磷素是极易被土壤吸持的成分。因此,磷素从土壤中淋失的可能性极少。相反,土壤吸持的磷素往往难以被作物吸收,这一点容易成为土壤肥力上的问题。在日本以火山灰等火山喷出物为母质的土壤上更是如此。除了相当新鲜的火山喷出物外,发育于火山喷出物的土壤,对磷素的吸持容量和强度都很大。 Phosphorus is easily absorbed by the soil components. Therefore, there is very little chance of phosphorus leaching from the soil. In contrast, soil-bound phosphorus is often difficult to be absorbed by the crop, which can easily become a soil fertility problem. This is especially true in Japan where volcanic ash and other volcanic eruptions are the parent material. In addition to fairly fresh volcanic eruptions, soils developed on volcanic ejections have a large capacity and intensity of phosphorus uptake.