On the Time-lag of Tensiometers

Abstract

Using several tensiometers commereially available in Japan, the author examined the effects of water amount on the time-lag of tensiometer's reading and on the relation between moisture content and tension. The structural character and amount of water which is required in changing a division on the reading are shown in Table 1.
The instrument which requires larger amount of water showed longer time-lag of reading and wider hysteresis loop than that of less amount of water. This tendency is intensified especially in the dry state of soil.
The disparity of water amount in various types of tensiometer may be attributed to the structural character of instruments such as type of manometer, connecting tube and area of cup surface. The betterment of these parts will improve the efficiency of the tensiometer.