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Estimating surface soil moisture from soil color using image analysis

Persson, Magnus LU (2005) In Vadose Zone Journal 4(4). p.1119-1122
Abstract
In this technical note the ability to estimate surface soil moisture (theta) from soil color using image analysis is evaluated. Four natural soils and uniform fine sand were used. Calibration soil samples with theta varying from 0 to 0.40 m(3) m(-3) in 0.05 m(3) m(-3) increments were prepared and photographed. The variations in soil color with theta were investigated in both the RGB (red, green, and blue) and HSV (hue, saturation, and value) color spaces. Generally, all tested soils became when wetted up to a certain limit (around 0.25 m(3) m(-3)). However, many soils actually became lighter again at the highest theta levels. This was due to that some water was visible on the soil surface causing reflections. A simple linear regression... (More)
In this technical note the ability to estimate surface soil moisture (theta) from soil color using image analysis is evaluated. Four natural soils and uniform fine sand were used. Calibration soil samples with theta varying from 0 to 0.40 m(3) m(-3) in 0.05 m(3) m(-3) increments were prepared and photographed. The variations in soil color with theta were investigated in both the RGB (red, green, and blue) and HSV (hue, saturation, and value) color spaces. Generally, all tested soils became when wetted up to a certain limit (around 0.25 m(3) m(-3)). However, many soils actually became lighter again at the highest theta levels. This was due to that some water was visible on the soil surface causing reflections. A simple linear regression model between S and V was selected to estimate theta from the soil color. The model performed excellent in the fine sand and in two natural soils with a root mean square error (RMSE) of 0.011 to 0.017 m(3) m(-3). In the two other soils RMSE was about 0.025 m(3) m(-3). An independent validation data was also collected for the sand. The calibrated model performed well also in the validation data set with a RMSE of 0.015 m(3) m(-3). From the limited data presented in this study, it seems that the relationship between soil color and theta is stronger in light colored soils with low organic matter content. Some examples of practical applications of the method are also suggested in the paper. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Vadose Zone Journal
volume
4
issue
4
pages
1119 - 1122
publisher
Soil Science Society of America
external identifiers
  • wos:000234472300026
  • scopus:35648985234
ISSN
1539-1663
DOI
10.2136/vzj2005.0023
language
English
LU publication?
yes
id
e6d4d19f-2599-4aea-ad76-27e0b2a06088 (old id 209789)
date added to LUP
2007-08-10 16:20:16
date last changed
2017-01-01 07:20:18
@article{e6d4d19f-2599-4aea-ad76-27e0b2a06088,
  abstract     = {In this technical note the ability to estimate surface soil moisture (theta) from soil color using image analysis is evaluated. Four natural soils and uniform fine sand were used. Calibration soil samples with theta varying from 0 to 0.40 m(3) m(-3) in 0.05 m(3) m(-3) increments were prepared and photographed. The variations in soil color with theta were investigated in both the RGB (red, green, and blue) and HSV (hue, saturation, and value) color spaces. Generally, all tested soils became when wetted up to a certain limit (around 0.25 m(3) m(-3)). However, many soils actually became lighter again at the highest theta levels. This was due to that some water was visible on the soil surface causing reflections. A simple linear regression model between S and V was selected to estimate theta from the soil color. The model performed excellent in the fine sand and in two natural soils with a root mean square error (RMSE) of 0.011 to 0.017 m(3) m(-3). In the two other soils RMSE was about 0.025 m(3) m(-3). An independent validation data was also collected for the sand. The calibrated model performed well also in the validation data set with a RMSE of 0.015 m(3) m(-3). From the limited data presented in this study, it seems that the relationship between soil color and theta is stronger in light colored soils with low organic matter content. Some examples of practical applications of the method are also suggested in the paper.},
  author       = {Persson, Magnus},
  issn         = {1539-1663},
  language     = {eng},
  number       = {4},
  pages        = {1119--1122},
  publisher    = {Soil Science Society of America},
  series       = {Vadose Zone Journal},
  title        = {Estimating surface soil moisture from soil color using image analysis},
  url          = {http://dx.doi.org/10.2136/vzj2005.0023},
  volume       = {4},
  year         = {2005},
}