비교란 Lysimeter를 활용한 논 토양에서의 제초제 Butachlor의 용탈특성

This study was conducted to investigate the leaching characteristics of herbicide butachlor in paddy soil using undisturbed lysimeter. Soil horizons of sandy loam, loam, and silty clay loam lysimeter were composed of 6, 6, and 5, and clay contents were ranged from 53.1-63.2, 40.2-47.7, and 32.6-39.2 %, respectively. Bulk densities of each lysimeter were 1.38, 1.30, and 1.35 Mg/m3, respectively. Butachlor was treated to each lysimeter at 15 days after rice planting, and water was supplied according to rice cultivation method. Pore volumes of sandy loam, loam, and silty clay loam lysimeter were calculated to 718.87, 764.15, and 735.85 L, and pore volume numbers of supplied water for rice cultivation were 0.98, 1.08, and 0.24, respectively. Movement of butachlor in each lysimeter was investigated through the residue of it in 30, 55, 85, and 125 cm soil water from topsoil and leaching water. Gas chromatography (GC) was used for butachlor analysis in water sample. Recovery and limit of quantitation (LOQ) of butachlor in water were 88.1-104.6% and 3 μg/L. Changes of moisture tension, humidity, and temperature in sandy loam, loam, and silty clay loam lysimeter was not significantly different during experiment period. Weight of silty clay loam lysimeter was higher than other lysimeter because of less leaching. Leaching volume of sandy loam, loam, and silty clay loam lysimeter were 705.9, 828.7, and 174.5 L, respectively. Total leaching content of butachlor (treatment content 770.57 mg) during experiment period in sandy loam, loam, and silty clay loam lysimeter were 0.01, 0, and 0.07 mg, respectively. These results showed that the movement of butachlor in sandy loam, loam, and silty clay loam paddy soil was low.