논토양의 토성에 따른 벼의 수량, 관개용수량 및 지하삼투수량의 차이를 구명코자 사양토, 식양토, 식토 등 3종류의 토성에서 1999년과 2000년 라이시미터(lysimeter) 조건에서 실험한 결과는 다음과 같다. 1. 벼의 초장과 분얼 및 쌀 수량은 토성 처리간 유의한 차이가 없었다. 2. 벼 생육기간 중 총관개용수량은 1년차에는 식양토, 사양토, 식토 순으로 각각 3,306, 2,650, 2,002 l/m2 이었고 2년차에는 사양토, 식양토, 식토 순으로 각각 5,281, 4,984, 3,968 l/m2 이었다. 3.벼 재배기간 중 총지하삼투수량은 1년차에는 식양토, 사양토, 식토가 각각 2,141, 1,228, 862 l/m2 이었고, 2년차에는 사양토, 식양토, 식토에서 각각 4,448, 3,833, 2,925 l/m2 이었다. 4. 지표면하 10cm까지의 깊이에 분포하는 벼 뿌리의 비율은 사양토 56.0%, 식양토 61.4%, 식토 72.0%로 식토일수록 표층부 분포 비율이 높았다. 5. 논토양에서 지하삼투수량은 토성의 영향도 있으나 토양 중 벼 뿌리 생장량의 영향도 있어서, 뿌리 생장량이 많았던 처리구의 지하삼투수량이 증가하는 것으로 나타났다.

The lysimeter experiment was conducted to investigate the temporal changes of irrigation requirement, soil water percolation and rice root distribution during rice growing period under different soil texture that were sandy loam, clay loam and clay paddy soil in 1999 and 2000. The irrigation requirement in the first year was 3,306 l/m2 in clay loam, 2,650 l/m2 in sandy loam and 2,002 l/m2 in clay soil. However, the highest irrigation requirement was 5,281 l/m2 in sandy loam and the next was 4,984 l/m2 in clay loam and 3,968 l/m2 in clay soil in the second year, Soil water percolation in the first year was 2,141 l/m2 in clay loam, 1,228 l/m2 in Sandy loam and 862 l/m2 in clay soil. However, in the second year, the highest water percolation of 4,448 l/m2 was measured in sandy loam, and was followed by 3,833 l/m2 in clay loam and 2,925 l/m2 in clay soil. Distribution ratio of rice roots measured in 0-10cm of soil depth was 56.0% in sandy loam, 61.4% in clay loam and 72.1% in clay soil, respectively. It was interpreted that the greater water percolation measured in the second year was caused mainly by the large amount of rice root growth. Therefore, it was concluded that the soil water percolation in rice paddy soil was affected greatly not only by soil texture but also the growth of rice root.

• 채제천(단국대학교 생명자원과학부)
• 김성원(단국대학교 생명자원과학부)