Food: Where Does it Come From pg2 -- EOCM-EO
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The Earthly Origin of Commercial Materials
Feeding our Food  (page 2 of  3)
 
Agricultural Explosion
 
These bottles and bottles and bags and bags of nitrogenous materials, that I was talking about -- before I began discussing "soup or chemistry," and tomatoes -- that green plants can use, and that people have learned how to make -- starting with (1) nitrogen from the air, and (2) a material that is a source of hydrogen, such as the methane of natural gas -- are sometimes called chemical fertilizers. They began being called chemical fertilizers because practical knowledge of how to control chemical reactions is what enabled people to produce them from nitrogen and methane. They may contain substances that are chemically identical to substances that what are commonly called natural fertilizers, may contain, and that natural soil may contain. By the way, the term fertilizer, which fundamentally means reproduction stimulator, or pregnancy and birth stimulator, is a misnomer that remained stuck, even after it was realized that these materials served green plants by being nutrients for the green plants, rather than by stimulating reproduction of the green plants, or stimulating production, of the green plants. I prefer to use the term industrially produced green-plant nutrients.

There are a number of kinds of industrially produced green-plant nutrients, but I am talking about industrial produced nitrogenous materials now. These were introduced into commerce in 1913, and they changed agriculture, and the human condition dramatically, and profoundly. Arguably, they changed the human condition as much, or more, than the communications revolution that started with the telegraph and telephone, or the transportation revolution that started with combustion-operated engines, steamships, railroads, and horseless carriages.

These nitrogenous materials can be industrially produced, and transported to soil, much more rapidly and economically than people have been able to supervise aerial nitrogen being converted into similar materials by the micro-organisms living in the soil, or in compost. Presently, a small percentage of human beings have control over the large-scale industrial processes that are used for (1) converting aerial nitrogen into huge amounts of inexpensive -- and concentrated, and thus light and inexpensive to transport -- ammoniacal nitrogen products, and (2) for converting these into urea, and into nitrate-nitrogen products.

Nitrate nitrogen becomes immediately available to metaphytes, as soon it dissolves in soil moisture. Metaphytes can easily convert into more and more material, in the form of edible metaphytes. Ammoniacal and urea nitrogen becomes rapidly transformed into nitrate nitrogen. Metaphytes need nitrogen, but cannot absorb the abundant molecular nitrogen of the air. They must have, generally, nitrate nitrogen, or may to some degree be able to use ammoniacial nitrogen directly, instead of waiting for soil micro-organisms to convert it into nitrate nitrogen. 

A Circle
How did all that aerial nitrogen, that's in the earth's atmosphere, get there, "to begin with?" Why, denitrifying bacteria converted nitrate nitrogen, in the soil, into molecular nitrogen, which escaped from the soil, into the air.

How did all that nitrate nitrogen get into the soil, "to begin with?" Well, I'll describe that part of the circle for you, where aerial nitrogen gets into the soil, naturally, but you're right, I have no idea where the circle started. It's a circle, dammit -- maybe it doesn't starts nowheres! OK, maybe I'm trying to be cute here, and maybe I don't know myself how the circle "started," and maybe I know that serious researchers have investigated clues to billions of years of life on earth, and have created hypotheses as to how the the present biosphere, with its present nitrogen cycles, developed over time, and maybe I don't remember much about what I've read about these hypotheses. But in terms of  windows of time consisting only of 1000's of years, as opposed to billions of years, the idea of a predictable, repeated circle of transformation of materials, each cycle having a length of only a few months or years, from an arbitrary origination point back to the same origination point, that doesn't change much from cycle to cycle, is relevant and useful.

The Haber Process, a mutation of the behavior of a single species, us -- along with a global population explosion of this species -- began altering nitrogen cycles in a big way. The Haber Process is a departure from the old ways of soil microbes, in regard to how aerial molecular nitrogen may be converted to soil nitrogen. 

