We’ve been enjoying fresh garden produce the last few weeks, and my summer apple tree was loaded with fruit. The dry conditions forced me to water the garden a few times, but cooler August temperatures kept the stress on plants manageable. Most folks assume that the right combination of soil, water, and sunshine will produce lots of plant growth and fruit. That’s true, but only to a certain extent. It takes much more for a plant to be healthy and grow.
It’s well understood that we sometimes have to “feed our plants” with the proper fertilizers. I add lots of organic matter in the form of composted plant materials and manure to the garden soil every year. I have written before about how happy that makes my earth worms. Their feeding and tunneling certainly enhance the growing conditions. The compost wouldn’t be composted if it weren’t for much smaller creatures, though. Worms and bugs help break down the organic matter, and I can see them as they work. The real important work is being done by things I can’t see, at least not without at microscope. It’s microbes and masses of fungal filaments called mycorrhizae that are key to making good soil that can feed plants out of the various particles of sand, silt, clay, and organic matter. Some of the microbes are multi-celled organisms just below visual size while others are single celled bacteria so small that most microscopes can’t see them. Single fungal filaments are called hyphae, and they are basically living chains of cells only one cell wide. All these living organisms feed on the minerals in the soil and bits of organic matter. Their feeding turns those raw materials into usable plant food. Nor is it just a few species. There are literally hundreds of species and millions of organisms living and working in any spadeful of good soil. The more, the merrier! One of the problems with heavily cultivated soil is that it looses much of its microbial diversity.
Plant roots, by themselves, aren’t very good at pulling nutrients out of the soil. They need the help of all those other life forms. Mycorrhizal communities physically link with plant roots and exchange nutrient laden fluids at a cellular level. Photosynthesizing plants share sugars they have manufactured with the mycorrhizal community in exchange for the basic plant foods that microbes make available. Forests, prairies, and even my garden, with many kinds of plants are physically linked at the cellular level in the soil.
It isn’t so different with our human bodies. I read somewhere that there are far more non-human cells in and on a human body than there are human cells. It’s the human cells that we see and understand to be us, but, just like plants, they couldn’t function very well as human cells without the help of whole communities of microbes. Hundreds of species of single-celled microbes live on us and in us. We may think that our guts digest our food and turn it into basic sugars that feed various kinds of human cells. It would be more accurate to think of our digestive system as the place where digestion happens, and it happens to a large extent because a host of beneficial microbes live there to do the work for us. When that microbial community falls out of balance, our whole bodies can’t work right. We may say that we’re sick. Our skin is normally home to many kinds of microbes. Some are beneficial, some are just along for the ride, and a few are quite nasty little bugs that can cause infection and disease. When enough of the good and even indifferent microbes are around on our skin, there isn’t room for the bad ones to multiply.
Sometimes when we’re sick, doctors prescribe antibiotics. These drugs attack microbes, but, unfortunately, not just the bad ones. Sometimes they knock out enough good microbes that surviving bad microbes take over and make us sick in other ways. That’s why it’s important that we take some drugs only when absolutely necessary. Keeping our good bugs happy and healthy is a big part of keeping us healthy.
We’re never alone. No higher level multi-celled organism ever is. Every plant and animal (including us) is actually a whole community of living things most of which we can’t see. We wouldn’t even exist if it were not so.
Steve Lekwa is the former director of Story County Conservation. Contact him at firstname.lastname@example.org.