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
Evaluate the impacts of different organic carbon sources (cover crops, organic soil amendments) on the ASD process
- 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 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 performed for all cover crop/organic amendment treatments, and data was collected on soil redox potential (Eh), temperature, and moisture to evaluate whether adequate anerobic conditions were achieved.
Assess the short- and long-term impacts 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
- After the ASD treatment period (21-28 days), cash crops (i.e. strawberries, tomatoes) were planted in accordance with local growing practices and certified organic standards.
- Visual crop assessments, soil sampling, and biometric assessments were conducted at defined time intervals (every 30-45 days, depending on crop cycle) to evaluate any treatment effects on crop performance/quality, soil nutrient dynamics, and soilborne pathogens and pests.
- Crop 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.
Key Findings
Anaerobic soil disinfestation (ASD) may reduce the prevalence of nematodes and soilborne viruses in specialty crop production systems
- Significant treatment effects (ASD vs. Control) 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.
- Notably, at one of the Pennsylvania high tunnel sites with a history of dagger nematode-transmitted viruses, none of the tomato plants grown in ASD-treated soil 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.
Location
Florida, PennsylvaniaCollaborators
Region
Northeast/Mid-Atlantic, Southeast
Topic
Soil Health, Crop Nutrient Management, Weed Management, Disease Management, Insect/Pest Management
Category
Vegetables/Fruits
Year Published
2025
