Distribution of Cadmium in Rice Paddy Soil Affected By Long-Term Application of Phosphate Fertilizer and Compost for 50 Years.

The potential risks originating from heavy metal accumulation in arable soils through fertilizer applications have been public concern. Continuous phosphate fertilizer application could increase the cadmium concentration in soils. Long-term application of compost can change the cadmium behavior in soils because high compost organic matter (OM) can increase the OM-metal complexes or the soluble DOC-metal complexes in the soils. This study was conducted to evaluate the effects of long-term application of phosphate fertilizers and compost on Cd distribution in rice paddy soil. A field experiment was conducted in department of Southern Area Crop Science, NICS in Miryang in Korea from 1967 to 2016. Control, NK, NPK, and NPK+ compost were selected as treatments. Total Cd concentration and plant available Cd concentration in surface soils were measured for 50 years. There was no significant increasing trend of total Cd concentration in soil amended with NK fertilizer for 50 years. However, total Cd concentration gradually increased in soils amended with NPK and NPK+compost for 50 years. Total Cd concentration in soil amended with NPK+compost was slightly lower than that with NPK. This might be attributed to leaching of Cd due to formation of soluble DOC-Cd complex in soil amended with compost. In conclusion, long-term application of phosphate fertilizer and compost may increase extractability of Cd and it¡¯s uptake to rice plant.