The Little Guys in the Soil

I know, I know, I’ve been very delinquent.  However I have been working hard, reading a lot and studying. I’m taking a Permaculture Design Course in San Diego on most weekends, and the information has been dazzling.  Even though I know a little or a lot of what is being presented, what amazes me is how related the information is and how it all works together.  For instance…

Gardeners know that the best pH for soil is somewhere around 6.5.  Higher or lower than that and the soil has too much acid or alkaline.  Here in San Diego we have alkaline soil.  Rainwater is excellent because it has a neutral pH.  What is so important about that neutral pH? Well, I’m going to tell you.  There are all kinds of nutrient in the soil in the form of trace minerals, such as iron, magnesium, copper, etc.  However these nutrients are bound up in the soil because of the pH… some are bound by a high pH, some by a low pH.  For instance, we have adequate iron in our soil, but because of the alkalinity, plants can’t access it and become iron deficient.  If you have neutral pH, then plants are able to feed themselves nutritiously.  To free up the iron, you should add mature compost and water as much as you can with collected rainwater.

Okay, so you knew all that.  So did I.  Here comes what I think is the interesting thing.

We know that the soil is teeming with little beings such as bacteria, fungi and nematodes.  Some are good, some are bad.  Such is life.  Picture if you will the soil in a forest, which has a lot of large materials such as logs and sticks being broken down by various fungus.  The soil in a vegetable garden, however, is loamy  with small particulate matter.  Well, in a forest situation, with an acid soil, there is high fungus activity and lower bacteria count in the soil. The soil isn’t usually turned over or bothered in any way.   In a vegetable garden, a slightly more alkaline soil is perfect because it has less fungus and more bacteria.  The soil is turned over frequently.  Weeds such as grasses prefer a pH range that is slightly more alkaline.  By changing the pH with the addition of different kinds of mulch, you can moderate the microbes in the soil, tipping the balance between fungi and bacteria, and edging out the grasses.  Cool, huh?

Fungus is extremely important where longer-lived trees are planted, because fungus travels underground, linking with the spreading roots of the trees and actually causing communication between them!  Fungus, it has been said, is nature’s Internet.  Mushrooms are called nature’s teeth, too, but that is an image that perhaps you just don’t want in your head.  Bacteria help soil that is often disturbed by helping leguminous plants fix nitrogen (yes, yes, I know, back to the darn legumes again), and help free up nutrients for the roots, usually by dying.  That’s not a happy thought but, again, that’s the way it goes.  If you till the soil, you kill off the bacteria and nematodes and fungus and all the other little critters.  There is a rise in fertility, but only briefly because that rise is the nutrition released by the decomposing bodies of all your soil critters!  Then there is just dead soil.  Then farmers pour on the salt-based fertilizers (NPK), which is just salting the land and making sure nothing can live in it. The crops grow, but since there aren’t any friendly critters freeing up nutrients, the resulting nutritional value of the produce is poor.  Only by mulching, composting, and cover-cropping can the soil come alive again, which nourishes the plants, which nourish us.

There is so much life in just a pinch of soil; so much going on that we still can only guess at.  To build up your soil with mulch, compost and organic practices is to give life to gajillions of life forms (yes, that many!) which all work to make your plants healthy, your food more nutritious, and gain back some of the topsoil that has disappeared through man’s blundering.

I hope this was as interesting for you as it is for me!