담수토양(湛水土壤)에 IBP 입제(粒劑)를 반부처리(反復處理)하고 후처리(後處理)한 약제(藥劑)의 분해(分解)에 미치는 영향(影響)을 시험(試驗)한 결과(結果) 1) IBP의 반부처리(反復處理)로 후처리(後處理)한 IBP의 분해(分解)가 촉진(促進)되었으며 그 효과(效果)는 약 53일간지속(日間 持續)되었으나 diazinon의 분해(分解)에는 영향(影響)이 없었다. 2) 토양살균(土壤殺菌)으로 IBP의 분해(分解)가 크게 억제(抑制)되어 분해속도(分解速度)는 무살균토양(無殺菌土壤)에 비해 3배(倍)이상 지연(遲延)되었으며 반부처리(反復處理)에 의해 생성(生成)된 IBP 분해촉진능력(分解促進能力)도 소실(消失)되었다. 3) IBP 반부처리(反復處理)로 인(因)한 토양미생물(土壤微生物)의 전체 colony수(數)는 변하지 않았다.
This experiment was conducted to see the effect of repeated application of IBP granular formulation(17%, 0,0-diisopropyl-S-benzyl thiophosphate) on the biodegradation of IBP and diazinon〔0,0-diethyl 0-(2-isopropyl-4-methyl-5-pyrimidinyl) phosphorothioate〕 in silt loam soil with 2.1% organic matter under flooded condition. The persistence of IBP in the soil was shortened by increasing the frequencies of application of the chemical. Enhanced degradation ability in the soil caused by repeated application of IBP was prolonged about 53 days, while the ability did not influence diazinon persistence in the soil. The half-lives of IBP in sterilized soil autoclaved at $121^{circ}C$ for 30 minutes were about 3 times longer than those in viable soil, suggesting that microbial process was a major factor for IBP degradation in the soil. The total colony number of soil microbes showed little difference between the soils with and without repeated application of IBP. A possible concern of specific soil microorganisms on the pesticide degradation in soil was discussed.
