THE ADVANTAGES OF IRRIGATION.
It is necessary to understand this problem of irrigation in order to
comprehend Southern California, the exceptional value of its arable
land, the certainty and great variety of its products, and the part it
is to play in our markets. There are three factors in the expectation of
a crop--soil, sunshine, and water. In a region where we can assume the
first two to be constant, the only uncertainty is water. Southern
California is practically without rain from May to December. Upon this
fact rests the immense value of its soil, and the certainty that it can
supply the rest of the Union with a great variety of products. This
certainty must be purchased by a previous investment of money. Water is
everywhere to be had for money, in some localities by surface wells, in
others by artesian-wells, in others from such streams as the Los Angeles
and the Santa Ana, and from reservoirs secured by dams in the heart of
the high mountains. It is possible to compute the cost of any one of the
systems of irrigation, to determine whether it will pay by calculating
the amount of land it will irrigate. The cost of procuring water varies
greatly with the situation, and it is conceivable that money can be lost
in such an investment, but I have yet to hear of any irrigation that has
not been more or less successful.
Farming and fruit-raising are usually games of hazard. Good crops and
poor crops depend upon enough rain and not too much at just the right
times. A wheat field which has a good start with moderate rain may later
wither in a drought, or be ruined by too much water at the time of
maturity. And, avoiding all serious reverses from either dryness or wet,
every farmer knows that the quality and quantity of the product would be
immensely improved if the growing stalks and roots could have water when
and only when they need it. The difference would be between, say, twenty
and forty bushels of grain or roots to the acre, and that means the
difference between profit and loss. There is probably not a crop of any
kind grown in the great West that would not be immensely benefited if it
could be irrigated once or twice a year; and probably anywhere that
water is attainable the cost of irrigation would be abundantly paid in
the yield from year to year. Farming in the West with even a little
irrigation would not be the game of hazard that it is. And it may
further be assumed that there is not a vegetable patch or a fruit
orchard East or West that would not yield better quality and more
abundantly with irrigation.
[Illustration: RAISIN-CURING.]
But this is not all. Any farmer who attempts to raise grass and potatoes
and strawberries on contiguous fields, subject to the same chance of
drought or rainfall, has a vivid sense of his difficulties. The potatoes
are spoiled by the water that helps the grass, and the coquettish
strawberry will not thrive on the regimen that suits the grosser crops.
In California, which by its climate and soil gives a greater variety of
products than any other region in the Union, the supply of water is
adjusted to the needs of each crop, even on contiguous fields. No two
products need the same amount of water, or need it at the same time. The
orange needs more than the grape, the alfalfa more than the orange, the
peach and apricot less than the orange; the olive, the fig, the almond,
the English walnut, demand each a different supply. Depending entirely
on irrigation six months of the year, the farmer in Southern California
is practically certain of his crop year after year; and if all his
plants and trees are in a healthful condition, as they will be if he is
not too idle to cultivate as well as irrigate, his yield will be about
double what it would be without systematic irrigation. It is this
practical control of the water the year round, in a climate where
sunshine is the rule, that makes the productiveness of California so
large as to be incomprehensible to Eastern people. Even the trees are
not dormant more than three or four months in the year.
But irrigation, in order to be successful, must be intelligently
applied. In unskilful hands it may work more damage than benefit. Mr.
Theodore S. Van Dyke, who may always be quoted with confidence, says
that the ground should never be flooded; that water must not touch the
plant or tree, or come near enough to make the soil bake around it; and
that it should be let in in small streams for two or three days, and not
in large streams for a few hours. It is of the first importance that the
ground shall be stirred as soon as dry enough, the cultivation to be
continued, and water never to be substituted for the cultivator to
prevent baking. The methods of irrigation in use may be reduced to
three. First, the old Mexican way--running a small ditch from tree to
tree, without any basin round the tree. Second, the basin system, where
a large basin is made round the tree, and filled several times. This
should only be used where water is scarce, for it trains the roots like
a brush, instead of sending them out laterally into the soil. Third, the
Riverside method, which is the best in the world, and produces the
largest results with the least water and the least work. It is the
closest imitation of the natural process of wetting by gentle rain. "A
small flume, eight or ten inches square, of common red-wood is laid
along the upper side of a ten-acre tract. At intervals of one to three
feet, according to the nature of the ground and the stuff to be
irrigated, are bored one-inch holes, with a small wooden button over
them to regulate the flow. This flume costs a trifle, is left in
position, lasts for years, and is always ready. Into this flume is
turned from the ditch an irrigating head of 20, 25, or 30 inches of
water, generally about 20 inches. This is divided by the holes and the
buttons into streams of from one-sixth to one-tenth of an inch each,
making from 120 to 200 small streams. From five to seven furrows are
made between two rows of trees, two between rows of grapes, one furrow
between rows of corn, potatoes, etc. It may take from fifteen to twenty
hours for one of the streams to get across the tract. They are allowed
to run from forty-eight to seventy-two hours. The ground is then
thoroughly wet in all directions, and three or four feet deep. As soon
as the ground is dry enough cultivation is begun, and kept up from six
to eight weeks before water is used again." Only when the ground is very
sandy is the basin system necessary. Long experiment has taught that
this system is by far the best; and, says Mr. Van Dyke, "Those whose
ideas are taken from the wasteful systems of flooding or soaking from
big ditches have something to learn in Southern California."
As to the quantity of water needed in the kind of soil most common in
Southern California I will again quote Mr. Van Dyke: "They will tell you
at Riverside that they use an inch of water to five acres, and some say
an inch to three acres. But this is because they charge to the land all
the waste on the main ditch, and because they use thirty per cent. of
the water in July and August, when it is the lowest. But this is no test
of the duty of water; the amount actually delivered on the land should
be taken. What they actually use for ten acres at Riverside, Redlands,
etc., is a twenty-inch stream of three days' run five times a year,
equal to 300 inches for one day, or one inch steady run for 300 days. As
an inch is the equivalent of 365 inches for one day, or one inch for 365
days, 300 inches for one day equals an inch to twelve acres. Many use
even less than this, running the water only two or two and a half days
at a time. Others use more head; but it rarely exceeds 24 inches for
three days and five times a year, which would be 72 multiplied by 5, or
360 inches--a little less than a full inch for a year for ten acres."
[Illustration: IRRIGATION BY ARTESIAN-WELL SYSTEM.]
[Illustration: IRRIGATION BY PIPE SYSTEM.]
I have given room to these details because the Riverside experiment,
which results in such large returns of excellent fruit, is worthy of the
attention of cultivators everywhere. The constant stirring of the soil,
to keep it loose as well as to keep down useless growths, is second in
importance only to irrigation. Some years ago, when it was ascertained
that tracts of land which had been regarded as only fit for herding
cattle and sheep would by good ploughing and constant cultivation
produce fair crops without any artificial watering, there spread abroad
a notion that irrigation could be dispensed with. There are large areas,
dry and cracked on the surface, where the soil is moist three and four
feet below the surface in the dry season. By keeping the surface broken
and well pulverized the moisture rises sufficiently to insure a crop.
Many Western farmers have found out this secret of cultivation, and more
will learn in time the good sense of not spreading themselves over too
large an area; that forty acres planted and cultivated will give a
better return than eighty acres planted and neglected. Crops of various
sorts are raised in Southern California by careful cultivation with
little or no irrigation, but the idea that cultivation alone will bring
sufficiently good production is now practically abandoned, and the
almost universal experience is that judicious irrigation always improves
the crop in quality and in quantity, and that irrigation and cultivation
are both essential to profitable farming or fruit-raising.