2006 Volume 32 Issue 1 Pages 154-158
In order to obtain the knowledge about the soil improvement by using earthworms, the change in the chemical and biological properties of soil added earthworms were investigated in a field. The effects of earthworms on the soil improvement were compared between the earthworms living in the litter layer and the earthworms living in the mineral soil layer. The influence of soil temperature on the activity of earthworms were studied. The earthworms living in a mineral soil layer enhanced the microbial activity, compared with the earthworms living in the litter layer. It suggests that activities of earthworms in the soil layer promoted the soil improvement than earthworms living in the litter layer. Moderation of soil temperature by shading in summer kept the high concentration of nitrate ions in the soil solutions. It consequently suggested that soil temperature affected on activating microorganisms by earthworms.
