Teaming with Microbes: The Organic Gardener’s Guide to the Soil Food Web by Jeff Lowenfels and Wayne Lewis (Review)
Teaming With Microbes is an illuminating book on the soil food web, the life underneath your feet that new gardeners, or simply uninformed gardeners, so often ignore.
Authors Jeff Lowenfels and Wayne Lewis have done an enormous amount of research on the co-evolution of plants and their surrounding soil microbes, insects and animals. While this can be a very complicated subject, they’ve done an excellent job of putting a difficult science into terms that most will understand.
In the food chain which we’re all familiar with from grade school science, the larger dominant creatures eat the smaller creatures to survive. But in the Soil Food Web, small and large creatures, the soil, and plants are interdependent, much more so than in a food chain.
To simplify the concept into a paragraph, plants (including grass) use photosynthesis not only to grow leaves, but to produce chemicals which they secrete through their roots (much like perspiration in humans). These chemicals, called exudates, attract beneficial bacteria and fungi, which unlock the nitrogen, phosphorous, potassium and other elements in the soil which plants use to prosper. The bacteria and fungi consume these exudates and are then eaten by bigger microbes (nematodes and protozoa), all of which action takes place in the root zone. Those protozoa and nematodes are eaten by larger nematodes and arthropods, which are in turn eaten by even larger arthropods and nematodes, which are then eaten by animals and birds. Earthworms feed on just about everything smaller than themselves and are a general indicator of soil health (more worms=better soil). All of this burrowing and activity just below the soil surface results in spaces or pockets through which air and water travel, carrying nutrients, and plant roots grow.
So what happens when a gardener introduces chemicals into this scenario? Quite simply, it disrupts the soil food web, creating toxins for some, warding off others, compacting your soil, and changing the relationship between the plants, bacteria, and fungi. More and more synthetic chemicals have to used every year to get the same yields (or the same green grass) and control the same pests. The authors explain:
“Important fungal and bacterial relationships don’t form when a plant can get free nutrients. When chemically fed, plants bypass the microbial-assisted method of obtaining nutrients, and microbial populations adjust accordingly… Once the bacteria, fungi, nematodes and protozoa are gone, other members of the food web disappear as well. Earthworms, lacking food and irritated by synthetic nitrates in soluble nitrogen fertilizers, move out…Soil structure deteriorates, watering can become problematic, pathogens and pests establish themselves and gardening becomes a lot more work than it needs to be.”
So what’s the key to keeping the food web intact? In a word, COMPOST (and compost tea). Spread two inches of it (preferably homemade) on all of your garden beds, around shrubs, under trees and on your lawn this year instead of fertilizers, pesticides, or herbicides (Use a clean fertilizer spreader to distribute the compost on the lawn). Cover the compost with a natural mulch (except your lawn), and let the soil food web go to work. Initially, you may notice a few growth problems, due to your garden or lawn’s chemical dependence. But within 6 months to a year, your garden beds, shrubs and trees should adjust – you should notice a marked change in the texture and color of your soil.
If your plants need an extra boost while they’re adjusting, try any of these: compost tea (best), fish emulsion, soybean meal, corn gluten meal, alfalfa meal, blood meal, or cottonseed meal (most are available at garden centers). All of these are consumed by the MICROBES in the soil, not the plants, so they’ll start performing their magic in a short time and bring your lawn and garden back into balance, which will reduce stress on your plants, reduce your workload and restore the parts of the soil food web which are lacking.
I highly recommend Teaming With Microbes – it’s full of useful information.