Assessing Soil Hydrothermal Dynamics Under Humid Conditions

ABSTRACT

Soil moisture and soil temperature are key drivers of crop productivity, yet their interactions under humid subtropical conditions remain insufficiently characterised. This study investigated soil hydrothermal dynamics in a cornfield at North Carolina A&T State University during the 2024 growing season. A capacitance‐based CropX probe continuously monitored soil moisture at depths of 10, 30 and 56 cm, and soil temperature at 10 and 30 cm. Results showed substantial fluctuations in surface moisture (18.4%–41.8%) and temperature (20°C–31°C) at 10 cm, while deeper layers remained stable (47%–49%). Hysteresis analysis revealed asymmetric wetting and drying dynamics, with nearly twice as many significant drying events as wetting events. Moisture depletion at 30 cm was associated with surface moisture declining below 34.2%, providing a practical threshold for irrigation scheduling under the conditions studied. Soil temperature correlated strongly with air temperature ( r ≈0.95) and inversely with surface moisture ( r  ≈ −0.58), reflecting the moderating effect of water on thermal stress. These findings highlight the value of depth‐specific sensor monitoring for optimising irrigation scheduling and improving crop resilience in humid subtropical agricultural systems.