Skip to main content
U.S. flag

An official website of the United States government

Data From: Gamma-Spectroscopy Method for Soil Water Content Estimation in an Agricultural Field

Published by Agricultural Research Service | Department of Agriculture | Catalog Last Checked: May 05, 2026 at 11:41 PM | Dataset Last Updated: November 22, 2025
Gamma-ray spectroscopy (GRS) enables continuous estimation of soil water content (SWC) at the subfield scale with a noninvasive sensor. Hydrological applications, including hyper-resolution land surface models and precision agricultural decision making, could benefit greatly from such SWC information, but a gap exists between established theory and accurate estimation of SWC from GRS in the field. In response, we conducted a robust three-year field validation study at a well instrumented agricultural site in Nebraska, United States. The study involved 27 gravimetric water content sampling campaigns in maize and soybean and 40K specific activity (Bq kg−1) measurements from a stationary GRS sensor. Our analysis showed that the current method for biomass water content correction is appropriate for our maize and soybean field but that the ratio of soil mass attenuation to water mass attenuation used in the theoretical equation must be adjusted to satisfactorily describe the field data. We propose a calibration equation with two free parameters: the theoretical 40K intensity in dry soil and a, which creates an “effective” mass attenuation ratio. Based on statistical analyses of our data set, we recommend calibrating the GRS sensor for SWC estimation using 10 profiles within the footprint and 5 calibration sampling campaigns to achieve a cross-validation root mean square error below 0.035 g g−1.

