Quantifying the effects of anaerobic soil disinfestation and other biological soil management strategies on nitrous oxide emissions from raised bed plasticulture tomato production

Authors: LI, ZHOUNA - University Of Florida; DI GIOIA, FRANCESCO - Pennsylvania State University; ZHAO, XIN - University Of Florida; Hong, Jason; Rosskopf, Erin; WILSON, PATRICK - University Of Florida; Pisani, Cristina; PAUDEL, BODH - University Of Florida

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/2021
Publication Date: 2/1/2022
Citation: Li, Z., Di Gioia, F., Zhao, X., Hong, J.C., Rosskopf, E.N., Wilson, P.C., Pisani, C., Paudel, B. 2022. Quantifying the effects of anaerobic soil disinfestation and other biological soil management strategies on nitrous oxide emissions from raised bed plasticulture tomato production. Journal of Environmental Quality. https://doi.org/10.1002/jeq2.20324.
DOI: https://doi.org/10.1002/jeq2.20324

Interpretive Summary: Soilborne pests are a major obstacle that must be overcome for the production of horticultural crops. Methyl bromide was an effective soil-applied broad-spectrum biocide, but its use has been banned due to its role in depleting the ozone layer. As a result, sustainable alternative methods for controlling soil borne pathogens and pests are needed. Nitrous oxide emissions are of concern in crop production due to its role as a greenhouse gas. Agricultural lands are known sources for emission of this greenhouse gas into the atmosphere. Emissions are related to many environmental factors as well as fertilization and fumigation practices. This study evaluated the influence of different alternatives to methyl bromide on emissions of nitrous oxide throughout a tomato production season in two locations representative of southern and northern Florida. Specific soil management methods evaluated included: untreated controls; conventional chemical fumigation; anaerobic soil disinfestation using molasses and composted poultry litter; composted yard waste+molasses at two rates; Soil Symphony Amendment, (SSA) a commercially available mix of microbes and nutrients; composted yard waste alone, and composted yard waste+SSA. Nitrous oxide emissions were measured throughout the entire cropping season. Emissions were highest on the day of planting in all treatments due to gas accumulation beneath the totally impermeable film covering the beds and the season-long cumulative measurements were not significantly different between soil treatments.

Technical Abstract: Soilborne pests are a major obstacle that must be overcome for the production of horticultural crops. Methyl bromide was an effective pre-planting soil broad-spectrum biocide, but its use has been banned due to its role in depleting the ozone layer. As a result, sustainable alternative methods for controlling soil borne pathogens and pests are needed. Nitrous oxide emissions are of concern in crop production due to its role as a greenhouse gas. Agricultural lands are known sources for emission of this greenhouse gas into the atmosphere. Emissions are related to many environmental factors as well as fertilization and fumigation practices. This study evaluated the influence of different alternatives to methyl bromide on emissions of nitrous oxide throughout a tomato production season in two locations representative of southern and northern Florida. Specific soil management methods evaluated included: untreated controls; conventional chemical fumigation; anaerobic soil disinfestation technique using molasses and composted poultry litter; composted yard waste+molasses at two rates; Soil Symphony Amendment (SSA), a commercially available mix of microbes and nutrients; composted yard waste alone, and composted yard waste+SSA. Static chambers were used to collect gas samples. These were sealed to the plastic mulch using vacuum grease. Each chamber was equipped with a silicone/PTFE septum mounted at the top of the head space and sealed to the bowl with epoxy cement. A gas-tight plastic syringe attached to a 10 cm long metal needle was used to withdraw 10 mL of air entrapped within the static chambers. Air samples were transferred into non-coated Vacutainer sampling tubes and immediately stored in a cooler on ice. To collect N2O flux measurements, four gas samples were collected from each chamber at 15 min. intervals following collection of the first with a total of five samples per replicated plot. Air samples were stored in a freezer (-20 ºC) in the laboratory before analysis. Nitrous oxide concentrations in samples were measured by gas chromatography (GC) using an HP 5890 Series II GC equipped with an electron capture detector (ECD) and an 80/100 Porapak Q stainless steel column. Nitrous oxide emissions were measured throughout the entire cropping season. Emissions were highest on the day of planting in all treatments due to gas accumulation beneath the totally impermeable film covering the beds and the season-long cumulative measurements were not significantly different between soil treatments.