Abstract
Rice production with confidence and safety is one of the main issues in Asian countries. For the past few decades, reduction technique of rice cadmium (Cd) has been clarified. Hence ministry of Agriculture, Forestry and Fisheries and National Institute for Agro-Environmental Sciences (2002) recommended the flooding water of paddy before and after the heading, and soil improvement using fertilizers. However lots of farmers express concern over rice degradation, rumor damage into price down and destruction of plow pan at harvest.
Therefore to generalize the reduction technique of Cd uptake by rice, we measured soil pH and soil Eh continuously, and analyze Cd concentration in both soil and rice in three different cultivated paddy fields. We concluded that 1) flood water management stabilized soil pH in neutral, and lowered soil Eh before and after the heading, 2) organic fertilizer was effective to reduce Cd in rice, 3) soil pH and Eh were not always the strict indicator of Cd uptake by rice, 4) climate condition did not affect the Cd concentration in rice.
