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Old 01-18-2011, 12:32 AM
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JDUtah JDUtah is offline
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Quote:
Originally Posted by Kiril View Post
Is it? Perhaps it is a "critical component" to your argument, but not one with the issues which surround chemical fertilizers and their impacts on soils and soil biology. But if you insist, please list all the microbes that use these synthetic/organic/mineral plant nutrients and where they typically obtain them and what percentage of each of the three sources listed is utilized.
OK let’s start with a bacteria type that organic fert nuts are crazy about. The Nittrogen fixing bacteria known as diazotrophs. These bacteria produce an enzyme known as Nitrogenase. This enzyme captures the Nitrogen found in the atmosphere and converts it into Ammonia (a "salt fertilizer"). They then use another enzyme called Glutamine synthetase to capture the N that is in the Amonia they just produced and use it to build glutamine. For those who don’t know glutamine is a Proteinogenic amino acid. Proteinogenic amino acids are basic building blocks used to make proteins. Protiens are the powerhouses of the cell if you will.



So here you have a soil microbe that captures Nitrogen from the atmosphere, turns it into “chemical fertilizer” (ammonia) in order to use it to make proteins. In fact, one of the enzymes I mentioned itself (Glutamine Synthetase) contains another "salt fertilizer" ion known as Ammonium.

This is just one example but there are thousands of types of soil microbes and each uses thousands of molecules to build itself and perform different functions. There is no way that I can provide an all inclusive list. But you knew that already didn’t you Kiril?



So as an alternative, let’s turn to some course notes provided by PhD. Stephen T. Abedon. He is a professor in the Department of Microbiology at Ohio State University. I found them in seconds using a simple google search for "Bacteria essential nutrients".

These notes cover the chapter entitled “Microbial Nutrition”. Note the underlined words.

Quote:
• Microbial nutrient requirements

a. Common microbial nutritional requirements include:
i. water
ii. a carbon source
iii. an energy source
iv. nitrogen
v. sulfur
vi. phosphorus
vii. potassium
viii. magnesium
ix. calcium
x. oxygen*
xi. various trace elements
xii. various organic growth factors**
xiii. *Not molecular oxygen but oxygen atoms incorporated into compounds other than O2.
xiv. **Of all common nutrient requirements, the need for specific organic growth factors is least shared among microorganisms.

b. Source utilization variation:
i. Note that not all microorganisms do or are even able to assimilate all of these nutrients from the same source(s).

ii. "There are many types of laboratory prepared media available for the isolation and the cultivation of bacteria. It is important to understand that whatever growth medium is used, it must provide the necessary nutritional requirements for the organism you wish to grow." (Krueger & Kolodziej, 1986)

• Nitrogen
a. Amino acids:
i. Used in amino acids and nucleic acids.
ii. Possible organic source = amino acids.
b. Inorganic sources:
i. Possible inorganic sources include:
1. NH4+ (ammonium---nitrogen in its lowest oxidation state)
2. NO3- (nitrate---nitrogen in its highest oxidation state)
3. atmospheric nitrogen (nitrogen fixing)
• Nitrogen fixation
a. Nitrogen from air:
i. The conversion of gaseous, elementary nitrogen (N2) into nitrogen available to cellular metabolism.
ii. Ultimately this is where all of the nitrogen found in all organisms comes from.(including soil microbes)

b. Uncommon metabolic pathway:
i. Only a minority of bacteria are capable of nitrogen fixation.
ii. See particularly Rhizobium spp..

• Sulfur
a. Amino acids:
i. Sulfur is found in some amino acids and in various vitamins.
ii. Possible organic source is sulfur-containing amino acids.
b. Possible inorganic sources included SO42- (sulfate ion).


• Phosphorus
a. Phosphorus is found in nucleic acids and phospholipids.
b. The dominant inorganic source of phosphorus is phosphate ion (PO43-).


• Trace elements
a. Usually present:
i. Trace elements are often assumed to be present unless highly pure synthetic components are utilized.
ii. Even distilled water often contains adequate amounts of these element for growth.
b. Enzyme cofactors are basically used as enzyme cofactors.
c. Examples of cofactors include:
i. copper
ii. iron
iii. molybdenum
iv. zinc
v. cobalt
vi. manganese
d. "Many microorganisms require a variety of trace elements, tiny amounts of minerals such as copper, iron, zinc, and cobalt, usually in the form of ions. Trace elements often serve as cofactors in enzymatic reactions. All organisms require some sodium and chloride, and halophiles require large amounts of these ions. Potassium, zinc, magnesium, and manganese (all plant nutrients) are used to activate certain enzymes. Cobalt is required by organisms that can synthesize vitamin B12. Iron is required for the synthesis of heme-containing compounds (such as cytochromes of the electron transport system) and for certain enzymes. Although little iron is required, a shortage severly ******s growth. Calcium is required by gram-positive bacteria for synthesis of cells walls and by spore-forming organisms for synthesis of spores." (p. 149, Black, 1996)
Like I said, this is basic college stuff. Entry level. I have to go, but can expand on the areas I highlighted if anyone wants.

The bottom line is... YES! Microbes need nutrients! And YES! These nutrients often include the SAME EXACT IONS as found in chemical fertilizers. Some of those that this Doctor mentioned are NH4 (Ammonium ion), NO3 (Nitrate ion), SO4 (Sulfate ion), PO4 (phosphate ion)

And you guys call me ignorant???

To the OP. sorry we hijacked the thread. But IMO no, organics do NOT have to be all or nothing. Unless of course you want certification from one of the organic associations.
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