Research Report 1.10

Assessment of the Influence of Manures for the Control of Soilborne Pests Including Fungi, Bacteria, and Nematodes

Dr. George Lazarovits, Pest Management Research Centre,
Agriculture and Agri-Food Canada, 1391 Sandford St,
London, ONT, Canada, N5V 4T3

COESA Report No.:  RES/MAN-010/97

Objectives & Expected Outputs
Executive Summary
Table of Contents

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Objectives and Expected Outputs

Objectives: To assess the potential use of manures and related organic materials for reducing plant diseases caused by soilborne pests.
Expected Outputs:
  1. To conduct an initial survey of a variety of manures (animal, poultry) from a various sources and in various stages of decomposition to determine whether these materials exhibit an ability to suppress Verticillium;
  2. To produce quantitative data as to the capacity of the "active" manures from various sources for reducing the survival of Verticillium and therefore controlling disease;
  3. To monitor changes in populations of beneficial microbes in the various types of manures;
  4. To identify factors which may influence disease control efficacy, such as: the source of the manure, rates of application, procedures used for composting, effect of soil type, etc. Treatments found effective in the laboratory will be field tested in microplots and on farm locations growing potato and tomato crops. Field observation will measure pathology, soil microbiology and agronomic changes in the crop plants tested. Information as to the appropriate methods of application of manures for disease control will be generated.
Type: Fed. Government, In-House                       
Spending Profile: 94-95: $20.0 K;    95-96: $40.0 K;    Total: $60.0 K

 

Executive Summary

The objective of this project was to determine if addition of manures to potato growing fields effects the severity of soilborne diseases. Two major soilborne diseases on potatoes in Ontario are Verticillium wilt caused by the fungus Verticillium dahliae and potato scab caused by Streptomyces bacteria. We used these two diseases as model systems to study the effects of manures on soilborne pathogens.

Results and conclusions:

  1. We developed a rapid and reproducible laboratory assay for determining the effect of manures on pathogens in a particular soil. The assay consists of mixing a small amount of manure with soil in test tubes. The mixture is incubated and the effects on pathogen populations determined by making serial dilutions of the soil onto semi-selective media. This assay gave the same results as field experiments more than 90% of the time. This assay is simple and rapid and allows for evaluation of many manure-soil combinations. This will enable us to provide farmers with information as to where certain manures can be safely applied and under what conditions.

  2. The effect of a manure on pathogens is determined by the soil to which it is added. Example: Chicken manure reduced the pathogen population in three out of four soils we tested. Thus, the fact that a particular manure reduces disease severity in one location does not guarantee it will do so at another location.

  3. Soil moisture can influence the effect of a manure on pathogens. Example: Liquid swine manure decreased the viability of V. dahliae in dry but not in wet soil.

  4. The most important factor that impacts on pathogens is the manure used. Example: In certain soils we found that fresh chicken and liquid swine manures decreased pathogen populations while solid cattle manure had no measurable effect. Wetting and aerobically incubating this chicken manure for one week destroyed its disease suppressive effect and may have increased the potential of potato scab. Thus, the impact on pathogens is determined by the source of manure and how the manure has been handled and stored.

Recommendations:

  1. Despite all that we have learned about why some manures are effective against pathogens and others are not, and why a manure can be effective in one soil but not another, there remains significant gaps in our knowledge. Manures and soils differ significantly in their chemical and biological properties and thus different manure-soil mixtures affect soil microorganisms in different ways. More research needs to be done so we can understand more about such interactions. Manures should not be looked upon as waste materials but rather as under utilized energy sources that can benefit soil microbial diversity.

  2. Potato growers should pretest manures with their soils to determine the impact on disease incidence. This can be done on a small section of their field or with our laboratory assay.

  3. Methods for manure handling, storage, and application need to be reevaluated to maximize the potential benefit of these products.

Table of Contents

Executive Summary 1
Overall Objective 3
Specific Objectives 3
Technology Transfer 3
Background 4
Influence of Manures on the Microbiology and pH of Soil From a Site Near Everett, Ontario Under Laboratory Conditions 7
Influence of Container Size and Soil Amendments on the Microbiology and pH of Soil From a Site Near Everett, Ontario Under Laboratory Conditions 20
Influence of Soil Moisture and Manures on the Microbiology and pH of Soil From a Site Near Everett, Ontario Under Laboratory Conditions 27
Influence of Soil Amendments on the Microbiology and pH of Soil From Sites Near Everett, Simcoe, and London Under Laboratory Conditions 36
Influence of Soil Amendments on the Microbiology and pH of Soil From Sites Near Everett, Simcoe, and London Under Greenhouse Conditions 57
Influence of Soil Amendments on the Microbiology and Chemistry of Soils at Two Ontario Field Sites and the Resulting Impact on Potato Diseases 69
Influence of Wetting and Aerobically Incubating Chicken Manure on the Microbiology and Chemistry of Soil From a Site Near Everett, Ontario Under Laboratory Conditions 114
Summary 119
Acknowledgments 121
Literature Cited 122

 


 

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Last Updated: May 16, 2011 02:30:58 PM