Soil life.
Less obvious, but just as important, are the microbes inhabiting the soil, and these too should be cherished and nurtured (at least most of them). Imagine for a moment if there were no "decomposers," the various insects, slugs, snails, earthworms — and microbes — inhabiting the soil, responsible for breaking down organic matter. We'd soon be up to our eyeballs in piles of leaves, grass clippings, branches, and any other organic matter that falls to the ground! (Not to mention that our compost piles would get very big, very quickly.)

Then plants would begin to die off, since they depend on these decomposers to break down organic matter, in the process releasing the nutrients within. Without the activity of these saprophytes (organisms that draw their nutrients from dead and decaying organic matter), carbon, nitrogen, sulfur, and other elements essential for plant growth would remain locked in large, insoluble organic molecules. By breaking down these large molecules, the microbes effectively "recycle" the nutrients so they can once again enter the biological cycles.

In effect, these "magicians" transform waste materials — kitchen scraps, grass clippings, manures — into valuable fertilizer!

The legume/bacteria connection.
We've mentioned several times throughout this course the relationship that forms between legumes (such as beans and peas) and nitrogen-fixing bacteria that form nodules on the plants' roots. The legumes benefit by the increased availability of nitrogen; the bacteria benefit from access to the carbohydrates manufactured by the plant.

This is a good example of a mutualistic relationship — both organisms benefit, and, as far as we know, neither does harm to the other. It is also a good example of a relationship with a high degree of specificity. Different strains of the nitrogen-fixing Rhizobium bacteria will form relationships with certain legumes, but not others.

Well, I think you get the point—not all microbes are bad, and some are very, very good. Perhaps you’ve heard the adage, "Feed the soil, and the soil will feed the plants." Now you know that when you take care of your soil, you are taking care of the millions and millions of microbes that live there. And you won't want to do anything to the soil that might harm this important, if invisible, community.

I'm done with my cheerleading — and you feel all warm and fuzzy toward our microbe friends, right? ....Think again....