Old ways and new 
Before 1913, when specific individual organisms of our specific species of soil surface-living metazoa, after separating nitrogen from the rest of the air, began being able to combine it chemically -- rapidly, and in large quantities -- with hydrogen (which is abundantly available today from the methane of natural gas), to form (gaseous) ammonia -- by catalyzing the chemical reaction with osmium and subjecting the reactants to high pressure, at least 3,000 lbs per square inch (that was a brief description of the Haber process), the only way that aerial nitrogen normally got into the soil, apparently, was when nitrogen-fixing bacteria, including nitrogen-fixing blue-green bacteria (it was once popular to call these blue-green algae), living in the soil (or in compost), absorbed molecular nitrogen from air that dissolved in soil moisture, or absorbed molecular nitrogen from the air, and converted it into the nitrogenous compounds of their cells.

In 1900, mined Chilean nitrate came into use, on a large scale, as a soil amendment. But Chilean nitrate was mined (in Chile); it wasn't manufactured. After 1913, Chilean nitrate was not needed much anymore; industrially produced nitrogen-containing substances became much cheaper.

Handy Cost Comparator
Pure urea is about 46% usable nitrogen. Solid and easily transported and inexpensive, nearly pure granules of commercial industrially-produced urea are about 45% usable nitrogen. Urea nitrogen is converted to nitrate nitrogen (nitrate nitrogen is called available nitrogen), by soil micro-organisms, when added to the soil. The richest-in-nitrogen compost, in contrast, though it also has other qualities that make it desirable for adding to the soil, that pure urea doesn't have, has maybe only about 2% usable nitrogen. So 200 pounds of compost can, for boosting soil nitrogen levels, be replaced with, roughly, only 9 pounds of urea. These amounts are not atypical  for spreading over a 500 square-foot backyard garden. 20 feet by 25 feet. You can lug around four 50-pound bags of compost -- or you can pick up just one 9-pound bag of urea. I've got a job for you: go the United States Postal Service website and compare the cost of shipping 4 50-pound boxes of anything from eastern Long Island to Manhattan, with the cost of shipping 1 9-pound package. Forget it, I did it myself already. From eastern Long Island to Manhattan it's $25.88, and $3.91. The shipping charges for 4 pounds of compost nitrogen are about 7 times a much as the shipping charges for 4 pounds of urea nitrogen. The actual weight of compost, having the same amount of nitrogen as urea, is 22 times as much. 

Of course, the nitrogen bound up in the organic matter of compost leaches out of topsoil, into lower layers of soil, where it is useless for agriculture, at a slower rate than the nitrogen of urea granules, that dissolve in the soil, leaches out.

Other "natural" components of the nitrogen circle
Nitrogen-fixing organisms may have moved aerial molecular nitrogen into the soil, but this nitrogen is not available to most green plants yet. It remains a component of the cellular material of the nitrogen-fixing organisms, for as long as the organisms live. I'll get to the exception later. After nitrogen-fixing organisms die, the nitrogenous compounds of their cells, are converted by decay organisms into ammoniacal nitrogen. Decay organisms also convert nitrogenous compounds from other sources, such as other no-longer living animal or vegetable matter, into ammoniacal nitrogen.

What happens to the ammoniacal nitrogen that decay organisms construct, our of cellular nitrogen? Some kinds of nitrifying bacteria convert the ammoniacal nitrogen into nitrite nitrogen; then other kinds of nitrifying bacteria convert this nitrite nitrogen into nitrate nitrogen.

So circularly far
So far, we have aerial nitrogen being converted into cellular nitrogen compounds by nitrogen-fixing organisms (including human organisms, who fix nitrogen extra-cellularly), then the nitrogen compounds of dead cells (both of nitrogen fixing organisms and other organisms) being converted to ammoniacal nitrogen by decay organisms, and then ammoniacal nitrogen then being converted into nitrate nitrogen, in steps, by nitrifying organisms.

Return to Introduction to Circles
Now, denitrifying bacteria have nitrate nitrogen again, to convert back into molecular nitrogen; which escapes the soil, and goes into the air: and we're back at the same part of the circle that we chose to start at.

Green Plants in the Circle
Of course, not only denitrifying bacterial can make something out of the nitrate nitrogen they find in the soil: green plants, for one, can get a handle on some of this nitrate nitrogen too, incorporating the nitrogen into their tissues. I'll try to get into the details of what their tissues consist of, later. Then I'll try to elucidate how they do most of our molecular work for us, pre-fabricating our tissues for us, from non-living chemicals, work that our tissues don't know how to do themselves, and, existing long before any metazoa existed, may have "invented" us metazoa, and how they tolerate us, and continue to enable our existence, as weak, semi-competant dependents, upon them, perhaps because we help them make sexual liaisons. We are just finally beginning to figure out how they "made" us, after thousands of years of near-total dependence on them, without them whispering a word to us, about how they pre-fabricated so many of our parts for us.

