Abstract
The water absorption by the roots of plants was focused as the main reason of the increase of suction in the ground. Field measurements were carried out to study the effect of the roots of plants on a long-term change of the suction in the ground by using tensiometers. It was made clear from the measurement that the water absorption by the roots of plants plays an important role in the recovery of the suction after rainfall and obtained some knowledge on the difference in the suction by the season in a year, the time in a day and species of plants.
