BBC LABORATORIES
Agricultural & Environmental Microbiological Services
[ Compost Analysis ]
Compost Microbial Profile
Six Functional Groups are analyzed for compost - always for concentration and sometimes for diversity. The groups include:
- -Heterotrophic Bacteria (Aerobic)
- -Anaerobic Bacteria (including facultative anaerobes)
- -Yeasts and Molds (Fungi)
- -Actinomycetes
- -Pseudomonads
- -Nitrogen-Fixing Bacteria (Free living)
Compost Maturity
What is it?
This analysis is a group of tests used to determine the potential phytotoxicity (toxicity to plants) that may be associated with the compost. All tests are conducted on an extract from the compost that is very similar to what the plant experiences in the presence of the compost and all tests are conducted with both the full strength extract as well as a diluted extract. It includes the maturity index (the impact the compost has on germination and root tissue development) as well as conductivity and pH measurements.
Why is it important?
Immature composts contain more substances that inhibit plant growth than mature composts. Immature composts can cause substantial damage to crops.
Compost Stability
What is it?
Compost stability refers to the degree to which the compost has been decomposed to more stable materials. Compost stability analysis is determined through a process called respirometry which measures the amount of oxygen utilized by a specific quantity of compost under conditions appropriate for microbial growth. Stable compost will have a lower respiration rate than unstable compost.
Why is it important?
Unstable compost can cause nitrogen deprivation to plants under certain circumstances and it can also cause problems when bagged for retail sales.