Effects of fertilizers on the vicissitude of cadmium in rice plant

Abstract

Some phosphatic fertilizer and phosphorite contained high concentration of cadmium, 4–77 μg/g Cd and were considered one of the causes increasing the cadmium content in rice plants. Unlike, the manure heap, the human excrements contained low cadmium, 0.003–0.03 μg/g Cd, but the Cd content in human excrements in Cd‐polluted areas ranged from 20.1 μg/g Cd to 85.0 μg/g, Cd in ash. The cadmium content of rice produced using prevailing methods of fertilizer culture, since around 1910, tended to be slightly higher than those during the Meiji periods, 1800's. After 1920, these values increased higer compared with those of before the beginning of import of phosphorite in Japan.

Key words:

• Cadmium
• Rice plant
• fertilizer
• Phosphorite
• Human excrement