User's Guide for Estimating
Methane and Nitrous Oxide
Emissions from Agriculture
Using the State Inventory
Tool
January 2017
T
Prepared by:
ICF
Prepared for:
State Climate and Energy Program,
U.S. Environmental Protection Agency
This section of the User's Guide provides instruction on using the 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 2017
Table of Contents
1.1	Getting Started	2
1.2	Module Overview	3
1.2.1	Data Requirements	4
1.2.2	Tool Layout	5
1.3	Methodology	6
1.4	Uncertainty	25
1.5	References	25
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.1

-------
Module 7 -Agriculture Module
January 2017
1.1 Getting Started
The Agriculture (Ag) module of the State Inventory Tool (SIT) was 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: 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: Since 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: 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. Since 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 enabled, a
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.2

-------
Module 7 -Agriculture Module
January 2017
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
E3 Microsoft Excel - Bookl
Fa
File Edit
View Insert
Format j
lools | Data Window Help I
	«	

f»


Spelling.,. F7
1

A I
B I
c I

a
1 Research,.. Alt+Click
1 1 H |
1 |
1 4 1
K

I]
izzi
|


Error Checking...





2




1>





3





Speech ~





4





Shared Workspace...





5










6





Share Workbook.,,






7





Track Changes ~
Compare and Merge Workbooks...






8











9











10





Protection ~






11





Online Collaboration ~





12




















Goal Seek.,,







13











14





Scenarios.,.






15




Formula Auditing ~






16










17




Macro ~
~
Macros.,,

Alt+F8


18





Add-Ins...
j
PprnrH Npiaj Marrn..



19



















AutoCorrect Options.,,
i
Security..




20




L




21





Customize...
g
| Visual Basic Editor
Alt+Fll


22





Options.,,

i Microsoft Script Editor



23




	



24








25








igure 2. Adjusting Print Margi
ns
l] e*
B	C	0 El F	Q
d in this Tool ind Click to proc*«d to tha r*»p»ct>v»
Daily CoOw
Rtslacwntnlt 01J
Drag cursor
to resize page
n6y>va>
I
wSyyMr
¦sfeyyvw
»Sy>wr
n by yen
Pa
Bjglf

r F—
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 2017
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.
Since 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 methane (Cl-U) and nitrous oxide (N2O) emissions from the
agricultural sectors shown in Table 1. 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.
Data Requirements
To calculate ChU 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.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.4

-------
Module 7 -Agriculture Module
January 2017
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-INhO
Typical Animal Mass (TAM)
Volatile Solids (VS) Production
Maximum Potential ChU 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
K Nitrogen Excreted
Crop Production
Fertilizer Utilization
TAM*
N20
Rice Cultivation
Seasonal Emission Factor
Area Harvested
cm
Ag. Residue Burning-ChU
Ag. Residue Burning-INhO
Residue/Crop Ratio
Fraction of Residue Burned
Dry Matter Fraction*
Burning Efficiency
Combustion Efficiency
Carbon Content
Nitrogen Content*
ch4, N2O
* For consistency in calculations, data that overlaps between sectors are pulled through from the
original input into subsequent uses.
Tool Layout
Since 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.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.5

-------
Module 7 -Agriculture Module
January 2017
Figure 3. Flow of Information in the Ag Module*
Control Worksheet
Individual Sector Worksheets
1. Choose a State
/" 2. Enteric Fermentation

Enter animal population data for each year
2. to 6. Enter Emission Factors and Activity Data for:
3a. CH4from Manure Management
Enteric Fermentation
Enter animal population data for each year
Manure Management
3b. N,0 from Manure Management
Ag Soils-Plant-Residues & Legumes
Review data imported from Manure CH4 worksheet
Rice Cultivation
4a. Ag Soils-Plant-Residues&Legumes
Ag Residue Burning ,
Enter crop production data for each year
N. J
4b. Ag Soils-Plant-Fertilizers

Enter fertilizer use by calendar year or growing year
\
4c. Ag Soils-Animals

Review data imported from Manure CH4 worksheet

5. Rice Cultivation

Enter area harvested for each year

6a. Ag. Residue Burning-CH4

Enter crop data and activity data for non-default crops

6b. Ag. Residue Burning-N20

V Enter nitrogen content for non-default crops
7. View Summary Data <	
—> Summary Data

