在散装小麦的房式仓 ,利用磷化氢环流熏蒸系统 ,对粮面用PVC塑料薄膜密封的小麦进行膜下环流熏蒸的试验。结果表明投药环流 1 3h后 ,磷化氢平均最低浓度与最高浓度比为 85 1 (ml/m3 ) /1 1 35 (ml/m3 ) =0 .75 ,此时粮堆内磷化氢浓度已分布的相当均匀。 1号仓熏蒸 7d时 ,平均浓度每天下降 5 .3%。 2号仓熏蒸 1 0d时 ,平均浓度每天下降了 5 .8%。与无薄膜的全仓环流熏蒸试验相比 ,膜下环流熏蒸磷化氢浓度达到均匀的时间短 ;气密性好 ,熏蒸时取得的Ct值大 ,杀虫效果更好 In the bulk warehouse of wheat, the phosphine circulating fumigation system was used to test the underfloor circulation fumigation of grain with plastic PVC film. The results showed that the average concentration of phosphine was 85 1 (ml / m3) / 1 1 35 (ml / m3) = 0.75 after fed-batch circulation for 13 h, and the concentration of phosphine in the grain was Distribution is quite uniform. Fumigation of No. 1 warehouse 7d, the average daily decline of 5.3%. 2 positions fumigation 10d, the average daily concentration decreased by 5.8%. Compared with the membrane-free whole-chamber circulation fumigation test, the membrane fumigation phosphine concentration reached a uniform time short; air tightness, Ct value obtained when fumigation, the insecticidal effect is better