The purpose of this experiment was to study the relationship of soil reflectance and soil moisture (tension). Fifty-seven samples were selected from surface samples representing 240 representative soil series widely distributed over the United States and supplied to Purdue's Laboratory for Applications of Remote Sensing (LARS) by the Soil Conservation Service (SCS). See experiment 781701. The 240 samples were selected to cover as large a range of visible spectral properties (colors) as possible. In experiment 781701, reflectance measurements were made of the soils equilibrated to a moisture tension of 0.1 bar. For this experiment, 57 of the 240 samples were selected to represent the range in soil charateristics known to affect reflectance such as iron oxide, organic matter content, texture, etc. Reflectance measurements of these 57 samples were made with the samples equilibrated to several other moisture tension levels . All 57 sample were run at oven dry; 12 of the 57 samples were run at 1/3 bar; 29 of the 57 were run at 15 bar; and 15 samples were run an 10 bar.

The study took place in 1980.

File 801601 contains soils data
File 801602 contains reference calibration data

Note: The reflectance of 6 soil sample were measured on 8/12/80 at 15 bar. After that time, concern was raised that at least some of the soil samples may have not equilibrated at 15 bar moisture tension. Some of these samples were rerun on 7/17/81.

The supporting docs include a brief summary of used instruments, a wavelength table (Wavelength_ASCII.txt), reflectance note and reflectance tables (ReflectanceTable206.txt and  ReflectanceTableMulti.txt), and file format description (ExperimentDataFormat3.txt). The format description file is in ASCII format in lines of 80 characters.

This research dataset is part the Field Research Data Library that consists of over 200,000 spectral observations of soils and vegetation that have been collected since 1972 till 1991 as part of the research focused on vegetation and soils at the Laboratory for Applications of Remote Sensing (LARS) located at the Purdue University.

Researchers should cite this work as follows:

• Peterson, J. B. (2015). Soil reflectance and soil moisture (tension) study (801601). Purdue University Research Repository. doi:10.4231/R7ZK5DM4

  BibTex | EndNote

1. Agriculture
2. Agronomy (Dept)
3. determining moisture content
4. Exotech 20C-SW
5. GE-DXW Lamp illumination
6. LARS
7. Remote Sensing
8. soil
9. soil reflectance
10. Soil Science
11. spectral observations
12. spectrometer
13. specular reflectivity

• Location: LARS Optical Lab, West Lafayette, IN
• County: Tippecanoe
• Latitude/Longitude: 0402500N / 0865500W
• Illumination: GE-DXW Lamp
• Experiment Type: Soils - Soil
• Spectrometer: Exotech 20C-SW
• Wavelength Range: 0.40-2.40 um