**WIND EROSION EQUATION (WEQ)**

**Guidance Document**

### USE OF MICROSOFT EXCEL SPREADSHEET

-   **Purpose** This guidance document will give the basic instructions
    to use the Wind Erosion Equation (WEQ) Microsoft Excel spreadsheet,
    computer version, developed by Keep, Sporcic and Nelson. Users will
    need, as a minimum, a 486 computer; Windows, 95, 98, or NT; MS Excel
    version 9.0 or more recent; 64 meg of RAM or more; and a copy of
    this document and the spreadsheet (**WEQv9.03.xls**) from the
    following web site:

-   WEQ Data Hyperlinks

> **WEQ EXCEL Spreadsheet model**:
>
> <http://www.weru.ksu.edu/nrcs/wepsnrcs.html>
>
> Choose the following path: /nrcs/downloads/WEQ/Latest Version WEQ
> MS-Excel Worksheet. Select: WEQ vs 9.03.xls.
>
> **Guidance Document for WEQ EXCEL Spreadsheet Model**
>
> <http://www.weru.ksu.edu/nrcs/wepsnrcs.html>
>
> Choose the following path: /nrcs/downloads/WEQ/Guidance Document for
> WEQ Excel Spreadsheet.
>
> Select: WEQ Guidance 12-17-08.doc.
>
> **Access to the National Agronomy Manual**:
>
> <http://directives.sc.egov.usda.gov/17894.wba>
>
> **Wind Parameters for WEQ** (Prevailing wind direction; Preponderance:
> and Erosive Wind Energy (EWE):
>
> [http://www.weru.ksu.edu/nrcs/](http://www.weru.ksu.edu/nrcs/%0D)
>
> [Choose the following path:
> /nrcs/downloads/WEQ/WEQ_Climate](http://www.weru.ksu.edu/nrcs/%0D)
>
> Select: WEQ_Climate.xxx.
>
> **WEQ Wind Parameters by Region and States in EXCEL Format;** Used to
> populate the climate section of the spreadsheet.
>
> <http://www.weru.ksu.edu/nrcs/>
>
> Choose the following path: /nrcs/downloads/WEQ/WEQ_Climate
>
> Select: WEQ Climate DB west.xls, WEQ Climate DB NP.xls, WEQ Climate
> SC.xls, or WEQ Climate Central.xls.
>
> **WEQ "E" tables** for each combination of C & I factors are on the
> www browser: <http://www.weru.ksu.edu/nrcs>
>
> Choose the following path: /nrcs/downloads/WEQ/WEQ_Climate
>
> Select: WEQ_Erosion_Table_I-104.pdf.
>
> **Random Roughness Photos**:
> <http://www.nrcs.usda.gov/technical/ECS/agronomy/roughness.html> or:
>
> [http://www.weru.ksu.edu/nrcs/wepsnrcs.html](http://www.weru.ksu.edu/nrcs/wepsnrcs.html )
>
> Choose: WEQ Information, look at the bottom of the page. These
> photographs are also available in printable format on this site.
>
> **C-Factor Map (Electronic**):
>
> <http://www.weru.ksu.edu/nrcs/wepsnrcs.html>
>
> Choose the following path: /nrcs/downloads/WEQ/WEQ_Climate
>
> Select: C-factor.zip (ArcMap 9.2)

-   **General --** The WEQ management period method EXCEL spreadsheet
    can be used in states that use the management period method to
    estimate wind erosion.

To use the spreadsheet model, the user will need to have a good
understanding of Part 502 of the National Agronomy Manual (NAM). Also,
planners will need to **have a basic understanding of the wind erosion
equation, be able to calculate residue reduction over periods of time,
understand irrigation (where the land is irrigated), and have basic
EXCEL spreadsheet skills**. The State Agronomist will need to set up the
wind climate data, crop data and operation (tillage) files. Cropping
systems developed on the model (WEQ Input Worksheet) can be saved to a
file and used as templates for future use by the client or for new
planning. The light yellow shaded areas are the **only** "user" data
required to run the program. The worksheet is "protected". This is not
because the user is not trustworthy; it is because some of the data
should only be changed state wide, and mostly because if a formula is
lost it can be very difficult to replace.

-   **Saving and using Templates --** Cropping systems can be saved as a
    **template** by saving the first five columns of data to an empty
    (new) workbook. To do so, highlight and **COPY** all the cropping
    system in the light yellow shaded area, beginning with the second
    line under the Crop and Management Records part of the WEQ Input
    Worksheet. Open a new workbook and paste special the values a clear
    worksheet. Set up the workbook to record a number of templates. Name
    this new template workbook and it is ready to be retrieved at a
    later time by copying out of the template workbook and then pasting
    (paste special, value) it into the WEQ Input Worksheet part of the
    model..

