Problems and improvement of volcanic ash soils in Japan with reference to the weathering sequence International symposium on distribution, characteristics and utilization of problem soils

agentes nocivos agronomic characters arcilla asia asie chemicophysical properties clay cobalt cobalto composition contaminantes contaminantes industriales deficiencia de minerales deficiency diseases disorders elements environment environnement estructura del suelo facteur nuisible fertilidad del suelo fosfatos functional disorders growing media heavy metals industrial pollutants injurious factors inorganic compounds japan japon lithological soil types maladie de carence medio ambiente medio de cultivo medios de enraizamiento metabolic disorders metal metales metales pesados metals milieu d'enracinement mineral deficiencies nutritional disorders pedogenese phosphate phosphates polluant polluant industriel pollutants rooting media sales salts sel site factors soil fertility soil genesis soil morphological features soil physicochemical properties soil structure soil types sol volcanique structure du sol substrat de culture trait morphologique du sol transition elements trastornos trastornos funcionales trastornos nutricionales trouble trouble fonctionnel trouble nutritionnel type de sol type de sol lithologique volcanic soils weathering