Soil regions map of Japan based on a reclassification of the 1:1 million soil map of Japan (1990) according to the unified soil classification system of Japan --2nd approximation (2002)-- was made (Kanno et al., Pedologist: 52: 129--133, 2008).
In a nonallophanic Andosol with low available P content, lateral roots of Brassica plants and buckwheat roots show spectacular growth at the interface between a P fertilizer and the soil. Although we used dicalcium phosphate dihydrate (DCPD) suspended in alginate gel beads in the following photo, similar root growth was observed when polyolefin-coated monoammonium phosphate was used as a P fertilizer.
In andosolization, element composition is very different between the original tephra and soil formation products. The changes in the element concentration of immobile elements can be roughly approximated by weight loss of tephra.
