No-till gardening feeds the soil
In no-till plots, the soil is not plowed, which reduces water runoff and evaporation losses.
At bottom, gardening is all about dirt — its care and feeding, its microbes and fungi, bacteria and earthworms.
Science has gradually recognized that the soil’s vibrant but delicate food web must be treated carefully to produce the best yields. Turning the soil before planting is generally conceded to be more disruptive than building it up year after year with rich natural substances.
“We lose organic matter whenever we till the soil,” says Mark Alley, an agronomist and professor of soil fertility and management at Virginia Tech. “That practice adds up a lot when you think about certain areas of Virginia having been tilled for more than 400 years.”
No-till growing means adding layers of plant and animal matter to the topsoil rather than plowing, shaping, and otherwise disturbing it.
“It reduces runoff and evaporation losses, increases organic matter in surface soils, which increases the rooting environment for seeds,” Dr. Alley says. “All this makes things more productive.”
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The same planting principles apply to backyard gardens. They vary from farm fields only in scale and in varieties grown.
The first year is the hardest for no-till practitioners. The ground must be cleared of debris, weeds and other obstructions before nutrient-rich compost and protective mulch can be used.
“Initially, some digging of perennial roots may be required,” says Charles Dowding, a commercial gardener and author of “Organic Gardening the Natural No-Dig Way” (Green Books). “If the soil is full of durable perennial weeds, a long-term (smothering) mulch for a year is worthwhile. It becomes much easier thereafter.”
The essence of no-till gardening is staying ahead of weed growth, not allowing weeds to seed and creating a clean plant bed with just a few weed seeds germinating, he says.
“In my garden, I manage, almost single-handed, over two acres of weed-free vegetables, fruit trees and bushes, flowers and herbaceous plants with lovely clean soil that I need to spend very little time weeding, compared to most of my neighbors,” says Mr. Dowding, from Somerset, England.
Because no-till encourages the soil food web to become so active, fewer nutrients need be added, and only soils with deficiencies will require synthetic minerals, he says.
“The only additions I make are occasional rock dust, from volcanic basalt, and seaweed. I am not certain that the soil needs them but I have a feeling that many soils are low on trace elements and therefore benefit from small additions of these intensely rich soil foods,” Dowding says. “Adding them to compost heaps is another way of making extra health available.”
Digging up the soil to destroy weeds is a failed practice, says Jeff Lowenfels, a lawyer from Anchorage, Alaska, and co-author of “Teaming With Microbes: A Gardener’s Guide to the Soil Food Web” (Timber Press). It only encourages weed growth by exposing seeds to sunlight, he says.
“Heck, we’ve all seen plants grow through pavement,” Mr. Lowenfels says. “They don’t need tilled soil. The least amount of disturbance when planting in a garden is best.”
Soil, then, is a great deal more than just the granular stuff holding plants erect. It teems with life but like any vigorous thing, must be nourished.
“In organic growing situations, the gardener has to make sure the microbes are getting enough food so that they can feed the plants,” Lowenfels says. “I call organic fertilizers ‘microbe foods,’ which is what they are.”
For more about no-till gardening, click on the Oregon State University Extension Service Web site.
http://features.csmonitor.com/gardening/2009/03/17/no-till-gardening-feeds-the-soil/http://extension.oregonstate.edu/news/story.php?S_No=870&storyType=gardeGardeners traditionally dig, or turn over the top layer of soil before planting to get rid of weeds, and make it easier to use fertilizers and to plant crops. This also speeds up the decomposition of crop residue, weeds and other organic matter. Tilling the soil is often the most strenuous of a gardener’s tasks.
A complex, symbiotic relationship exists between the soil surface and the underlying micro-organisms, however, which contributes to a natural, healthy soil structure. Digging into the bed can interfere with this process and disturb the natural growing environment. It can also cause soil compaction and erosion, and bring dormant weed seeds to the surface where they will sprout.
With ‘no-till’ gardening, once the bed is established the surface is never disturbed. Amendments such as compost, manure, peat, lime and fertilizer are ‘top dressed’, i.e added to the top of the bed where they will be pulled into the subsoil by watering and the activity of subsoil organisms. Weeding is largely replaced by the use of mulch. By adding material in layers, the underlying soil surface remains spongy, making it easy for the young roots of newly planted seedlings to work through the soil. This is similar to the way soil is formed in nature.
Benefits of no-till gardening
http://www.eartheasy.com/blog/2009/01/no-till-gardening/
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