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为明确完全不透性膜(totally impermeable film,TIF)对熏蒸剂在田间应用时散发和残留的影响,采用静态散发箱技术测定了TIF与聚乙烯膜(polythene film,PE)对氯化苦、1,3-二氯丙烯(1,3-dichloropropene,1,3-D)和棉隆施用后所产生的异硫氰酸甲酯(methyl isothiocyanate,MITC)大气散发的控制效果,并应用气相色谱法检测了揭膜后3种熏蒸剂在土壤中的残留情况。结果表明,在20 g/m~2(棉隆为15 g/m~2)剂量下,氯化苦、1,3-D及MITC透过PE的累积散发率为施用量的6.42%、7.37%和22.27%,透过TIF的累积散发率为施用量的0、0.65%和2.05%,表明TIF极大地降低了熏蒸剂向大气的散发量,可有效控制熏蒸剂向大气扩散。揭膜后氯化苦及1,3-D在各处理土壤中的残留量均低于0.30 mg/kg,说明TIF没有增加土壤中氯化苦和1,3-D的残留量;但MITC(15 g/m~2)在TIF下10~20 cm土壤中的残留量在3.28~3.41 mg/kg之间,高于在PE下的残留量(0.46~0.47 mg/kg),表明TIF能提高MITC在土壤中的持效浓度。
In order to clarify the effect of totally impermeable film (TIF) on the emission and residual of fumigant in field application, the static emission box technique was used to determine the effect of TIF and polythene film (PE) on chloropicrin, The control effect of 1,3 isothiocyanate (1,3-D) and methyl isothiocyanate (MITC) produced after application of cotton was analyzed by gas chromatography The method tested the residuals of three kinds of fumigants in the soil after uncovering. The results showed that the cumulative elution rates of chloropicrin, 1,3-D and MITC through PE at a dose of 20 g / m ~ 2 (cotton was 15 g / m ~ 2) were 6.42% and 7.37 % And 22.27%, respectively. The cumulative distribution rate of TIF through TIF was 0, 0.65% and 2.05% of the application rate, indicating that TIF greatly reduced the amount of fumigant released into the atmosphere and effectively controlled the diffusion of fumigants into the atmosphere. After removing the film, the residues of chloropicrin and 1,3-D in the treated soils were all less than 0.30 mg / kg, indicating that TIF did not increase the content of chloropicrin and 1,3-D in the soil; however, MITC ( 15 g / m ~ 2) were higher than those under PE (0.46 ~ 0.47 mg / kg) in the range of 10 ~ 20 cm soil depth under TIF, indicating that TIF could be increased MITC persistence concentration in soil.