591

CO

LIBKARl AGRIG. DEPT,

CIRCULAR No. 4. S. 28.

United States Department of Agriculture,

. DIVISION OF SOILS.
Cooperating with the Utah Experiment Station.

THE SOILS OF SALT LAKE VALLEY, UTAH.

OBJECT OF RECENT SURVEY.

In July, 1899, the Division of Soils, in cooperation with the Utah
Agricultural Experiment Station, undertook a survey of that portion
of Salt Lake County lying immediately west of the Jordan River and
extending to the Great Salt Lake and the Oquirrh Mountains on the
west, the object being to map the soils with particular reference to
the extent of, and damage from, alkali and seepage waters.

EARLY IRRIGATION WORK.

Irrigation began here a half century ago and, for the most part,
has been confined to that portion of the area nearest the river Jordan
and south of the Twelfth street road. This irrigated portion con-
sists of a number of benches, one above another, extending in a gen-
eral direction parallel with the river and comprising an area about
two miles wide and sixteen miles long, extending south from the
Twelfth street road and bordering on the river — together with an-
other portion not quite so wide, which turns westward — following
the contour of the foothills and extending nearly to the point of the
Oquirrh Mountains. The land slopes toward the river, or to the
north, at the rate of fifty to one hundred feet per mile.

The earliest irrigation was successfully practiced on the Jordan
meadows or bottom land, but later, when canals were constructed
and irrigation began on the benches, the bottom land became so wet
that the greater part of it has been abandoned and now lies as pas-
ture or waste land.

RECENT IRRIGATION IMPROVEMENTS.

The latest, largest, and uppermost of the canals running over these
bench lands is the Utah and Salt Lake, which is about two hundred
feet above the level of most of the river bottoms and the low lands
to the north. At its furthermost extremity this canal is about eleven
miles west of the river. In the last six or seven miles of its course
it passes over soil that is underlaid quite close to the surface by
gravel, which is in turn underlaid at a considerable depth by an im-
pervious layer of clay. The clay outcrops from one to two miles

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north of the canal on considerably lower land. As a result of this
structure and the considerable irrigation on the upper lands, a large
area has here become so damaged by seepage water and alkali that
it has been abandoned.

Both the South and North Jordan canals, which lie between the
Utah and Salt Lake canal and the river, are responsible for much
similar damage, especially at their outer extremities. Parallel with
the Twelfth street road and about one mile south of it is a strip of
land extending from the river about ten miles west, varying from
one-half to one and one-half miles in width, all of which is more or
less damaged by seepage water and alkali. Indeed, the damage has
gone so far that a chain of lakes has been formed in this area, pre-
senting a water surface of a thousand or more acres. This has all
resulted from the seepage and surplus waters from the irrigated dis-
tricts above. The total area which has been successfully irrigated is
about fifty square miles, of which about ten square miles have been
ruined by seepage water and alkali.

Of the larger, much lower, and level area, mostly north of the
Twelfth street road and adjacent to Salt Lake City, extending from
the river Jordan to Great Salt Lake and comprising about one hun-
dred and twenty-five square miles, none has been successfully farmed,
with the exception of a narrow belt along the river, although many
attempts have been made and much money expended in this en-
deavor. About eleven years ago this area was the seat of an exten-
sive boom — suburban townsites were laid out, streets graded, canals
constructed, and artesian wells sunk ; railroads were built and oper-
ated, parks were laid out and trees planted, buildings were erected
for homes and stores, and, in the aggregate, hundreds of thousands
of dollars were expended, for which no returns have ever been real-
ized, excepting, perhaps, by the shrewd speculator.

The first-year crops that were cultivated gave fair returns ; the
second year failure was general, and the third year absolute. At
present there are in this area many deserted houses and much unused
land, which bears evidence of having once been cultivated. The
cause of this failure and of the damage wrought by irrigation have,
perhaps, never been fully understood by any one.

Four months were spent in a thorough and detailed examination
of this area, and the large amount of data thus collected has given
a far better understanding of the existing conditions than has ever
before been realized. It is hoped that this knowledge will suggest
the lines to be followed in order to overcome the difficulties that will
be encountered in future attempts to farm this land.

