Healthy soil and sustainable growing

[Ken Hargesheimer <minifarms2@yahoo.com>]

When Soil is Plowed

Dr. Elaine Ingham, describes an undisturbed grassland—where a wide diversity of plants grow, their roots mingling with a wide diversity of soil organisms—and how it changes when it is plowed.

 

A typical teaspoon of native grassland soil contains between 600 million and 800 million individual bacteria that are members of perhaps 10,000 species.  Several miles of fungi are in that teaspoon of soil, as well as 10,000 individual protozoa.  There are 20 to 30 beneficial nematodes from as many as 100 species. Root-feeding nematodes are quite scarce in truly healthy soils.  They are present, but in numbers so low that it is rare to find them.

 

After only one plowing, a few species of bacteria and fungi disappear because the food they need is no longer put back in the system.  But for the most part, all the suppressive organisms, all the nutrient cyclers, all the decomposers, all the soil organisms that rebuild good soil structure are still present and trying to do their jobs.

 

But tillage continues to deplete soil organic matter and kill fungi. The larger predators are crushed, their homes destroyed.  The bacteria go through a bloom and blow off huge amounts of that savings-account organic matter.  With continued tillage, the "policemen" (organisms) that compete with and inhibit disease are lost.  The "architects" that build soil aggregates are lost.  So are the "engineers"—the larger organisms that design and form the larger pores in soil.  The predators that keep bacteria, fungi, and root-feeding organisms in check are lost.  Disease suppression declines, soil structure erodes, and water infiltration decreases because mineral crusts form.  Dr. Elaine Ingham, BioCycle, December 1998.  (From ATTRA News, July 06)

 Ken Hargesheimer