An in situ probe‐spacing‐correcting thermo‐TDR sensor to measure soil water content accurately

Abstract

<p>To reduce the possibility of probe deflections, conventional thermo-time domain reflectometry (T-TDR) sensors have relatively short probe lengths (≤4 cm). However, short probes lead to large errors in TDR-estimated soil water content (θv). In this study, two new 6-cm-long probe-spacing-correcting T-TDR (CT-TDR) sensors were investigated. Compared to conventional 4-cm-long T-TDR sensors, the 6-cm-long CT-TDR sensors reduced errors in TDR-estimated θv. Errors in heat pulse (HP) estimated θv because of probe deflections were reduced when linear or nonlinear probe spacing correcting algorithms were implemented. The 6-cm-long CT-TDR sensors provided more accurate θv estimations than do the conventional 4-cm-long TTDR sensors.</p>