Abstract
Ground freezes from the surface downward, and during this process soil moisture is drawn upward. The moisture content of soil that has frozen is high, whereas the moisture content of non-frozen soil below that is low, because water is drawn upward toward the soil that has frozen. If high-moisture soil can be improved to yield low-moisture soil using this phenomenon, low-cost improvement will be possible. Moisture can be reduced by repeated freezing and thawing, changes in soil temperature, then, soil moisture change through winter were monitored in outdoor experiments. It was shown that unsuitable soil could be improved by repeated freezing and thawing, that the decrease in moisture content was finished within one season.
