Progress 07/01/09 to 06/30/11
Outputs
Progress Report Objectives (from AD-416) 1. Determine emission reductions of 1,3-D using a modified (winged) application shank compared to standard application shanks (accomplished in the first year field trial). 2. Determine 1,3-D emissions from approved nursery treatments and surface treatments with tarp or irrigation. 3. Determine effects of surface soil treatment on weed, and nematode control efficacy. This is a multi-year project and research activities in the funding period will focus on collecting information on emission reductions and efficacy improvement using low permeable tarps. Approach (from AD-416) Two field trials and laboratory soil column tests are planned to achieve the study objectives. The research activities will take three years to complete. A first year field trial will focus on surface soil treatment including irrigation that produces different soil moisture conditions for fumigation and organic amendment with composted manure in a sandy loam soil. Soil column tests in the 2nd year will determine the effectiveness of different organic materials and soil moisture condition on emission reductions in a different soil type (clay loam), providing information for the following year field trial. A 3rd year field trial will be testing treatments after integrating the results from the first two years and test organic amendment with soil moisture effect on emission reductions in a clay loam soil. This Reimbursable Agreement supports Objective 2 & 3 of the parent project. Tree and vine nurseries in California must deliver crops free of economically important plant parasitic nematodes under the California Department of Food and Agriculture�s Nursery Stock Nematode Control Program, which is achieved mainly by soil fumigation. Adoption of alternative fumigants (e.g., Telone products) to methyl bromide (MeBr) in the nursery industry has been a challenge because they are less efficacious than MeBr. One field trial was conducted in the fall 2010 to determine more options for emission reduction and efficacy improvement by low permeability tarp, and totally impermeable film (TIF). Treatments included TIF and standard polyethylene (PE) tarp in combination with different fumigation rates (full, half, and quarter rate) of Telone C35. Fumigant concentration in air under the tarp (above soil surface), gaseous fumigant distribution in soil profile, and efficacy on pests (nematodes, pathogens and weeds) were determined. All sample analyses were completed and most of the data were compiled. Fumigant retention time and concentration under tarp and in soil all increased leading to higher soil fumigation Telone C35 concentration-time (CT) exposure indices under TIF than standard tarp. Half rate resulted in 100% pest control on nematodes or no differences from the full rate for most pathogens tested. TIF tarp at full fumigant rate yielded the lowest weed biomass in the treatment plots after 5 months of fumigation. Only the quarter fumigant rate showed <100% pest control on nematodes and pathogens although no differences from standard tarp for all rates were observed. To conclude how much fumigant application rates can be reduced under TIF tarp without sacrificing efficacy more field data are needed as soil conditions change. TIF is a long-term potential solution to reduce the environmental impact of soil fumigation and improving efficacy.
Impacts
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Progress 10/01/09 to 09/30/10
Outputs
Progress Report Objectives (from AD-416) 1. Determine emission reductions of 1,3-D using a modified (winged) application shank compared to standard application shanks (accomplished in the first year field trial). 2. Determine 1,3-D emissions from approved nursery treatments and surface treatments with tarp or irrigation. 3. Determine effects of surface soil treatment on weed, and nematode control efficacy. This is a multi-year project and research activities in the funding period will focus on collecting information on emission reductions and efficacy improvement using low permeable tarps. Approach (from AD-416) Two field trials and laboratory soil column tests are planned to achieve the study objectives. The research activities will take three years to complete. A first year field trial will focus on surface soil treatment including irrigation that produces different soil moisture conditions for fumigation and organic amendment with composted manure in a sandy loam soil. Soil column tests in the 2nd year will determine the effectiveness of different organic materials and soil moisture condition on emission reductions in a different soil type (clay loam), providing information for the following year field trial. A 3rd year field trial will be testing treatments after integrating the results from the first two years and test organic amendment with soil moisture effect on emission reductions in a clay loam soil. Documents Reimbursable with California Department of Food and Agriculture. Log 40551. This agreement was established in support of Objective 3 of the in-house project. Open-field perennial nurseries in California are required to produce clean crops under the CDFA nursery nematode control program, which is achieved by soil fumigation. Stringent environmental regulations, however, require low emissions from soil fumigation. The goal of this project was to identify effective methods that reduce emissions and improve efficacy in perennial nurseries. Two field trials were conducted to compare the effectiveness of totally impermeable film (TIF) on emission reductions in comparison with standard polyethylene tarp from shank-injection of Telone C35. Because the TIF can retain fumigants more effectively than standard PE tarp, the potential of using reduced fumigation rate under the TIF was tested by comparing the full rate and half rate on emissions and fumigant distribution over time in soil as well as efficacy data on selected nematode and weed species. Preliminary data show that the TIF can effectively reduce emissions. Other data are still being compiled and analyzed.
Impacts
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