Given all the adverse consequences of
large-scale industrial agriculture,
a number of people in the United
States and elsewhere in the world
have looked at other
forms of agriculture,
organic agriculture,
sustainable agriculture.
Let's talk about them.
Organic agriculture aspires
to work with natural systems
rather than dominate them.
Some of the goals are to enhance
biodiversity in the fields,
keep as much organic matter and
as many nutrients in the soil
and on the farm as possible, maintain
the soil by increasing the soil mass,
the biological activity
of organisms in the soil,
and beneficial chemical
properties of the soil.
Organic agriculture avoids the
use of synthetic fertilizers
and synthetic pesticides.
It tries to reduce as many adverse
environmental effects of agriculture
as possible.
Organic agriculture still utilizes
fossil fuels and mechanization.
Organic agriculture
still plows the soil.
Organic agriculture can still be
detrimental to the environment.
Organically grown foods are often
sold at a premium price, at least
in some countries, and that is
sometimes an advantage for the grower.
There are other practices
in sustainable agriculture
that allow us to say that they are
definitely more favorable and more
desirable for the natural environment.
Sustainable agriculture fulfills
the need for food and fiber
while enhancing the quality
the soil, minimizing
the use of non-renewable resources,
and allowing economic viability
for the farmer.
So sustainable farming has
even perhaps a broader-reaching
set of goals than organic farming.
A farmer practicing
sustainable method wants
to be able to continue agriculture on
a given piece of land indefinitely.
Here's some other features
of sustainable agriculture,
and some of these are also
found in organic agriculture.
Intercropping is when
two or more crop species
are planted in the same
field at the same time
to promote a synergistic
interaction between them,
so for example, corn and peas.
Corn requires much
nitrogen from the soils.
And peas are a legume that fix nitrogen,
or the microorganisms associated
with the pea plants fix
nitrogen in the soil.
So growing those two plants
together benefits each.
Crop rotation is rotating the crop
species in a field from one season
to another.
So using the same example, you might
plant peas for one year in a field
and there's a buildup of nitrogen.
And then in the next year, you
plant corn in that same location,
and the corn makes use of that nitrogen
that's been accumulating in the soil.
Agroforestry is intercropping trees
with vegetables or other crops.
So agroforestry is another kind
of sustainable agriculture.
The trees can act as
a windbreak that catch
soil that might have otherwise
blown or washed away.
And the trees can also be a crop
themselves, say if you had fruit trees
or if you cut down the tree and used
the biomass for burning, for example.
Contour plowing is plowing
and harvesting parallel
to the topographic contours of the land.
It helps prevent erosion by
water, while still allowing
for the practical advantages of plowing.
So you try to keep as much of
your land more or less level,
and then step down to the next contour.
No-till agriculture
is when farmers do not
till their fields, leaving crop
residues in the field between seasons.
It's done in some sustainable
agricultural practices.
It prevents soil degradation, for
intact roots hold the soil in place,
reducing erosion.
It reduces CO2 emissions because
intact soil undergoes less oxidation;
however, sometimes farmers
need to use an herbicide
to keep some of the undesirable species
from overtaking the crop species.
So that becomes a problem
with no-till agriculture.
We should also talk about the role of
biotechnology, which some would argue
has a place in sustainable agriculture
and others would argue does not.
We need to introduce a
term, genetically modified,
as in genetically modified crop
or genetically modified organism,
which is often abbreviated as GMO.
Genetically modified refers
to a process in which
a gene with a desirable
trait from one organism
is inserted into another organism.
Genetically modified crops and
livestock offer the possibility
of greater yields and food quality.
They do so by breeding
strains of plants or animals
that are resistant to drought or
disease or perhaps cold temperatures.
This increases productivity,
maybe extends the growing season,
and decreases the need for pesticides.
GMOs are banned by the European
Union but are abundantly used
in the United States.
In commercially grown crops in the
United States, perhaps 85% to 90%
of corn and soybeans and some of the
other species that are commonly grown
are GMO crops.
GMOs appear to be safe
for human consumption,
although we can't say that for certain.
And there do seem to be
some concerns about few food
allergies in some people.
There are some legitimate
concerns that GMOs
will breed with native
plant or animal species
and then escape to wild populations.
We also need to consider the
demand for land and water
in different forms of agriculture.
Modern industrial agriculture
uses a large amount of land area.
This use of land can lead to
habitat fragmentation and halt
succession of an entire landscape.
We also need to consider the concept
of maximum sustainable yield.
The maximum sustainable
yield of a renewable resource
is the maximum amount
that can be harvested
without compromising the future
viability of that resource.
So if we want to consider
soil as a resource,
we want to grow food in
a sustainable way that
doesn't compromise the ability of that
soil to support food in the future.
We might also consider that when
we're talking about a wild population,
the maximum harvest that can
be removed from a population
and can be replaced by that population.
So we can consider that when we
take trees down from a forest.
We cut down trees.
We don't want to cut down so many
trees that we're removing nutrients,
that we're eroding the soil, that we're
preventing the regrowth of that forest.
We can ask that question, how
much food can be grown on a soil
without depleting the soil of
its nutrients in a similar way?
Those are some of the issues comparing
different kinds of agriculture,
contrasting organic agriculture
with sustainable agriculture.
And an environmental scientist has to
weigh the pros and cons of all of these
and try to make a decision.
What is best for a given landscape?
What is best for a given piece of land?
What is best for humanity?
