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Soil Development and

Status

Neil Dominy

State Soil Scientist

Lincoln, Nebraska

www.ne.nrcs.usda.gov

Neil.dominy@neusda.gov

USDA is an equal opportunity provider and employer.

Objectives

Setting the stage for the day

ClORPT

Soil Survey changes

Importance and complexity of Soils!

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INTRO Pictures

What is soil?

The unconsolidated mineral or organic material on the immediate surface of the earth that serves as a natural medium for the growth of land plants.

NRCS

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Hans Jenny

1941: soil is open system, properties are functionally

related; system changes when property(ies) change(s).

Jenny’s CLORPT equation

s = ƒ (cl, o, r, p, t)

Soil Forming Factors

Soil = CLORPT

Climate

Organisms/Biota

Relief (Topography)

Parent Material;

Time (Stability)

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Climate

Climate: Precipitation

http://www.nefb.org/ag-ed/

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Climate: Frost Free Days

Climate Resiliency 2012 and 2015

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Living Organisms

Organisms Vegetation

Prairie

Trees

Critters that mix the soil

Prairie dogs, gophers

Worms and all the bugs

More organisms in a spoonful of soil than

humans living today

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Living Soil

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Landscape position

Landscape Position

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Landscape Catena

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loess

till

eolian sand Soil Parent Materials in Nebraska

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TIME

Time

Effects of climate and living organisms, modified by

topography, on the development of soil from parent

material takes time.

Stability of a site is required to provide soil development

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Human Influence

Four general Processes of soil formation

Transformation – weathering synthesis of minerals and

decomposition of Organic matter

Translocation – movement of mineral and organic

materials in the developing soil

Addition – of organic matter or by deposition

Loss – leaching of soluble constituents or by erosion

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General soil map

NRI Erosion Data

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NRI Erosion data

Soil Mapping 1965 to 2004 what has

changed?

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Eroded soils correlation 1965 and 2004

ShC2 Sharpsburg silty clay loam, 4 to 6 percent slopes, eroded 7647

Yutan, eroded-Aksarben silty clay loams, 2 to 6 percent

slopes

ShD2 Sharpsburg silty clay loam, 6 to 12 percent slopes, eroded 7646

Yutan, eroded-Judson complex, 6 to 11 percent

slopes

ShD3 Sharpsburg silty clay loam, 6 to 12 percent slopes, severely eroded 7646

Yutan, eroded-Judson complex, 6 to 11 percent

slopes

MnC Monona silt loam, 6 to 12 percent slopes 8125 Pohocco silty clay loam, 6 to 11 percent slopes, eroded

MnC2 Monona silt loam, 6 to 12 percent slopes, eroded 8125 Pohocco silty clay loam, 6 to 11 percent slopes, eroded

MhE2 Monona silt loam, sand substratum, 12 to 30 percent slopes, eroded 8146 Pohocco-Pahuk complex, 11 to 17 percent slopes, eroded

MhC2 Monona silt loam, sand substratum, 6 to 12 percent slopes, eroded 8145 Pohocco-Pahuk complex, 6 to 11 percent slopes, eroded

Current Soil Survey data

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Why are surface soils

important

Infiltration

Water holding capacity

Soil Life

Many more!

http://soilquality.org.au/factsheets/w

ater-availability

Silt loam soilAvailable Water holding Capacity (AWC)

(cm H2O/ 25 cm soil)

(in. H2O/ ft. soil)

SOM = 0% 1% 2% 3%

2.3 cm

1.10 in.

3.2 cm

1.54 in.

4.2 cm

2.02 in.

5.1 cm

2.45 in.

Source: Berman Hudson, 1994. JSWC 49:189-194.

soil

matrix

water

Soil organic matter “sponge” water+

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Conclusion/Questions

ClORPT

Understanding the Importance of Soil

“Our Soil – A layer of life” MASWCD

More to do!