Legumes grab up nitrogen fast -- directly from nitrogen-fixing organisms.
Some nitrogen-fixing organisms make nitrogen directly available to specific green plants that they live symbiotically with. My soybeans plants, that I grow so I can have fresh soybean seeds (not dried soybeans) -- to steam in their shells, pop out, and eat -- could not produce the amount of nitrogen-containing high-protein seeds, beans, that they do, if not for the fact that they allow nitrogen-fixing rhizopus bacteria to rent root-space, and fix nitrogen there. I like to pull up a Glycine max plant occasionally, squeeze one of the pea-size root tumors between my fingers, break it open, and release the moist contents, so I can inhale the delicious rhizopal fragrance, of these very moist, pea-sized, nitrogen-fixing, advanced bio-technology incubators. This is where the soybean plant gets much of the nitrogen it needs to make the amino acids of its seeds, that humans are so crazy about. And the amino acids of its seeds are where I get much of the nitrogen-containing amino acids I need to make my amino acid polymer (protein ) muscles, my amino-acid polymer enzymes, and to make my nucleic acids, which I need to keep both short term records, and records to bequeath to my progeny. The soil, the rhizopus bacteria, the soybean plants -- I'd be nothing without them. I love those guys! I love smelling them.

People grab up legumes fast
The usual main limiting factor, in regard to how much of any green plant can be grown in an area of soil, is the quantity of usable nitrogen in the soil. Here's the deal: the main limiting factor, in regard to how much of any animal can roam over any area of soil, is often the quantity of plant life that is available to them (or to the animals they eat) growing in that soil, for use as nutrients, either by being directly alimented or utilized indirectly, by alimenting other animals that have alimented the plants. Except as human animals practice intentional population control, via sexual abstinence, contraception, or homicide, the main limiting factor is the same for humans.

Where does our human cellular nitrogen come from?
We get our cellular nitrogen from green plants or animals that ate green plants, etcetera. Green plants get their cellular nitrogen from the soil. So indirectly, we get our cellular nitrogen from the soil.

Before 1900, we relied on micro-organisms to put aerial nitrogen into the soil. Between 1900 and 1913, Chilean nitrate was mined, and added to soil. Beginning in 1913, people began fixing aerial nitrogen themselves, using the "Haber Process," as described above: combining aerial nitrogen, and hydrogen, in the presence of osmium, at high pressure, to form ammonia.

What's the world population today, about 6 billion? In 1900 the world population was about 1.5 billion. Much of the material of that 4.5 billion new people can be traced to Haber-Process fixed-nitrogen, not naturally fixed-nitrogen.

Cyanophytes fix nitrogen naturally,  at lower temperature and pressure, without osmium, do not require huge factories, and are handy in other ways too
Free-living soil cyanophytes are one of the main organisms living in soil that fix aerial nitrogen, bringing it from the air to their cellular material. Some species don't require any organic nutrients, only inorganic materials, such as the minerals of rocks. Some species that live on the surface of rocks, convert the rocks into soil, into organic material. Some species increase the organic material in soil by converting dissolved non-organic material, or fine particles of non-organic material, into organic material. Increasing the organic material in soil makes the soil hold water and nutrients, that green plants need, better, making the soil more hospitable to green plants. Of course, cyanophytes don't normally convert aerial nitrogen into handy bags of concentrated nitrogen products, or work as fast as Haber-process factories do. Free-living cyanophytes prefer alkaline and neutral soils. Most cultivated food plants do also.

Other bacteria that fix nitrogen
Other bacteria that fix nitrogen often colonize the surface or interior of plant roots. They are often nourished by dead plant material that is released from the living plant. But they also live in the soil, unattached to roots. 

"The different forms of biological nitrogen fixation enable rice to yield one or two tons of grain per hectare without supplementary mineral [industrially produced] fertilizer. This is on of the reason Asian farmers have harvested from one to two tons of rice per hectare for centuries without applying such fertilizers"

"...Genetic improvements and better farm practices rapidly increased yields in the 20th century. Today yields in Japan, North Korea, South Korea, Australia and the U.S. (notably in California) average about six tons per hectare."

