FARM COMPOSTING DEMONSTRATION

Existing Standards

According to BBC Laboratories, Inc. (Tempe, Arizona) the typical concentrations of microorganisms found in composts are within the following ranges per gram of compost at maturity (the numbers are written in exponential notation, where 1.0E=09 means that there are nine zeros before the decimal, or 1,000,000,000):

FUNCTIONAL GROUP MINIMUM MAXIMUM
Heterotrophic Bacteria (Aerobic) 1.0E+09 1.0E+10
Anaerobic Bacteria 1.0E+06 1.0E+08
Yeasts and Molds 1.0E+02 1.0E+04
Actinomycetes 1.0E+04 1.0E+06
Pseudomonads 1.0E+02 1.0E+04
Nitrogen Fixing Bacteria 1.0E++03 1.0E+06

The population distribution changes with the stage of decomposition. As changes occur in the level of nitrogen, temperature, and pH, and the material becomes more difficult to decompose, populations change.

The Composting Council (Alexandria, Virginia; E-mail: comcouncil@aol.com) suggests certain parameters to test for during the composting process (composting high rate) and at stabilization. The following table shows their recommendations:

PARAMETER COMPOSTING
HIGH RATE		 STABILIZATION STAGE
Carbon to Nitrogen Ratio 30:1 (beginning) - - - - -
Range 40:1 - 25:1 less than or = 20:1
Moisture 55% - - - - -
Range 45% - 60% 45% - 60%
Decomposition Temperature (deg.F) 113 113
Temperature Range (deg.F) 104 - 122 104 - 122
Pathogen Control 131 - 140 - - - - -

Moisture and temperature indicate when turning should occur during the composting high rate. The Compost Council has designed a plan for high maintenance, high processing rate in which stabilization can reached in six weeks or more. Other plans are based on less maintenance and can take up to six months for the compost to stabilize.