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WIND EROSION EQUATION Recent Changes (NAM) USDA-NRCS. Wind Erosion continues to be a serious problem in the semiarid and arid regions of the US. The Good Old Days. The Good Old Days cont. WEQ Changes made!.

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Wind erosion equation recent changes nam usda nrcs l.jpg

WIND EROSION EQUATIONRecent Changes (NAM)USDA-NRCS


Slide2 l.jpg


The good old days l.jpg
The Good Old Days semiarid and arid regions of the US.


The good old days cont l.jpg
The Good Old Days semiarid and arid regions of the US.cont.


Weq changes made l.jpg
WEQ Changes made! semiarid and arid regions of the US.

  • WEQ has been updated to account for irrigation effects, random roughness and I Factor adjustments.

  • WEQ changes are outlined in the new edition of the National Agronomy Manual.


Introduction weq excel spreadsheet l.jpg
Introduction WEQ Excel Spreadsheet semiarid and arid regions of the US.

  • Cover NAM changes

  • Changes to Ridge Roughness

  • Addition of Random Roughness

  • Quick intro to the Excel spreadsheet

  • Demo how to edit and make changes

  • Answer Questions


Spreadsheet history l.jpg
Spreadsheet History semiarid and arid regions of the US.

  • Began as a spreadsheet by Tom Keep

  • Then Circular 2, NAM amendment Sept. 12, 1997 was incorporated

  • SGe calculations added, 1998

  • Krd-Ridge Roughness formulas added in 1998


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Circular 2 Changes semiarid and arid regions of the US.

  • I Adjustment for Irrigation

    -Above 180 no adjustment

    -180 or less, reduce one I class

  • IF – ‘Irr. Factor’ reduces Erosive Wind Energy (EWE) for mgt period

  • Random Roughness (Krr) combined with Ridge Roughness (Krd)


Adjustments to i l.jpg
ADJUSTMENTS TO “I” semiarid and arid regions of the US.

  • Irrigation adjustment (IF)

    -adjustment applies to all soils


Ewe irrigation adjustment l.jpg
EWE IRRIGATION ADJUSTMENT semiarid and arid regions of the US.

  • Effects of wet soil is accounted for by adjusting the EWE for the mgt period

  • Bare wet soil remains non-erodible wet:

    • 1 day for coarse textured soils

    • 2 days for medium textured soils

    • 3 days for fine textured soils

  • See sheet “WEG tab” for table


Adjustments to i irrigation l.jpg
ADJUSTMENTS TO “I” - IRRIGATION semiarid and arid regions of the US.


Krr random roughness factor l.jpg
“Krr” RANDOM semiarid and arid regions of the US.ROUGHNESS FACTOR

  • Soil cloddiness raises the threshold wind speed at which erosion begins

  • Provides sheltered area among clods where moving soil can be trapped

  • Spreadsheet reduces RR (clodsize) by one half after 15 days.


Krr random roughness factor13 l.jpg
“Krr” RANDOM semiarid and arid regions of the US.ROUGHNESS FACTOR

  • Non-oriented surface roughness

    • Cloddiness

  • Usually created by tillage implements

  • Values represented as standard deviation, in inches, of roughness heights

  • Use Random Roughness-Guidance sheet

  • Roughness assigned to each tillage implement (ideal conditions)


Random roughness krr l.jpg
Random Roughness - Krr semiarid and arid regions of the US.


Ridge roughness krd l.jpg
Ridge Roughness- Krd semiarid and arid regions of the US.

  • Revised NAM has new tables

  • Based on I values and Preponderance

  • Low Preponderance values indicate less of the erosive wind is from the prevailing wind direction.

  • Higher Krd values indicate that ridges are less effective

  • Krd can be lower than 0.5 now


Irrigation input requirements l.jpg
Irrigation Input Requirements semiarid and arid regions of the US.