Resources

42 resources available

  • ArithmeticAvg.csv

    CSV
    Download

  • CalibrationDataK40.csv

    CSV
    Download

  • CalibrationDataVeg.csv

    CSV
    Download

  • CombinedTimeSeries.csv

    CSV
    Download

  • SOCandLatticeValues.csv

    CSV
    Download

  • V_Wt_AvgPore.csv

    CSV
    Download

  • 2021_08_05_Example_Soil_Vegetation_Calibration_revised_Datasheets.xls

    XLS
    Download

  • 2021_08_19_Example_Soil_Vegetation_Calibration_Datasheets.xls

    XLS
    Download

  • 2021_09_03_Example_Soil_Vegetation_Calibration_Datasheets.xls

    XLS
    Download

  • 2021_09_17_Example_Soil_Vegetation_Calibration_Datasheets.xls

    XLS
    Download

  • 2021_10_15_Example_Soil_Vegetation_Calibration_Datasheets.xls

    XLS
    Download

  • 2021_10_29_Example_Soil_Vegetation_Calibration_Datasheets.xls

    XLS
    Download

  • 2021_11__12_Example_Soil_Vegetation_Calibration_Datasheets.xls

    XLS
    Download

  • 2021_12__03_Example_Soil_Vegetation_Calibration_Datasheets.xls

    XLS
    Download

  • 2022_04_15_Example_Soil_Vegetation_Calibration_Datasheets.xls

    XLS
    Download

  • 2022_03_25_Example_Soil_Vegetation_Calibration_Datasheets.xls

    XLS
    Download

  • 2022_05_18_Example_Soil_Vegetation_Calibration_Datasheets.xls

    XLS
    Download

  • 2022_05_27_Example_Soil_Vegetation_Calibration_Datasheets.xls

    XLS
    Download

  • 2022_08_03_Example_Soil_Vegetation_Calibration_Datasheets.xls

    XLS
    Download

  • 2022_08_17_Example_Soil_Vegetation_Calibration_Datasheets.xls

    XLS
    Download

  • 2022_08_31_Example_Soil_Vegetation_Calibration_corrected_Datasheets.xls

    XLS
    Download

  • 2022_09_17_Example_Soil_Vegetation_Calibration_Datasheets.xls

    XLS
    Download

  • 2022_10_05_Example_Soil_Vegetation_Calibration_Datasheets.xls

    XLS
    Download

  • 2022_10_22_Example_Soil_Vegetation_Calibration_Datasheets.xls

    XLS
    Download

  • 2023_05_15_Site3_Soil_Calibration_Datasheets.xlsx

    XLSX
    Download

  • 2023_06_08_Site3_Soil_Calibration_Datasheets.xlsx

    XLSX
    Download

  • 2023_06_21_Site3_Soil_Calibration_Datasheets.xlsx

    XLSX
    Download

  • 2023_07_10_Site3_Soil_Calibration_Datasheets.xlsx

    XLSX
    Download

  • 2023_07_24_Site3_Soil_Calibration_Datasheets.xlsx

    XLSX
    Download

  • 2023_08_09_Site3_Soil_Calibration_Datasheets.xlsx

    XLSX
    Download

  • 2023_08_28_Site3_Soil_Calibration_Datasheets.xlsx

    XLSX
    Download

  • 2023_09_21_Site3_Soil_Calibration_Datasheets.xlsx

    XLSX
    Download

  • 2023_10_23_Site3_Soil_Calibration_Datasheets.xlsx

    XLSX
    Download

  • Site3BulkDensitySummary2023.xlsx

    XLSX
    Download

  • CalcArithmeticAverage.R

    R
    Download

  • CalcVerticalWeightedAverage.R

    R
    Download

  • DepthWeightsFunction_SensAnalysis.R

    R
    Download

  • EffectOfNumberSamplesInFootprint.R

    R
    Download

  • gSMS_Results.html

    HTML
    Download

  • gSMS_Results.txt

    TXT
    Download

  • NumCalNeeded.R

    R
    Download

  • README.md

    MD
    Download

Find Related Datasets

Search by Tags

Click any tag below to search for similar datasets

Complete Metadata
@type dcat:Dataset
accessLevel public
bureauCode 
                                            [
  "005:18"
]
contactPoint 
                                            {
  "fn": "Becker, Sophia, M.",
  "hasEmail": "mailto:sophbecker16@gmail.com"
}
description <p dir="ltr">Gamma-ray spectroscopy (GRS) enables continuous estimation of soil water content (SWC) at the subfield scale with a noninvasive sensor. Hydrological applications, including hyper-resolution land surface models and precision agricultural decision making, could benefit greatly from such SWC information, but a gap exists between established theory and accurate estimation of SWC from GRS in the field. In response, we conducted a robust three-year field validation study at a well instrumented agricultural site in Nebraska, United States. The study involved 27 gravimetric water content sampling campaigns in maize and soybean and <sup>40</sup>K specific activity (Bq kg<sup>−1</sup>) measurements from a stationary GRS sensor. Our analysis showed that the current method for biomass water content correction is appropriate for our maize and soybean field but that the ratio of soil mass attenuation to water mass attenuation used in the theoretical equation must be adjusted to satisfactorily describe the field data. We propose a calibration equation with two free parameters: the theoretical <sup>40</sup>K intensity in dry soil and a, which creates an “effective” mass attenuation ratio. Based on statistical analyses of our data set, we recommend calibrating the GRS sensor for SWC estimation using 10 profiles within the footprint and 5 calibration sampling campaigns to achieve a cross-validation root mean square error below 0.035 g g<sup>−1</sup>.</p>
distribution 
                                            [
  {
    "@type": "dcat:Distribution",
    "title": "ArithmeticAvg.csv",
    "format": "csv",
    "mediaType": "application/csv",
    "downloadURL": "https://ndownloader.figshare.com/files/46381309"
  },
  {
    "@type": "dcat:Distribution",
    "title": "CalibrationDataK40.csv",
