Abstract
Knowledge of soil moisture is needed to understand crop water use, hydrology, and microclimate. A reliable, rapidtechnique is needed, and recently an impedance soil moisture probe (Theta Probe) has been accepted by the scientificcommunity. The purposes of this study were to calibrate the probe for soils of Central Iowa through field sampling, todetermine the number of samples needed for calibration, and to determine the effect of temperature on calibration. Laboratorycalibration was conducted on Des Moines lobe soils across a range of water contents and temperatures. Including atemperature term increased the R2 from 0.85 to 0.87. Field calibration was based on Theta Probe measurements on similarsoils combined with gravimetric sampling and soil temperature determination. Although some scatter existed, the fieldcalibration was adequate for Iowa soils (R2 = 0.77). Inclusion of temperature did not significantly improve the calibrationfor the field data. To determine the appropriate number of samples needed for the field calibration, regression equations weredetermined from sample numbers ranging from 2 to 89, and the standard error was determined for each. Based on the standarderror analysis, 20 samples was an adequate number, with no further improvement for additional data points.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
