|Thomas, J -|
|Ou, L-T -|
|Dickson, D -|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 12, 2009
Publication Date: N/A
Technical Abstract: Reducing emissions of pre-plant soil fumigants is important because EPA is proposing untreated buffer zones around fields for injection applications of current fumigants. Credits will be given to proven emissions reductions practices that would decrease the downwind off-site concentrations of fumigants. Such credits would allow growers to safely treat soils closer to the field boundaries. All experiments included a virtually impermeable film (VIF). In all cases, VIF was superior to standard polyethylene film (PE) row covers for retaining fumigants in the soil. PE covers were often not much better than bare soil. In one study, only 2% of the total emissions of methyl bromide came through VIF covered rows, but 98% came from the bare middles. However, 76% of the total emissions came through PE covered rows and 24% came from the bare middles. In another study, emissions of methyl isothiocyanate (MITC) from drip tape applications of metam sodium were much less than from broadcast injection applications. Coulter injection decreased emissions compared with shank injection. Truly effective barrier films appear to be the best defense against emissions and for field buffer zone credits under almost all Florida weather and soil conditions. Proposed soil surface compaction and/or water seals, and soil amendments may prove to be effective, but they need more field verification across time and locations.