Selenium Contents in Astragalus and Uncultivated Soils in Japan.

Abstract

This reports a study of the selenium (Se) content in some Astragalus (Se indicator plants), related plants (vetch), and soils in Japan. The Se content of Japanese Astragalus was 0.06-2.17 mg/kg of dry weight. The Se content in Hedysarum and Oxytropis, the species of vetch, was 0.05-2.04 mg/kg. We did not find any vetch in Japan in which Se had accumulated. Se content in plants is influenced by Se level in the soil. We measured the Se content in the surface soils in Japan and plotted a Japanese Se map ; the soil content was 0.2-1 mg/kg, except around a few volcanoes such as Tateyama Murodo (148 mg/kg) and Mt. Zao (10.0 mg/kg). We showed in detail the Se content in the soils and plants around the Tateyama Murodo region. The Se content of soils and ashes from many volcanoes such as Mt. Unzen and Mt. Pinatubo (Philippines) was low (0.1-0.6 mg/kg).