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-   **Irrigated Circles -** Many center pivot irrigated fields are
    planted in a circular pattern. To estimate wind erosion on fields
    planted and/or tilled in a circular pattern, two estimates need to
    be made. The first estimate should be made after selecting a NS
    tillage direction and the second should be an EW tillage direction.
    The average of the two estimates is the correct soil loss value.

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-   **Definitions -** The first sheet in the spreadsheet (**Instr**) has
    most of the column headings defined and an explanation of the
    information required for the spreadsheet to run. Please print a
    blank worksheet (**Res Wks** tab at the bottom) and the calculation
    sheet (**Calc**) before reading the **Instr** sheet. **Remember only
    the shaded cells need data input by the user.** Please read the
    **Instr** sheet before starting.

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-   **Circular Reference Bug -** There is a circular reference bug in
    the sheet. As you enter data for the first time you will find an
    error caution will come up and tell you there is a circular formula
    error in the sheet. **DO NOT** **PANIC** and call for help! Just
    close the warning box when it pops up and continue to add the data
    needed for the run. The error warning will stop when the first
    harvest is entered.

-   **Adding to the Climate database --** Persons authorized to change
    or add to the Climate database will click on the Climate tab
    unprotect the sheet and enter the data from Exhibit 502-7a in the
    National Agronomy Manual. The table is located at the following WEB
    location: <http://www.weru.ksu.edu/nrcs/wepsnrcs.html> Follow the
    subdirectories to /nrcs/downloads/WEQ/WEQ_Climate and select the
    correct climate DB for the area. There is a limit to the number of
    climate stations that can be included. It is suggested that only
    data needed in state where the sheet is used and the adjacent states
    be kept in the master file.

To copy the needed data from the above file, open the WEQ vs 9.xx.xls in
Excel and the Climate file mentioned above. Select the Climate file and
copy each states data to the bottom of the climate sheet in the WEQ
sheet. Be sure to get all the data columns. Next locate and highlight
all other state's data that you do not need, and hit the delete key.
Once the needed climate locations have been added, and the unwanted
states have been removed, sort the entire table on the first column (B).
This will take out all the blank rows and size it down to read the
needed locations. Lastly the sheet should be protected once again.

-   **Adding to the Crops database --** To add a new crop to the Crops
    database two types of data are needed, Residue data and Green Growth
    data. Residue data is entered on one line, and green growth data is
    entered by 15 day growth intervals. The first growth period must be
    adjusted for emergence. If it takes 10 day to emerge then there will
    be only 5 days of growth the first period. It is intended that the
    growth periods express an average dry matter (lbs/ac) accumulation
    for the period. The growth periods can be extended as long as
    additional dry matter is added to the crop. Residue is expressed as
    dry matter (lbs/ac) left above ground after the harvest operation.

Residue data needed is: an estimated yield, the unit wt. per acre, the
residue in lbs/ac at harvest, the residue/unit wt. (lbs/ac divided by
the unit wt), the cover residue table (either Corn, S Grain, or Cotton),
and the flat small grain equivalent chart to be used (See Exhibit 502-10
pg 502-61 of the NAM). Green growth data needed is: a growth curve table
name (unique to the state), dry matter (lbs/ac) accumulative by 15 day
intervals, the flat small grain equivalent chart to be used (See Exhibit
502-10 pg 502-61 of the NAM), the green growth equation for the selected
chart for perpendicular and the green grow equation for selected chart
for parallel. Much of the green growth data and residue data is
developed locally. Green growth table names are tied to regressed curve
equations and can be copied to new cell (crops) as needed.

The crop name column is used to indicate residue values (no number after
the name) and green growth values (numbers after the names). Example: a
line with the name Corn, grain is a line of residue values, a line with
the name Corn 15 indicates this is the first 15 day green growth period
for corn.

Persons authorized to change or add to the Crops database will click on
the Crop tab and unprotect the sheet, enter the above data, resort the
data table, and protect the sheet again so that data will not be
accidentally lost. Passwording the sheet is optional. Data enter in this
table must be similar to surrounding states.

-   **Adding to the Operations database-** Residue reducing tillage
    operations vary by speed, soil type, depth, spacing, amount of
    residue present, type of residue (fragile or non-fragile), and soil
    moisture. It is not assumed that the listed operations will reflect
    all the situations where this model will be used. There four
    perimeters needed for each operation, % residue remaining (% residue
    mass reduced using the operation), random roughness (RR) created by
    the operation (inches), ridge height created (inches), and ridge
    spacing (inches). The N and F listed in the name indicates
    Non-fragile or Fragile residue is being tilled. In the old NAM Part
    503 subpart E pages 503-13 and 503-14, tables 1 and 2 list the N and
    F crops.

