Because we turned away from much of the art of agriculture in
the absence of a complete science of it, we have a serious confusion. That is
all the more serious now and at the moment we discover that we have rapidly
mounting numbers of people and are soon running out of ample food for them. We
are confused about the natural performances or about the biology in
agriculture. We have permitted ourselves to be led astray and are asking the
science of agriculture now to bring us back to where we can understand the
basic principles rather than merely mimic any practice. We dare not be mere
followers of traditions. We must face the problems and solve them. All of that
calls for rather clear diagnoses. Let us try and comprehend the fact then that
soil fertility properly coupled with plant nutrition is a form of creation, a
form of outdoor biology, and not a matter merely of scientific technology. In
that combination wisely used there may be some solution for our food problem.
Now what are some of these confusions about the basic facts
of soil fertility and plant nutrition? First of all, we seem to have lost sight
of the fact that the creative business of agriculture has always started in the
soil. That great truth was told us about six or more thousand years ago, but we
didn’t take that remark very seriously. We are beginning to appreciate it now.
We shall face it more seriously when we have the least of creative capacity left
in the soil and when we need to know most about it.
In terms of wise fertilizer use, the most shocking confusion
prevails when we talk about soluble fertilizers, considering water as the
agency for solution, and then we make laws requiring that fertilizers must be
water-soluble and thereby so-called “available”. In fact and in nature, these
soluble fertilizers are never taken out of the soil because the plant takes
them into itself along with water it takes from the soil. The use of the major
amount of water by the plant is that of keeping the respiring leaf tissues
moist for the exchange of the gases, namely carbon dioxide and oxygen. That
escape of water from the leaf is what we call “transpiration”, and it is in
that service where most of the absorbed water goes from the soil into the
atmosphere. That use of soil water is controlled by the meteorological
situation inviting water to evaporate from the leaves of the plants against the
forces holding the water in the soil. The plant is an innocent connection
between those two opposing forces acting on the water. Does the moisture in
your breath move nutrient form your bloodstream into the tissues, or from your
stomach into your bloodstream? But yet we take to the concept that the
transpiration by the plant has something to do with the movement of nutrient
from the clay of the soil into the roots. The transpiration stream of water
from the soil, through the plant and into the atmosphere is independent of the
nutrient stream from the soil into the roots. That may not be true for
nutrients moving within the plant’s conducting tissue. The water uptake by the
roots is the result of atmospheric conditions favoring evaporation from the
leaves with a set of dynamics which are more than a match against the forces holding
the water on the surfaces within the soil.
Nutrient intake by crops is a function of three colloids, or
possibly four, in contact. First of all, there are the nutrients on the clay
colloid, or on the organic colloid of the soil. The soil colloid is in contact
with the root membrane which is another colloid. That root membrane is in
contact with the contents of a cell on the inside, namely the protoplasm, or
the cytoplasm. Then, in turn, that cell is in contact with another cell. In
that you have the combination of the three or four colloids in contact. The
movement of the nutrient ions from the clay into the root membrane and into the
cells follows the chemical laws controlling their traverse there because of the
differences in activities, adsorption capacities, interfering ions and other
factors along that line.
That movement of nutrients into the root is independent of
the transpiration of water. We have demonstrated transpiration going forward
regularly, or water moving from the soil through the plant to the atmosphere
when the nutrient ions were moving in the reverse direction, namely, going from
the plant back to the soil. We have demonstrated the ions going into the plants
regularly when there was no transpiration. You can demonstrate this when you put
a bell jar with atmosphere saturated with CO2 and with water over
that plant. In that case, you can stop the transpiration but you don’t stop the
ionic nutrient movement into the plant. Some recent work at the California
Technological Institute has shown that the desert plants put water back into
the soil while they are growing, therefore the water can be going back into the
soil while the nutrients are going in the opposite direction. We must get rid of this water-soluble
fertilizer bugaboo in considering soil fertility and plant nutrition, because
transpiration runs independently of our control and we need to concentrate our
efforts on keeping the stream of fertility flowing more regularly into the
plants.
Let us not cover either our ignorance or our responsibility
toward maintaining the soil fertility by trying to blame the water situation in
the soil and the rainfall. The idea that the drought is responsible for the failure of plant nutrition persists.
But what is commonly called drought
isn’t trouble in terms of water only. It is apt to be due to the fact that the
upper layer of the soil, where the fertility is, dries and the roots must go
down through a tight clay layer which has almost no fertility. Then, because of
the crop failure in the absence of plant nutrition in that soil layer of stored
water, we try to blame the drought or the bad weather. Drought may be merely
that soil situation in which we have no soil fertility deep enough to feed the
plants when they are compelled to have their roots go deeper to get stored
water. We have emphasized the water so much that the situation suggests itself
as a relic of the old “saloon” days, when men thought they had to stay in a
saloon and drink, but forgot to take some groceries home for the family. Plants
will scarcely emphasize drink to that much neglect of food. Our confused
thinking about drink for plants emphasized the water facts as an alibi for our
ignorance of plant nutrition and the soil fertility factor where the emphasis
properly belongs. During the drought we don’t use the water to the best of our
ability. We neglect to remind ourselves that the plant is about 95% air, water
and sunshine, and only about 5% fertility. We are too indifferent to that fact
to consider carefully how we can use that 5% as the requirement to produce the
other 95% of plant growth, a performance which offers chances as a gamble
better than one would scarcely anticipate.
We blame the water. We blame the weather. The water of
transpiration from the plants is like the water going over the millwheel, only
a part of that coming down the millstream. The amount of grist that one grinds
in the mill is determined not so much by the amount of water going over the
millwheel, the amount of which is fixed or limited, as by the diligence with
which wheat is kept going into the millstones for 24 hours a day at full
capacity. We haven’t been keeping the soil fertility well and properly supplied
to the crop plant and are therefore in error when for disturbed yields we blame
the drought.
- Excerpt from Albrecht's Foundation Concepts - Vol. 1 - pgs.53-55; 1953
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