1 Presented in both table and graphical formats in MMTC02E
8. Export Data <	
Uncertainty

Review information on uncertainty associated with the 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 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, and
agricultural residue burning. Since 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
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 agricultural residue burning; (7) review summary information;
and (8) export data. The general equations used to calculate ChU and N2O emissions from
agriculture are shown in the discussion of each specific sector.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.6

-------
Module 7 -Agriculture Module
January 2017
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.
	Figure 4. Control Worksheet for the Ag Module	
E State Inventory Tool - Methane and Nitrous Oxide from Agriculture Module
•a File Edit Module Options
State Inventory Tool - Methane and Nitrous Oxide from Agriculture Module
This is very important - it selects the correct default variables for your state.
in this Tool and Click to proceed to the respective worksheets.
Reset Worksheet
Select All Defaults
Animal Group
Dairy Cattle
Dairy Cows
Dairy Replacement Heifers
(ka/animal/Yrl Factor Used
Default? (Check for Yes)
varies by year
varies by year
varies by year
Required Data
Input Cells
Replacements 12-24 mos.
varies by year
varies by year
varies by year
varies by year
varies by year
Individual Default
Data Check Boxes
Manure Management Animal
Dairy Cattle
~ m \Control/ Enteric Fermentation / CH4 from Manure Management / N2Q from Manure Management / Ag Soils-Plant-Residues&Legumes ,
The first type of required data in the control worksheet is emission factors by animal type
for enteric fermentation. ChU is produced as part of the normal digestive processes of
animals. The amount of ChU produced by domesticated animals depends primarily on the
type of animal (e.g., ruminant or non-ruminant), the age and weight of the animal, and the
quantity and quality of the feed consumed (IPCC 1997). In general, ruminants produce
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.7

-------
Module 7 -Agriculture Module
January 2017
more ChU than non-ruminants, and higher quality of feed produces lower emissions. The
default emission factors for cattle are dependent on diet characteristics, such as digestible
energy and ChU yield, which vary by diet and individual animal, and are provided on a
regional basis from EPA (2016). Default emission factors for other livestock types do not
vary by animal production characteristics, and are also from EPA (2016). After completing
the control worksheet for this sector, use the gray arrow to navigate to the sector
worksheet.
Enteric Fermentation Sector Worksheet
The activity data required to populate the orange cells in the enteric fermentation worksheet
are the average animal populations, over the course of the inventory year, for the following
animals: cattle, sheep, goats, swine, and horses. The cattle population is separated into
dairy and beef animals. Dairy animals are further disaggregated into cows and replacement
heifers, while beef animals are disaggregated into bulls, cows, replacement heifers (for
breeding stock), steer and heifer stockers (prior to moving into feedlots), and steer and
heifer feedlot animals. An example of the data requirements used in the enteric
fermentation sector worksheet is presented in Figure 5. Box 1 discusses additional notes if
users plan on providing state-specific animal population data instead of using the default
data.
Figure 5. Example of Activity Data Applied in the Enteric Fermentation Worksheet
D State Inventory Tool - Methane and Nitrous Oxide from Agriculture Module
H] File Edit Module Options
Type a question for hel|
I
J
I
M
2. Enteric Fermentation Emissions in California
possible
populat
Emissions from Enteric Fermentation are calculated by multiplying each animal
population by an animal- and region-specific emission factor. Those resulting
values, in kg CHt, are then converted to million metric tons (MMTCHJ, MMT carbon
equivalent (MMTCE), MMT carbon dioxide equivalent (MMTCO^), and then summed.
For more information, please refer to the Agriculture Chapter of the User's Guide.
Enteric Fermentation
Dairg Cattle
Dairy Cows
Dairy Replacement Heifers
Replacements 0-12 mos.
Replacements 12-24 mo;
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
R7 Default Anrnal Data?
Number of
Emission
Emission Factor
[kg CHWhead)
['000 head)
29,459,100
Animal
Populations