  • Enter the number of Irrigations, including pre-plant and post harvest irrigation

  • “Non-erodible wet days” will be calculated based on soil texture (WEG)

  • Drip irrigation poses a problem. Need to estimate the % of surface that is non-erodible wet


Circle irrigation l.jpg
Circle Irrigation semiarid and arid regions of the US.

The soil texture determines the number of non-erodible wet days (1,2,or 3) per irrigation

It takes this system 96 hours to make one complete circle. For WEQ this is one irrigation.

Day 3-24 hrs

Day 4-24 hrs

Day 1-24 hrs

Day 2-24 hrs


Field width l.jpg
Field Width semiarid and arid regions of the US.

  • With the WEQ Speadsheet, field width is the distance across the short side of the field or average short side of a polygon.


Field width vs unsheltered distance l.jpg
Field Width vs semiarid and arid regions of the US.Unsheltered Distance

Field

Width


Field width vs unsheltered distance20 l.jpg
Field Width vs semiarid and arid regions of the US.Unsheltered Distance

  • The Excel Spreadsheet model will determine L using the length/width ratio of the field, the angle of deviation, wind preponderance and the resulting wind erosion direction factor.


Computer requirements l.jpg
Computer Requirements semiarid and arid regions of the US.

  • Need 486 minimum.

  • 586 is better

  • Windows 95, 98, or NT

  • Excel version 7.0

  • 16 mg of RAM or better

  • File name WEQvs8.01.xls


Instr sheet l.jpg
INSTR semiarid and arid regions of the US. sheet

  • Wind Erosion Model Worksheet Legend

    -Definitions

  • Describes input data and column headings

  • New-Krd, Krr, IF, No. of Irr, and TWF

Read this sheet first.


Res wks sheet required inputs l.jpg
Res semiarid and arid regions of the US.WKS sheetRequired Inputs

  • Operation Dates

  • Crop Names

  • Operations

  • Percent Flat Residue

  • Number of irrigation per mgt period

  • Yield adjustment

  • Prod., Farm, Tract, Field, C, I, Field Width, LW ratio, Tillage Dir, Field Dir, Irr (y/n)


Calc sheet l.jpg
Calc sheet semiarid and arid regions of the US.

  • Detailed calculations by Mgt Period

  • Note Krd, Krr, and IF factors added here

  • No inputs needed or allowed


Data tables l.jpg
Data Tables semiarid and arid regions of the US.

  • Crop table

    -Need to maintain crop data;

    residue produced and green growth

  • Tillage table

    -Residue reduction

    -Random roughness assigned to tillage


Data tables cont l.jpg
Data Tables cont. semiarid and arid regions of the US.

  • Climate data, the wind direction, EWE, and Preponderance must be added for climate stations in your state.


Summary l.jpg
Summary semiarid and arid regions of the US.

  • If Users have a basic understanding of the EXCEL spreadsheet, they can use this model.

  • State Agronomist should become familiar with the wind data (climate file), crop data, and operation (tillage) files before beginning use in a new state.


Limitations l.jpg
Limitations semiarid and arid regions of the US.

  • We can not change tillage direction in each mgt period.

  • Need to create templates and save for later use.

  • It does not allow for crusting (no I factor adjustment for a period of crusting).


Limitations29 l.jpg
Limitations semiarid and arid regions of the US.

  • Growth curve data is limited

  • Do not have SGe curves for all crops both green and dry


Where to get more information l.jpg
Where to get more information semiarid and arid regions of the US.

  • Call State Agronomists for assistance:

  • State Agronomists can call:

    Mike Sporcic, [email protected] , 505-761-442

    or,


Where to get more information31 l.jpg
Where to get more information semiarid and arid regions of the US.

  • Gary Tibke– (785)537-5541

    [email protected]

  • Lorenz Sutherland--(719)384-5408 [email protected]

  • Websites for WEQ www.nm.nrcs.usda.gov/techserv or www.weru.ksu.edu/nrcs

We’re Done


Questions short demo end l.jpg
Questions & Short Demo semiarid and arid regions of the US.END


The end l.jpg
The End semiarid and arid regions of the US.


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