Using the Soil Conditioning Index Using the Soil Conditioning Index to Assess Management Effects to Assess Management Effects

on Soil Carbonon Soil Carbon

USDA Natural Resources Conservation ServiceUSDA Natural Resources Conservation Service

Soil Quality National Technology Soil Quality National Technology Development TeamDevelopment Team

Lesson Objectives

• Introduce the Soil Conditioning Index – Discuss the tool’s background

– Explain how the model works

• Convey the current and potential uses of SCI

• Highlight the SCI considerations in RUSLE2

Water & Nutrient

Holding

Benefits of Soil Carbon

Time

Soil

Qua

lity Aggregation &

Infiltration Productivity

Air & Water Quality; Wildlife Habitat

Soil Carbon

Historic Loss of Soil Carbon

30003500400045005000550060006500700075008000

1900

1910

1920

1930

1940

1950

1960

1970

1980

1990

Year

Soil

C (g

m-2

)

ConventionalTillage

ReducedTillage

53% of 1907

61% of 1907

(Lal et al., 1998)

The Soil Conditioning Index (SCI):

• Expresses the effects of the system on Expresses the effects of the system on organic matter trends as a primary indicator organic matter trends as a primary indicator of soil conditionof soil condition

• Provides a means to evaluate and design Provides a means to evaluate and design conservation systems that maintain or conservation systems that maintain or improve soil conditionimprove soil condition

SCI Timeline

1950 1960 1970 1980 1990 2000

• Origins trace back to 1950’s ARS research in Renner, Texas

• SQI and NSSC make changes to OM maintenance levels (2000)

• SQI adds soil texture component (2001)

• SQI and NSSC calibrate to US using coefficients for climate & decomposition in RUSLE (2002)

• NSSC Agronomists further develop model and apply it to 1980’s practice criteria

SCI Potential Uses:

• Automatic output from RUSLE2

• Based on actual conservation plan

• Can help landowner with decision-making

• Valid at the field scale

• Based on NRI data• Holds promise for

watershed, MLRA, state & national uses

• Currently, part of CSP and Resource Quality Criteria

Field Office Tool Performance Measure

Soil Conditioning Index (SCI=Soil Disturbance+Plant Production+Erosion)

+ 1- 1

Improving

Degrading Sustaining

SCI

Car

bon

(lbs)

The SCI formula is: (OM x 0.4) + (FO x 0.4) + (ER x 0.2) =SCI(OM x 0.4) + (FO x 0.4) + (ER x 0.2) =SCI

• OM accounts for organic material returned to OM accounts for organic material returned to the soil (as a function of biomass produced)the soil (as a function of biomass produced)

• FO represents field operation effects FO represents field operation effects • ER is the sorting and removal of surface soil ER is the sorting and removal of surface soil

material by sheet, rill and/or wind erosionmaterial by sheet, rill and/or wind erosion

Where:Where:

SCI Model Variables:

Field Operations

Biomass Production

Erosion

Biomass Production

OM subfactor calculation:OM =(RP - MA) / MAOM =(RP - MA) / MA

• RP is average annual above and below RP is average annual above and below ground biomass returned to the soil ground biomass returned to the soil – includes mulch or manureincludes mulch or manure– expressed as REV (corn equivalent) expressed as REV (corn equivalent)

• MA is Maintenance OM Level (REV) for the MA is Maintenance OM Level (REV) for the location location

Where:Where:

43999 *RENNER TX 5719

Maintenance Amt. Including

Roots CITY

CODE CITY STATEReference Condition

27497 LINCOLN NE 545528002 LAS VEGAS NV 199733003 RALEIGH NC 585834001 BISMARK ND 433934002 WILLISTON ND 408434248 FARGO ND 474935001 CLEVELAND OH 5420

Location

SCI Model Variables:

Field Operations

Biomass Production

ErosionField Operations

Soil Tillage Intensity Rating (STIR)SOIL DISTURBING ACTIONS SOIL

FIELD OPERATIONS DISTURBANCEINVERT MIX LIFT SHATTER AERATE COMPACT RATING (SDR)

Primary tillage Plow, moldboard, complete inversion 5 5 5 5 5 4 29 Plow, moldboard, incomplete inversion 4 5 5 5 5 4 28 Plow, deep chisel, twisted point 4 4 5 5 5 2 25 Plow, deep chisel, straight point 3 4 4 4 5 2 22 Plow, chisel, twisted point 3 4 5 5 5 2 24 Plow, chisel, straight point 2 3 4 4 4 2 19 Plow, chisel, sweeps 2 3 5 4 4 3 21 Plow, disk plow 4 5 5 5 5 4 28 Disk, offset 4 5 4 5 5 4 27 Disk, Tandem primary (> 6" depth) 4 5 4 4 5 4 26 Power rotary tiller 5 5 5 5 5 4 29 Ground driven rotary tiller 4 5 5 5 5 4 28 Paratill/paraplow 0 0 5 5 3 2 15 Undercutter (8-12" sweeps) 0 0 5 5 4 3 17 V-blade 0 0 5 5 3 3 16 Vee ripper/subsoiler 3 3 4 5 5 2 22 Bedder-ridger 5 5 5 5 5 3 28Secondary tillage Disk, Tandem finishing (< 6" depth) 2 3 3 3 4 3 18 Field cultivator, straight point 3 3 3 4 3 2 18

Soil Tillage Intensity Rating

(STIR)

Aggrading

Degrading

Steady State

FIELD OPERATIONS (FO) SUBFACTOR

SCI Model Variables:

Field Operations

Biomass Production

Erosion Erosion

TABLE 4 EROSION (ER) SUBFACTOR

EROSION (ER) SUBFACTOR

Aggrading

Degrading

Steady State

NSSC and Long-term OM Research Sites

RESEARCHORGANIC MATTER FIELD OPERATIONS EROSION

SOILLOCATION

Maintenance Amount lbs./acre

Crop Rotation

Average Annual Residue

Equivalent Lbs. /ac.

