It was less than three generations ago that Pasteur’s work in
France suggested the bacterial causation of disease. Even though we are coming
to see that the bacterial entry into the body may be encouraged by weakness
induced by deficiencies of many kinds, yet the fear of microbes, germs and
bacteria is almost universal. Everybody is afraid of getting germs. Pasteur
told us that heat is the best weapon for fighting these microscopic life forms
and we have been heating, boiling, steaming and sterilizing in the fight
against microbes.
Now that the science of microbiology has brought us
penicillin, streptomycin and other similar microbial products as protection for
our bodies against the microbes, particularly since we are learning to live
with them more for our benefit than for our harm. We are coming to see that
microbes are a foundational part of the pyramid of life forms, of which we are
the topmost. If we are to live complacently with them, we must remember that
they are next to the soil in that pyramidal structure. They are between the
soil and the plants. They either cooperate with, or compete with, the plants
for the creative power in the form of nutrients in the soil. Hence, they are a
part of the biotic foundation on which animal and human life depend. Microbes
are now recognized as important because they eat more simply than all other
life. They also eat first of the fertility of the soil.
1.
struggle
for calories
Microbes are less complex in their anatomy and in many
respects are less highly developed than plants. Unlike plants, the microbes
cannot make their own energy-food compounds by the help of sunlight. On the
contrary, sunlight kills microbes. By the process of photosynthesis, plants
build their own carbohydrates for body energy from carbon dioxide in the air
and from hydrogen and oxygen in water from the soil. Plants make many
carbonaceous complexes from these three simple elements which they build into
intricate energy-giving compounds of high fuel value and as deposits above the
soil or as additions within its surface layer. Plants work in the light.
Microbes work in the dark. Unable to derive energy directly from the sun, they
must get it from these chemical compounds passed on to them by the death of the
plants.
As a means of getting energy for heat and work, the microbes
burn or oxidize organic compounds, just as we do in our bodies. Microbial life
depends on just such compounds as make up dead plant and animal bodies. It
simplifies them. It tears them apart. It is the wrecking crew taking over dead
plant and animal tissues or return the separate elemental parts back to the
air, water, soil or other points of origin. It is working in the dark and
sending back to simplicity all that the plants built up to complexity.
This microbial struggle is what we call decay. The process of
rotting organic matter is the result of microbial processes of digestion and
metabolism of the organic matter, by which the energy initially put into
chemical combination through plant photosynthesis, is released again for microbial
life service.
As humans, we too use organic compounds such as sugars,
starches, proteins, fat and other food components to provide our energy. This
occurs as part of the process by which we break down these compounds into
carbon dioxide, water, urea and other simple substances eventually thrown off
as body excretions. Humans, like the microbes, are struggling for calories. In
humans we call it digestion and metabolism. For the microbes, it means decay,
or the simplification process which the different substances are undergoing
when we commonly say “They are rotting.”
2.
competition
with crops
Plowing under some organic matter in the garden or field is a
good way of disposing of crop residues because the microbes “burn” or oxidize
them. They do it slowly, however. Yet the process of microbial combustion of
such materials may have disastrous effects on a crop planted soon after
plowing, when we say we “burned out” the crop.
Microbes need more than energy “go” foods. They need the “grow”
foods, too, just as we do. They do not demand that their nitrogen be given them
in the complete proteins or the more complex compounds of this element as we
do. Nevertheless, they are just as exacting in their needs for nitrogen, at
least in its simpler forms. This is a “grow” food necessary to balance their
energy foods in the proper ratio just as we demand the balance in speaking of
our own nutritive ratio, or the balance of carbohydrates against proteins in
our own diets or in the ration of feeds for our domestic animals.
So when we plow under any woody residue of stalks, leaves or
other parts of plants that have given up their protein contents for seed
making, these residues are an unbalanced microbial diet. They do not permit the
microbes to grow rapidly on them. They are too much carbohydrate. As a diet
they are deficient in “grow” foods. They are short in proteins, or nitrogen,
and in minerals, hence decay very slowly.
Woody crop residues, like straws, have long been used for
roof covers in the Old World. They last well but need to be replaced more often
at the ridge top than over the entire roof. It is at the ridge tops that birds
sit more often to leave their droppings, which are rich in urea nitrogen. When
this soluble nitrogen – along with the mineral salts of the bird droppings – is
added to the straw, the first rain hastens its decay. This decay, however, is
limited to the ridge of the roof, or to the area in which these supplements of
nitrogen balance the microbial diet originally consisting of straw. Until this
balance was brought about the straw was too carbonaceous to decay, and was good
thatch. Microbes require little of the “grow” foods but without it they do not
carry out their decay processes.
When strawy crop residues or sawdust, for example, are plowed
into the soil, the soil microbes are offered a diet that is high in carbon, or
energy, and low in bodybuilding foods. Since the microbes are well distributed
throughout this plowed soil, they are in such intimate contact with the clay
that they make colloidal exchanges with it for its available nutrients. They
can take ammonia nitrogen, potassium, phosphorus, calcium and other nutrients
for their own growth from the clay to balance the sawdust as a more adequate
diet.
