Soil Properties of Allophanic and Non-allophanic Horizons of Volcanic Ash Soil in Kyushu District, Japan
Nobuhiko Matsuyama, Haruki Fujisawa, Chihiro Kato, Choichi Sasaki, Masahiko Saigusa

This study examined the contrasting physical and chemical properties of allophanic and non-allophanic horizons in Japanese volcanic ash soils described in the Soil Survey Data Book before Land Reclamation. A total of 748 investigation points and 1570 soil horizons from the Kyushu District were divided into two groups based on their exchange acidity y1: allophanic horizons y1< 6 and non-allophanic horizons y1> 6. Volcanic ash soils from the Kyushu District were characterized as dark, weakly adherent, soft, dry, humic, and active-Al rich. Soil acidities of the two horizons had significantly different pH, exchange acidity y1, and exchangeable Ca. Mean humus content of LayerⅠ(topsoil), Ⅱ(subsoil), and Ⅲ(deeper subsoil) were 11.1±5.8, 9.7±6.0, and 7.6±6.0%, respectively, for allophanic horizons and 8.2±7.0, 6.7±6.9, and 4.4±5.3%, respectively, for non-allophanic horizons. Humus content of non-allophanic horizon was relatively lower compared to allophanic horizons in the Kyushu District.

Full Text: PDF     DOI: 10.15640/jaes.v10n2a5