    "format": "csv",
    "mediaType": "text/plain",
    "downloadURL": "https://ndownloader.figshare.com/files/46381312"
  },
  {
    "@type": "dcat:Distribution",
    "title": "CalibrationDataVeg.csv",
    "format": "csv",
    "mediaType": "application/csv",
    "downloadURL": "https://ndownloader.figshare.com/files/46381315"
  },
  {
    "@type": "dcat:Distribution",
    "title": "CombinedTimeSeries.csv",
    "format": "csv",
    "mediaType": "text/plain",
    "downloadURL": "https://ndownloader.figshare.com/files/46381318"
  },
  {
    "@type": "dcat:Distribution",
    "title": "SOCandLatticeValues.csv",
    "format": "csv",
    "mediaType": "application/csv",
    "downloadURL": "https://ndownloader.figshare.com/files/46381321"
  },
  {
    "@type": "dcat:Distribution",
    "title": "V_Wt_AvgPore.csv",
    "format": "csv",
    "mediaType": "text/plain",
    "downloadURL": "https://ndownloader.figshare.com/files/46381324"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2021_08_05_Example_Soil_Vegetation_Calibration_revised_Datasheets.xls",
    "format": "xls",
    "mediaType": "application/vnd.ms-excel",
    "downloadURL": "https://ndownloader.figshare.com/files/46381327"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2021_08_19_Example_Soil_Vegetation_Calibration_Datasheets.xls",
    "format": "xls",
    "mediaType": "application/vnd.ms-excel",
    "downloadURL": "https://ndownloader.figshare.com/files/46381330"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2021_09_03_Example_Soil_Vegetation_Calibration_Datasheets.xls",
    "format": "xls",
    "mediaType": "application/vnd.ms-excel",
    "downloadURL": "https://ndownloader.figshare.com/files/46381333"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2021_09_17_Example_Soil_Vegetation_Calibration_Datasheets.xls",
    "format": "xls",
    "mediaType": "application/vnd.ms-excel",
    "downloadURL": "https://ndownloader.figshare.com/files/46381336"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2021_10_15_Example_Soil_Vegetation_Calibration_Datasheets.xls",
    "format": "xls",
    "mediaType": "application/vnd.ms-excel",
    "downloadURL": "https://ndownloader.figshare.com/files/46381339"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2021_10_29_Example_Soil_Vegetation_Calibration_Datasheets.xls",
    "format": "xls",
    "mediaType": "application/vnd.ms-excel",
    "downloadURL": "https://ndownloader.figshare.com/files/46381342"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2021_11__12_Example_Soil_Vegetation_Calibration_Datasheets.xls",
    "format": "xls",
    "mediaType": "application/vnd.ms-excel",
    "downloadURL": "https://ndownloader.figshare.com/files/46381345"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2021_12__03_Example_Soil_Vegetation_Calibration_Datasheets.xls",
    "format": "xls",
    "mediaType": "application/vnd.ms-excel",
    "downloadURL": "https://ndownloader.figshare.com/files/46381348"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2022_04_15_Example_Soil_Vegetation_Calibration_Datasheets.xls",
    "format": "xls",
    "mediaType": "application/vnd.ms-excel",
    "downloadURL": "https://ndownloader.figshare.com/files/46381351"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2022_03_25_Example_Soil_Vegetation_Calibration_Datasheets.xls",
    "format": "xls",
    "mediaType": "application/vnd.ms-excel",
    "downloadURL": "https://ndownloader.figshare.com/files/46381354"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2022_05_18_Example_Soil_Vegetation_Calibration_Datasheets.xls",
    "format": "xls",
    "mediaType": "application/vnd.ms-excel",
    "downloadURL": "https://ndownloader.figshare.com/files/46381357"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2022_05_27_Example_Soil_Vegetation_Calibration_Datasheets.xls",
    "format": "xls",
    "mediaType": "application/vnd.ms-excel",
    "downloadURL": "https://ndownloader.figshare.com/files/46381360"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2022_08_03_Example_Soil_Vegetation_Calibration_Datasheets.xls",
    "format": "xls",
    "mediaType": "application/vnd.ms-excel",
    "downloadURL": "https://ndownloader.figshare.com/files/46381363"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2022_08_17_Example_Soil_Vegetation_Calibration_Datasheets.xls",
    "format": "xls",
    "mediaType": "application/vnd.ms-excel",
    "downloadURL": "https://ndownloader.figshare.com/files/46381366"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2022_08_31_Example_Soil_Vegetation_Calibration_corrected_Datasheets.xls",
    "format": "xls",
    "mediaType": "application/vnd.ms-excel",
    "downloadURL": "https://ndownloader.figshare.com/files/46381369"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2022_09_17_Example_Soil_Vegetation_Calibration_Datasheets.xls",
    "format": "xls",
    "mediaType": "application/vnd.ms-excel",
    "downloadURL": "https://ndownloader.figshare.com/files/46381372"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2022_10_05_Example_Soil_Vegetation_Calibration_Datasheets.xls",
    "format": "xls",
    "mediaType": "application/vnd.ms-excel",
    "downloadURL": "https://ndownloader.figshare.com/files/46381375"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2022_10_22_Example_Soil_Vegetation_Calibration_Datasheets.xls",
