Predictive soil property map: Electrical conductivity (salinity)
type: Dataset
description: These data were compiled to demonstrate new predictive mapping approaches and provide comprehensive gridded 30-meter resolution soil property maps for the Colorado River Basin above Hoover Dam. Random forest models related environmental raster layers representing soil forming factors with field samples to render predictive maps that interpolate between sample locations. Maps represented soil pH, texture fractions (sand, silt clay, fine sand, very fine sand), rock, electrical conductivity (ec), gypsum, CaCO3, sodium adsorption ratio (sar), available water capacity (awc), bulk density (dbovendry), erodibility (kwfact), and organic matter (om) at 7 depths (0, 5, 15, 30, 60, 100, and 200 cm) as well as depth to restrictive layer (resdept) and surface rock size and cover. Accuracy and error estimated using a 10-fold cross validation indicated a range of model performances with coefficient of variation (R2) for models ranging from 0.20 to 0.76 with mean of 0.52 and a standard deviation of 0.12. Models of pH, om and ec had the best accuracy (R2 > 0.6). Most texture fractions, CaCO3, and SAR models had R2 values from 0.5-0.6. Models of kwfact, dbovendry, resdept, rock models, gypsum and awc had R2 values from 0.4-0.5 excepting near surface models which tended to perform better. Very fine sands and 200 cm estimates for other models generally performed poorly (R2 from 0.2-0.4), and sample size for the 200 cm models was too low for reliable model building. More than 90% of the soils data used was sampled since 2000, but some older samples are included. Uncertainty estimates were also developed by creating relative prediction intervals, which allow end users to evaluate uncertainty easily.
issued: 2025-11-22T09:42:27.657757
modified: 20200827
spatial: Location
contact point: Organization
  fn: Travis W Nauman
keyword: accuracy-and-error-estimated
keyword: amerigeo
keyword: amerigeoss
keyword: arizona
keyword: available-water-capacity
keyword: bulk-density
keyword: calcium-carbonate
keyword: ckan
keyword: colorado
keyword: colorado-river
keyword: colorado-river-basin
keyword: colorado-river-basin-above-hoover-dam
keyword: digital-soil-mapping
keyword: electrical-conductivity
keyword: environmental-conditions
keyword: environmental-raster-layers
keyword: erodibility
keyword: geo
keyword: geoscientificinformation
keyword: geoss
keyword: gypsum
keyword: hoover-dam
keyword: interpolate
keyword: machine-learning
keyword: maps-and-atlases
keyword: national
keyword: nevada
keyword: new-mexico
keyword: north-america
keyword: organic-matter
keyword: predicitve-modeling
keyword: predictive-mapping
keyword: predictive-maps
keyword: random-forest-models
keyword: random-forests
keyword: restrictive-layer
keyword: rock
keyword: sodium-adsorption-ratio
keyword: soil-conductivity
keyword: soil-density
keyword: soil-forming-factors
keyword: soil-ph
keyword: soil-properties
keyword: soil-property-maps
keyword: soil-sciences
keyword: soil-texture
keyword: soils
keyword: surface-rock-cover
keyword: surface-rock-size
keyword: texture-fractions
keyword: uncertainty
keyword: united-states
keyword: usgs-5e90b25782ce172707ed6af7
keyword: utah
keyword: wyoming
theme: {geospatial}

Original Metadata
type: Distribution
description: The metadata original format
format: XML
issued: 2022-07-28T20:54:48.312378
modified: 2025-11-22T09:42:27.630952
access URL: https://data.usgs.gov/datacatalog/metadata/USGS.5e90b25782ce172707ed6af7.xml
media type: text/xml

Digital Data
type: Distribution
description: Landing page for access to the data
format: XML
issued: 2022-07-28T20:54:48.312388
modified: 2025-11-22T09:42:27.631394
access URL: https://doi.org/10.5066/P9SK0DO2
media type: application/http

US Migrating
type: Agent