\documentclass[10pt,letterpaper, final]{report} % \documentclass{} required in all files

\usepackage{../preamble/myWEPS} % This is now our single preamble file inclusion (it assumes a “.sty” file extension)

\begin{document}

\subsection{Skill Building} \label{subsec:Skill_Building_2}

In this exercise, we begin with a pre-built management file and make a WEPS run.
Then we add another crop to the rotation in the management editor (MCREW) and make a second run.
We will also consider a strip tillage system and reduced tillage to address the erosion problem.

\begin{itemize}
\item{Exercise 2 uses a previously built management record as a starting template
that is then modified via MCREW (Management/Crop Rotation Editor for WEPS).}
\item{It outlines how to:}
	\begin{itemize}[noitemsep]
	\item{Perform a regular (normal) WEPS simulation run}
	\item{Perform a Yield Calibration run to calibrate the average yield for the selected crop record}
	\item{Insert another cropping system (single year rotation) into the current management rotation}
	\item{Convert the existing management rotation into a reduced tillage system}
	\end{itemize}
\item{It demonstrates how to modify an existing management rotation within MCREW
using basic editing functions:}
	\begin{itemize}[noitemsep]
	\item{Inserting another management file's content}
	\item{Deleting rows (operation entries)}
	\item{Inserting new operation records}
	\item{Making Target Yield adjustments}
	\item{Correcting length of management rotation when necessary}
	\end{itemize}
\item{Learn to evaluate output reports and interpret results
relevant to achieving specific erosion risk goals:}
	\begin{itemize}[noitemsep]
	\item{Determine if erosion exceeds the Soil Loss Tolerance (T) value for the specified soil}
	\item{Determine whether ground cover is adequate to protect seedlings from wind erosion damage}
	\end{itemize}
\end{itemize}

\begin{figure}[H]
\centering
	\includegraphics[scale=1]{images/Example_2/Ex2-photo.jpg}
\end{figure}

\subsection{Scenario} \label{subsec:Scenario_2}

\begin{itemize}

\item{The farm is located in \textbf{Lubbock County, Texas}, just south of the airport.
Note that the centroid of this county is nearby (33.61020º N, 101.82054º W)
and is close enough one could use the county centroid coordinates as has been done with previous versions of WEPS.
However, we would like to use the actual site's coordinates \textbf{(33.63260º N, 101.81114º W)},
previously determined by using the WEPS Map Viewer as outlined in Exercise 1.
This will ensure that we are selecting a soil that actually exists on the field site
by using the new CSIP Soil Service selection option.
The user should enter the actual coordinates in the latitude/longitude fields though,
to ensure that we get the exact same answers shown for this example.
}
\item{The soil in the field is an \textbf{Amarillo Fine Sandy Loam}.}
\item{The crop rotation is \textbf{continuous Stripper Cotton}.
It may be helpful to add Milo or Sorghum to the rotation.}
\item{There is also some new technology from Texas A\&M,
using \textbf{Strip Tillage} and \textbf{Ridge Till Planters} that we would like to also model for an alternative.}
\item{The field is a \textbf{half section of land (320 acres)} and is \textbf{oriented east and west}
(see X-length/Y-length green rectangle in center of
\cref{fig:WEPS_interface_loaded_for_Exercise_2_initial_run}).}
\item{Normal yield for the Cotton is ¾ bale or \textbf{375 lbs lint/ac.}}
\item{Sorghum should yield an average of \textbf{25 bu/ac.}}

\end{itemize}

\subsection{Complete the following steps:} \label{subsec:Complete the following steps_2}

\textbf{Step 1}: Start up the WEPS interface and add the information shown in (\cref{fig:WEPS_interface_loaded_for_Exercise_2_initial_run}).
Set the latitude and longitude fields to the site coordinates: \textbf{33.63260º N, 101.81114º W}.
Be sure to show the field as a rectangle (simulation area is \textbf{5280 by 2640 feet})
with the short side (\textbf{Y-length = 2640 ft}) on the east and west,
as shown in (\cref{fig:WEPS_interface_loaded_for_Exercise_2_initial_run}).

\begin{figure}[H]
\centering
	\includegraphics[scale=1.74]{images/Example_2/WEPS_interface_Ex_2.jpg}
\caption{WEPS interface loaded for Exercise 2 initial run.}
\label{fig:WEPS_interface_loaded_for_Exercise_2_initial_run}
\end{figure}

\textbf{Step 2}: Click the ‘Man’ pull down black arrow
{\scalerel*{\includegraphics{images/icons/down_arrow.png}}{\strut}
(lower right side) to display the management files under "System Templates".
Load the pre-built file called \textbf{Cotton, stripper; FC, SCsweep, Bed.man}
by clicking the name of the file in the list. 

