WHAT ARE THE CHARACTERISTICS OF HEALTHY SOIL?
Tillage rips up the soil-based fungal network that would otherwise be available to help plants obtain nutrients and water from the outer reaches of the root zone.
A conversation with geologist and soil scientist Dr. David R. Montgomery of the University of Washington. For the entire interview, please click on the link.
HART HAGAN: What are the characteristics of healthy soil?
DAVID MONTGOMERY: There are two things I like to look at in terms of defining characteristics of healthy soil. One is the soil organic matter content.
Now, you can't put a number on it, like X percent organic matter equals Y amount of soil health because it matters where you're located. A high soil organic matter content in Arizona, for example, would be a pathetic one in Iowa.
But the other way to measure soil health is through soil life.
It gets more complicated when you bring in the measure of soil life because how do you measure it? How do you track it? You can look at microbial respiration, which is the activity of breathing in and out of life in the soil.
You could also look at the diversity of life in the soil, as a measure of soil health. In effect, healthy soils tend to have an abundance and diversity of life relative to what you would expect for a particular region.
You'd want to measure soil organic matter and have some measure of the abundance and activity of life in the soil. And there are various measures that have been proposed for how to do that.
One of the tricky bits is, how do you then interpret your results? Are you measuring it relative to the potential for a site? It gets more complicated when you start looking into it.
It's like human health in that regard. We have a couple simple things we can measure to gauge human health. There's our body temperature, the oxygen content of our blood, our blood pressure. There's a number of numbers that we can come up with to try and gauge health.
But no one of those numbers really tells you about the health of any particular human. It's a much more integrated kind of a thing. Soils are similar. You have to gauge it in context, and you have to gauge it from a number of angles.
If you look at the abundance of soil life and soil organic matter, there's a lot of unhealthy soil on farms around the world today. But that can actually be fixed.
I think that can be turned around. I don't think it's inevitable that we degrade the land to feed ourselves. We could flip that on its head.
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For the entire interview, please click on the link.