Proceedings of Past Forest Nursery Association Meetings:
|The Use of Chemical Fumigants and Potential Alternatives at Weyerhaeuser Mima Nursery
|Thomas S. Stevens
|1996: Salem, OR
|Potential loss of methyl bromide as a soil fumigant by year 2000, due to its ozone depletion potential, has resulted in extensive exploration of both chemical and non-chemical alternatives at the Weyerhaeuser Mima Nursery. Although not as effective as methyl bromide/chloropicrin (MB/CHL), both Basamid granular (Dazomet) incorporated, rolled and water sealed and chloropicrin, injected and tarped, provided control of targeted soil pathogens. However, neither fumigant controlled weeds as well as MB/CHL. Bare fallowing fields between Douglas-fir seedling crops significantly reduced soil pathogens in contrast to oat and pea green manure cover crops. Brassica spp., used as green manure crops, were not effective in reducing soil pathogens, as compared to bare fallow or MB/CHL fumigation treatments. In addition to MB/CHL fumigation, application of yardwaste compost and fungicides had a positive effect on Douglas-fir seedling growth. Unfortunately, seedling mortality was greater in compost amended treatments.
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