Ecoscience: Topsoil Erosion

article image
PHOTO: MOTHER EARTH NEWS STAFF
Anne and Paul Ehrlich warned that topsoil erosion in the U.S. was exceeding sustainable levels.

In the midst of today’s fuss and furor about our present
shortages (and continued depletion) of resources–especially of energy–the accelerating loss of one of
our most precious treasures, our topsoil, has gone almost
unnoticed, Yet this neglected resource–which is today, and
has been in the past, the basis of much of America’s
wealth–is so slowly renewable as to be virtually
irreplaceable.

Recent farming practices, abetted by federal and state farm
assistance that has actually encouraged increased
crop production at the expense of conservation measures,
are leading to unprecedented topsoil erosion–by wind and water–of
America’s crop and grazing lands. The source of our future
productivity is being overused, abused, blown away, and
quite literally washed down the river.

How and why is this happening In a country where
sophisticated agricultural technology has been almost
universally adopted and where farmers have access to state
and federal assistance and extension services? Was nothing
learned as a result of the disastrous 1930’s Dust Bowl?
Just how serious is the problem anyway?

Lessons Learned

The Dust Bowl crisis did indeed stimulate an effective
national soil conservation program. Farmers were
taught–and encouraged through incentives–to employ
various techniques that diminish soil erosion and protect
fertility.

Among the methods were contour plowing, terracing, and
strip planting (the alternation of earth-retaining crops
with relatively erosive ones) … all of which help protect
topsoil on sloping land from water erosion. Wind erosion
was reduced by planting windbreaks of trees or tall crops.

The depletion of soil nutrients, and both kinds of
erosion, were combated with crop rotation … that is, the
planting of a cash crop (such as corn, soybeans, or wheat)
in alternate years with grasses or soil-enriching legumes
(alfalfa or clover, for example) that provide–in
addition–good pasturage for livestock.

Then, in the 1950’s, grain production soared as a
result of the development of higher-yielding strains, the
increased use of fertilizers, and–in some areas–the
availability of improved water supply from irrigation
projects. Production soon far outstripped demand, and
prices began to fall.

To help stabilize farmers’ incomes, the government
instituted a grain reserve program through which it
bought and held surpluses and actively promoted their sale
abroad. The “Soil Bank”–which paid farmers to keep a
portion of their land out of production–was also
initiated at that time. Sensible agriculturists, of course,
withheld their least productive fields, which were
most often those on hillsides or those with the thinnest,
poorest soil. Because this is the kind of land most
susceptible to erosion if plowed and planted, the Soil Bank
did effectively contribute to the nation’s soil
conservation efforts.

Lessons Forgotten

However, everything changed In 1972, when–in the face of a
2% growth in the global population–there was a 4% worldwide
shortfall in the production of grain … the basis of the
diets of the majority of human beings. One of the worst-hit
nations was the Soviet Union, which quietly proceeded to
buy over 20 million tons of grain–mostly wheat–from
the United States.

Our country suddenly became very hard pressed to meet its
domestic demand and other foreign obligations. As a result,
grain prices went through the roof in 1973 … and were
soon followed by substantial price rises for grain-fed meat
and poultry.

A second major drop in grain production in 1974 aggravated
the entire situation, nearly wiping out U.S. grain reserves
(which, for practical purposes, are the world’s only
real food reserves) and bringing on severe famine
in several impoverished countries.

The U.S. government’s response was to abolish the Soil
Bank. (The grain reserve program was already being
dismantled by Secretary of Agriculture Earl Butz and
friends, whose fondness for “free market” farm policies had
a lot to do with the disastrous fluctuation of farm incomes
in the 1970’s.) Farmers were encouraged by the Department
of Agriculture’s (USDA) policies -to plant
fence-to-fence and boost production by every possible
means.

The higher production that resulted, however, was followed
by rock-bottom prices, which–together with increased
farming costs (mainly a result of increased consumption of
fuel and fertilizer) and higher loan interest
rates–reinforced the pressure to produce more. In
order to stay in business , many farmers had to coax every
possible kernel of grain out of the ground, so corn and
wheat growers responded to the economic squeeze by
abandoning or cutting back on soil conservation practices.
The costs of increased erosion would be paid decades in the
future … while the profits gained from bigger harvests
were needed immediately.

Courting Disaster

In 1976 severe droughts reappeared in the western plains,
complete with dust storms. Some farmers, unable to make a
living, simply gave up and left their bare land to blow
away with the wind.

