溴甲烷和硫酰氟对进境美国苜蓿草的穿透效果研究初探

Primary study on the penetration of methyl bromide and sulphuryl fluoride into alfalfa from America

为明确溴甲烷和硫酰氟对捆包苜蓿草的熏蒸穿透效果,本文分别使用溴甲烷和硫酰氟对捆包苜蓿草进行了帐幕熏蒸,并研究了2种熏蒸剂在苜蓿草不同深度内的穿透。结果表明,随熏蒸进行,2种熏蒸剂均可逐渐穿透到捆包苜蓿草内部(60 cm深度),其中溴甲烷完全穿透至60 cm深度的时间为24 h,高浓度熏蒸48 h后,苜蓿草内部20 cm、40 cm和60 cm处的溴甲烷浓度仍仅有外部空间的77.3%、57.8%、56.2%;硫酰氟完全穿透60 cm深度的时间为8~12 h,高浓度熏蒸48 h后,20 cm、40 cm、60 cm深度内的硫酰氟浓度分别是空间硫酰氟浓度的102.2%、101.8%、97.2%,苜蓿草内部硫酰氟浓度与外部空间浓度基本达到平衡。这些结果表明,硫酰氟熏蒸对进境捆包苜蓿草的穿透力强于溴甲烷。

The effect of methyl bromide （MB） and sulfuryl fluoride （SF） penetration into different depths of alfalfa was studied. The results showed that with increasing of fumigation time,two fumigants were gradually penetrating into the core of alfalfa. The time that MB fumigation completely penetrated into the 60 cm depth of alfalfa was about 24 h,and after 48 h exposure, the proportion of the concentration of MB in the 20,40 and 60 cm depth of the alfalfa to the chamber was 77.3%,57.8%,56.2% respectively. The time that SF fumigation completely penetrated into the 60 cm depth of alfalfa was about 8-12 h,and after 48 h exposure,the proportion of the concentration of SF in the 20,40 and 60 cm depth of the alfalfa to the chamber was 102.2%,101.8%,97.2% respectively,the concentration of SF in the alfalfa core was close to equilibrium with the chamber. It is clear that SF penetrates imported alfalfa more readily than MB.