\textbf{Step 3}: Click the ‘Soil’ pull down black arrow
{\scalerel*{\includegraphics{images/icons/down_arrow.png}}{\strut} (lower right side)
to display the soils in \textit{TX303 - Lubbock County, Texas}
under the “CSIP Soil Service” folder for this site.
Open the \textit{AfA - Amarillo fine sandy loam, 0 to 1 percent slopes} folder
and load the soil called \textbf{Amarillo{\_}TX303{\_}AfA{\_}90{\_}FSL.ifc}
by clicking the name on the list.

\textbf{Step 4}: Make a standard run as shown in Exercise 1
by clicking the Run button {\scalerel*{\includegraphics{images/icons/run.png}}{\strut}
in the located in the WEPS toolbar.
Type in the run name of: \textbf{\textbf{Cotton, stripper, Conv, TX}}.
Upon completion, a popup window containing warning messages
of the crop not reaching maturity during specific simulation years will appear.
We will address that issue in the next iteration of this exercise.
The Run Summary report window will appear when the popup warning message window is dismissed.
Note that these warnings are still accessible
if the user clicks on the "Warnings" button at the bottom of the Run Summary report
(\cref{fig:Initial_WEPS_Summary_Report_2}).

\begin{figure}[H]
\centering
	\includegraphics[scale=1.75]{images/Example_2/Run_Summary_Ex_2.jpg}
\caption{Initial WEPS Summary Report showing average annual soil loss and cotton lint yield.}
\label{fig:Initial_WEPS_Summary_Report_2}
\end{figure}

\textbf{What was the average annual soil loss by wind erosion for this simulation run? Answer: }
The continuous Cotton run gave a \textbf{16.9 t/ac/yr} soil loss
(\cref{fig:Initial_WEPS_Summary_Report_2}).

\textbf{How much cotton lint is harvested? Answer:}
This rotation produced \textbf{400.7 lbs/ac} of cotton lint on average per year
(\cref{fig:Initial_WEPS_Summary_Report_2}).

\textbf{The inventory states that we should have 375 lbs/ac lint.
Is this different enough to calibrate the cotton yield? Answer: }
Although this yield is probably ok since we are close to our \textbf{$\pm$5$\%$} threshold,
we will follow our guideline and still calibrate the cotton yield.
The predicted Harvest Yield is \textbf{$\sim$6.9$\%$}
greater than the Expected Yield,
which exceeds the Expected Yield by greater than \textbf{5$\%$}.

\subsection{Make a Yield Calibration Run} \label{subsec:Make a Yield Calibration Run_2}

\textbf{Step 1}: Adjust the harvest date and perform a Yield Calibration Run.

\textbf{Step 1a}:
Following what was learned in Exercise 1, configure MCREW to make a Yield Calibration run
with a target yield of \textbf{375 lbs/ac lint} for the cotton crop
(\cref{fig:Modified_mgt_in_MCREW_Ex_2}).

\textbf{Step 1b}:
Move the harvest date forward from \textbf{Oct 20, 01} to \textbf{Oct 31, 01}
(\cref{fig:Modified_mgt_in_MCREW_Ex_2}).

Remember that we had a popup window appear at the conclusion of the initial run
showing that we had not reached 100$\%$ crop maturity prior to harvesting for all of the simulation years.
Note that these warning messages are also listed under the "Warnings" tab
at the bottom of the Run Summary report (if clicked on) as shown in
\cref{fig:Initial_WEPS_Summary_Report_2}.
This new harvest date should now allow sufficient time for the cotton crop
to reach maturity for all of the simulated harvests
prior to executing the Yield Calibration run.

\textbf{Step 1c}:
Save the modified management file to a different name to distinguish it from the original unmodified management file.
Call it \textbf{Cotton, stripper; FC, SCsweep, Bed-Modified.man}.
To do so, in MCREW click on the floppy icon {\scalerel*{\includegraphics{images/icons/MCREW_floppy.jpg}}{\strut}
or go to the \textbf{File} menu and select the \textbf{Save As...} option.

\begin{figure}[H]
\centering
	\includegraphics[scale=1.38]{images/Example_2/Modified_mgt_file_Ex_2.jpg}
\caption{Modifications to cotton management file in MCREW.}
\label{fig:Modified_mgt_in_MCREW_Ex_2}
\end{figure}

\textbf{Step 2}: Execute a Yield Calibration Run.
The default run name will include the text \textbf{\_calib} appended to it.
So, the run name \textbf{Cotton, stripper, Conv, TX\_calib} will be fine.