In the Corn Belt, still under the pressure to produce,
farmers increased corn and soybean acreage enormously by
putting land under continuous cropping. The loss
of nitrogen, formerly obtained by rotating cash crops with
leguminous pasturage, was compensated for by applying more
and more synthetic fertilizers. (Even though soybeans are
legumes and do add nitrogen to the earth, they tend to
contribute to erosion problems because their root systems
don’t hold soil well.)

Some farmers gave up strip cropping and terracing on
slopes, partly to increase grain production (the alternate
crop used in the former techniques had often been less
remunerative than the in demand corn and wheat) and partly
because such procedures are incompatible with using the
latest oversized farm machinery. Worse still, some farmers
even completely abandoned the practice of contour plowing!

The most scandalous aspect of all, though, is that such
activities have been encouraged–and even financially
supported–by the USDA. In recent years, perhaps half of the
funds intended to support farmers’ conservation practices
and paid out through the Agriculture Stabilization and
Conservation Service (ASCS) have, In reality, been spent on
such measures as improved irrigation and drainage systems
… that do more to increase yields than they do to protect
soil.

In 1977, when the Carter administration instituted Its new
“set aside” program (the Soil Bank by another name), the
ASCS didn’t allow pasture to be counted as cropland. So, in
order to establish their less-valuable land as “normal”
cropped acre age–and thereby qualify it for federal
subsidies–many farmers plowed and planted every
square Inch of their property in cash crops.

As a result of this lack of attention to conservation, the
USDA’s Soil Conservation Service warned, in the mid-1970’s,
that–through water erosion alone–the nation was
losing topsoil at an annual rate of three billion tons …
as much as was being lost before the first national
conservation programs were established in the 1930’s, and
twice the amount that should be allowed. The Council for
Agricultural Science and Technology (CAST), a private group
supported by several mid-western universities, estimated in
1975 that “one-third of All U.S. cropland was suffering
soil losses too great to be sustained without a gradual but
ultimately disastrous decline in productivity.” And in late
1978, Secretary of Agriculture Bob Bergland dramatically
announced, “We are on a collision course with disaster. ”

Heavy Losses

The most recent–and the most exhaustive–study
of this problem is a comprehensive “Soil Erosion Inventory”
undertaken by the Soil Conservation Service (SCS) in 1977,
and released last spring. It showed that the nation
(excluding Alaska) lost some two billion tons of topsoil to
water erosion during 1977 and–in ten Great Plains states
alone–nearly 1.5 billion tons more to the wind.

Water erosion losses that year averaged four to five tons
per acre on cropland, pasture, and range land. Since only
the deepest soils can sustain losses at such rates, the
average is clearly far too high.

Moreover, the average figure tends to conceal the much
higher rates that prevail in some of our most fertile
states. Iowa, for instance, loses an estimated 9.9 tons per
acre … Illinois, 6.7 … Missouri, 10.4 … and
Louisiana, 7.9. (Worse yet, the soil in our Caribbean
possessions is being eroded at an average rate of over 40
tons per acre per year!)

Wind damage is a serious problem mainly in the relatively
dry Great Plains states and the cultivated parts of the arid
West, which are–in turn–not terribly vulnerable
to water erosion. The average loss of cropland soil to wind
erosion, in the ten states surveyed by the SCS, was over
five tons per acre in 1977 … but in three of those
states, losses exceeded eight tons per acre (in Texas, the
rate of erosion was nearly three times the
average).

The SCS concluded that well over half of the
nation’s cropland needs conservation treatment … as does
the great majority of our pasture, rangeland, and woodland.

Annual soil losses that can be “tolerated”–that is,
the rates at which they can be replenished by natural
processes and good husbandry–vary from one to five
tons per acre, depending on the depth and quality of the
topsoil. (Complete destruction of cropland is–for practical
purposes–irreversible. Although severe damage can, in
time, be repaired, it can be done only at very high expense
in comparison to the cost of conservation practices
designed to preserve and protect the soil in the first
place.)

With careful husbandry (which includes erosion protection
and the regular addition of crop residues and other organic
material), new soil can be built up … at the
rate of about one inch per century. Nature, however, takes
several times longer.

Lower Yields

So far, fortunately, no serious general decline in national
productivity has manifested itself as a result of the
recent trends toward “chemical” farming and the neglect of
conservation … probably because soil losses can–for
a while–be masked by the application of more
fertilizers and other chemicals. But high erosion rates
clearly cannot be sustained for very long.