18,672,435
3,982,442
1h.h7K.lloU
J.744 ,Li7H
<
Return to
lontrol Sheet
0.0002
0.0003
0.822
0.169
o uu LI
0.000
0.406
0.048
n n-:
0.107
0.023
0.046
0.001
0.002
0.032
1.795
Check All Boxes
Emissions
(MMTCE)
Emissions
(MMTCO.E)
0 750
0.079
0.168
0.004
0.006
0.117
6.583
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.8

-------
Module 7 -Agriculture Module
January 2017
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 ChU 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
1.9

-------
Module 7 -Agriculture Module
January 2017
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 1,000 kg of animal mass per day.
•	The CH4-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 B0 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
ChU-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 multiplying animal
populations by the TAM, VS rates, and number of days per year to obtain the total annual
VS produced. 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
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 types manure handled in manure management systems and the MCF for
each system.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.10

-------
Module 7 -Agriculture Module
January 2017
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
Emissions (MMTCO2E) =
Animal Population ('000 head) x TAM (kg) x VS (kg/1,000 kg animal
mass/day)
x 365 (days/yr) x Bo (m3 CH4/kg VS) x MCF x 0.678 kg/m3 x 25 (GWP)
-r 1,000,000,000 (MMTCO2E)
Figure 6. Example of Activity Data Applied in the Manure Management ChU
Worksheet
E State Inventory Tool - Methane and Nitrous Oxide from Agriculture Module
S) File Edit Module Options
005
Type a question for help ~ _ &
A
he
IK
la
ToT
HE
TsT
mr
3a. CH4 from M inure Management in California
Click here to find
possible animal
population data
sources
Methane emissions from Manure Management are calculated by multiplying each animal population by the typical
animal mass (TAM) and the average volatile solids (VS) produced per kilogram (kg) of animal mass per year to
estimate the amount of VS produced. For each animal, this VS total is muliplied 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 (MMTCO^E), and then summed. For more information, please refer to the Agriculture Chapter of the User's
Guide.	
<
Return to
Control Sheet
Check All Boxes
Clear All Data
CH4 from Manure Management
1990
W Default Aninal Data?
Dairj Cattle
~airy Cows
Dairy Replacement Heifers
Beef Cattle
Feedlot Heifers
Feedlot Steer
Bulls
Calves
Beef Cows
Beef Replacement Heifers
Steer Stockers
Heifer Stockers
Swine
Breeding Swine
Market Under 60 lbs
Market 60-119 lbs
Market 120-179 lbs
Market over 180 lbs
Poultrg
Layers
Volatile

Number of
Solids (VS)
[kg VSflOOO
[ 000 headj
(TAM) (kg)
TAM Data
VS Data
Animal Population Data
Mai Pot.
Emissions (m1
CH, J kg VS)
Veighted
MCF
Emissions
(m1 CH,)
Emissions
(Metric
Tons
CH,)
Emissions
(MMTCH.)
0.00
X
0.488




0.00
X
0.018






0.00
X
0.020




0.00
X
0.020


0.00

0.012


0.00
X
0.012


0.00







0.00
Maximum Potential
CH4 Emissions

0.00

0.00






"i5






0.471


0.00
X
0.471


0.00
X
0.471


0.00
X
0.471


~ n \ rnritrn EnterjcTermentatjon ril l frnm M.muip M.-imnprrirnt : N2Q frnn Manuir Management / An SoikPiantjtesjdues&i egumes
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 CH4 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
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.11

-------
Module 7 -Agriculture Module
January 2017
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 TAM (kg), the K-nitrogen excreted (kg/1,000 kg mass/day), and 365 days
per year. 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
Emissions (MMTCO2E) =
Animal Population ('000 head) x TAM x K-Nitrogen (kg/day) x 365 (days/yr)
x Emission Factor (liquid or dry) x 298 (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.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.12

