Thermal and Starvation Stress Response of Escherichia coli O157:H7 Isolates Selected from Agricultural Environments.

Pathogens exposed to agricultural production environments are subject to multiple stresses that may alter their survival under subsequent stress conditions. The objective of this study was to examine heat and starvation stress response of Escherichia coli O157:H7 strains isolated from agricultural matrices. Seven E.

Fate of Antibiotics and Antibiotic Resistance during Digestion and Composting: A Review.

Antibiotics and antibiotic-resistant bacteria (ARB) enter the environment through municipal and agricultural waste streams and pose a potential risk to human and livestock health through either direct exposure to antibiotic-resistant pathogens or selective pressure on the soil microbial community. This review summarizes current literature on the fate of antibiotics, ARB, and antibiotic resistance genes (ARGs) during anaerobic digestion and composting of manure and wastewater residuals. Studies have shown that removal of antibiotics varies widely during mesophilic anaerobic digestion, even within the same class of antibiotics.

Intermittent rainstorms cause pulses of nitrogen, phosphorus, and copper in leachate from compost in bioretention systems.

Bioretention systems rely on vegetation and mixtures of soil, sand, and compost to filter stormwater runoff. However, bioretention systems can also leach metals and nutrients, and compost may be a major contributor to this leaching. To safely implement bioretention systems, it is crucial to determine the composition of compost leachate.

Soil Parameter Mapping and Ad Hoc Power Analysis to Increase Blocking Efficiency Prior to Establishing a Long-Term Field Experiment.

The spatial heterogeneity of soil and weed populations poses a challenge to researchers. Unlike aboveground variability, below-ground variability is more difficult to discern without a strategic soil sampling pattern. While blocking is commonly used to control environmental variation, this strategy is rarely informed by data about current soil conditions.

Influence of Seeding Ratio, Planting Date, and Termination Date on Rye-Hairy Vetch Cover Crop Mixture Performance under Organic Management.

Cover crop benefits include nitrogen accumulation and retention, weed suppression, organic matter maintenance, and reduced erosion. Organic farmers need region-specific information on winter cover crop performance to effectively integrate cover crops into their crop rotations. Our research objective was to compare cover crop seeding mixtures, planting dates, and termination dates on performance of rye (Secale cereale L.

Long-term crop and soil response to biosolids applications in dryland wheat.

Biosolids have the potential to improve degraded soils in grain-fallow rotations. Our objectives were to determine if repeated biosolids applications in wheat ( L.)-fallow could supply adequate but not excessive N for grain production and increase soil C without creating a high risk of P loss.

Biosolids applications to tall fescue have long-term influence on soil nitrogen, carbon, and phosphorus.

Repeated applications of biosolids provide long-term benefits by increasing soil organic matter and N supply but can cause excess accumulation of P. Our objective was to determine the residual effects of repeated surface applications of biosolids on N availability and fate, tall fescue ( Schreb.) response, soil C, and P.

Gaseous nitrogen and bacterial responses to raw and digested dairy manure applications in incubated soil.

A study was conducted under laboratory conditions to compare rates of nitrous oxide (N(2)O) and ammonia (NH(3)) emissions when soil was amended with anaerobically digested dairy manure slurry containing <30% food byproducts, raw dairy manure slurry, or urea. Slurries were applied via surface and subsurface methods. A second objective was to correlate genes regulating nitrification and denitrification with rates of N(2)O production, slurry treatment, and application method.

Quantifying benefits associated with land application of organic residuals in Washington State.

This study was conducted to quantify soil C storage, N concentration, available P, and water holding capacity (WHC) across a range of sites in Washington State. Composts or biosolids had been applied to each site either annually at agronomic rates or at a one-time high rate. Site ages ranged from 2 to 18 years.

Validation of a 2 percent lactic acid antimicrobial rinse for mobile poultry slaughter operations.

Poultry processing antimicrobial interventions are critical for pathogen control, and organic, mobile operations in Washington seek alternatives to chlorine. Laboratory and field studies (three replications each) evaluated lactic acid efficacy as a chlorine alternative. For the laboratory study, retail-purchased, conventionally processed chicken wings inoculated with Salmonella were randomly assigned to the following treatments: Salmonella inoculation followed by no treatment (10 wings) or by 3-min rinses of water, 50 to 100 ppm of chlorine, or 2% lactic acid (20 wings for each rinse treatment).

Estimating plant-available nitrogen release from manures, composts, and specialty products.

Recent adoption of national rules for organic crop production have stimulated greater interest in meeting crop N needs using manures, composts, and other organic materials. This study was designed to provide data to support Extension recommendations for organic amendments. Specifically, our objectives were to (i) measure decomposition and N released from fresh and composted amendments and (ii) evaluate the performance of the model DECOMPOSITION, a relatively simple N mineralization/immobilization model, as a predictor of N availability.

Decomposition and plant-available nitrogen in biosolids: laboratory studies, field studies, and computer simulation.

This research combines laboratory and field studies with computer simulation to characterize the amount of plant-available nitrogen (PAN) released when municipal biosolids are land-applied to agronomic crops. In the laboratory studies, biosolids were incubated in or on soil from the land application sites. Mean biosolids total C, organic N, and C to N ratio were 292 g kg(-1), 41.