ACS Value

Midwest Bio-Systems Creates the Best Value Compost

Because of Midwest Bio-Systems’ belief that compost should be a highly beneficial product for the soil and plant, we have never limited ourselves to the usual government or industry standards for determining compost value.

Government entities addressing the issue of compost standards take a “public health” approach to compost. Their regulations will invariably be concerned with what is not in the compost — disease pathogens, heavy metals, and other “constituents of concern.” So a “Grade A” or “Class 1″ label can be applied in many places where the only criterion is what’s not in it. Such an approach tells us little about a compost’s benefit to the soil and plant.

Secondly, there is a “waste management” approach. It essentially wishes to reduce the volume of organic waste, which composting does well, and “make it disappear.”

Composting organizations take a broader view and show deeper interest in the soil value of the compost product. Composting organizations were, however, not formed to promote one form of composting over another, but to advance the concept and practice of composting in general. It behooves them to adopt standards which their members will accept and embrace.

In states where attempts have been made towards adopting demanding criteria, organization officials typically find the veteran composters balking. Little have they realized that the commitment to excellence would multiply the value of their finished product both at the marketplace and in the soil.

Beyond the public health and waste management issues, compost organizations have succeeded in identifying middle ground acceptable to their constituents for definitions of quality. Tests such as pH, soluble salts, an NPK approach to nutrient content, moisture levels, organic matter, maturity (phytotoxicity), stability, and particle size may be included.

This is good and valuable information. Nevertheless it lacks the measure of quality we (MBS) require to call a finished product, ACS Quality. Remember our purpose is to beneficially affect plant roots now as well as energy and nutrient conversion months from now.

Midwest Bio-Systems determines compost quality by:

What the profile of the microbiological assay shows regarding the finished compost product (diversity of species, enumeration of microbes, and aerobic:anaerobic ratios)?
How soil health is improved
How crop yield is increased
How plant health is enhanced
How production costs are reduced while simultaneously generating additional income.

What should be included in these optimum standards?

Sulfides and sulfates: A quality compost should test 0 parts per million (ppm) for sulfides at all times. The producer wants the sulfur in his product to break down with oxygen and form sulfates. A process which has become anaerobic causes sulfur to break down with hydrogen and form sulfides, which can be toxic to plant life and hinder microbial proliferation.

The nitrogen process: Our goal is to have nitrogen in the nitrate form NO3 at levels in the 600-900 ppm range. Many composters focus on %N and interpret value in the soil by the level of N. This approach does not look at in what form the N is held. Is it unstable and odor producingammonia or the stable and odorless nitrate? Users err in evaluating compost by the same criteria they use to evaluate a fertilizer. The compost user does not amend the soil for the purpose of nutrient content as much as for introducing beneficial biological activity, which also impacts soil physics and chemistry. Vicki Bess of BBC Labs in Tempe, AZ writes in her literature, “Populations of these free living nitrogen-fixing bacteria will proliferate as the available nitrogen in the compost decreases. As a consequence there is typically an inverse relationship between biologically available nitrogen in the compost and the concentration of free living nitrogen-fixing bacteria.” Those beneficial bacteria are what the compost end user covets.

In compost, N-P-K and trace elements are encapsulated in the humus and stored until beckoned by the plant—thus producing high energy with long term beneficial plant growth, if the humification process is proper.

Conductivity: Many composters across the country and around the world treat high salt levels as an impassable barrier. But again, an effective humification process allows effective transformation of many salt ions in manure and other compost feedstocks to a benign substance. It is critical to have sufficient negatively charged ions present in the compost windrow. If the composter does not endeavor to get his windrows into the humification phase, the salt problem in the soil will worsen. We have observed soil sodium levels go from 799 ppm (before ACS compost was applied) to 53 ppm after ACS compost was applied (rate of 7 tons/acre) while the accompanying base saturation percentage of sodium lowered from over 29% to below 3%. The quality of the compost makes the difference.

Redox potential: A redox reading outside the desired 26-29 range indicates the materials have variously gone anaerobic, too dry, or too wet.

Microbiology analysis: Here we learn what is in the compost. The greater the diversity and quantity of beneficial microbes, the more valuable and effective the compost will be in disease, weed, and insect suppression.

We would like to see at least a 10:1 ratio of aerobic to anaerobic bacteria (ten aerobes for every one anaerobe). We learn about the number of fungi, actinomycetes, pseudomonads, and nitrogen-fixing bacteria living in the compost from the microbiological assay.

Diversity promotes numerous interspecies relationships and interactions. More varied and flexible response to environmental stresses and fluctuations are therefore possible.