Thursday, July 18, 2013

Is there such a thing as organic compost

A friend of mine wanted me to address a question she fielded one day: "Is there really such a thing as organic compost?"

There are two kinds of organic: one is biological, one is a fabricated label. The former refers to  the carbon content of a material, the latter refers to the  method and the level of chemicals used in the growing process.

In terms of the biological sense, ALL compost is organic. It is the accelerated biological process by which microbes physically break down the biologically organic aspects of a material. But, as all things are a mixture of organic compounds and inorganic compounds (water for example is inorganic---it has no carbon; a tree is made of carbon, water, nitrogen, and minerals) there are inorganic residues in all composts. In the industry, we use  a test called the "organic matter" test to determine what percentage of the finished product is organic, what percentage is inorganic (minerals, i.e., "soil"--in other words, little particles of sand silt and clay.) so for this reason, NO composts are completely organic.

Confused yet?

As for the other type of organic, the one subject to labels and laws, there are certainly many ways to achieve that level of certification. It is the same process by which you certify your tomatoes--know the origin of everything you put into it. That means verify the "organic-ness" of  the feed for the animals that contribute the manure, verify the carbon source. In extreme cases, insist that the chainsaws used to cut the tree branches use organic vegetable oils rather than petroleum based oils. There are some materials that are specifically banned in "organic" composts--biosolids mainly but also construction glues and paint.  You then have to document it and submit those documents to the certifying organization for approval.

I think the bigger question should be directed towards the quality of the compost. It is well documented that compost is an excellent bio-remediator. It is used to clean contaminated soil, it is used to increase the infiltration properties of soil, it is used to increase the bio-diversity of the topsoil layer. But that same remediation property also pertains to the materials that go into it. The  microbes present in the compost pile don't care if the carbon they are eating is a carbon from a certified organic tree or from petro-carbons (diesel fuel). If a pile is fully composted and cured and managed properly (the specifics of its ingredients were taken into account and the recipe tweaked accordingly) there will be every benefit to the soil, whether the initial ingredients were certified organic or not. By the same token, if a pile is built using only certified organic ingredients but mismanaged, not fully composted, nor cured, it could  prove temporarily detrimental to your over all project.

The decompostion of organic matter is going happen regardless of whether we want it to. Some areas of the world have the right environmental conditions to make this rapidly occur naturally. The southwest does not. Until we collectively reach a good balance of organic material in our soils, I think our time and energy should be spent correcting that imbalance. The semantics of whether it's organic can come later