Effects of Pesticide Formulations on the Residues in Paddy Rice

농약(農藥)의 제형(劑型)이 수도체중(水稻體中) 잔류량(殘留量)에 미치는 영향(影響)

The present study was performed to elucidate pesticide residues in paddy rice applied with different application schedules and frequencies of pesticide formulations. Pungsanbyeo($Japonica{\times}Indica hybrid$) of rice(Oryza sativa L.) was chosen as target crop. Isoprothiolane(diisopropyl-l,3-dithiolan-2-ylidene malonate) 40EC (emulsifiable concentrates), 12G (granular), and chlorpyriphosmethyl [0,0-dimethyl 0-(3,5,6-trichloro-2-pyridyl) phosphorothioate] 25EC, 3G were selected as pesticide formulations. The closer the isoprothiolane EC application to harvest, the higher the residues in rice straw retained at harvest; however the G application on 30 days before harvest resulted in highest residue. Chlorpyriphosmethyl residues were higher as it was applied nearby to harvest. Degradation rate of chlorpyriphos-methyl in husked rice was quite similar to in rice straw, on the other hand isoprothiolane in the rice was more stable than that in rice straw. Translocated amount of applied G formulation to husked rice was meager irrespective to the chemicals. Percent reduction of isoprothiolane residues in husked rice by polishing was not related to application frequencies but to application date before harvest. Residual portions in rice straw, husked rice and polished rice of total input amount during rice cultivation were ranged from 0.19% to 0.99%, 0.01% to 0.48%, and 0.15%, respectively.

농약(農藥)의 제형(劑型), 살포시기(撒布時期) 및 사용회수(使用回數)를 달리 하였을 때 수도(水稻)의 수확물중(收穫物中) 농약잔류량(農藥殘留量) 변화를 조사(調査)하기 위하여 isoprothiolane과 chlorpyriphos-methyl의 유제(乳劑) 및 립제(粒劑)에 대하여 풍산(豊産)벼를 대상으로 시험(試驗)한 결과(結果)는 다음과 같다. 1) Isoprothiolane 유제(乳劑)는 수확기(收穫期)에 근접(近接)하여 철포(撤布)할수록 볏짚중(中) 잔류량(殘留量)이 높았으나 립제(粒劑)는 수확(收穫) 30일전(日前) 살포에서 최고수준(最高水準)에 달하였다. Chlorpyriphos-methyl은 제형(劑型)에 관계없이 수확기(收穫期)에 근접(近接) 살포할수록 볏짚 잔유량(殘留量)이 높았으나 그 수준(水準)은 isoprothiolane 보다 현저히 낮았다. 2) 현미중(玄米中) 잔류량(殘留量)은 chlorpyriphos-methyl유제(乳劑)의 경우 볏짚에서와 류사(類似)한 분해률(分解率)을 보였으나 isoprothiolane유제(乳劑)는 볏짚에서 보다 그 잔류량(殘留量)이 안정(安定)하였다. 립제(粒劑)는 락제(樂劑)와 무관(無關)하게 현미(玄米)로의 이행(移行)이 매우 경미(輕微)하였다. 3) 도정(搗精)에 의한 현미중(玄米中) 잔류양(殘留量)의 제거률(除去率)은 유제(乳劑)의 철포시기(撤布時期)가 수확기(收穫期)에 인접할수록 높았고 살포회수(撒布回數)와는 관계가 없었다. 4) 수도재배기간중(水稻栽培期間中) 살포농약(撒布農藥)의 수확물중(收穫物中) 잔존률(殘存率)은 볏짚에 $0.19%{\sim}0.99%$, 현미(玄米)에 $0.01{\sim}0.48%$, 백미(白米)에 0.15%이었다.