\textbf{Step 2a}: Save a local copy of the calibrated cotton crop record for future retrieval, if desired.

After the calibration run has completed,
a Biomass Adjustment Factor of \textbf{0.9531} is displayed.
First, save a copy of this calibrated record as a local crop record.
Do so by clicking on the \textbf{Save As} button on the \textit{Calibration Factors} window
(\cref{fig:Cotton_Calibration_Factors_window_Ex_2}).
This will bring up a WEPS FileChooser window
(\cref{fig:Save_local_calibrated_crop_record_window_Ex_2}).
This calibrated crop will be removed when replacing the planting operation
with a reduced till planter later in this exercise.
Therefore, saving this file locally will not only allow retrieval for this exercise,
but other projects in the future.

\begin{figure}[H]
\centering
	\includegraphics[scale=1.75]{images/Example_2/Cotton_calibration_window_Ex_2.jpg}
\caption{Cotton Calibration Factors window.}
\label{fig:Cotton_Calibration_Factors_window_Ex_2}
\end{figure}

\begin{figure}[H]
\centering
	\includegraphics[scale=1.75]{images/Example_2/Save_local_calibrated_crop_record_Ex_2.jpg}
\caption{Saving calibrated cotton crop record in a local file.}
\label{fig:Save_local_calibrated_crop_record_window_Ex_2}
\end{figure}

\textbf{Step 2b}:
Select \textit{Use in Current Project}.
The new cotton harvest yield estimate is \textbf{368.9 lbs/ac lint},
which is within 5$\%$ of the Target Yield.
However, the average annual soil loss is even greater than the previous run's result at \textbf{17.4 t/ac/yr}
(\cref{fig:Run_Summary_Cotton_Calib_Run_Ex_2}).
Note that we received no maturity warning messages for the calibration run,
so we resolved that issue.

\begin{figure}[H]
\centering
	\includegraphics[scale=1.75]{images/Example_2/Run_Summary_Cotton_Calibration_Run_Ex_2.jpg}
\caption{Run Summary report from Cotton calibration run.}
\label{fig:Run_Summary_Cotton_Calib_Run_Ex_2}
\end{figure}

\textbf{What can be done when the soil loss is too high?} Let’s consider some options for lowering soil loss.

\textbf{What management period has the highest erosion loss?}
Hint: Open the Detailed Report and check the total flat mass of residue at that time on the Erosion \& Crop Veg Res \& Biomass (details) report.

\textbf{Answer:} The period \textbf{(Mar 1-14, 01)} immediately following the \textit{Chisel, sweep, shovel} operation,
had \textbf{4.4 tons/ac}, which is also the period prior to planting (\cref{fig:Detailed_cotton_report_Ex_2}). 

\begin{figure}[H]
\centering
	\includegraphics[scale=1.3]{images/Example_2/Detail_cotton_report_Ex_2.jpg}
\caption{Detailed Report showing loss and residue at the planting and vegetative material at harvest.}
\label{fig:Detailed_cotton_report_Ex_2}
\end{figure}

\textbf{What is the total residue (flat mass) at planting time?}

\textbf{Answer:} About \textbf{58 lbs/ac} and \textbf{1$\%$} surface cover are present at planting as shown in \cref{fig:Detailed_cotton_report_Ex_2}.

\textbf{How much total residue do we have after the Shredder, flail or rotary operation?}
\textbf{Answer:} The biomass (residue) after shredding is \textbf{2166 lbs/ac}
(0 lb/ac leaf and stem [crop] + 1961 lbs/ac flat mass [residue] + 205 lbs/ac standing mass [residue])
as shown in
\cref{fig:Detailed_cotton_report_Ex_2}.

Note: Cotton is a perennial crop.
Many cotton crop harvesting operations will not kill the crop.
In this case however, the \textbf{Harvest, cotton} operation is configured to kill the cotton crop.
Similarly, if a defoliant was used before harvest,
the leaf residue would have shown up at that time in the residue column,
but a defoliant operation would not have killed the crop.

Cotton does not produce enough residue itself to control erosion.

We will now add sorghum to the rotation to see how it affects the residue and erosion rates.

