Directly or indirectly all plant and animal waste ends up in the soil. Microbes living in the soil convert those wastes to organic matter that makes nutrients available to your crops. Those nutrients are the raw materials crops use to create their finished product the grains, fruits and vegetables that farmers sell. |
Like a factory, the soil is a structure in which microbes work. If the factory is designed properly, if there are enough supplies, and if there are enough of the right types of microbes, the factory takes all the raw materials to generate a high quality final product. |
A proper soil 'building' must have 'ventilation' and 'plumbing' because the microbial 'workers' need air and water. Spaces between the soil molecules are the ventilation and plumbing. Compounds of silicon, aluminum, and iron dominate in soils. Other minerals present include calcium, magnesium, sodium, nitrogen, phosphorous and sulfur. The proportions of these minerals, plus organic matter determine the quality of the structure, Farmers construct this building by balancing these elements in the soil. A soil test is the blueprint.
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If the 'soil factory' is set up properly, the microbe workers begin to volunteer. Microorganisms make carbon, nitrogen, phosphorous and sulfur available for plant use. They are specialized, and here are billions per gram in the soil. Microbe types are bacteria, fungi, algai, protozoa and viruses. |
Bacteria make up the greatest portion, in both numbers and kinds. The biggest groups in the soil are:
- Pseudomonas are among the most active. Fluorescent varieties work in the rhizophere (the area closest to the root zone where plants take up nutrients).
- Arthrobacter make up a large proportion of the bacteria population. Their main job is degrading organic molecules and breaking minerals into usable components.
- Streptomyces send out hypha (appendages) that penetrate between soil particles They release enzymes to degrade organic compounds that are difficult for other micro-organisms to handle. Streptomyces produces the 'earthy' smell of a freshly plowed furrow.
- Cyanobacteria are often present in nitrogen poor soil. Once called blue-green algae, their photosynthetic nature requires them to be in the top layers of the layers of the soil. They accumulate organic nutrients that are then available for other bacteria to use.
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- Other groups of bacteria fix atmospheric nitrogen used by plants. They are symbiotic and cooperate
with Rhizobia (root bacteria) and Azotobacter to transform nitrogen into nitrates that plants can use.
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The region where the roots and soil make contact is called the Rhizophere. The bacteria population is largest here, and contains different types than in root free soil. Their growth is encouraged by amino acids, vitamins and sugars released by the roots. They in turn feed the plant by making nutrients available to the roots hairs. One critical goal of soil management is ensuring the health of reproduction of these Rhizophere bacteria.
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Many types of soil fungi also occupy Rhizophere. There are two main groups collectively known as mycorrhizae:
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- Ectomycorrhizae surround and enclose the roots sheath .They do not penetrate the root.
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- Ectomycorrhizae panatrate the root cells.
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These Fungi work together producing substances that improve water uptake and dissolve phosphorous. In addition to this direct action on plants, Mycorrhizae stimulate bacteria in the root zone, assisting in the breakdown of amino acids and nitrogen.
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The above micro-organisms are just a sample of the billions of ‘workers’ in a complicated ‘soil factory’. The important principle however, is simple as it is essential.
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Use accurate soil testing to insure that the structure of the soil is as good as possible. This means the soil must contain the right balance of minerals and organic matter. It them will encourage the wide range of micro-organisms that will ceaselessly work to provide your crops with the nutrients they need to give you the harvest you need to succeed. |
