Aluminum Dynamics in Nonallophanic Andosols from Northeastern Japan

We studied Al dynamics in nonallophanic Andosols from northeastern Japan by determination of Al solubility and Al release rates, selective dissolution analyses of active Al fractions, and examination of liming effect on the active Al. Aluminum solubility of the nonallophanic Andosols was lower than that of gibbsite in the lower pH range and showed oversaturation in the higher pH range, indicating that the Al solubility was controlled by Al-humus complexes. There was a close relationship between Al saturation (KCl-extractable Al/effective CEC) and the amount of pyrophosphate extractable Al, indicating that exchangeable Al is equilibrated with organically complexed Al. Liming (CaCO_3 treatment) largely reduced the amount of organically complexed Al (pyrophosphate- and CuCl_2-extractable Al), confirming that a portion of Al-humus complexes are labile

Changes in Elemental Composition with Andosolization

A total of 57 elements in volcanic ash soils from 18 pedons distributed in Japan were analyzed and the relationships between noncrystalline material content and that of individual elements were examined. The content of the noncrystalline materials was estimated by using acid-oxalate extraction. Oxalate-extractable Fe (Fe_o) and Al (Al_o) corresponds to Fe in ferrihydrite and Al in allophane-imogolite plus Al complexed with humus, respectively. Silicon and alkaline or alkaline-earth elements such as Na, K. Ca, and Sr tended to decrease during the process of volcanic ash soil formation, i.e., andosolization. In contrast, the contents of Al, Y and the first transition metals tended to increase with the increasing content of noncrystalline materials. The first transition metals showed a high correlation with Feo suggesting their similarity in chemical behavior during andosolization. The lanthanoid elements tended to increase with the increasing Al_o and Fe_o content

Relationship between the timing of vessel formation and leaf phenology in ten ring-porous and diffuse-porous deciduous tree species

The goal of this study is to clarify how different aspects of plant function are coordinated developmentally for species of ring-porous versus diffuse-porous deciduous trees, comparing the timing of leaf phenology and vessel formation in twigs and stems from an ecophysiological viewpoint. Cylindrical stem cores and twigs were collected at intervals from early spring through summer from five ring-porous and five diffuse-porous species in a cool temperate forest, and leaf and vessel formation were observed simultaneously. We found that the first-formed vessels of the year were lignified in twigs around the time of leaf appearance and at or before full leaf expansion of each tree in both groups of species with flush-leaves. Vessels in stems were lignified 2 weeks before to 4 weeks after leaf appearance and before or around full leaf expansion of the tree in ring-porous species. This was significantly earlier than in diffuse-porous species, in which stem vessel lignification was 2–8 weeks after leaf appearance and at or after full leaf expansion of the tree. The timing of vessel formation in twigs compared to stems was significantly earlier in ring-porous species than in diffuse-porous species. Lignification of vessels in stems occurred within 2 weeks of lignification in the twigs of ring-porous species and 2–8 weeks after lignification in twigs of diffuse-porous species. These results indicate the order and time-lag of leaf and vessel formation. Ring-porous species showed intensive leaf/vessel production, whereas diffuse-porous species showed less intensive leaf/vessel production

Organic Carbon Accumulation in Andosols: (1) Unaccounted Andosols in Japanese Forest Soil

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