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

posted on 2024-05-23, 21:19 authored by Sophia BeckerSophia Becker, Trenton E. Franz, Tanessa Morris, Bailey Mullins

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.


ODF: National Agricultural Producers Data Cooperative: A Strategic Framework for Innovation

National Institute of Food and Agriculture

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Data contact name

Becker, Sophia, M.

Data contact email


Ag Data Commons

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Temporal Extent End Date



  • Non-geospatial

Geographic Coverage


Geographic location - description

Data is from an agricultural field within the Eastern Nebraska Research and Extension Center near Mead, Nebraska, United States. The US-Ne3 site is within the United States Department of Agriculture Long-term Agroecosystem Research (LTAR) Network as well as the Ameriflux network. US-Ne3 is a no-till, rainfed site with a maize–soybean rotation. Lat, Long: 41.1797, -96.4397

ISO Topic Category

  • environment

Ag Data Commons Group

  • Long-Term Agroecosystem Research
  • Platte River - High Plains Aquifer

National Agricultural Library Thesaurus terms

gamma radiation; spectroscopy; soil water; models; decision making; Nebraska; gravimetric water content; corn; soybeans; biomass; water content; equations; statistical analysis; data collection; agricultural land

OMB Bureau Code

  • 005:18 - Agricultural Research Service

OMB Program Code

  • 005:040 - National Research

ARS National Program Number

  • 216

Pending citation

  • No

Public Access Level

  • Public

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