SR9182 - Survival of pathogens during storage of livestock manures

Lead researcher

Dr. Ann Huber, Soil Resource Group (EDITOR"S NOTE: researcher's contact information not available)

Objectives

1. To compare the decline in indicator and pathogen populations over time in the major livestock manure types during storage under Ontario conditions.
2. To compare the decline in pathogen levels over time in static (no fresh manure addition) vs dynamic manure storage (fresh manure addition; standard Ontario practices).
3. To establish typical indicator and pathogen loads to fields at land application time.
4. To field verify the presence and magnitude of the main pathogens of concern for each manure type.
5. To identify some of the determinant factors for population declines in stored manure, and thereby identify possible two-tech options for reducing loading rates by storage management.

Expected benefits

The results will contribute to science-based development of standards and regulations relating to the Nutrient Management Act and will aid producers in manure management decisions aimed at reducing the pathogen risk to the environment resulting from land application of livestock manure.

Results

This study did not demonstrate large or consistent differences in pathogen reduction rates between covered and uncovered beef manure piles. However, covering manure piles has other benefits, in particular reducing contaminated runoff or leaching from piles and subsequent contamination of the surrounding environment. Pathogen die-off was much faster in the summer than in the winter, and hence shorter storage times are required in the summer to achieve significant reductions. While the current study was not set up to examine the effect of aeration, it was also observed that air entering the interior of the piles through the sampling tubes, promoted composting and hence pathogen reduction. This indicates that even passive aeration could be a beneficial management practice. The effect and management implications should be further quantified for Ontario

Because the broiler litter used in this study heated so quickly causing very rapid pathogen die-off, we were unable to demonstrate a difference in pathogen decline between any of the conditions tested (under roof versus outdoor storage; winter versus summer). However, storage of poultry litter under roof has the other environmental benefits of reducing runoff and associated pathogen and nutrient contamination of surrounding environment, and reducing odour and ammonia losses to the atmosphere.

Indicator and pathogen levels at the end of each storage period at land application time were determined for standard and modified manure management under winter and summer storage conditions. Potential E.coli loadings have been determined for typical application rates for each manure type for raw and stored manures.

In all cases, storage of manure without fresh additions, promoted pathogen reduction. The level of pathogen reduction achieved is a function of manure type, (liquid or solid, and percent dry matter), temperature, and time. This provides for some simple, cost-effective management options to achieve significant levels of environmental risk reduction. Seasonal differences in storage times required for pathogen reduction must be accounted for.

Related information

• Other projects which were funded through the New Directions Research Program in 2006