Chemical and Physical Properties of Andosols in Aomori Prefecture Described in a Soil Survey Report on Reclaimed Land

The chemical and physical properties of allophanic and non-allophanic Andosols in Aomori prefecture described in a Soil Survey Report on Reclaimed Land (SSRRL) are discussed. Volcanic ash soil and non-volcanic ash soil having more than 15 g P2O5 kg-1 of phosphate absorption coefficient are regarded as Andosols. In this study, 251 soil profiles and 657 soil horizons were classified into two groups based on exchange acidity y1; into allophanic Andosols (y1<6) and non-allophanic Andosols (y1≥6). The physical properties (soil color, texture, gravel, stickiness, consistence (dry), tilth and wetness) in SSRRL were scored into 6 classes from 0 to 5. The mean humus contents of non-allophanic Andosols was 13.1% at a depth of 0-15 cm, 11.0% at 15-30 cm and 7.7 % at 30-50 cm and were slightly higher than those of allophanic Andosols. Non-allophanic Andosols have a relatively high texture score compared with allophanic Andosols. Moreover, non-allophanic Andosols are relatively sticky. As compared with allophanic Andosols, non-allophanic Andosols have higher clay content and are sticky and hard. Thus, the differences of chemical and physical properties of allophanic Andosols and non-allophanic Andosols described in SSRRL were evaluated.