The results of this work are embodied in the following statements,
pending the completion of a detailed report :

FIG. l.— Map of a portion of Salt Lake Valley, Utah.

CLIMATE.

Rainfall records previous to the establishment of the Government
weather service at Salt Lake City, show an annual variation of from
10 to 29.5 inches. At Salt Lake City the mean annual rainfall,
according to the record of the past twenty-five years of the U. S.
Weather Bureau, is 16 inches, with a minimum of 10.3 and maxi-
mum of 23.6 inches. Of this annual rainfall, less than three inches
fall during the four warmest months of the year — June, July, Aug-
ust, and September. These four driest and warmest months, having
a total mean rainfall of less than three inches and a mean tempera-
ture of 70.4° F., are accompanied by a low, relative humidity — con-
ditions favoring excessive evaporation.

It is estimated that the annual evaporation from a free water sur-
face in this locality is eight feet. Calculations from data of one of
the salt companies show the evaporation from their ponds to be thir-
ty-seven inches for the four months of June to September. It must
be borne in mind, however, that this is from a saturated brine, and
that the vapor tension, and consequently the evaporation, is much
lessened by the presence of large quantities of salt.

Since the greater part of vegetable growth is made during these
four months, these data show how important and necessary is irri-
gation for the production of crops. Indeed, no farming is carried on
without irrigation except in the case of wheat, which makes most of
its growth prior to June, and from which small yields is the rule
rather than the exception.

WATER SUPPLY.

The Jordan River, from which all of the irrigation water used on
the above area is taken, is the main channel through which the waters
of a large number of streams extending well back into the mountains
east and south, as well as the waters of Utah Lake and its inflowing
streams, make their way to the Great Salt Lake. The annual pre-
cipitation in the mountains exceeds that in the valleys and is largely
of snow, which lingers on the highest mountains during the greater
part of the summer. The melting snow and the numerous moun-
tain springs make the irrigation water supply constant, plentiful,
and of good quality. The Utah and Salt Lake and the South Jor-
don canals get their water supply from the Jordan River, near the
Jordan Narrows, and it is representative of the water of Utah Lake,
which was found to contain eighty-nine parts of soluble matter in
one hundred thousand parts of water. Of this only about fifty parts
are likely to remain in solution and accumulate in the soil to the det-
riment of plants.

A few miles below the head of the South Jordan canal the seepage
waters from the adjacent irrigated districts begin to return to the
Jordan River. This seepage water, together with the unused por-
tion of waters of the mountain streams to the east — Big and the Lit-
tle Cotton Woods, Mill Creek, and City Creek, make the composi-
tion of the river water exceedingly variable during the remainder of
its course. The seepage waters, with their high salt content, tend
to make the water poor, while the mountain streams dilute and im-
prove its quality.

The mean salt content of the North Jordan canal is about one hun-
dred and seventy parts in one hundred thousand, or, practically, twice
as much as that of the South Jordan. Below this the water of the
Jordan, because of the entrance of mountain streams, improves ; and
we find the mean salt content of the Surplus and the North Point
Consolidated canals to be about one hundred and thirty-five parts in
one hundred thousand. About two hundred and fifty parts to one
hundred thousand is the limit of safety.

In large irrigation canals water may flow for many miles and de-
teriorate very little in quality, while in small ditches the deterioration
may become apparent through the evaporation of water and collec-
tion of salts from the banks of the ditch.

The aggregate capacity of the irrigation canals on this area is about
six hundred cubic feet per second, but very much less than this
amount of water is required or used on the twenty-five thousand
acres that are now under irrigation. During the entire summer of
1899, large volumes of water were constantly passing the intake of
the Surplus canal, and there is apparently enough water going to
waste to irrigate all of the better lands west of Salt Lake City, bet-
ween the river and the Lake.

SOILS.

The soils of this area have been classed under eight heads —

(1) Jordan sands.

(2) Jordan sandy loams.

(3) Jordan loams.

(4) Jordan clay and clay loams.

(5) Jordan meadows.

(6) Bingham gravelly loams.

(7) Bingham stony lands.

(8) Salt Lake sand (oolitic sand dunes).

