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2/25/2016
1
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!
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