nrcs soils data national soil information system nasis
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NRCS Soils Data
National Soil Information System
NASIS
NRCS Soil Data
Origins pre-date computers and modelsdata collection spans decades.
Not designed or maintained with modeling in mind.
Not perfect; need to have a procedure to handle errors and omissions.
Must be adapted to meet model needs
NRCS Soil Databases
Characterization Data
70+ years Support classification and
Soil Taxonomy Support interpretations Point data, measured Horizons
NASIS
~20 years, early computer tech
Interpret char. data Provides interp. data for
broad landuse decisions Mapunit based, not pt. Layers
NRCS Soil Databases
Both NASIS and Soil Taxonomy are landuse independent.
Characterization data may provide clues.
Use Soil Taxonomy to fill or fix bad records.
NRCS Soil Databases
NASIS reports a Representative Value (RV) and a range, hi and lo.
Use the value that best reflects the landuse being modeled.
The RV works better for empirical models like RUSLE than a process model like EPIC or APEX
Layer 1
Layer 2
Layer 3
Ap
AB
Bt1
Bt2
2Bt3
2Bt4
Comparison of Soil Carbon Data SourcesKenyon Soil
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
0 50 100 150 200 250
Depth (cm)
% O
rgan
ic C
arb
on
NSSL
APEX
STATSGO
Total Carbon Stores (Mg/ha)
0
50
100
150
200
250
300
350
400
To
tal
Carb
on
(M
g/h
a)
NSSL
APEX
STATSGO
EFFECT OF NASIS RV CARBON
Kenyon
Apex Output
Unadjusted
C
Adjusted
C
Corn Yield (bu) 180 176
Carbon Trend -400 174
Total N (lbs) 82 28
Total P (lbs) 4.3 2.6
Sediment (tons) 1.66 1.5
Evesboro NASIS RV pH
Layer (depth) NASIS
pH
Adjusted
pH
Layer 1 0.18 m 3.6 5.8
Layer 2 1.02 m 4.3 5.7
Layer 3 1.52 m 4.3 5.0
EFFECT OF NASIS RV pH
Evesboro
Apex Output
Unadjusted
pH
Adjusted
pH
Corn Yield (bu) 15 147
Carbon Trend -41 77
Total N (lbs) 99 40
Total P (lbs) 6.5 3.0
Sediment (tons) 0.5 0.04
Evesboro NASIS RV Bulk Density
Layer (depth) NASIS
BD
Adjusted
BD
Layer 1 0.18 m 1.39 1.39
Layer 2 0.46 m 1.43 1.43
Layer 3 0.69 m 1.80 1.66
EFFECT OF NASIS RV Bulk Density
Weikert
Apex Output
Unadjusted
BD
Adjusted
BD
Corn Yield (bu) 81 86
Carbon Trend 91 147
Total N (lbs) 135 97
Total P (lbs) 9.8 8.9
Sediment (tons) 2.5 2.1
Updates for modeling
Established research grade position for modeling support for Soil Survey.
Rapid C project. Collecting soil carbon data at NRI points.
Error and omission checking. Begin collection of dynamic soil propeprties and
data structure for dissemination.