1 . The Jordan sands comprise a small area, usually a narrow belt
along the bluffs bordering on the Jordan meadows or river bottom
soils. The sand is generally fine-grained and continuous to six or
more feet in depth, though occasionally underlaid at a less depth by
loam or clay.

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2. The Jordan sandy loam is the most important soil, both in point
of area and of quality. It is a light sandy loam, ranging from one
to several feet in depth and varying somewhat in its underlying
strata. The most usual profile is two feet of sandy loam, one and
one-half feet of loam and one foot of sand, all of which is underlaid
by clay to a considerable depth.

3. The next most important type of soil is the Jordan loam, which
is somewhat heavier than the sandy loam and, like the above, varies
much in depth and underlying strata. Its most usual form is three
feet of loam underlaid by clay, which frequently .contains veins or
pockets of fine sand.

4. An unimportant type of soil, agriculturally, at present is that
of the clay and clay loams, which are low, level, wet areas lying
near the lake (usually called "playas") and extending back into the
better lands like fingers of a bay. It is all very salty and usually
void of any vegetation. The clay is quite continuous to a consider-
able depth, although frequently inlaid with veins, or pockets, of very
fine sand. The fingers, which extend far back like wide, irregular
canals from four to eight feet deep, would furnish efficient drainage
outlets for the adjacent good lands.

5. The Jordan meadows comprise a narrow belt, from a few rods
to a half mile in width, which borders on the river Jordan. The soil
being formed from the sediment of the river, is black and contains
much organic material. It varies in depth from one to several feet,
and in texture from sandy loam to clay. The most common form,
however, is two feet of loam, two feet of clay, and one foot of coarse
sand, all of which is underlaid by gravel. Where the gravel is not
present, the soils are now usually very wet, and but little used ex-
cept for pasture. The wetness is caused by seepage from canals and
irrigated lands above. If drained, they would be fertile and pro-
ductive.

6. Lying for the greater part above the irrigation canals is a large
area of good land, which contains gravel within three feet or less of
the surface. The gravel frequently comes to the surface, but it is
here too small to materially interfere with cultivation. Below the
surface the gravel becomes larger, and at several feet in depth may
approach the size of bowlders. This area, considerable of which is
dry-farmed to wheat, is called the Bingham gravelly loam.

7. The Bingham .stony loam comprises a small and unimportant
area near the foothills, which is too stony to be cultivated.

8. The Salt Lake sands (oolitic sands) are chiefly carbonate of
lime, spherical in form and about the size of No. 10 shot. This sand
is probably formed by the throwing down of carbonate of lime in the
water of the lake, which is washed to the shore where the wind still

transports it further inland. It constitutes for the most part dunes
along the lake shore and is of no importance agriculturally.

As is frequently the case with alluvial and sedimentary soils, the
soils of Salt Lake Valley, especially those north of Twelfth street
road, are heterogeneous and much mixed up, perhaps more so than
is usual. They were probably first formed in the bed of the old lake,
Bonneville, by sedimentation, and after its subsidence further modi-
fied by the vacillating shore of the more modern Great Salt Lake
and the inflowing streams from the adjacent mountains.

ALKALI.

The salts, as they occur in the soil, vary greatly in quantity. In
the best agricultural lands the amount present is frequently less than
.05 of 1 per cent, while in the salt flats there may be as high as ten
per cent, exclusive of the crust that frequently forms in much greater
concentration. Sodium chloride, or the common salt of commerce,
forms from fifty to ninety-seven per cent of the total salts present.
Besides this, there are considerable quantities of the sulphates of
soda, lime, and magnesia, chlorides of lime and magnesia, and also
carbonate of soda, or true black alkali. The black alkali is nearly
always present in amounts varying from a trace up to several per
cent in small local spots. There is, in the aggregate, a large area in
which it occurs in sufficient quantity (.1 per cent) to be fatal to crops.