\subsection{Adding a Crop to a Rotation} \label{subsec:Adding a Crop to a Rotation_2}

Close all the report windows, leaving only the main interface window open.
Click the ‘Man’ button {\scalerel*{\includegraphics{images/icons/manNew.jpg}}{\strut}
to open the MCREW management editor.
The management file loaded in MCREW should still be
\textbf{Cotton, stripper, FC, SCsweep, Bed-Modified\_CALIB.man}.

\textbf{Step 1}:
Since we have a previously calibrated the \textbf{Cotton} crop record
(see the 0.9531 Biomass Adj. Factor value in
\cref{fig:Cotton_Calibration_Factors_window_Ex_2}),
it would be better if we selected the same calibrated crop record that we had saved previously
as a local record, but with a crop name that reflects that it has been calibrated.
So, we should right click on the dropdown arrow for the Cotton crop record and
select the \textbf{Cotton\_CALIB.crop} record from the \textit{Local Crop and Residue Records} list
to replace the Cotton crop record
(\cref{fig:MCREW_local_crop_selection_2}).

One can click on the "Yield" button
{\scalerel*{\includegraphics{images/icons/yCalOff.png}}{\strut}
to ensure that it contains the correct
calibrated Biomass Adj. Factor value of 0.9531.
While in this MCREW view, disable the "Select Yield For Calib."
for the \textbf{Cotton\_Calib} crop
by removing the checkmark from the box
(\cref{fig:MCREW_Rotation_Years_Popup_2}).

\begin{figure}[H]
\centering
	\includegraphics[scale=1.38]{images/Example_2/Load_local_calibrated_cotton_record_Ex_2.jpg}
\caption{Selecting a locally saved calibrated cotton crop record in MCREW.}
\label{fig:MCREW_local_crop_selection_2}
\end{figure}

\textbf{Step 2}: Right-click the last row in the Operation Name column of the cotton file.
Select \textit{Insert Management} and double-click the \textit{Example Mgt. files} directory
(if it isn't already selected).
Choose \textit{Sorghum,Grain;MT,CMZ19.man}
and click the Select button {\scalerel*{\includegraphics{images/icons/select.png}}{\strut}.

Note: The sorghum crop comes into the rotation in the second year.
MCREW sees that this rotation
cannot fit into year one following the last operation listed in MCREW,
so it makes an adjustment to the dates.
All of these new operation dates in year two seem reasonable. 

\textbf{Step 3}: Since the management file has been significantly modified,
we should save it with a new name.
Note that the rotation name in the \textbf{Rotation} field has turned blue,
showing that the current management file being edited
has been modified (\cref{fig:MCREW_Rotation_Years_Popup_2}).

\begin{figure}[H]
\centering
	\includegraphics[scale=1.38]{images/Example_2/MCREW_Rotation_Years_Popup_Ex_2.jpg}
\caption{MCREW popup window asking for number of rotation years if any dates in the rotation exceed the current listed value.}
\label{fig:MCREW_Rotation_Years_Popup_2}
\end{figure}

Click \textit{File} menu and then the \textit{Save as...} menu option.
Notice that MCREW has detected that we only have “1” in the
\textbf{Years in Rotation} box (\cref{fig:MCREW_Rotation_Years_Popup_2}),
which we forgot to change prior to saving the management file.
Therefore, we must either change the value in the popup window's \textbf{Number of years}
box to a number greater than 1 or accept the default value of 2.
Click \textit{OK} to accept the change to a 2-year rotation.
MCREW then asks for a new name for the 2-year rotation.
Enter \textbf{Cotton, Stripper, Conv-Sorghum, MT, TX}, and click ‘Save As’.


\textbf{Step 4}:
Note that this new 2-year rotation was saved into the current WEPS Project folder by default.
To save a copy as a local template management file,
you must (in MCREW) click the \textbf{File} menu,
then the \textbf{Save as Local Template} menu option,
and then click on the \textbf{Save} button in the FileChooser window.

The default location will be the \textbf{LocalDB/man} folder.
If one goes to another location and desires to return to the default location,
they can click on the \textbf{Def Loc} (default location) button
{\scalerel*{\includegraphics{images/icons/Def_Loc_button.jpg}}{\strut}
or the \textbf{Local T} (local template) button
{\scalerel*{\includegraphics{images/icons/Local_T_button.jpg}}{\strut}.\footnote
{This default location applies to NRCS Field Office configured versions of WEPS running Microsoft Windows.
Other WEPS configurations and operating systems may vary as to the location of this folder.}
You may wish to post it to a shared server site so others in your work group can use the same management file.

\textbf{Step 5}: Make a \textbf{non-calibrated} run with this 2-year management rotation file.
Note that cotton crop was previously calibrated.