If it is necessary to add or change the operations table, authorized
persons may change or add to the Operations in the database. The new
data mentioned above can be added to the bottom of the worksheet. **Do
not change the names of the brown colored operations.** They are used in
formulas and if change will cause the sheet to give incorrect answers.
Start the process by clicking on the "Oper" tab at the bottom of the
workbook. Click tools, and unprotect to unlock the sheet to add or
change the data. Enter or change the data as needed and protect and or
password as instructed above.

# Step by Step

This is a step by step process to show how to use the program. Start the
step by step process after reading the **Instr** sheet (the tab at the
bottom of the WEQ Excel spreadsheet).

**Step 1 -** Fill in the **Producer**, **Planner**, **Location** (Farm
number or Sec., Town., Range), **Tract**, **Field**, and **Crop
Rotation** boxes.

**Step 2 -** Use the drop down menu to select the **Climate Data
Station**. When the climate data station is selected, the model
automatically pulls the data from the **Climate** sheet (see the tab at
the bottom of the worksheet).

**Step 3 -** Fill in the **C Value** (in whole numbers. Divide the
isobar interval only once from the C factor map)**,** enter the **Field
Width in feet** (short side of field)**, Tillage Direct.** (EW or NS,
drop down)**, Length/Width Ratio** (drop down), **Field Direction** (EW
or NS, drop down)**, Irrigation** (Y/N, drop down)**,** and **Adjusted
Soil "I", which is the assigned I value the soil texture plus the
adjustment for knolls and crusting** (drop down). When **Irrigation** is
checked yes, this automatically places the I factor into the next less
wind erodible soil group. Therefore when you have an I value based on
sieving and want to take credit for irrigation induced non-erodible wet
days, you need to change your "adjusted sieved I" by one higher wind
erodibility group before checking yes in the irrigation block.

**Step 4 -** Determine the **Wind Erodibility Group** (WEG) from the
FOTG soil survey, and fill in the number (1-7 or 4L, drop down).

**Step 5 -** Place **1/1/xxxx** on the first line of worksheet (next to
Start Rotation). Start the first management period on January 2,
(current year) with an **Over winter** **loss** operation. Go to the
**Operation Date** column on row 13. Put in the date **1/2/xxxx**. Next
place the cursor in the **Crop** column next to the date, left click in
the box to activate the pull down and select the previous crop harvested
(select from the list). Move to the **Operation** column. In cell C13,
click the pull-down and select the **Over winter loss, fragile (F) or
non-fragile** **(N)** **operation** (see NAM Part 503 Subpart E, table 1
& 2, for definition), repeat these steps with correct dates until all
tillage operations, planting operations, and harvests are completed. As
you select the planting operation change the crop to the new crop being
planted.

**Step 6 -** The next date after planting will be the end of the first
15-day growth period. The date can be entered as a formula. In the blank
date column A, type **=**, then point and click on the cell just above
and type **+15**, then hit the return key. This will enter a formula
that tells the computer, to type the date above and add 15 days. All
growth periods are 15 days except winter wheat or other winter crops,
which have a 60-day growth period over winter (see the **Crop** table
for details). The 15-day date formula can be copied down for the number
of growth periods for the crop planted. Next, in the **Crop** column
click and select the growing crop name with a number **(15 to 75 days
after planting)** next to it. Continue to select down the column a
series of growth periods.

**Example of a 2^nd^ way** to enter crop during growth: **Bean 15**,
**Bean 30**, **Bean 45**, **Bean 60**, and **Bean 75** can be copied and
moved at the same time to the **Crop Name** column of the **Res Wks**.
This must be done using the **paste special** function. Select the Crop
Tab and find the correct series of grow names, highlight them and copy
them. Change back to the **Res Wks** sheet, place the cursor in the
first cell under **Crop** (column B) where crop growth begins, right
click and click on **paste special**, then select the radio button for
**value** under the paste section, and click OK.

In the **Operation** column enter (click and select) **"Grow"** for all
the growth periods. **"Grow"** can be pasted in the first cell for
"Grow" and then copied down the sheet (**Res Wks**) as needed**.** All
growth series of data can be copy from the tables in groups and **paste
special** used to paste only the **values** to the **Res Wks**. If you
copy and paste normal you will lose the formatting in the cells.

**Step 7** - Enter the **Harvest date**, the harvested **crop name**
(without a number extension), and the word "**Harvest**" for above
ground crops or "**Harvest, root crop**" for root crops, in the
**operation column**.

**Step 8** - Enter the **date** of any post harvest tillage**, crop
name**, of the crop just harvested, and the name of the **operation.**
Repeat step 5, 6, 7, and 8 for any additional crops in the rotation. 100
management periods can be used in each calculation. If more are needed
try removing lines where there is no erosion. An example would be to
reduce the number of operations of **"Grow"** to just what is needed to
take erosion to zero for the rest of crop growth period.