-------
Module 7 -Agriculture Module
January 2017
Figure 7. Example of the Manure Management N2O Worksheet
E State Inventory Tool - Methane and Nitrous Oxide from Agriculture Module
File Edit Module Options
Type a question for help ~ _ fi
A
JE
EE
C
3b. N20 from
Manure Management in California
NjD 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 NJD. 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)
Total K-Nitrogen
Excreted (kg)
1990
Unvolatilized N
from Manure in
Anaerobic
Lagoons and
Liquid Sgstems
(kg)
Unvolatilized N
from Manure in
Solid Storage.
Drglot & Other
Sgstems (kg)
Emissions from
Anaerobic
Lagoons and
Liquid Sgstems
(kg NiO-N)
Dairg Cattle
~airy Cows
~airy 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 Not on Feed

Animal Population Data

4,159.014

17.081,974




475.537


~^^fc.975

322.301

375.623




16,577,424

2.154,829

114.515

15,183.270

24.106,425




931,298

3,207,803




NA

4.159.014 I I NA

K-Nitrogen and TAM
are applied here
NA



400





256,633

10.179

257
271.213
10,757

271
316,083
12,537

316



1,657,742

14,919,682

1,658
215,483
1,939,346

215
11,452
103,064

11
NA
15,183,270

NA
NA
24.106,425

NA



NA

16,339

NA
NA


NA
Emissions from
Solid Storage.
Drglot. fc Other
Sgstems
(kg NiO-N)
<
Return to
lontrol Sheet
Total NzO
Emissions
(kg NzO)
h < ~ h \ Control / Enteric Fermentation / CH4 from Manure Management \ N2Q from Manure Management / Aq SQils-Plant-Residues&Legumes 1 <
Emission
(MTCE)

206,560

455,044

38,47

484,281

761,013

64,34




83,180

130,712

11,0!

341,639

536,862

45,38




317

1,128

9

139

495

4

204

723



215

764

6

251

891

7




186,496

295,670

24,99

24,242

38,433

3,24

1,288

2,042

17

303,665

477,188

40,34

482,129

757.631

64,05




327

513

4







	0 m aoo

•> ico ino

OOO J K
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
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
1.13

-------
Module 7 -Agriculture Module
January 2017
more detail in Step 4. Within the control worksheet data must be entered by crop type for
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, kjeldahl (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
E State Inventory Tool - Methane and Nitrous Oxide from Agriculture Module
File Edit Module Options
Type a question for help ~ _ fi
A
m
4a. Ag Soils- Plant Residues &. Legumes in California
Click here to
find possible
crop production
data sources
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 NjD. 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 N^O. Emissions from histosols are calculated by converting
acres cultivated into hectares, multiplying by an EF, and then converting to NjO. This amount is also converted to
MMTCE, MMT carbon dioxide equivalent (MMTCO2E). For more information, please refer to the Agriculture Chapter of the
User's Guide.
<
Return to
Control
Check All Boxes
1990 |
Agriculture Soils - Emissions from Residues, Legumes, & Histosols
Default Crop Data?
Legumes and Crop Residue Calculations
Alfalfa
Corn (or Grain
All Wheat
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
Units
'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 hundr£dnisiflii£_
"000 hundi
'000 hundi
'000 hundredweight
metric tons
metric tons
Crop
Production
N Returned to
Soils (kg)
N-Fixed bj
[metric tons}
Urops (fcg)
KHHK
B.346,771
2:5,6130
3.0SS.910
~8,165
.siu.ssi:
13,340
290,438
48,988
Crop Production Data
Enter Histosol Data (off screen)
Direct NtO
Emissions
(metric tons NzO)
Direct
Emissions
(MMTCE)
Dry Matter Fraction
Fraction Residue Applied
Nitrogen Content
~ * / Fi I-11 Fhihihi 1'dln 11 / '"H~ hi 1 Mil 1 j'h M.-i i.-i :hi m' I I '.jTP hi i M^i i rn M.-i i.-i ihi m' I \ An Rnils-Plant-Rpsirlupsftl pnumps / An S I <
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.14

-------
Module 7 -Agriculture Module
January 2017
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
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 N2O to N2O-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 N2O-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.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.15

-------
Module 7 -Agriculture Module
January 2017
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 N2O to N2O-N) x 298 (GWP) -r 1,000,000,000 (kg/MMTC02E)
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
E State Inventory Tool - Methane and Nitrous Oxide from Agriculture Module
: ®jj File Edit Module Options
Type a question for help
A
I
th
!

