Evening star., 1934-01-21
BY RExFORD GUY TUGWELL.

from the Clty nave peeL leu "
believe that, however anything
else might change, there Will always
remain the brown earth OF the country
side. It has been regarded as a grea'
world mother to whom. even after pc
RODS of blackest revolution or the wor-
ship of false gods, men might return
and derive new strength.
In a state of primitive culture, TINS
might be quite true; for to all practical
purposes, the slow destruction of this
earth's surface by vast, geological
changes. would have no significance 10
the human race. Left alone, this eartn
of ours would have flung itself cease
lessly through space, rain would have
fallen. been caught by the broad leaves
of trees or speared by the narrow places
of grass. Gradually it would have per-
colated to some stream, running thus
away to the sea; then it would return
again as rain So the circle, endIeSsly
repeated, would have been closed. Inc
highest mountain would very gradually
wear down to rolling plain-oarr1ng
some great cataclysm which might once
more squeeze together the earthS sur
face and reform its mountains. ms,
biologists might be willing to say. would
have been the normal development our
planet should have taken, with changes
so slow and so imperceptible that we
should never realize their existence.
But the earth and climate were not
left to their own devices. Men con-
ceived the desire to cultivate plants,
and to warm themselves and fashion
the instruments they invented from the
wood of trees Hillsides were stripped
of their forests to supply these needs;
the soil was turned and exposed to
wind and rain. Natures cover was
stripped off the earth, and great areas
Of bare soil invited the elements
Through mans own efforts. therefore,
the greatest of our resources was made
impermanent We have now to think
of its conservation.
Wind and Water.
Even the ancients realized that water
flowing down a hillside could move
tons Of soil, and they formed elaborate
bench-like steps out of the hillsides to
check the run-off. Today it is possible
to drive for hours through the hilly
lands of Spain, Southern France, Italy,
Sicily and Greece without ever losing
sight of the sharply indented slopes OF
hills covered with vineyards and
orchards of oranges, lemons, almonds
and olives. In our own country the
lands which stretch out, apparently
limitlessly, from our Western frontier,
for a long time made unnecessary re-
sort to such drastic measures for pres
ervation. BY the middle of the last
century we had begun to use terraces
in some parts of the Southeastern
States: but it was not until the begin
ming of this century that the entire
problem began to get careful study.
Erosion is of two principal sorts
wind and water. Today throughout an
area of many hundred square miles
where the States of Colorado, Okla
homa, New Mexico and Texas meet
there has been a long drought which
has so dried the top soil that for more
than year the wind has been carrying
1t away in spite of the efforts of the
SO, 900 farmers of the district. There
Is misery in that country for men and
stock. This is an example Of wind
erosion's destructive force. No one
would go into this area now in search
of traditional rural stability and peace
AL that has been lost.
Sheet Washing and Outlying.
But erosion by water is of more COM
pelling general concern. 1t happens over
wider areas and is practically continuous
there. Water can carry soil away in
two fashions: 1t can wash it off the
top Of rolling, fat lands in thin layers
of mud or it can dramatically carry it
in concentrated form through V-shaped
hollows, which may soon develop into
good sized troughs and eventually into
miniature valleys or gullies. One is
called sheet washing" the other gully
ing" Both are caused by the same
hot &c ho
which has been laid bare by men can
not absorb all the rain which falls and
SO must run off" In this running it
carries with it particles of the earth
over which it passes. The overwhelming
effects of this process are caused by the
fact that even if the slope is increased
only four times, the velocity Of the
water is about doubled and the power
of the water to carry away soil is in
creased some 30 times.
The cumulative results OF water
erosion are overwhelming. A billion and
q half tons of soil are carried away
by erosion each year; and OF this
80 600 900 tons has been conservatively
estimated to be the minimum amount
of plant food material which is lost.
This represents drain of such elements
as potash, phosphoric acid, nitrogen,
lime and magnesia which is Il times
greater than that annually removed by
the crops themselves, Its commercial
value would be over $4,000, 100000 of
which evidence shows that at least
5000 100000 can be charged up as a
direct tangible loss to the farmers OF
the Nation. Such loss would be
staggering blow to any industry! A
further result, not so directly connected
with the farming problem. but still OF
the utmost Importance. is the contribu-
ton which erosion makes to the spec
tacular floods which periodically ter
rorize the countryside and to the sub
sequent sitting up OF river channels ana
engineering works.
The Economic Problem.
From a purely economic standpoint.
the problem is equally acute, for the
cost of terracing an area Is mches
high, 20 feet wide and 1000 feet long
in light soils on moderate slopes has
been estimated to range from S1.5O to
SIS an acre, depending upon the num-
ber and depth of the gullies. ms,
however, is figured on the usual costs
for labor, team and tractor power
Frequently. during of seasons. the
farmer might be able to construct ter
races Will d VA a6 AVA
practically nothing.
On the credit side of the ledger the
actual gains accruing to the farmer
seem considerable. Credit institutions
making loans on agricultural land have
become aware of erosion's dangers. A
representative of the Federal Land
Bank at Houston, Tex, said recently
that he had analyzed 200 foreclosed
farms and found 10 per cent to be
definitely badly eroded,' and that "in
numerous instances within few years
securities upon which we have made
loans have gone to utter destruction
and have been abandoned because OF
erosion" Three nationally known in,
surance companies have commenced
control work on properties whose mort. y
cages they hold, in order that thelr
Investment might not be literally
washed away.
The Engineering Side.
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