Geoscience Reference
In-Depth Information
within and across all landscapes. For each location, soil facilitates roots from a plant
or a canopy of plants to be anchored in a specifi c location to thrive and reproduce.
Soil together with its vegetative cover keeps the contemporary gas composition of
the atmosphere relatively constant - a stable condition required for the existence
and survival of human life. Soil retains water from irregular rainfall and irrigation
events and offers it with dissolved essential nutrients to plants through their roots in
a remarkable, unswerving manner. Soil is the home of countless microorganisms
that cause the decomposition and transformation of decayed organic bodies with
some of them contributing to the fi xation of atmospheric nitrogen. Other microbial
species cooperate with roots to such an extent that we could say that they are graz-
ing on the roots causing at the same time a profi t for the plant. This type of symbio-
sis helps both sides - the plant and the microbes. In addition to the activity of
microorganisms, we fi nd that soil is the home of ants, termites, earthworms, and
huge numbers of related macrofauna that all contribute directly or indirectly to the
global vegetative community. Plants could not exist without this continuing chain of
infl uence. The life of herbivores is impossible without plants and the same is valid
for us, even if we succeeded in transforming mankind from omnivores to herbi-
vores. And we are not speaking about the majority of us who reject the idea of only
veggies.
The modern vocabulary of ecologists permanently retains the term biodiversity.
It means the degree of variation of life at all biological levels starting from cellular
level up to plants and animals. Biodiversity depends upon the favorable conditions
for existence and for evolution of all forms of life. It is our pleasant duty to mention
that the biodiversity in soil is much greater inside of the soil than above the soil
surface among plants and all animals. Those among the ecologists who are so con-
scientiously worried about biodiversity should be careful about soil in a same way
or even more as they are about living organisms. Why? Because if the biodiversity
of soil were lost, an immediate loss of biodiversity on the entire planet Earth would
follow. We expect ecologists to preferentially protect soils from their misuse and
from the potential, eventual destruction of soils' ability to support life on Earth.
However, many commonly accepted practices of managing soils are destructive
even though laymen do not recognize them. A typical example is the planting and
cultivation of monocultures that allows a single crop or plant to be grown in a farm-
er's fi eld or similar areas for a large number of consecutive years. Such a practice
steadily leads to the exhaustion of a certain nutrient or group of nutrients which
become the most important factor for plant growth with harvests becoming more
and more reduced year after year. Even when the availability of the essential nutri-
ent is increased by an annual supply of mineral fertilization, one or more other
required nutrients or substances start to diminish or virtually disappear. Eventually
with continued monoculture, this lack of irreplaceable matter causes a weakening of
the root system, a reduction of growth of the aboveground plant parts, and a deterio-
ration of the effectiveness of the physical, chemical, and biological properties of the
soil. However, this result is only one part of the ugly face of monocultures.
Repetitiously cultivating the same crop on the same fi eld also enhances the
development of weeds and plant diseases because the natural processes of plant
