Cadmium Phytoremediation Potential of Napiergrass Cultivated in Kyushu, Japan

Abstract

Napiergrass (Pennisetum purpureum Schumach), a C4 tropical species, has been used for forage since it has high dry matter productivity, sustainability over several years in low-altitudinal sites of Kyushu, and little damage from serious pests. Recently, this grass has gained attention due to its potential as a bioethanol feedstock and for phytoremediation. Napiergrass cultivar Wruk Wona was grown as an annual crop in cadmium- (Cd-) contaminated soils under two cutting frequencies. Annual dry matter yield was not affected significantly by cutting frequency, but the concentration and uptake of Cd were higher when cut twice rather than only once, due to high Cd content of the herbage from the second cutting. Therefore, the soil Cd concentration was reduced by 4.6% when managed by cutting twice in a single year of Napiergrass cultivation.