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Wednesday, December 12, 2012

Living soil

I recently read an article by someone who investigated the ecosystem of a corn field.  The author visited acorn field in Iowa and said that the only living thing he found was the corn.  He implied that herbicides, insecticides, GMO crops and other crop protectants had turned the soil into a sterile environment.  The first fact is that yes, farmers are trying to eliminate competition from other species in terms of water, nutrients, and organisms that may attack the corn plant and reduce its efficiency to convert sunlight into energy. We seem to have done that very efficiently. 

On the other hand, the soil is still full of life despite all that we have done.  The soil is full of organisms.  Bacteria, nematodes, Protozoa, algae, insects, worms, and fungi all inhabit the soil below the surface.  The fact is that if the soil is sterile, crop growth would be nearly impossible.  Bacteria convert nitrogen fertilizer into forms available to the plant, whether the source is soil organic matter, fertilizer or manure.  All of the above also mention organism are essential in the breakdown of organic crop residues that are left in and on the soil.  This breakdown is essential for nutrient cycling.  Mycorrhyzae are are special fungi that are found in the soil.  They have filaments throughout the soil that help feed nutrients and water to the plant roots.  We all know about the value of nitrogen fixing bacteria to legumes.  Yes there are also some organisms that can be harmful to crop production as well.  One of the ways that we minimize their effect is to balance plant nutrients.  Another way is by using varieties that are resistant to the harmful organisms.  This does not mean that we eliminate the harmful organism. it means that we just reduce its harmful effects.  Sterile soil in a corn field?  Impossible!  To learn more read this from Colorado State University. 

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