Measurement of spatial average of field soil water content by the long heat probe method

Abstract

The long heat probe method was developed and tested to measure the average soil water content under field conditions. The length of the probe was 20 cm and 5 or 10 m. The probe consists of a thermometric metal wire resistor to detect the average temperature of the probe along the heating resistor. The twin transient-state cylindrical-probe method was improved for this measurement. The results show that when the relationship between the thermal conductivity and the soil water content was linear, the method enabled to measure accurately the average soil water content both in the field and laboratory.

Key Words:

• average soil water content
• long heat probe method
• thermal conductivity