And even though overall U.S. cropland productivity hasn’t
suffered a decline, neither has it grown significantly
since the early 1970’s … and it’s quite possible that
declining soil fertility, due to over-intensive cropping
and erosion, is a factor in that lack of growth.

Soil erosion is a major contributor to national pollution
problems as well. In the past decade, our government has
made considerable progress in forcing industry to clean up
its act. The greatest cause of water pollution today is
runoff from what are called “non-point sources” … that
is, mainly farms. Most of the two billion or more tons of
soil washed annually from U.S. croplands ends up in our
rivers, lakes, and estuaries. The silt fills up reservoirs
and clogs irrigation ditches, drainage systems, harbors,
and river channels.

And along with the billions of tons of soil go
additional millions of tons of fertilizers and
pesticides. In two-thirds of the river basins in the United
States, water quality is adversely affected by such
agricultural pollution.

Poorly managed farms also produce air pollution
… in the form of dust particles blown from unprotected
dry land. The ultimate in this form of pollution Is the
dust storm, for which the 1930’s were famous. Few Americans
outside of the plains states realize, however, that such
storms recurred in the 1950’s and 1970’s. (Each
generation of plains farmers apparently must learn the same
lesson all over again.)

In the United States, a return to sensible policies
encouraging soil conservation ironically may come about,
not because American agriculturists and the USDA
have suddenly become farsighted and concerned about future
productivity, but because federal clean water laws require
that streams and lakes be “fishable and swimmable” by 1983.
And the most effective way to control and prevent the water
pollution resulting from farm runoff is to employ
conventional soil protection practices. Of course, the
effects of such techniques can–and should–be
abetted by a curtailed use of farm chemicals.

Yet despite the mandate of our national cleanwater laws,
not much is being done. Farmers are still being encouraged
by USDA policies–and forced by economic
circumstances–to struggle for bigger harvests while
ignoring conservation practices and allowing their resource
base to be undermined and destroyed.

A Rural Clean Water Program was enacted by Congress in 1977
… but fell victim, in 1978, to administration budget
cutting and bureaucratic wrangling over which agency should
run it. No funds were appropriated for the program during
that year.

That President Carter, who proudly calls himself a farmer,
should head an administration which has consistently
slashed funding for soil conservation programs is
both astonishing and disgraceful. Such “cost cutting”
strikes us as the falsest of economies in a hungry world in
which the population is expected to increase by nearly two
billion by the end of the century.

A sizable-and growing-number of the earth’s people are
dependent on U.S. food exports. The U.S., in turn, depends
on the $25 billion or more that such food exports earn each
year to help meet Its oil import bill.

It remains to be seen how much if any of the damage that
has already been done to United States farmland can be
reversed. At the very least, we as a nation must do our
utmost to prevent any further destruction of our
irreplaceable soil resources.  


Sources for this study included James Risser’s “Soil
Erosion Creates a Crisis Down on the Farm” a series of
articles published in the
Des Moines Register inSeptember 1978 and reprinted in the Conservation
Foundation Letter, December 1978the Soil
Conservation Service’s
1977 National Resource
Inventories (U. S. Department of Agriculture,
1979)
and William Lockeretz’s “The Lessons of
the Dust Bowl” which appears in the
American
Scientist, vol. 66, September/ October 1978, page
560.

For background material on U.S. agricultural problems,
see S.M. Schneider and L. Mesirow’s
The Genesis
Strategy (Plenum, 1976)and Chapters
6 and 7 of Paul R. Ehrlich, Anne H. Ehrlich, and John
P. Holdren’s
Ecoscience: Population, Resources,
Environment (W. H.
Freeman and Co.
).


Paul Ehrlich (Bing Professor of Population Studies and
Professor of Biological Sciences, Stanford University) and
Anne Ehrlich (Senior Research Associate, Department of
Biological Sciences, Stanford) are familiar names to
ecologists and environmentalists everywhere. As well they
should be. Because it was Paul and Anne who–through
their writing and research–gave special meaning to
the words “population”, “resources”, and “environment” in
the late 1960’s. (They also coined the term coevolu
tion, and did a lot to make ecology the household word
it is today.) But while most folks are aware of the
Ehrlichs’ popular writing in the areas of ecology and
overpopulation (most of us–for instance–have
read Paul’s book The Population Bomb) . . . far too few
people have any idea of how deeply the Ehrlichs are
involved in ecological research (research of the type that
tends to be published only in technical journals and
college textbooks). That’s why it pleases us to be able to
present–on a regular basis–these
semi-technical columns by authors/ecologists/educators Anne
and Paul Ehrlich.