HR: 0800h
AN: H21B-1345    [Abstracts]
TI: Mitigating the Effects of Electrical Conductivity and Temperature on a Low-Cost Soil Moisture Sensor
AU: * Campbell, C S
EM: colin@decagon.com
AF: Decagon Devices, Inc, 950 NE Nelson Ct, Pullman, WA 99163 United States
AU: Cobos, D R
EM: doug@decagon.com
AF: Decagon Devices, Inc, 950 NE Nelson Ct, Pullman, WA 99163 United States
AU: Campbell, G S
EM: gaylon@decagon.com
AF: Decagon Devices, Inc, 950 NE Nelson Ct, Pullman, WA 99163 United States
AU: Teare, B
EM: brody@decagon.com
AF: Decagon Devices, Inc, 950 NE Nelson Ct, Pullman, WA 99163 United States
AB: Dielectric soil moisture measurements are now widely used, both in research and in commercial agriculture. Although measurements are often made in locations where electrical conductivity (EC) and temperature fluctuations are low, high levels of either can cause difficulty in analyzing dielectric moisture data. Several researchers have proposed using higher probe frequencies to mitigate these effects, but there are limits to that approach, both in cost and effectiveness. The objective of this research was to determine what could be done to decrease salt and temperature sensitivity of the soil moisture probe in different soils. Sensitivity to EC was found to be considerable in both course- and fine- textured soils at low probe frequencies. Increasing the probe frequency removed much of the EC sensitivity in all soil types. Although temperature sensitivity was also diminished by higher frequencies, it was still clearly evident in the fine-textured, high EC soils. After testing a range of operational frequencies, optimum performance was found to be around 70 MHz; higher frequencies appeared to cause probe performance to worsen. A probe that combined higher frequency soil moisture measurement with temperature, and EC was also evaluated.
DE: 1842 Irrigation
DE: 1862 Sediment transport (4558)
DE: 1866 Soil moisture
DE: 1895 Instruments and techniques: monitoring
SC: Hydrology [H]
MN: Fall Meeting 2005