Let’s see if WEPS will give us an appropriate yield for the sorghum in this rotation.
Return to the main interface by clicking the Close button
{\scalerel*{\includegraphics{images/icons/close.png}}{\strut}
in MCREW.
Click the Run button {\scalerel*{\includegraphics{images/icons/run.png}}{\strut}
and call the run \textbf{Cotton, stripper, Conv-Sorghum, MT, TX}.
Note that since we are now running a 2-year rotation,
we generate additional simulated climate years,
which in this case caused three years of cotton to be harvested
slightly before the crop reached 100$\%$ maturity
(\cref{fig:WEPS_Run_Summary_screen_showing_soil_loss_and_yields_without_calibration_2}).
Since it is so close to 100$\%$, we will ignore the message this time.

\textbf{What is the soil loss?}
\textbf{Answer:} The Run Summary shows an unacceptable predicted average loss of \textbf{10.6 t/ac/yr} (\cref{fig:WEPS_Run_Summary_screen_showing_soil_loss_and_yields_without_calibration_2}). 

\begin{figure}[H]
\centering
	\includegraphics[scale=2.2]{images/Example_2/Cotton_Sorghum_uncalib_Ex_2.jpg}
\caption{WEPS Run Summary screen showing soil loss and yields without calibration.}
\label{fig:WEPS_Run_Summary_screen_showing_soil_loss_and_yields_without_calibration_2}
\end{figure}

\textbf{Step 6}: Make a \textbf{Yield Calibration} run for the sorghum crop only.

The yields for both crops are also higher than the expected (target) yields
at 437.8 lb/ac of Cotton lint and 58.0 bu/ac for Sorghum grain.

Close the Run Summary report.
We will now prepare to make a Yield Calibration run to calibrate only the sorghum crop.
We previously calibrated the cotton crop under a continuous cotton rotation
and we are still using that calibrated crop record
(one can verify this by checking the \textit{Biomass Adj. Factor} value in MCREW for the cotton crop).
By using the previously calibrated record for subsequent simulations,
we can see the potential effects of changing the cropping rotation has on the cotton yields.
In fact, if the changes to the rotation happen to affect the availability of soil water
during the growing season for the cotton crop,
re-calibrating that crop would defeat that yield affect feature within WEPS.
Since we are interested in the yiled impacts due to conservation practice changes,
there is no need to re-calibrate the cotton crop.
This is the reason we disabled that crop record from being re-calibrated by default in this rotation.

\textbf{Step 6a}:
Click the Yield Calibration button {\scalerel*{\includegraphics{images/icons/yCalOff.png}}{\strut}
to display the extra MCREW columns for setting the necessary Yield Calibration fields for the two crops.

\textbf{Step 6b}:
Enter \textbf{25 bu/ac} yield for the \textbf{Harvest Target Yield} for the new sorghum crop.
Check that the \textbf{Select Harvest for Calib.} and the \textbf{Select Yield for Calib.} boxes
are selected (contain a checkmark).

\textbf{Step 6c}:
Ensure that the \textbf{Select Harvest for Calib.} and the \textbf{Select Yield for Calib.} boxes
are \textbf{NOT} selected for the cotton crop (does not contain a checkmark in at least one of those boxes),
since we do not want to re-calibrate the cotton crop.

\textbf{Step 6d}:
Save the changes to the modified management file and close MCREW by clicking on the blue arrow icon.

\textbf{Step 6e}:
Execute the Yield Calibration Run.
Accept the default run name which should be \textit{Cotton, stripper, Conv-Sorghum, MT, TX{\_}calib}.

\textbf{Step 6f}:
Upon completion of the Yield Calibration Run and when the "Calibration Factors" popup window appears,
click on the \textit{Use in Current Project} button to switch the listed management rotation file to
the newly calibrated management file, which should be named
\textbf{Cotton, stripper, FC, SCsweep-Sorghum,MT\_CALIB.man}
(highlighted in "Calibration Factors" popup window in
\cref{fig:Calibration_window_and_Run_Summary_Report_showing_Biomass_Adjustment_Factor_for_sorghum_2})
and should now be displayed at the bottom of the WEPS main interface window.

\begin{figure}[H]
\centering
	\includegraphics[scale=2.2]{images/Example_2/Run_Summary_Sorghum_calib_Ex_2.jpg}
\caption{Calibration window showing Biomass Adjustment Factor for sorghum and the Run Summary Report.}
\label{fig:Calibration_window_and_Run_Summary_Report_showing_Biomass_Adjustment_Factor_for_sorghum_2}
\end{figure}

Predicted yields for the calibration run are reasonable at 410.6 lb/ac cotton lint and 25.6 bu/ac sorghum.
The problem of the sorghum yield over estimation is now resolved.
Note that the calibrated cotton yield went up due to more soil water availability for the cotton crop
in the 2-year rotation compared to the previous one year continuous cotton crop rotation.
However, the soil loss is even higher now at \textbf{17.2 t/ac} (\cref{fig:Calibration_window_and_Run_Summary_Report_showing_Biomass_Adjustment_Factor_for_sorghum_2}).