HE
ns
m
R
4b. Ag Soils Plant Fertilizer Emissions in California

Return to
Control Sheet
i Check All Boxes
fertili
Emissions of NJD 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 N;>0 emitted. This
amount is also converted to MMTCE, MMT carbon dioxide equivalent (MMTCO-E). For more information, please
refer to the Agriculture Chapter of the User's Guide.
Clear All Data
Pleose choose between either
calendar year or growing year
inputs. When using default
data only growing year may be
used.
*"* Calendar year
Growing year
Agriculture Soils - Emissions from Fertilizers
1990
Default Fertilzer Data?
Fertilizer Calculation:
Growing Year Entry
Total
Fertilizer Use
(kg N)
Total N in
Fertilizers
(Calendar Year)
Unvolatized
N(kg)
Volatized N
(kg)
Direct NzO
Emissions
(metric tons)
Organic
Compost
Fertilizer
Application Data
Indirect NzO
Emissions
(metric tons)
3 C
Direct
Emissions
(MMTCE)
Indirect
Emissions
(MMTCE)
^ | 0.064931 [
Agriculture Soils - Emissions from Fertilizers
1991
V Default Fertilizer Data?
~ h/ -4 Tim Mdriutp [¦llH--Mi^mprit / N:-'i ' t-nm [-'Inn rp Mdmnprrpnt- / "n -.-ik—'.-rNRp-l:!.--;:1 -Tim— \ An Rnik-Plant-Fprtili^prs / Ar I <
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
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
1.16

-------
Module 7 -Agriculture Module
January 2017
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 (Nhh) 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
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
Emissions (MMTCO2E) =
Total N x fraction unvolatilized (0.9 synthetic or 0.8 organic)
x O.Ol (kg N20-N/kg N) x 44/28 (Ratio of N2O to N2O-N) x 298 (GWP)
-r 1,000,000,000 (kg/MMTC02E)
Equation 8. Emission Equation for Indirect N2O Emissions from Agricultura
Emissions (MMTCO2E) =
Total N x fraction volatilized (0.1 synthetic or 0.2 organic)
x 0.001 (kg N20-N/kg N) x 44/28 (Ratio of N2O to N2O-N) x 298 (GWP)
-r 1,000,000,000 (kg/MMTC02E)
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	1.17

-------
Module 7 -Agriculture Module
January 2017
Figure 10. Example of the Agricultural Soils Animals Worksheet
~ State Inventory Tool - Methane and Nitrous Oxide from Agriculture Module
Sj File Edit Module Options
I Type a question for help
A
mr
jk
jlh
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 NjD. 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.
<
Return to
Control Sheet
Agriculture Soils - Emissions from Animals A Runoff
1990
K-NITROGEN EXCRETED BY MANAGEMENT SYSTEM (kg)
Number of	Indirect Animal
Animals Total K-Nitrogen NiO Emissions
('000 head)	Excreted (kg) (metric tons N)
Unmanaged
Sjstems -
Pasture. Range,
and Paddock
Unmanaged
Dailj Spread
DIRECT EMISSIONS (MT N)
Manure
Applied to	Pasture. Rang
Soils	and Paddock
Dair| Cattle
Dairy Cows
Dairy Replaceme
Beef Cattle
Feedlot
Feedlot Steer
Bulls
Calves
Beef Cows
Steer Stockers
Total Beefl
Swine
Breeding Swine
Market Under 60 lbs
Market 80-119 lbs
Market 120-179 lbs
Market ouer 180 lbs
Poultrj
Layers
Hens > 1 yr
Animal Population Data

61,731,470

K-Nitrogen and TAM
are applied here
266.812
281,970
r
i r
i r
r
n, r
~i / N2Q from Manure [-''ariaaernent / Aa buls-4sr^~:es[suess'_es:uries Aal.ols—lans-"e-silzers Aa Soils 'Animals . -Mce lult:
The SIT calculates emissions by multiplying each animal population (entered in the manure
management worksheet) by the TAM for animal type, the daily rate of N excreted by animal
type, and 365 days per year. 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
US Inventory (EPA 2016).
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 2016) to obtain the amount of emissions in INhO-N/yr.
Indirect emissions from volatilization to NH3 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
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.18

