When her honour, Lieutenant Governor Judith Guichon, a rancher herself, was here to kick off the new Applied Sustainable Ranching program at our local Thompson Rivers University campus, she reminded us that 2015 is the UN year of the soil.
In doing so, she mentioned the billions and billions of living microorganisms that dwell in topsoil. These organisms take from the atmosphere 95 per cent of what plants need to grow: carbon, oxygen and nitrogen.
The rest comes from the mineral, organic and chemical components of soil. Unless you specify, soil samples from most labs don’t give you a biological assay of what is in your soil.
One would think given this is the “year of the soil” this might change. I don’t know if it has.
For the soil microbiology to do its magic, it needs to have air in the soil. These are called aerobic processes. If the soil is compacted by machinery, animals, or chemical salts applied too generously (how much is too much?) then aerobic processes can’t work and anaerobic (without oxygen) processes take over.
As I understand, alcohol is one of the products created under these conditions. Roots stop growing down in the soil when they reach this compacted layer, because they don’t like alcohol.
Deep rooting creates and maintains deep topsoil and increases the availability of nutrients and minerals available at deeper horizons.
I have been doing some digging in my fields and have noted earthworms as deep as three feet or more; this excites me because I know that roots looking for nutrient can follow the worm paths.
Perhaps the most encouraging measure of soil health happens when more and more litter — dead plant material — is left on the surface.
This provides insulation so the soil doesn’t freeze as easily and therefore the biological life can function for a much longer season and produce plant food. This kind of soil warms earlier in the spring and therefore growth is earlier. Bare and compacted soil freezes faster and growth stops.
We know when organic matter in the soil gets used up the protein content of plants grown there is reduced.
This has happened in our “breadbasket” — the Prairies. We know, though, that soil can be restored to original organic content in a few years by using the original plant communities (seeded often) to jumpstart restoration. Work on this has been done at the land Institute in Kansas.
David Zirnhelt is a member of the Cariboo Cattlemen’s Association and chair of the advisory committee for the Applied Sustainable Ranching program which is starting at Thompson Rivers University in Williams Lake this January.