Determination of Post Fumigation Recovery of Soil Microbial Communities over Time
Water Management Research
2013 Annual Report
1a.Objectives (from AD-416):
1) Determine the recovery of microbial community structure after fumigation with time.
2) Examine the effect of fumigants on both target and non-target organisims in soil.
3) Compare these non-target organisms in fumigated vs. non-fumigated control sites.
1b.Approach (from AD-416):
Soil samples will be collected from different aged fumigated sites from calla lily field in Moss Landing, CA. Fumigated sites ranging in age approximately from few months to 30 years, will be selected. Non-fumigated fields will be used as a control. From each site, four transects will be identified and from each transect, soil samples will be collected from 4 different locations and 2 depths (0-5 cm and 5-15 cm). Phospholipid fatty acid (PLFA) analysis will be used to study the microbial community structure recovery for non-target organisms. Determination of Fusarium oxysporum and Pythium spp. populations will be done using dilution plating on Komada’s and P5ARP medium respectively.
This agreement supports Objective c “Determine soil microbial community structure following soil fumigation in fields soils with respect to time” of Objective 4 “Develop effective, practical, economical and environmentally acceptable approaches to replace methyl bromide as a pre-plant soil fumigant in ornamental and strawberry production systems” of the parent project. All equipment necessary for the phospholipid fatty acid (PLAF) analyses was procured and installed in the laboratory and is functioning properly. Grower cooperators and sampling sites were identified. Soil samples were collected in fumigated strawberry fields and flower fields. Both conventional and organic production systems are being compared. Extraction of the soil samples is in progress. Personnel have traveled to MIDI-Inc for training in microbial identificaation system software.