**Step 9 -** End the run with a **12/31/xxxx date,** last harvested
**crop name**, and the **End Rotation** operation.

**Step 10 -** Enter any **irrigations** for the periods listed. Enter
the **number** of irrigations in each period (This is NOT the cumulative
number of irrigations or "Irrigation Days").

**Step 11** -- In the **Flat Res.** column on each line of the run enter
**0** when residue is 100% standing (no flat residue), and 100 when all
the residue is flat (as in heavy inversion tillage). Example, if 60% of
the residue is standing after a tillage, then enter 40 or 0.4 and hit
the return key. The number will be in percent.

**Step 12** - Finally, adjust any **yield values** that are different
than the default yields in column G-H. You can change the yield by 50%
up or down by using the drop down in the **Yield Adjustment** column
(F).

## Example

-   Iam Windy farms, tract 123 on an irrigated circle (field 1) of
    continuous grain corn, where the soil has an I of 56. The circle
    field has a diameter of 2640 ft, and is near Clovis, NM. The C
    is 100. The grower tills and/or plants approximately perpendicular
    to the damaging winds from the west during the spring critical
    period. The field is farmed north and south. Iam plants corn on 4/15
    and harvests 10/15. The stalks are disked with an offset disk and
    packer on 11/1. In the spring the field is disked and packed again
    on 3/15. On 4/1 the circle is moldboard plowed, conventionally, and
    packed. Then, on 4/10 a seedbed maker is used to set up the field
    for the corn planter. The corn is cultivated on 5/15. His average
    yield has been 200 bushels/acre.

**Step 1** - Fill in: **Iam Windy**, **MAS**, **Clovis, NM**, tract
**123**, field **1**, and **Corn, grain** on the WEQ Input Worksheet.

**Step 2 -** Select the climate data station of **Clovis, NM** from the
pull down list.

**Step 3 -** Put **100** in the C box, **2640** feet in the width box,
**NS** for tillage direction, length width ratio is **1.0**, field
direction is **EW**, Irrigation is **Y** (yes), and the soil I factor is
**56**.

**Step 4 -** WEG is **5**.

**Step 5 -** Enter **1/1/1999** in the first line (cell A13) of the
table, and select (cell B13) **Corn, grain, high yield** from the
**Crop** table drop-down list. Enter **1/2/1999**, copy **Corn, grain,
high yield** from the above cell to row 14 in the crop column, select
**Over winter loss N** in the **operation** column. Enter the first
tillage on **3/15/1999**, copy **Corn, grain, high yield** from the cell
above, select **Disk, offset, heavy N** from the **Oper** drop down
list. Do the same for the **Packer, roller** on the same date**.** Enter
**4/1/1999** and put in the **Plow, moldboard, conventional** and
**Packer, roller.** Enter **4/10/1999** and copy **Corn, grain, high
yield**. There is no seedbed maker operation, but a
**Chisel-disk-harrow-packer (comb) N** is close, so use it. Enter
**4/15/1999**, **Corn, grain, high yield** and **Planter, DD opener, 30
in sp N**.

**Step 6 -** Copy the 4/15 date and add 15 days to the formula. Copy or
select **Corn, grain 15** through **Corn, grain 75** from the **Crop**
table to the crop column. Type or select **Grow** in the **Operation**
column and copy down to match the **Crop** column. Copy down the
**Operation Date** column to match the growth cells. Note that there is
a cultivation on the second growth date. Copy the six columns of data
from 5/15 down one line to add the cultivation. On the second 5/15 date
in the **Operation** column copy and paste or select the **Cultivator,
rowcrop, 3** **in ridge** operation.

**Step 7 -** Enter the harvest date **10/15/1999**, copy down the crop
**Corn, grain, high yield** and type or select the word **Harvest**.

**Step 8 -** Add the post harvest tillage on **11/1/1999**. Copy both
tillage operations from the cells above.

**Step 9 -** End the run by entering **12/31/1999**, copy **Corn, grain,
high yield** and copy or select the **End Rotation** operation.

**Step 10 -** Estimate the number of irrigations needed for each growth
period or use Iam's records for each period. **The number of Irrigations
for the WEQ management period procedure is the number of times that
irrigation water will wet the soil surface, and not "irrigation days"**
as used in many of the irrigation water calculations.

**Step 11 -** Go down the **Flat Res** column and estimate the **percent
flat residue**. Start on the Harvest Operation. Estimate about 50% of
the residue is flat after harvest and 100% is flat after the fall
tillage. Enter **50** in the flat Res column after harvest, and **100**
in the management period for fall packing. Note only the 1^st^ period
after harvest has standing residue.

#### Step 12 -- Select .5 on the drop down in column F, Yield Adjustment. This increases the 135 bu/ac to 200 bu/ac.

See the attached example: (Res Wks sheet and Calc sheet).

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