\textbf{How much flat mass do we have now after planting Cotton on the detailed report?}
\textbf{Answer:} Remember to click the Detailed Report and select the
\textit{Erosion and Crop Veg, Res \&  Biomass (details)} screen (which should be the default selection).
On \textbf{May 15-31 01}, there is about \textbf{164 lbs/ac} flat mass
and the erosion rate is a \textbf{Trace} at the time of cotton planting (\cref{fig:Detailed_Report_showing_soil_loss_and_flat_mass}).

\begin{figure}[H]
\centering
	\includegraphics[scale=1.3]{images/Example_2/Detail_report_sorghum_Ex_2.jpg}
\caption{Detailed Report showing soil loss and flat mass.}
\label{fig:Detailed_Report_showing_soil_loss_and_flat_mass}
\end{figure}

\textbf{What is the date of the first erosion period after harvest of the sorghum?}
\textbf{Answer:} After the \textit{Bedder, hipper, disk hiller} operation listed on
\textbf{Mar 15-31, 01} shows \textbf{4.6 tons/ac}
(\cref{fig:Detailed_Report_showing_soil_loss_and_flat_mass}).

\textbf{When do the erosion periods occur in this rotation and what tillage operations
created the surface conditions that allowed it to occur?}
One might find the \textit{Total Wind Erosion Soil Loss} graph helpful
(\cref{fig:Total_Wind_Erosion_Soll_Loss_2}),
which is accessible via the
\textit{QuickPlot} toolbar icon menu selection
(\cref{fig:Quick_Plot_Selection_2})
from the main WEPS screen or any of the WEPS Reports for this simulation run.

\begin{figure}[H]
\centering
	\includegraphics[scale=1.7]{images/Example_2/Quick_Plot_icon_menu_selection_2.jpg}
\caption{QuickPlot icon and menu selection.}
\label{fig:Quick_Plot_Selection_2}
\end{figure}

\textbf{Answer:} From \textbf{Mar 15-31, 01} through \textbf{May 15-30, 01}
following the \textit{Bedder, hipper, disk hiller} operation and
\textbf{Dec 1-14, 01} through \textbf{Jun 15-24, 02}
following the \textit{Shredder, live, flail or rotary} operation
(\cref{fig:Detailed_Report_showing_soil_loss_and_flat_mass}).

\begin{figure}[H]
\centering
	\includegraphics[scale=1.3]{images/Example_2/Total_Wind_Erosion_Soil_Loss_Ex_2.jpg}
\caption{Graph of Total Wind Erosion Soil Loss for 2-year cotton and sorghum rotation.}
\label{fig:Total_Wind_Erosion_Soll_Loss_2}
\end{figure}

Note that the \textit{Bedder, hipper, disk hiller} operation
not only buried most of the remaining above ground sorghum residue
but also converted or buried most of the remaining standing residue.
This left the field much more susceptible to wind erosion.
Likewise, the \textit{Shredder, live, flail or rotary} operation
converted most of the remaining standing cotton residue to flat residue.
Since standing residue is about 10 times more effective than the same
amount (mass) of flat residue,
the field surface again became much more susceptible to wind erosion.

Regardless, the average annual wind erosion of \textbf{17.2 tons/ac}
for this simulation run is still too high.
\textbf{Reduced tillage} may save a considerable amount of soil at this site.

\subsection{Reduced Tillage} \label{subsec:Reduced Tillage_2}

Let’s try one last set of adjustments to our set of runs.
We know cotton is glyphosate ready for weed control and strip-till works for cotton.
We also know that standing residue is much more effective than flat residue at controlling wind erosion.
So, we will start with the management rotation used in the last run and eliminate some of the tillage.
Close the report windows, leaving only the main interface window open.