    "format": "xls",
    "mediaType": "application/vnd.ms-excel",
    "downloadURL": "https://ndownloader.figshare.com/files/46381378"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2023_05_15_Site3_Soil_Calibration_Datasheets.xlsx",
    "format": "xlsx",
    "mediaType": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
    "downloadURL": "https://ndownloader.figshare.com/files/46381381"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2023_06_08_Site3_Soil_Calibration_Datasheets.xlsx",
    "format": "xlsx",
    "mediaType": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
    "downloadURL": "https://ndownloader.figshare.com/files/46381384"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2023_06_21_Site3_Soil_Calibration_Datasheets.xlsx",
    "format": "xlsx",
    "mediaType": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
    "downloadURL": "https://ndownloader.figshare.com/files/46381387"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2023_07_10_Site3_Soil_Calibration_Datasheets.xlsx",
    "format": "xlsx",
    "mediaType": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
    "downloadURL": "https://ndownloader.figshare.com/files/46381390"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2023_07_24_Site3_Soil_Calibration_Datasheets.xlsx",
    "format": "xlsx",
    "mediaType": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
    "downloadURL": "https://ndownloader.figshare.com/files/46381393"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2023_08_09_Site3_Soil_Calibration_Datasheets.xlsx",
    "format": "xlsx",
    "mediaType": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
    "downloadURL": "https://ndownloader.figshare.com/files/46381396"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2023_08_28_Site3_Soil_Calibration_Datasheets.xlsx",
    "format": "xlsx",
    "mediaType": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
    "downloadURL": "https://ndownloader.figshare.com/files/46381399"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2023_09_21_Site3_Soil_Calibration_Datasheets.xlsx",
    "format": "xlsx",
    "mediaType": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
    "downloadURL": "https://ndownloader.figshare.com/files/46381402"
  },
  {
    "@type": "dcat:Distribution",
    "title": "2023_10_23_Site3_Soil_Calibration_Datasheets.xlsx",
    "format": "xlsx",
    "mediaType": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
    "downloadURL": "https://ndownloader.figshare.com/files/46381405"
  },
  {
    "@type": "dcat:Distribution",
    "title": "Site3BulkDensitySummary2023.xlsx",
    "format": "xlsx",
    "mediaType": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
    "downloadURL": "https://ndownloader.figshare.com/files/46381408"
  },
  {
    "@type": "dcat:Distribution",
    "title": "CalcArithmeticAverage.R",
    "format": "R",
    "mediaType": "text/plain",
    "downloadURL": "https://ndownloader.figshare.com/files/46381585"
  },
  {
    "@type": "dcat:Distribution",
    "title": "CalcVerticalWeightedAverage.R",
    "format": "R",
    "mediaType": "text/plain",
    "downloadURL": "https://ndownloader.figshare.com/files/46381588"
  },
  {
    "@type": "dcat:Distribution",
    "title": "DepthWeightsFunction_SensAnalysis.R",
    "format": "R",
    "mediaType": "text/plain",
    "downloadURL": "https://ndownloader.figshare.com/files/46381591"
  },
  {
    "@type": "dcat:Distribution",
    "title": "EffectOfNumberSamplesInFootprint.R",
    "format": "R",
    "mediaType": "text/plain",
    "downloadURL": "https://ndownloader.figshare.com/files/46381594"
  },
  {
    "@type": "dcat:Distribution",
    "title": "gSMS_Results.html",
    "format": "html",
    "mediaType": "text/html",
    "downloadURL": "https://ndownloader.figshare.com/files/46381597"
  },
  {
    "@type": "dcat:Distribution",
    "title": "gSMS_Results.txt",
    "format": "txt",
    "mediaType": "text/plain",
    "downloadURL": "https://ndownloader.figshare.com/files/46381600"
  },
  {
    "@type": "dcat:Distribution",
    "title": "NumCalNeeded.R",
    "format": "R",
    "mediaType": "text/plain",
    "downloadURL": "https://ndownloader.figshare.com/files/46381603"
  },
  {
    "@type": "dcat:Distribution",
    "title": "README.md",
    "format": "md",
    "mediaType": "text/plain",
    "downloadURL": "https://ndownloader.figshare.com/files/46381606"
  }
]
identifier 10.15482/USDA.ADC/25723959.v1
keyword 
                                            [
  "gamma-ray spectroscopy",
  "soil water content"
]
license https://creativecommons.org/licenses/by/4.0/
modified 2025-11-22
programCode 
                                            [
  "005:040"
]
publisher 
                                            {
  "name": "Agricultural Research Service",
  "@type": "org:Organization"
}
spatial 
                                            "{"type": "Point", "coordinates": [-96.4397, 41.1797]}"
temporal 2021-07-19/2023-10-23
title Data From: Gamma-Spectroscopy Method for Soil Water Content Estimation in an Agricultural Field

data.gov

An official website of the GSA's Technology Transformation Services

Looking for U.S. government information and services?
Visit USA.gov