混合农药对拟菊酯杀虫剂土壤降解的抑制影响

多菌灵、呋喃丹、丁草胺对3种拟菊酯杀虫剂在粘壤土和砂壤土中的厌气降解有显著的抑制作用。氯氰菊酯、溴氰菊酯和氰戊菊酯在土壤厌气条件下的半衰期分别为20.64、20.82和24.82天,加多菌灵培养可使其分别延长2.30、2.34.3.18倍,加呋喃丹分别延长2.12、2.37、2.37倍;加丁草胺分别延长1.87、1.75、2.58倍。好气条件下,3种拟菊酯杀虫剂降解加快,半衰期分别为11.98、17.64、和21.78天,混合农药对其降解的抑制作用大为降低,仅呋喃丹仍对3种拟菊酯杀虫剂的降解有明显抑制,表明多菌灵、呋喃丹和丁草胺对3种拟菊酯杀虫剂的降解抑制主要是抑制厌氧微生物的结果。

Inhibitory Effects of Combined Pesticides on Degradation of Pyrethroid Insecticides in Soil

Cypermethrin, deltamethrin and fenvalerate were incubated with carbendazim, carbofuran,or butatrchlor, respectively, in anaerobic or aerobic soils for 45 days, Significant inhibitory effectsof carbendazim, carbofuran, and butarchlor on anaerobic degradation of 3 pyrethroids wereobserved. 20.64, 20.82, and 24.82 days of half life for cypermethrin, deltamethrin, andfenvalerate were extended to 47.40, 48.63, and 79.0 days by carbendazim, to 43.86, 49. 29,and 58.78 days by carbofuran, and to 38.54,36.45, and 64.11 days by butarchlor. The aerobicdegradation rates of 3 pyrethroids were faster than their anaerobic degradation rates. Exceptcarbofuran, carbendazim and butarchlor displayed very weak effects on 3 pyrethroids in aerobicsoil, revealing that the inhibitory effects of these pesticides on degradation of 3 pyrethroidsresulted from the inhibition of anaerobic microorganisms in soils by them.