Pedogenetic acidification process of forest soils in Northern Kyoto

The distribution coefficient for cesium in different clay fractions in soils developed from granite and Paleozoic shales in Japan

“…This difference can be partly explained by the inhibition of Cs adsorption on the expanded interlayers or the frayed edge sites of the illitic minerals due to interlayering of the hydroxy-Al polymers (Maes et al 1998;Nakao et al 2009). The 2:1 phyllosilicates in the acidic forest soils in the deeper horizons tend to retain the hydroxy-Al polymers in their expanded interlayers to a greater extent than the upper horizons (Funakawa et al 1993). The XRD analysis confirmed a greater extent of hydroxy-Al polymer interlayering in the SW-CB soil clays than in the SW-Bs soil clays ( Fig.…”

Clay mineralogy and its relationship to soil solution composition in soils from different weathering environments of humid Asia: Japan, Thailand and Indonesia

“…The 2:1 layers of HIV are thought to be stable, probably because the buffering capacity of interlayered materials is such that it can react with acid more easily than the 2:1 layers. Such a preferential dissolution of interlayered materials in 2:1 layers is widely observed in the surface horizons of acidic forest soils (Ross and Mortland, 1966;Bouma et al, 1969;Gjems, 1970;Hirai et al, 1989;Funakawa et al, 1992). In ID-S samples, small to negligible amounts of easily weathered minerals are present in soils from a tropical rainforest climate and relatively stable landscape conditions; this indicates limited potential for acid Fig.…”

Clay-mineralogical characteristics of soils distributed under warm-temperate forest climate in Nyu Mountains, Fukui Prefecture, Central Japan

“…On the other hand, smectite predominated in the surface horizon of this soil, resulting in the eluviation of hydroxy aluminum from the chlorite-smectite intergrade interlayer. A similar eluviation of the interlayered hydroxy aluminum of 2 : I-type minerals was observed in Brown Forest soils under the Cool-temperate climate, as mentioned above (Hirai et al 1989(Hirai et al , 1991Funakawa et al 1993;Takahashi et al 2001), and the interlayered hydroxy aluminum of smectite was easily released because of the low layer charge (Egashira 1993). The precipitation of this hydroxy aluminum in the smectite interlayer was suggested, based on the existence of exchangeable and or water-soluble aluminum dissolved from the parent materials in the soil profile.…”

“…Chlorite and its analogues predominate in the sUlface horizon of these soils because of the increase in the amount of hydroxy aluminum in the interlayer due to the decrease of the amounts of silicates associated with surface weathering of RedYellow soils and Yellow-Brown Forest soils (Kato 1962;Nagatsuka 1975). On the other hand, hydroxy aluminum is eluviated from the interlayer of 2 : I-type minerals in the surface horizon of Brown Forest soils under the Cool-temperate climate, resulting in the decomposition of organic acids (Hirai et al 1989(Hirai et al , 1991Funakawa et al 1993). The clay-mineralogical characteristics of the zonal soils distributed under the Warm-temperate deciduous broad-leaved forest climate in the transition zone between the above two climate zones, however, have not been detennined.…”