor
® Do Not Apply National Adjustment Factor
Emissions (MMTCE)
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
Enteric Fermentation
2.485
2.399
2.425
2.453
2.548
2.577
2.576
2.647
2.635
4.703
4.798
4.878
Manure Management
1.768
1.804
1.834
1.839
1.948
2.040
2.055
2.182
2.105
4.415
4.562
4.908
Ag Soils
1.915
2.318
2.296
2.341
2.420
2.499
2.572
2.470
2.379
3.283
3.385
3.472
Rice Cultivation
0.258
0.233
0.258
0.286
0.317
0.304
0.327
0.338
0.300
0.330
0.359
0.308
Liming
-
-
-
-
-
-
-
-
-
Urea Fertilization
-
-
-
-
-
-
-
-
-
Agricultural Residue Burning
0.011
0.009
0.011
0.011
0.012
0.010
0.012
0.012
0.010
0.010
0.011
0.010
TOTAL
6.438
6.763
6.823
6.930
7.246
7.430
7.542
7.648
7.428
12.742
13.114
13.576
Step (10) Export Data
The final step is to export the summary data. Exporting data allows the estimates from
each module to be combined later by the Synthesis Module to produce a comprehensive
GHG inventory for the state.
To access the "Export Data" button, return to the control worksheet and scroll down to step
10. Click on the "Export Data" button and a message box will open that reminds the user to
make sure all sections of the module have been completed. If you make any changes to the
Ag module later, you will then need to re-export the results.
Clicking "OK" prompts you to save the file.
The file is already named, so you only need
to choose a convenient place to save the
file. After the file is saved, a message box
will appear indicating that the data was
successfully exported.
While completing the modules, you are
encouraged to save each completed
module; doing so will enable you to easily
make changes without re-running it entirely.
Note: the resulting export file should not be
modified. The export file contains a summary
worksheet that allows users to view the results, as well as
a separate data worksheet with an unformatted version of
the results. The second worksheet, the data worksheet,
contains the information that is exported to the Synthesis
Tool. Users may not modify that worksheet.
Adding/removing rows, moving data, or making other
modifications jeopardize the ability of the Synthesis
Module to accurately analyze the data.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.29
-------
Module 7 - Agriculture Module
January 2022
Following data export, the module may be reset and run for an additional state.
Alternatively, you may run the remaining modules of the SIT to obtain a comprehensive
profile of emissions for your state.
1.4 Uncertainty
In the upper right-hand corner of the summary worksheet is a button: "Review discussion of
uncertainty associated with these results." By clicking on this button, you are taken to a
worksheet that discusses the uncertainty surrounding the activity data and emission factors,
and how the uncertainty estimates for this source category affect the uncertainty of the
emission estimates for your state.
1.5 References
AAPFCO. 2017. Commercial Fertilizers 2014. Association of American Plant Food Control
Officials and The Fertilizer Institute. University of Kentucky, Lexington, KY.
U.S. EPA. 2021. Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 - 2019.
Office of Atmospheric Programs, U.S. Environmental Protection Agency. EPA 430-R-21-
005. Available at: https://www.epa.aov/ahaemissions/inventorv-us-areenhouse-aas-
emissions-and-sinks-1990-2019.
Carpenter, G.H. 1992. "Current litter practices and future needs." 1992 National Poultry
Waste Management Symposium. Auburn University Printing Service. Auburn, Al.
Holzapfel-Pschorn, A., R. Conrad, and W. Seiler. 1985. Production, oxidation, and emission
of methane in rice paddies. FEMS Microbiology Ecology 31:343-351.
IPCC. 2006. 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Volume 4:
Agriculture, Forestry, and Other Land Use. The National Greenhouse Gas Inventories
Programme, The Intergovernmental Panel on Climate Change. [H.S. Eggleston, L.
Buendia, K. Miwa, T. Ngara, and K. Tanabe (eds.)]. Hayama, Kanagawa, Japan.
IPCC. 1997. IPCC Guidelines for National Greenhouse Gas Inventories, 3 volumes: Vol. 1,
Reporting Instructions; Vol. 2, Workbook; Vol. 3, Draft Reference Manual.
Intergovernmental Panel on Climate Change, Organization for Economic Co-Operation
and Development. Paris, France.
Lindau, C.W. and P.K. Bollich. 1993. "Methane Emissions from Louisiana First and Ratoon
Crop Rice." Soil Science 156: 42-48. July 1993.
Sass, R.L., F.M. Fisher, P.A. Harcombe, and F.T. Turner. 1990. "Methane production and
emission in a Texas rice field." Global Biogeochemical Cycles 4:47-68.
TVA. 1991 through 1994. Commercial Fertilizers. Tennessee Valley Authority, Muscle
Shoals, AL.
U.S. Geological Survey. 2021. "Crushed Stone," 2017 Minerals Yearbook. U.S. Department
of the Interior/U.S. Geological Survey, Washington, D.C. Available online at:
httPs://www.usas.aov/centers/nmic/crushed-stone-statistics-and-information#mvb.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.30
-------
Module 7 - Agriculture Module January 2022
West, T.O., and A.C. McBride. 2005. "The contribution of agricultural lime to carbon dioxide
emissions in the United States: dissolution, transport, and net emissions," Agricultural
Ecosystems & Environment 108:145-154.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module 1.31
------- |