It seems quite probable that this accumulation of salt came chiefly
from two sources — i. e., from the higher lands to the south and from
the waters of Great Salt Lake. It is most likely that the lake is the
source of. the greater portion of them, for when it was from thirty to
fifty feet higher than now, it would have submerged nearly all the
area under consideration, and must have also contained much salt in
solution. Upon the subsidence of the water the soil would, of course,
be left heavily impregnated with salts. Besides, within the memory
of the present inhabitants, the lake has again submerged a consider-
able part of this area, and, according to reliable records, the lake in
1868 was twelve feet above its present level, and at this height must
have covered at least fifty square miles of what is now mapped as
dry land. The water at that time carried, approximately, 13.5 per
cent of salt, and land submerged for a considerable length of time in
such a solution would certainly be left very salty when the water
subsided. More land than that merely covered by the lake must
have been affected by it. The water-table of the low land adjacent
to the shore must have risen to an elevation equal to or exceeding
the level of the lake water, while in time of storms the waves may
have rolled inland for considerable distances. It is fair to assume
that all land now having an elevation not to exceed twenty feet

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above the present lake level, was more or less affected by its waters
at that time.

Practically all of the comparatively level area north of Twelfth
street road, when considered to a depth of five feet, is salty land.
There are considerable portions of it, however, in which the salt con-
tent of the first, and sometimes the second, foot is so small as to in-
dicate that it could be safely used for agricultural crops. Below the
second foot the salt increases very rapidly and far exceeds the limit
for most plants. This increase continues as we descend until within
one foot of the water-table, where the maximum is reached. Below
the water-table the saltiness is quite constant for a number of feet,
diminishing slightly as we descend. On this type of land, usually
sandy loam or loam, the water-table is seldom more than six or seven
feet below the surface, though it is occasionally as much as ten feet.
It is on this land that numerous, unsuccessful attempts have been
made at farming during recent years, and the failure has undoubt-
edly been due to the following causes :

In its natural state this land is, for the most part, covered with a
growth of greasewood. The salts having been carried from the sur-
face into the deeper soil by the natural precipitation, were undoubt-
edly largely prevented from rising again by this deep-rooted plant
absorbing the soil moisture at its roots, thus preventing much sur-
face evaporation. When this land was broken up for cultivation,
the soil moisture instead of being thus absorbed in the lower soil,
rose into the upper, bringing the salts with it, to the detriment of
the shallow-rooted agricultural plants. The land, being level and
underlaid with a strata having a fairly close texture, had naturally
poor drainage. The water-table was rarely more than seven feet
below the surface and frequently of less depth, and upon the appli-
cation of irrigation water it gradually rose. When the water-table
was within three feet of the surface much evaporation naturally oc-
curred from the resulting moist soil surface. In this condition the
salts from the lower soil rapidly rose to the surface and were left by
evaporation as incrustations, or were moved up and down in the sur-
face soil with the movement of the rain and irrigation water, in such
concentration as to prevent the growth of most plants.

Under these conditions farming was a failure, and at present few
attempts are being made to do anything with this kind of land.
There are a few places of limited extent along the border of draws,
or on ridges, where the natural drainage is sufficiently good for irri-
gation farming to be carried on. With good judgment as to irriga-
tion and cultivation, some of these places are producing alfalfa and
garden products successfully. These places, while insignificant in

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themselves, are very suggestive as to the means by which all of this
area might be reclaimed.

As an illustration of the effect that elevating the water-table has
upon the accumulation of salt in the surface soil, take, for example,
the playas and all low ground where the water-table is within three
feet or less of the surface and we find that the surface portion of the
soil is almost invariably the most salty, and is very often covered by
a salt crust.

The irrigated land south of the Twelfth street road has, for the
most part, good, natural drainage, and is generally quite free from
salts. There are a few areas, however, including the greater part
of the Jordan meadows, which form an exception. Here, owing to
poor, natural drainage, seepage water has accumulated from the ir-
rigation of lands above, and the injury is more from water than from
salt. In most cases, however, the seepage water is accompanied by
an accumulation of salts immediately at or near the surface. The
source of these salts is usually from the seepage water accompanied,
perhaps, by an upward movement of the original salts of the soil.
This accumulation at the surface is brought about by the excessive
evaporation from the wet surface of the soil.

THE PROBLEMS OF THE AREA.