-- M. S. Swaminathan, "Rice," Scientific American, 1984 January, page 81, 91.

"Blue-green algae [their scientific name is cyanophytes; cyanophytes are considered bacteria; blue-green algae are algae the way sea-horses are horses] are often the first plants to colonize bare areas of rock and soil. A dramatic example of such colonization is provided by the island of Krakatoa in Indonesia, which was denuded of all visible plant life by its cataclysmic volcanic explosion of 1833. Filamentous blue-green algae were the first plants to appear on the pumice and volcanic ash; within a few years they had formed a dark green gelatinous growth. The layer of blue-green algae formed in such circumstances eventually becomes thick enough to provide a soil rich in organic matter for the growth of higher plants." -- Patrick Echlin, "The Blue-Green Algae," Scientific American, 1966 June, page 75, 80.

Why do we need nitrogen; where in us goes the nitrogen we "eat"? Nitrogen is necessary to construct amino acids and proteins, and nucleotides and nucleic acids.

Much of the substance of us is proteins, which are polymers of amino acids, and each amino acid  molecule contains at least at least 1 nitrogen atom. Our nitrogen requirements, which are supplied by proteins or amino acids that we eat, which green plants make from (inorganic) nitrates and ammoniacal nitrogen they find in soil, which get into the soil from the air via soil micro-organisms, or via human industry, are rather high. And nitrogen tends to be a limiting factor in how much of any (protein-containing) food-plant one can grow on any area of land.

Amino acids are necessary what we construct our proteins out of: proteins  are chains, strings -- polymers -- of amino acids. Proteins form the substance of much of our muscles, much of our skin, much of our soft tissues, most of our hair, most of our nails, and all enzymes -- which we need to control the size and speed of our on-going chemical reactions, our life-processes -- are proteins. Therefore our tissues that aren't proteins, nevertheless required proteins, in order to regulate their production.

And our proteins required nucleic acids as a "template" for their production.

Nucleotides are necessary to construct our nucleic acids -- nucleic acids are strings, polymers, of nucleodtides. You might say that nucleic acids are the substance that our "data-and-program files," our "plans," or "templates" (for our proteins) are made out of, a little bit like paper and ink are the substance that an architect's plans (for a building) are made out of. But this is an oversimplification; it  is not a precise metaphor. Although we are composed of  many different kinds of (often distinctively) different cells, nearly every single cell of a human being has, at least during part of the life of the cell -- and  most cells have throughout their life -- a full set of plans for the entire human, as opposed to a set of plans for the distinctive cell the plans are housed in. 

Relatively recently, biologists have been figuring out how particular program and data subsets, in the complete program and data set, are implemented in any particular cell, at any particular time, and how other subsets aren't.

During the growth, development, and maintenance of a human being,  each mitotic cell division causes this entire set of plans to be duplicated. Duplication of the cell requires nitrogen for its nucleic acids, and nitrogen for its protein.

Nucleic acid are needed in cells not only to store genetic information, but a different set of nucleic acids is also needed to transmit information from the genetic storage area in the nucleus, to the construction and operating areas of the cytoplasm. Other nucleic acids residing in the cytoplasm, or in cell organelles, manage various cell operational activities.

Nucleic acids in cells store information regarding the immune responses that cells have learned, and can execute in response to different pathogens.  Nucleic acids in the brain have a storage function in regard to new mental operations we have "learned," or things we have "remembered." Cerebral learning and memory are handy to have, in addition to the basic general growth and development and regeneration operating plans that we inherited from ancestors. So nucleic acids store individual human memory, such as immune response memory, and conscious memory -- as well as genetic "memory," the "memory" of how to construct an individual human being that is passed on from parent to offspring.

So we need nitrogen for nucleic acid construction, as well as for protein construction, but I don't know the relative amount of nitrogen that is used for one or the other. What I do know, is that nitrogen is a key element of our substance, our matter. We need plenty of it; its availability to plants, in soil, is key to determining how much of any plant will grow in soil; its availability to humans, in proteins, in plants, is key to determining how many human will grow in the earth's biosphere. Plus the availability of food plants, in general, is key in determining how many humans will grow in the earth's biosphere.

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