磷化氢点施药在粮堆中的运动分布

本文报告了采用小布袋埋藏法、探管投药法和磷化氢发生器仓外施药法点(局部)施药后磷化氢在散装粮堆中的运动分布情况。结果表明，在试验仓中三种方式施药后磷化氢的主要运动方向为施药点下方，向四周扩散比较少，在施药点上方几乎检测不到磷化氢气体。小布袋埋藏施药后基本在1～2d后施药点可测到浓度，磷化氢在施药点(主要在下方)滞留的时间约3～6d；探管施药时磷化氢在主要分布的施药点下方，在第8～10d后检测不出磷化氢，但总体浓度水平较低；用钢瓶装二氧化碳气体与发生器混合施入气体时，在施药点下方2h后即可检测到较高浓度，但1d后在施药点4m的范围内即基本检测不到磷化氢。

Phosphine Diffusion and Distribution after Spot Application in Grain Bulk of Bin

Phosphine diffusion and distribution after phosphine spot application in grain bulk were investigated with three phosphine-application methods separately in three bins.The three phosphine-application methods included applying aluminium phosphide tablets packed in cotton bags,applying tablets into plastic probes and applying phosphine from on-site generator mixed with carbon dioxide from cylinder.The results indicated that phosphine mainly diffused downward from the application spot for all the three methods.The time when phosphine was first detected under the application spot was short for applying phosphoine mixed with carbon dioxide,and long for probe method.The duration of detected phosphine nearby the spot was less than six days for cotton bags application,ten days for probes method and two days for applying phosphine mixed with carbon dioxide.Furthermore,the concentration level of detected phosphine was high for mixed application,medium for cotton bag method and low for probe method.