The areas damaged by seepage and alkali would be less extensive
if there had been a more judicious management of the irrigation
water. Because of an abundance of water, it has at times been used
in excessive amounts, and, furthermore, waste or surplus water is
too often allowed to run on to vacant lands when the canal gates
should be closed. Each irrigation should be of sufficient quantity
to wet the ground to a considerable depth and yet cause little or no
drainage. The soil moisture should be conserved by the best means
of cultivation and cropping, thus making the intervals between irri-
gations as long as possible. It is true that lands are sometimes of
such a character that large areas cannot be irrigated without causing
seepage water to escape. Where damage is already done, the land
can sometimes be redeemed by warding off the seepage by means of
a drain along the upper side of the affected area. It will, however,
usually require a system of drains to affect this, and, if salts have
accumulated to a considerable extent, thorough drainage is the only
recourse.

DRAINAGE.

Of the one hundred and twenty-five square miles lying mostly
north of Twelfth street road and between Salt Lake City and the
lake, ninety square miles, or about fifty-eight thousand acres, are

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capable of reclamation. For this portion, tile drainage is recom-
mended as of general application. There is a constant and plentiful
water supply of good quality for irrigation, which may be obtained
without the construction of costly dams and storage reservoirs so
frequently required in many of the irrigated districts.

The soil is of good texture and the land lies so as to be easily irri-
gated. Furthermore, its proximity to the metropolis of the State
makes it more valuable than if it were far removed from a commer-
cial center. The excess of salts is the principal obstacle in the way
of this area being profitably farmed. The problem, therefore, re-
solves itself into how to get rid of the salts. There is no antidote
for them, except in the case of sodium carbonate or black alkali.
For this, gypsum is a corrective. Unfortunately, where there is an
excess of sodium carbonate there is also an excess of the other salts,
and to convert the black alkali into white alkali by the use of gyp-
sum would still leave an excess of salts in the soil. There is only
one feasible way of getting rid of these salts, and that is by provid-
ing a thorough system of under drainage and washing them out by
flooding.

Surface washing without drainage is of little avail, for the first
application of water dissolves the salts and they pass into the ground
only to return to the surface when evaporation commences. If tile
drains are present the dissolved salts will pass through them and
thus be carried away, so that further damage from them need not
be feared. The question that must be answered is, Will it pay to
reclaim these lands? This will be determined by the present value
of the land, the cost of reclaiming, and the value of the land after
being reclaimed.

An estimated value for the land of fifteen dollars per acre, while
much less than some of it is being held for, is more than its real
value, which, in its present condition, is merely nominal. Good farm-
ing land on the east side of the Jordan River, having a water right
and free from alkali, can easily be sold at from seventy-five to one
hundred dollars per acre. There is no reason why the alkali land
west of the river should not be pretty nearly as valuable when re-
claimed and a good water right secured.

The cost of drainage will vary somewhat, according to the char-
acter of the soil and the price of labor and material. The Jordan
sandy loams and Jordan loams will be most easily reclaimed because
of their lighter texture. The distance between drains will be deter-
mined by the texture of the soil. The more open the texture and
structure of the soil, the more readily will water pass through it and
the greater can be the distance between drains. The depth should
be three feet or more. The rate of removing the salts will depend
principally upon the rate of movement of the soil waters.

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For drains three feet deep and at a uniform distance of one hun-
dred feet apart, the cost should not exceed fifteen dollars per acre.
While the proper distance between drains can be accurately ascer-
tained only by experiment, yet it is our judgment that a distance of
one hundred feet between drains could frequently be increased and
would seldom require to be decreased. In addition to the 'above,
there would be the cost of constructing outlets to conduct the water
to the lake or river. For this area, the expense would be compara-
tively small, on account of the long draws that now extend back into
the land like irrigation canals. These may require deepening and
supplementing in places.

In order to be carried out in the most economical way, drainage
should be made a community affair, and the systems should be plan-
ned with reference to a general scheme, especially where a large
number of land owners are involved.

FRANK D. GARDNER,

Assistant, Division of Soils.

JOHN STEWART,

Assistant Chemist,

Utah Experiment Station.

The publication of this circular, approved by Prof. Milton Whitney, Chief of
the Division of Soils, and Prof. Luther Foster, Director of the Utah Experiment
Station, is hereby authorized.

JAMES WILSON, Secretary.

YC 67893