\textbf{Step 1}: Click the ‘Man’ button on the main interface.
Be sure that you have the \textit{Cotton,Stripper-Sorghum, MT, TX{\_}calib.man} file loaded.
We are going to change, remove, or replace many of the tillage operations.
Pressing and holding the Control Key on your keyboard while clicking
in the \textit{Date} column enables one to select nonconsecutive operations.
When all unnecessary operations are highlighted,
right-click under the Operation Name column to select \textbf{Delete row(s)}
as shown in \cref{fig:Removing_excess_tillage_operations}
or select the \textbf{Delete row(s)} option under the \textbf{Edit} menu in MCREW.
%% Not working correctly!!!!

\begin{figure}[H]
\centering
	\includegraphics[scale=1.3]{images/Example_2/MCREW_delete_operations_Ex_2.jpg}
\caption{Removing excess tillage operations.}
\label{fig:Removing_excess_tillage_operations}
\end{figure}

\textbf{Step 2}:
Change the standard planter for the cotton from \textit{Planter, double disk}
to \textit{Planter, ridge till} by clicking the drop-down arrow
on the \textit{Planter double disk} row
and first selecting the \textit{CRLMOD Operations} folder
and then selecting the \textit{Planter, ridge till} operation
(\cref{fig:Illustration_of_changing_operations}).

\begin{figure}[H]
\centering
	\includegraphics[scale=1.3]{images/Example_2/MCREW_Change_operation_Ex_2.jpg}
\caption{Illustration of changing operations.}
\label{fig:Illustration_of_changing_operations}
\end{figure}

\textbf{Step 2a}: You will need to re-select your locally calibrated crop (Cotton\_CALIB)
after selecting the new operation,
since MCREW cannot yet replace a planting operation with another planting operation
without also removing the existing crop record
(\cref{fig:MCREW_reselect_crop}).} 

\begin{figure}[H]
\centering
	\includegraphics[scale=1.3]{images/Example_2/MCREW_reselect_crop_Ex_2.jpg}
\caption{Re-selecting the locally saved calibrated cotton record.}
\label{fig:MCREW_reselect_crop}
\end{figure}

\textbf{Step 3}: By selecting the dropdown choice list arrow,
change \textit{Cultivator, row, 1st pass ridge till} on June 25 to \textit{Sprayer, post emergence}
(under the CRLMOD Operations Folder
(\cref{fig:Replacing_operation_in_MCREW_2}).

\begin{figure}[H]
\centering
	\includegraphics[scale=1.3]{images/Example_2/MCREW_replace_operation_Ex_2.jpg}
\caption{Replacing operation in MCREW.}
\label{fig:Replacing_operation_in_MCREW_2}
\end{figure}

\textbf{Step 4}: Add additional operations.
Right-click the May 15 operation \textit{Planter, ridge till} and select \textit{Insert Operation}
from the mouse menu.
This will bring up a WEPS FileChooser window.

\begin{figure}[H]
\centering
	\includegraphics[scale=1.3]{images/Example_2/MCREW_insert_operation_Ex_2.jpg}
\caption{Inserting Operation into MCREW.}
\label{fig:Inserting_Operation_into_MCREW_2}
\end{figure}

\textbf{Step 4a}:
In the WEPS FileChooser window, double-click the \textit{CRLMOD Operations} folder (if not already selected)
and scroll to find \textit{Strip till bed conditioner} operation (\cref{fig:Inserting_Operation_into_MCREW_2a}).
Once selected, this operation will be placed above the operation name you clicked to insert it.
They will also share the same date as the operation below it until modified appropriately.

\begin{figure}[H]
\centering
	\includegraphics[scale=1.3]{images/Example_2/MCREW_insert_op_FileChooser_Ex_2.jpg}
\caption{Inserting Operation into MCREW via FileChooser selection.}
\label{fig:Inserting_Operation_into_MCREW_2a}
\end{figure}

\textbf{Step 5}:
Continue to delete, change or add operations until the MCREW matches
\cref{fig:MCREW_reduced_tillage_ridge_till_alternative_rotation},
e.g. add another \textit{Strip till bed conditioner} operation following the cotton harvesting operation.
Set the date for that operation to match the planting date for the sorghum.

\begin{figure}[H]
\centering
	\includegraphics[scale=1.3]{images/Example_2/MCREW_reduced_till_Ex_2.jpg}
\caption{Window showing reduced tillage ridge till alternative calibration run.}
\label{fig:MCREW_reduced_tillage_ridge_till_alternative_rotation}
\end{figure}

Be sure the crop records are the previously calibrated ones
(e.g. \textbf{0.9531} and \textbf{0.5664} respectively for the \textit{Biomass Adj. Factor}
values).
For completeness, also check to ensure that the target yields are set
to 375 lbs/ac for cotton and 25 bu/ac for sorghum.
Save the new file as \textit{Cotton, stripper, Sorghum, StripTill, TX},
then save and close MCREW to return to the interface.

