Water Balance and Nutrient Losses of Paddy Fields Irrigated from a Pumping Station

양수장지구 구획논 물수지와 영양염류 유출부하

The study was carried out to investigate the water balance and losses of nutrients from paddy fields during cropping period. The size of paddy fields was 95 ha and the fields were irrigated from a pumping station. The runoff loading was the highest in June because of the high concentrations of nutrients due to applied fertilizer. When the runoff losses of nutrients were compared to applied chemical fertilizer, it was found that 39.1 % to 42.5 % of nitrogen lost via runoff while runoff losses of phosphorus account for 6.3 % to 8.0 % of the total applied amount during cropping period. When the ratio was calculated between nutrients losses by infiltration and the applied of chemical fertilizer, two year results showed 9.1 % to 10.7 % for nitrogen and 0.2 % for phosphorus, respectively.