OM Subfactor

Average Annual Soil Disturbance

Rating

Tillage system

FO Subfactor

Erosion Rate

ER Subfactor

CONDITIONING INDEX

Renner, TX 5526WWheat,C

ot,GS 5526 0 101 chisel, disk 0 0.8xT 0 0

Culbertson, MT 4121S.Wheat,

Fallow 753 -0.82 60 vee blade 0.4 0.2xT 0.75 -0.02

Clarinda, Ia 5482 Cont. Corn 6213 0.13 86 mb plow 0.15 1.2xT -0.4 0.03

SCI Outcomes at NSSC initial calibration sites

Corn/Soybeans Corn/Soybeans/Cover Crop Corn/Winter Wheat

LOCATION SLOPE

%Fall

plowSpring plow

Fall mulch-

till

Spring mulch-till No-till Spring

plowSpring

mulch-till No-till Fall plow Fall mulch-till No-till

GRAND RAPIDS, MI 6 -0.04 0.00 +0.07 +0.11 +0.53 +021 +0.30 +0.70 +0.26 +0.53 +0.78GRAND RAPIDS, MI 10 -0.28 -0.18 -0.10 -0.07 +0.43 +0.03 +0.16 +0.65 +0.10 +0.45 +0.75

MEMPHIS, TN 6 -0.66 -0.53 -0.50 -0.41 +0.11 -0.29 -0.17 +0.43 -0.45 +0.09 +0.54MEMPHIS, TN 10 -0.73 -0.73 -0.68 -0.68 -0.17 -0.59 -0.45 +0.25 -0.61 -0.20 +0.41

HURON, SD 6 -0.14 -0.12 -0.15 +0.03 +0.43 +0.12 +0.20 +0.63 +0.08 +0.34 +0.62HURON, SD 10 -0.38 -0.35 -0.38 -0.20 +0.33 -0.06 -0.06 +0.458 -0.10 +0.24 +0.62

SALINA, KS 6 -0.43 -0.40 -0.38 -0.28 +0.23 -0.25 -0.06 +0.41 -0.29 +0.03 +0.40SALINA, KS 10 -0.71 -0.68 -0.68 -0.58 +0.05 -0.55 -0.30 +0.26 -0.59 -0.21 +0.28

SCI Validation using systems across the U.S.

Winter Wheat / Summer Fallow

Winter Wheat / Grain Sorghum / Summer Fallow Winter Wheat / Grain Sorghum

LOCATION SLOPE

%

Fall plow

Fall mulch-

tillNo-till Fall plow Fall

mulch-till No-till Fall plow Fall mulch-till No-till

RAPID CITY, SD 6 -0.10 +0.13 +0.44 +0.03 +0.08 +0.44 +0.19 +0.27 +0.53RAPID CITY, SD 10 -0.22 +0.01 +0.42 -0.13 -0.05 +0.41 +0.08 +0.17 +0.51

NORTH PLATTE, NE 6 -0.18 +0.02 +0.45 -0.16 -0.05 +0.38 +0.12 +0.24 +0.57NORTH PLATTE, NE 10 -0.45 -0.16 +0.43 -0.39 -0.27 +0.33 -0.08 +0.11 +0.55

WICHITA, KS 6 -0.53 -0.28 +0.33 -0.49 -0.38 +0.22 -0.21 -0.02 +0.46WICHITA, KS 10 -0.77 -0.57 +0.25 -0.77 -0.66 +0.09 -0.49 -0.23 +0.38

CLOVIS, NM 6 -0.05 +0.15 +0.47 +0.05 +0.14 +0.42 +0.27 +0.36 +0.59CLOVIS, NM 10 -0.11 +0.06 +0.47 -0.09 +0.02 +0.42 +0.16 +0.31 +0.59

SCI Validation using systems across the U.S.

Regression of SCI Outcomes and Measured Carbon Change

Running SCI in RUSLE2

RUSLE2 Features Affecting SCI

• User addition of irrigation water• User addition of wind- and irrigation-induced

erosion

• User-adjustable crop yield• User-adjustable residue burial amount• User-adjustable mulch or external residue

application

Add wind erosion from

WEQ and irrigation induced erosion.

SCI Summary

• Easy to use tool to estimate soil condition

• Validated using long term research data

• SCI is being used nationally for conservation assessment in CSP & CEAP

• Now part of RUSLE2 and coming to a field office near you!!

Soil Conditioning IndexSoil Conditioning Indexinin

RUSLE2RUSLE2 http://fargo.nserl.purdue.edu/ http://fargo.nserl.purdue.edu/

rusle2_dataweb/RUSLE2_Index.htmrusle2_dataweb/RUSLE2_Index.htm

The Ultimate Goal

The End