\textbf{Step 6}: Make a normal (non-calibrated) WEPS run for the strip till rotation
since we have previously calibrated both the cotton and sorghum crop records.
Label the new run  \textit{Cotton, stripper, Sorghum, StripTill, TX}
to reflect the changes made in the management rotation.

\begin{figure}[H]
\centering
	\includegraphics[scale=1.9]{images/Example_2/Run_Summary_striptill_Ex_2.jpg}
\caption{Run summary showing Average Annual Soil Loss of 0.4 tons/acre.}
\label{fig:Run_summary_showing_Average_Annual_Soil_Loss_of_0.4_tons/acre}
\end{figure}

Average Annual Soil Loss is now predicted to be only 0.4 tons/ac
(\cref{fig:Run_summary_showing_Average_Annual_Soil_Loss_of_0.4_tons/acre}).
This run shows that it is possible to effectively control erosion
using a cotton-sorghum rotation as designed in \cref{fig:MCREW_reduced_tillage_ridge_till_alternative_rotation}.
Leaving the cotton stalks standing,
in permitted zones in the U.S.
(\cref{fig:TX_Cotton_Stalk_Destruction_Zones})\footnote{\href{https://texasagriculture.gov/Regulatory-Programs/Cotton-Stalk-Destruction/Cotton-Stalk-Destruction-Methods}{https://texasagriculture.gov/Regulatory-Programs/Cotton-Stalk-Destruction/Cotton-Stalk-Destruction-Methods}}
is very effective method of controlling wind erosion.
 
\begin{figure}[H]
\centering
	\includegraphics[scale=1.2]{images/Example_2/Cotton_Stalk_Destruction_Zones-TX.jpg}
\caption{Texas Department of Agriculture Cotton Stalk Destruction Zones.}
\label{fig:TX_Cotton_Stalk_Destruction_Zones}
% Ref: https://texasagriculture.gov/Portals/0/images/REG/Cotton%20Stalk%20Destruction%20Map.pdf
\end{figure}

The Detail Report shows there is 1076 lbs/ac Flat Mass and 129 lbs/ac Standing Mass
with 31$\%$ Surface Cover of sorghum residue after planting cotton
(\cref{fig:Tabular_Detail_Report_showing_surface_cover_needed_to_meet_the_Soil_Loss_Tolerance_year_1 _Cotton_stripper_ridge_till}).

\begin{figure}[H]
\centering
	\includegraphics[scale=1.3]{images/Example_2/Detail_Report_striptill_cotton_Ex_2.jpg}
\caption{Tabular Detail Report showing surface cover needed to meet Soil Loss  Tolerance (year 1).}
\label{fig:Tabular_Detail_Report_showing_surface_cover_needed_to_meet_the_Soil_Loss_Tolerance_year_1 _Cotton_stripper_ridge_till}
\end{figure}

Likewise the Detail Report also shows 1474 lbs/ac Flat Mass and 246 lbs/ac of Standing Mass
with 31$\%$ Surface Cover of cotton residue after planting sorghum (\cref{fig:Tabular_Detail_Report_showing_surface_cover_needed_to_meet_the_Soil_Loss_Tolerance_year_2 _Sorghum_ridge_till}).

\begin{figure}[H]
\centering
	\includegraphics[scale=1.3]{images/Example_2/Detail_Report_striptill_sorghum_Ex_2.jpg}
\caption{Tabular Detail Report showing surface cover needed to meet the Soil Loss Tolerance (year 2).}
\label{fig:Tabular_Detail_Report_showing_surface_cover_needed_to_meet_the_Soil_Loss_Tolerance_year_2 _Sorghum_ridge_till}
\end{figure}

\textbf{Step 7}:
If you do not believe the increased yield levels WEPS predicts with this rotation,
one can make another "Yield Calibration" run to force the yields to match within $\pm$5$\%$
of the target yields.
The results are not much different, as noted in
\cref{fig:Run_summary_showing_Average_Annual_Soil_Loss_of_0.7_tons/acre}.

\begin{figure}[H]
\centering
	\includegraphics[scale=1.9]{images/Example_2/Run_Summary_striptill_calibrated_Ex_2.jpg}
\caption{Run summary showing Average Annual Soil Loss of 0.7 tons/acre.}
\label{fig:Run_summary_showing_Average_Annual_Soil_Loss_of_0.7_tons/acre}
\end{figure}

\end{document}