Journal of Korean Society of Agricultural Engineers ISSN:1738-3692(Print) 2093-7709(Online) 한국농공학회논문집

The pollutant concentrations at experimental paddy plots with three (excessive, standard, reduced) different fertilization rates were investigated during 2001-2002 irrigation seasons. Mean concentrations of pollutants in ponded water were not significantly different among three experimental plots, but the T-N concentrations in percolated water significantly depended on fertilization rates. The T-N, T-P and COD_Cr, concentrations in ponded water during early irrigation season (late May to mid-June) were much higher than those during later irrigation season likely due to fertilization and low uptake by young rice crops. The T-N concentrations decreased but the concentrations of T-P and COD_Cr, increased three days after tillering fertilization. The removal rates of T-N by paddy plots were 0.13-0.16g/㎡ㆍd for an excessive fertilization plot, 0.08-0.25 g/㎡ㆍd for a standard fertilization plot, and 0.03-0.34 g/㎡ㆍd for a reduced fertilization plot three days after tillering fertilization. On the other hand, T-P and COD_Cr, were released three days after tillering fertilization.