Abstract
Reduction of low-level Cadmium contamination in brown rice was examined under three nitrogen fertilization conditions: application of methane-fermented manure liquid (MF), application of ammonium sulfate fertilizer (CF) and no nitrogen fertilization (NF). Rice was grown in the pots with gray lowland soil and andosol amended with cadmium (Cd) at the concentration of 2 and 5 ppm, respectively, and fertilized as above. Several parameters including soil redox potential (Eh), amount of Cd absorbed by rice plants and its partition to brown rice, were periodically determined during the growth. In both gray lowland soil and andosol, soil Eh was significantly lower in MF than in CF and NF during the growth period from panicle initiation to heading, and Cd absorption by rice plants and Cd allocation to brown rice were also lower in MF than in CF and NF. Split application of MF resulted in a lower Cd concentration in brown rice than basal application without reducing brown rice weight. These results suggested that applying MF, in both kinds of soil, reduces the low-level Cd contamination in brown rice.
