BBC LABORATORIES
Agricultural & Environmental Microbiological Services
[ Compost Tea Guide ]
What is compost tea?
Compost tea is typically made as an aqueous aerobic extraction of compost and contains both the soluble nutrients from the compost and the extracted portion of the microorganisms from the compost. Many times compost tea also contains nutrient supplements to help the microorganisms to grow after they are extracted.
Why is compost tea used?
Compost tea is used as a nutrient component for the plant and a microbial inoculant. Some compost teas contain organisms that specifically assist in activities such as stimulating plant growth and suppressing plant disease. Other compost teas may provide a general microbial population that serves to out-compete some plant pathogens for nutrients and other resources rather than to specifically inhibit the growth of a pathogen.
How is compost tea applied?
Compost tea is used both as a soil drench and as a foliar spray. It may be used full strength, although it is often diluted prior to use.
How does microbiological quality impact compost tea?
Since most compost tea users are depending on compost tea to serve as a microbiological inoculant of either soil or foliage, the concentration and variety of microorganisms present have a very significant impact on the compost tea performance.
[Click Here] for Microbial Concentrations
Species Richness Diversity in Compost Tea
What is species richness diversity (SRD)?
Species richness is a measurement of diversity that indicates the number of different types of microorganisms present in a sample.
This analysis results in an index number that characterizes the microbial complexity of the compost tea based on the analysis of six functional groups of microorganisms.
Why is microbial diversity important in compost tea?
A high species richness diversity in compost tea provides a greater chance that particular microorganisms needed for specific tasks, such as disease suppression, will be present. Additionally, a high microbial diversity also increases the pool of microorganisms available to meet the particular environmental conditions encountered after compost tea application. This results in a greater probability that organisms appropriate for survival under application conditions will thrive.
| Classification | Species Richness Diversity Index |
|---|---|
| High Diversity | > 8.0 |
| Moderate Diversity | 4.5 - 8.0 |
| Low Diversity | < 4.5 |
Pathogen Inhibition Assays for Compost Tea
Why test your compost tea in a pathogen inhibition assay?
Compost tea can be screened for microorganisms that can actively inhibit the growth of specific plant pathogens in a pathogen inhibition assay. This analysis is helpful in developing and identifying compost teas that have potential for disease suppression in a particular application. These assays are available for many plant pathogens in the BBC Laboratories culture collection as well as isolates from client locations.