-------
Module 7 -Agriculture Module
January 2017
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 Chk 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
CH4 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
State Greenhouse Gas Inventory
of rice grown from the stubble after harvest of the primary crop.
Tool User's Guide for the Ag Module	1.19

-------
Module 7 -Agriculture Module
January 2017
Figure 11. Example of Activity Data Applied in the Rice Cultivation Worksheet
E State Inventory Tool - Methane and Nitrous Oxide from Agriculture Module
:Sj File Edit Module Options
Type a question for help ¦* _ fi
5. Rice Cultivation in California
Emissions from Rice Cultivation are calculated by multiplying the area harvested for the primary and
find possible
crop production
(MMTCCKE), and then summed. Rice is cultivated in seven
i, California, Florida,
refer to the Agriculture Chapter of the I
2_
Rice Cultivation
1990
W Default Harvested Area?
3
Emission
Factors
Area Harvested
Rice Cultivation
Most of the world's rice, and all of the rice in the United States5, is grown on flooded fields.
When fields are flooded, aerobic decomposition of organic material gradually depletes the
oxygen present in the soils and floodwater, and anaerobic conditions develop in the soils.
At that point, ChU is produced through anaerobic decomposition of organic matter by
methanogenic bacteria. However, not all of the ChU that is produced is released into the
atmosphere. As much as 60 to 80 percent of the ChU produced is oxidized by aerobic
methanotrophic bacteria in the soils (Holzapfel-Pschorn et al. 1985, Sass et al. 1990). Some
of the ChU is also leached to ground water as dissolved ChU. The remaining non-oxidized
CH4 is transported from the soil to the atmosphere primarily by diffusive transport through
the rice plants. Additional ChU can escape from the soil via diffusion and bubbling through
the floodwaters.
Other factors that influence ChU emissions from flooded rice fields include soil temperature,
soil type, fertilization practices, rice cultivar selection, and other cultivation practices (e.g.,
tillage, seeding, and weeding practices). However, while it is generally acknowledged that
these factors influence CH4 emissions, the extent of the influence of these factors
individually or in combination has not been well quantified. Thus, the method for estimating
emissions is based on a range of measured emissions per unit area of flooded rice field per
season.
CH4 emissions from rice cultivation are calculated based on the acreage of rice grown (i.e.,
flooded) multiplied by emission factors for the amount of CH4 emitted per flooding season.
The results are converted to MMTCO2E by multiplying by the GWP of CH4 (25) and the ratio
of C to CO2 (12/44) and dividing by 109 to convert from kg to million metric tons, as shown
in Equation 9.
Equation 9. Emission Equation for Rice Cultivation
Emissions ((MMTCO2E) =
Area Harvested (*000 acres) x 1/2.471 (ha/acre) x Emission Factor (kg
ChU/ha-season) 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.
5 Eight states currently grow rice: Arkansas, California, Florida, Louisiana, Mississippi, Missouri,
Oklahoma, and Texas.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module	1.20

-------
Module 7 -Agriculture Module
January 2017
Step (6) 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 12 and Figure 13 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
1.21

-------
Module 7 -Agriculture Module
January 2017
Figure 12. Example of Activity Data Applied in the Agricultural Residue Burning
CH4 Worksheet
E3 State Inventory Tool - Methane and Nitrous Oxide from Agriculture Module
File Edit Module Options
EJHJ®
Type a question for help ,
TH
K 1 L
jH


p l
6a Ag Residue Burning CH4 Emissions in California
Click here to
find possible
crop production
data sources
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. For more,infnrmiiitinn nlpfiTFi rrafFir tn thr flinriri ilti irs Phantiftr nf thft I Iw'fr fni lirlft
<
Return to
lontrol Sheet
Check All Boxes
CH4 from Agricultural Residue Burning
Burning Efficiency Combustion Efficiency Carbon Content
Production
[metric tons)
Burning
Efficiency
Combustion
Efficiency
000 bushels
'000 bushels
000 poun
¦ . i : ;
Bailey
Corn
Peanuts
Rice
Soybeans
Sugarcane
Wheat
Other
Crop Production Residue/crop Ratio Fraction Residue Burned Dry Matter Fraction
Figure 13. Example of the Agricultural Residue Burning N2O Worksheet
£3 State Inventory Tool - Methane and Nitrous Oxide from Agriculture Module
IS] File Edit Module Options
BE®
Type a question for help » . 5 X

