I love the word soil. It has a round, lush sound. Dark, moist, full of magic. When people say “dirt,” I am so disappointed. The word sounds harsh, dry and lifeless to my ears.
Everything we grow depends on soil. How can we care for our soil? What does it mean to treat soil well or poorly? And what is soil anyway?
Soil is composed of two parts: minerals, which make up the non-living part, and biota, minute creatures which bring the soil to life. Some soil biota help to build the soil and support healthy plants, and we call these beneficials. Others can cause problems for gardeners, such as root rots, molds and mildews, and are considered pathogens. But both play important roles in growth and decay cycles in the natural world.
Who are these critters that make the soil come alive?
A spoonful of ordinary backyard soil may contain billions of bacteria of thousands of different kinds, which help water move through the soil more easily and ward off soil diseases, as well as recycle organic matter. Then there are the earthworms that tunnel through the soil and add their castings which promote healthy plant roots and feed many soil dwellers. Arthropods feed on bacteria, fungi and earthworms, keeping soil life in balance. Nematodes support root growth and pass vital nutrients along to plants through their manure. Then there are the soil-dwelling protozoa – single-celled organisms that eat bacteria, keeping the bad bacteria in check.
And then there are the fungi, which are vitally important to soil health. Beneficial forms are found in virtually every kind of soil on earth. Healthy soil supports the growth of a fungus known as mycorrhiza. Here is a fungus that every gardener should know about. This knowledge may well change the way you garden.
Mycorrhizal fungi establish a symbiotic relationship with the roots of 95 percent of the earth’s plants. The fungi attach themselves onto the roots of trees, shrubs, flowers and vegetables, and then extend way out into the surrounding soil, as much as 200 times further than the roots of the plants themselves.