It is unfortunate for the plants when woody residues are plowed
under. When the microbes are more intimately in contact with the soil than are
the plant roots, the microbes eat first of the available fertility elements.
While the microbes are balancing their sawdust diet by taking the fertility of
the soil into their own body compounds, we do not appreciate the production of
the microbial crop, nor the proportion of the available fertility which they
appropriate for their own needs. Instead we see how poorly the corn crop or
other plants grow when planted soon after straw, heavy weeds or sawdust are
plowed under. We say “The crop is burned out,” when it is extra fertility and
not water that is needed. Yes, the microbes eat first. This disaster follows
inevitably when the soil is too low in fertility to feed both the microbial
crop within and the farm crop above the soil.
But unfortunately the disaster is only temporary. While the
energy compounds are being consumed, the excessive carbon is escaping to the
atmosphere as carbon dioxide. The nitrogen and inorganic nutrient elements are
kept within the soil. Thus while the carbon supply in the soil is being
lessened by volatilization, the ratios of the carbon to the nitrogen and to the
inorganic elements are made more narrow. These ratios approach that of the
microbial body composition – more nearly that of protein.
Thus by decay the straw with a carbon-nitrogen ration of 80
to 1 leaves microbially manipulated residues going toward what we call “humus”
and toward a carbon-nitrogen ratio of nearly 12 to 1. This resulting substance
is then more nearly like the chemical composition of the microbes themselves.
So when no large, new supplies of carbonaceous organic matter are added to the
soil, new microbes can grow only by consuming their predecessors or the humus
residues of their creation.
Humus residues, used as food by the microbes, comprise a diet
low in energy values, but high in body-building values. Humus is also
unbalanced, but unlike straw, it is unbalanced in the opposite respect. It is
not badly unbalanced, because “grow” foods, like proteins, can be “burned” for
energy. Man can live by meat (protein) alone, as Steffanson and other Arctic
explorers have demonstrated. It is a bit costly, however, so we use
carbohydrates to balance the protein. In that case the proteins are going for
tissue building rather than to provide energy. The microbes also can use
protein-like compounds for energy and very effectively. We encourage them to do
this when we plow under legumes. Here again they balance their own diets but
with benefit to the crop above the soil, rather than with disaster which
follows the plowing under of straw.
When we plow under proteinaceous organic matter, such as
legumes, with not only a high content of nitrogen but also a high content of
calcium, phosphorus, magnesium, potassium and all the other inorganic nutrient
elements, the microbes are placed on a diet of narrow carbon-nitrogen ratio. The
ratio of carbon to the inorganic nutrients is also narrow. It is like an
exclusively meat diet would be for us, or like a tankage diet would be for a
pig. The energy foods in such a ration are low in supply. Conversely, the
nitrogen and minerals are a surplus. This surplus is not built into microbial
bodies. Instead, it is liberated in simpler forms which are left in the soil as
fertilizers for farm crops.
What we plow under determines what we have as left-overs for
the crops. The microbes always eat first. The crops we grow “eat at the second
table.” In wise management of the soil we must consider whether the composition
of the organic matter we plow under is a good or poor diet for the microbes. If
the soil is so low in fertility that it grows only a woody crop to be plowed
under, then there can be little soil improvement for the following crop. It
gives the microbes only energy foods. They must exhaust still further the last
fertility supply in the soil to balance their diet and consequently the crops
starve.
But if the soil is high in fertility so that it grows legumes,
and if we then plow these protein-rich, mineral-rich forages under, the
microbes receive more than energy foods. Given the nitrogenous, fertility-laden
green manures plowed under, they pass this fertility back to the soil. Here
their struggle is for energy, a struggle by which they are not in competition
with the crop, the energy for which comes not from the soil but from the
sunshine instead.
Microbes eat first. On poor soil with little humus and
inorganic fertility, this spells disaster to the farm crop if we plow under
only the poor vegetation which such soils produce. Growing merely any kind of
organic matter to let it go back to the soil is not lifting the soil to higher fertility;
any more than one lifts himself by pulling on his bootstraps. On soils that are
more fertile in mineral nutrients, the idea in plowing cover crops to turn
under is to help the farm crop. It helps them if we plow under the more
proteinaceous and leguminous cover vegetation which fertile soils produce.
While we have been mining our soils to push them to a lower
level of fertility, the microbes that originally were working for us are now working against us. They are eating first, not
only so far as the plants are concerned, but indirectly so far as even we and
our animals are concerned.
It is in this competition with the microbes that inorganic
fertilizers and mineral additions to the soil can play their role by balancing
the microbial diet. Such minerals are taken by both the plants and the
microbes. But if the fertilizers are put deeper into the soil, they may be
below the layer where they affect the microbes, either favorably or
unfavorably. They will serve the plants, which send their roots down there,
under the power coming from the sunshine. They will not affect the microbes
unless they are mixed into the humus-bearing surface soil. Putting the
fertilizers down deeper puts their nutrient contents where the plants, rather
than the microbes, eat first. This is fertilizing, by means of inorganics, the
fertilizing crop that combines them with organics to serve the microbes when
this fertilizing crop is turned under for true soil improvement. This is a way
of composting the inorganics within the body of the soil itself.
-
Excerpt from The Albrecht Papers Vol.1 - 1948
