Enhancing the Sustainability of Organic Specialty Crop Production Systems via Anaerobic Soil Disinfestation

Project Director: Francesco Di Gioia, Pennsylvania State University

Project overview

Soilborne plant pathogens and root-feeding nematodes can severely limit yields in organic specialty crop systems. Conventional soil fumigants, although effective at eliminating these pests, can also destroy important soil microorganisms and are not permitted in USDA certified organic production systems. As such, there is a need for natural pest/pathogen management solutions in organic specialty crop systems. 

Anaerobic soil disinfestation (ASD) is a NOP-compatible, soil-friendly alternative to fumigation in which decomposable organic material is tilled in, then the soil is covered with an air-tight tarp and drip-irrigated to saturation. The resulting burst of anaerobic activity inhibits crop pathogens and promotes a disease-suppressive soil microbiome when aerobic conditions are restored. 

This study analyzes the soil health impacts and efficacy of ASD in managing key soilborne pests and pathogens in organic vegetable and strawberry production systems in Florida and Pennsylvania.

Farmer takeaways

  • Anaerobic soil disinfestation (ASD) may be an effective, economic, NOP-compliant method for managing/reducing soilborne pests, pathogens, and nematodes in organic specialty crop production systems, including vegetables and strawberries.
  • Primary barriers of widespread implementation of ASD as a natural pest management method for organic specialty crop production systems include: (1) lack of knowledge and training, and (2) material cost. Information dissemination and farmer-to-farmer knowledge sharing is important for understanding the potential benefits and technical requirements of ASD.

Project objectives and approach

Assess the short- and long-term impact of ASD on soil ecology and microbiome dynamics in organic specialty crop systems, examining any consequent/interacting effects on nutrient dynamics, soilborne pests and pathogens, and overall soil health

  • Replicated randomized trials were conducted at open field and high tunnel vegetable and strawberry production sites in Florida and Pennsylvania. The trials evaluated cover crops (mowed vs. tilled in) and organic amendments (wheat middlings, molasses, soybean meal, poultry litter, and combinations thereof) as organic carbon sources to support the ASD process.
  • Anaerobic soil disinfestation (ASD) was initiated for all treatments, after which soil oxidation-reduction potential sensors were installed in each plot to monitor soil redox potential (Eh) during the ASD treatment for 21-28 days. Additional data on soil temperature and moisture was collected and processed weekly.
  • Visual assessments, soil sampling, and biometric assessments were conducted at defined time intervals (every 30-45 days, depending on crop cycle) to evaluate any treatment effect on the crop, soil nutrient dynamics, and soil microbiome.
  • Plant samples were measured for fresh and dry weight, and tissue samples were collected and analyzed for nutrient content. At harvest, produce was analyzed for quality and yield.

Optimize and evaluate opportunities for integrating ASD in organic specialty crop systems as a biological method to enhance soil health and manage soilborne plant pathogens, nematodes, and weeds

Key findings

Anaerobic soil disinfestation (ASD) may reduce the prevalence of nematodes and soilborne viruses in specialty crop production systems

  • Significant treatment effects (cover crop incorporation, organic amendments) were observed for bacterivorous, fungivorous, omnivorous, and predatory nematodes. However, no treatment effects were observed for plant-parasitic nematodes, of which population sizes were consistently small.
  • None of the tomato plants grown in post-ASD treated soil at a commercial Pennsylvania high tunnel with a history of dagger nematode-transmitted viruses developed viral symptoms. Detection of virus-transmitting nematodes decreased significantly post-ASD (75% to 6%).

Anaerobic soil disinfestation (ASD) may lead to higher gross returns in organic specialty crop production systems (i.e. strawberry), despite higher labor and materials costs

  • A financial analysis indicated that, for the strawberry trial, ASD treatments led to higher gross returns than the control in both growing seasons. The net return of the ASD treatments varied with the carbon and nitrogen application rates, as well as by season.
  • No negative effects of ASD were observed in strawberry fruit quality attributes.

Resources

USDA - Project Report - OREI 2021-51300-34914

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Location

Florida, Pennsylvania

Collaborators

Region

Northeast, Southern

Topic

Soil Health, Crop Nutrient Management, Weed Management, Disease Management, Insect/Pest Management

Category

Vegetables/Fruits

Year Published

2025