jlI
I
	E

6b Agricultural Residue Burning N20 Emissions in California
Nitrous oxide emissions are calculated using the methodology explained on the Ag. Residue Burning-CH, 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. For more information, please refer to the Agriculture Chapter of the User's Guide.
<
Return to
)ontrol Sheet
N2O from Agricultural Residue Burning Burning Efficiency Combustion Efficiency Nitrogen Content
rg Matter
Combustion
Efficiency
[metric tons)
Barley
Corn
Peanuts
Rice
Soybeans
Sugarcane
Wheat
000 bushe
lo J4U
25 h0(1
30,429
381,477

jijij iju-hPl;
310,832
Crop Production Residue/crop Ratio Fraction Residue Burned Dry Matter Fraction
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 CbU in units of
carbon (CHk-C). Finally, emissions of CbU-C are converted to full molecular weights for ChU
emissions by multiplying by the mass ratio of CH4 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
1,22

-------
Module 7 -Agriculture Module
January 2017
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 10.
Equation 10. 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 (7) Review Summary Information
The steps above provide estimates of total 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 14 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
1.23

-------
Module 7 -Agriculture Module
January 2017
Figure 14. Example of the Emissions Summary Worksheet in the Ag Module
D State Inventory Tool - Methane and Nitrous Oxide from Agriculture Module
BE®
• Ble Edit Module Options
Type a question for help H _ i? X
M
XI
J
I
JUL
7 California Emissions Summary
<
Return to
lontrol Sheet
(So to the
Summary Figure;
>
Review discussion of uncertainty
associated with these results
This Worksheet Provides o Summary of Agriculture Emissions for CA Once All Prior Worksheets Hove 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, Histosois:
Ag Soils-Plant-Fertilizers:
Rice Cultivation:
Ag Residue Burning:
Red Clover, White Clover, Birdsfoot Trefoil, Arrow leaf Clover, Crimson Clover, Histosois
Organ if" hriirrl Rlnnrl fnmnnTt Mthir r Sewage Sludge, Tankage
Adjustment Factor
The "National Adjustment Factor" is app]j«|Jg0&&as Emissions and the State n^gtow Tool. The method used in the SIT underestimates indirect emissions from fertilizers
and overestimates indir^^«?tssions from livestock and all direct sou rcesS^^i cultural soils emissions relative 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
199*
1997
1998
1999
2000
2001
=
Enteric Fermentation	1.795	1.758	1.780	1.687	1.775	1.856	1.883	1.708	1.891	1.778	1.807	1.827
Manure Management	1.491	1.508	1.526	1.460	1.545	1.613	1.520	1.619	1.559	1.683	1 734	1.835
Ag Soils	2.959	2.845	2.812	2.892	2.979	3.065	3.191	2.982	2.845	3.031	3167	3.350
Rice Cultivation	0.192	0.173	0.192	0.213	0.236	0.226	0.243	0.251	0.223	0.246	0 267	0.229
Agricultural Residue Burning	0.024	0.024	0.023	0.023	0.030	0.022	0.025	0.016	0.012	0.011	0 013	0.010
TOTAL	6.462	6.308	6.333	6.275	6.565	6.782	6.643	6.568	6.330	6.747	6.987	7.251
Step (8) 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
8. 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.
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.
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
1.24

-------
Module 7 -Agriculture Module
January 2017
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
EPA. 2016. Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 - 2014. Office of
Atmospheric Programs, U.S. Environmental Protection Agency. EPA 430-R-16-002.
Internet address: https://www.epa.aov/ahaemissions/inventorv-us-areenhouse-aas-
emissions-and-sinks-1990-2014
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. 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.
State Greenhouse Gas Inventory Tool User's Guide for the Ag Module
1.25

-------