For those who want to create or maintain good healthy soils, whether they be home gardeners or farmers, here are a few simple guidelines to follow.
- Avoid fast-acting high-analysis fertilizers, especially in liquid forms. Your important soil organisms are not adapted to big bursts of nutrients. The use of strong synthetic fertilizers (10-10-10, urea, ammonium nitrate, etc.) will eventually result in lifeless compacted soil and salt buildups. If liquids must be used, I suggest well-diluted fish and kelp. If chemical-type fertilizers must be used, try gradual-release (osmocoated) types supplemented with trace minerals. Low-analysis dry organic types (many now available - see www.groworganic.com - work best for sound biological systems.
- Work the soil as little as possible. No-till is best, limited-till is next best, plowing is next best, and rototilling is the worst. The more you can avoid disturbing the established biological communities and earthworm tunnels underground, the better.
- Mulch with organic materials that will decompose. Try to add organic matter from the top rather than tilling it into the soil. After earthworm populations build up in the soil underneath mulch, it will quickly disappear as the worms feed on the bottom layer. Grapes, fruit trees, and berries are great candidates for a mulching program. Also, apply mulch between rows in a garden and cover bare spots in flower beds.
- Add useful organisms, such as nitrogen-fixing bacteria for legumes and mycorrhizal fungi spores at planting time. These can be dusted on seeds or transplant roots, blended into the soil, scattered in planting holes, or added to seed starting mixes. Plants that have the right types of beneficial microbes on their roots can uptake far greater amounts of nutrients and moisture.
- Do bio-assays to take the guesswork out of soil improvement. Soil Foodweb, MycoRoots, and other labs can give you a biological profile of your soil, much like soil-chemistry tests (which I find are still recommending strong additives like superphosphate - quick death to mycorrhizal fungi). Find ways to keep the living things in the soil prospering, and your plants will also do well. If you don't want to do bio-assays, just stick a shovel into the ground and see if you have lots of earthworms. (If you have trouble getting the shovel in, that's the first signal of soil problems, and it's not just that the soil is clay. Go dig next to a nearby wild shrub or grassy patch. Easier? That's what you are aiming for - soil kept loose by living microorganisms.)
- Don't let the soil lie bare. Even temporary cover crops in for just a few weeks can provide nutrition for microbial life in the soil, plus they contribute valuable organic matter as their roots decompose. Cow peas, annual clovers, and ryegrass are just a few of the many choices available.
- Use varieties that have not been developed for chemical fertilization. In general, older varieties (including some earlier hybrids) seem to be much more responsive to biological growing methods than newer varieties specifically bred for synthetic fertilizers.
If you can't do all of the above, just look over the list of possibilities and do any that fit your situation. Each step can help your soil. (I realize that some of these steps may be difficult for big farms but all should be fairly easy for home gardens or market growers.)
I'm often asked about how to convert a lawn away from chemicals. First, use a mulching mower to recycle the cut blades of grass - this is pretty much a must-do. Contrary to a popular belief, this will not cause thatch to build up. Thatch is a signal that the soil is lifeless - killed off by overuse of liquid fertilizing services, weed-and-feed "lawn food" and fungicides. For a lawn with healthy soil, the cut blades get eaten on nearly the first bounce. Also, set your mower a little higher, mow a little more often, top-dress with compost once or twice a year, add mycorrhizal spores plus minor and trace minerals (our MycoMinerals is excellent for this), and fertilize only with slow-acting forms (see above) when necessary.
You might also try to lose the notion that a nice lawn must have a very dark green color. In many cases, that's a sign of way too much nitrogen - not healthy for turf in the long run, and the excess runoff of N is a looming disaster for many cities that rely on well water.
It's not complicated, folks. It might be more effort, but there are payoffs.
Good growing, my friends,