Abstract
At Tokotan region in Hokkaido, the field is composed mainly of volcanic soil and has been frozen every year to the extent of about 60cm under the soil surface.
Freezing of the soil has been resulted into the formation of plane structure, the soil errosion and thus the reducing of productive power of the field. It is important thing that the soil should be improved to maintain or recover the productive power of soil at such regions.
In order to make sure the effects of the panb reaking on the improvement of soil condition, we investigated the physical properties of soil before and after the pan-breaking as the preliminary experiments.
Moreover, from the studies on operating method of the pan-breaker, it was found that some parts of the pan-breaker should be improved.
