PURPOSE: To effectively and economically improve soil by burying compression molded organic blocks in the new surface of a slope formed out of a fill, concurrently with or after the application thereof to the surface.

CONSTITUTION: Compression molded organic blocks 4 are buried partly in the new surface of a slope formed out of a fill 1, concurrently with the application thereof to the surface. As an alternative method, after a work for applying the fill 1, the new surface of the slope formed therewith is partly drilled, and the blocks 4 are buried in drilled holes. In this case, the blocks 4 have the capability of feeding nutritive substances and holding high water retaining function over a long term. Thus, soil is effectively improved.