Cultural Practices to Reduce Cd Content in Edible Parts of Staple Crops in Korea

Abstract

Objectives of this study were to determine the uptake and translocation of Cd in rice plant from soil with applying the water management and soil ameliorators and to investigate the correlations among heavy metal contents in the brown rice, soil pH and chemical species of Cd existing in soil by sequential extracting method with paddy soil contaminated with Cd near abandoned mine. To identify the effect of soil ameliorators on Cd uptake in rice plants, compost and lime were treated. Plants were grown with irrigation water concentrated by 0.01mg kg^ of cadmium in two soil types (sandy loam and clay loam) with treatments of intermittent irrigation and continuous submersion conditions. Compared to intermittent irrigation plots, average Eh value in the continuous submersion plots was low at 136.7mV whereas pH value was high at 0.3. Eh value was decreased in the treatment of soil ameliorator while pH value was increased by 0.2～0.3. Cd content of leaves and brown rice had significantly positive correlation with Eh value in soils while was negatively correlated with soil pH. At the harvest stage, Cd content in the leaves and brown rice was decreased in the continuous submersion plots by 30% relative to the intermittent irrigation plots. In case of soil ameliorator applied plots, Cd content of leaves and brown rice was lower by 35% than that of N, P, K fertilizer plots, respectively. Compared to the soil types, Cd content of leaves and brown rice in sandy loam soil was lower by 64 and 37% than that in clay loam soil, respectively. Order of reduction to Cd uptake was the compost and lime mixture plot>silicate plot>lime plot. However, the effect of Cd uptake reduction by soil ameliorator was decreased in the N, P, K+compost and N, P, K+phosphate plots. Cd uptake reduction by water management and soil ameliorator was more effective in the sandy loam soil than that in the clay loam soil.Special Revie