IRRIGATION
This is a topic on which a book might be written. The reader will draw
a sigh of relief, however, on learning that I shall content myself with
giving a few facts and suggestions, since I am well aware that, in
spite of its title, this chapter will be dry to many.
The first rays that fall from the lamp of history reveal vast systems
of irrigation in full operation. In many parts of the globe artificial
watering is absolutely essential, and there are few agricultural
regions which might not be rendered far more productive if the supply
of moisture could be regulated in accordance with the needs of each
crop. The question, as we shall consider it, is a practical one. In
California and other sections, the land _must_ be irrigated; here, and
wherever the rainfall is more equally distributed throughout the year,
we _can_ water if we find the practice remunerative. The increased
yield from the proper application of water is often marvellous. Mr.
James Neilson, in a paper read before the New Jersey State Board of
Agriculture, gives some interesting facts observed abroad. In regions
along the Cavour Canal, the people were able to mow in one season six
heavy burdens of grass, and in the vicinity of Edinburgh, by the use of
sewage water, five or six crops of grass annually. In Belgium, "sandy,
barren land (resembling the pine barrens of New Jersey) was put into
profitable cultivation when it could be irrigated." The plain of
Gennevilliers, near Paris, seemed utterly worthless for cultivation. It
consisted almost wholly of coarse gravel, and bore no rent. No land
owner would make any effort to use water, so the city of Paris bought
about twenty-five acres and turned upon it part of the sewage. It now
rents for nearly $50 per acre, with sewage supplied. In parts of Spain,
land is worth $2,500 irrigated, and but $125 without the privilege of
water. The enormous and long-continued crops of strawberries raised in
California prove that water is equally effective in our new land, where
the climate is similar, as in the older countries. Will irrigation pay
in our latitude, where we hope for seasonable rains? I think that in
many sections it will, and occasionally I hear of remarkable results
obtained by the free use of water. In one instance a gravelly hillside,
almost worthless for ordinary cultivation, became the wonder of the
neighborhood, so large were the crops of strawberries secured by
irrigation.
Mr. Chas. W. Garfield, Secretary of the Michigan State Pomological
Society, gives an interesting account of his visit to Mr. Dunkley, a
successful gardener, at Kalamazoo: "A force," he writes, "were picking
strawberries from rows of vigorous plants, and as we opened the vines
in advance of the pickers, a more delightful strawberry prospect we had
never seen. The varieties were Monarch, Seneca Chief, and Wilson, and
under the system of irrigation employed they were just prime for
market, after all the other berries in the vicinity had ripened and
were gone. Very remunerative prices were thus secured. His vines were
vigorous and independent of the rains. Every berry that set reached
perfection in size and form." The abundant moisture greatly increases
the size of the fruit, but retards the ripening. When the fruit has
reached the proper stage for maturity, the water is withheld, and then
the berries ripen fast, but in their perfect development are firm, and
are shielded from the sun by the luxuriant foliage. "We water," said
Mr. Dunkley, "only to supplement the rain. If the season is wet, we
employ our artificial system but little, or not at all, and in such
seasons get no profit from our investments; but generally, sometime
during a season there is a drought that shortens some crop; then we
irrigate, and have the advantage of neighboring gardeners." This
statement suggests the practical question, Do droughts or dry seasons
occur with sufficient frequency to warrant the outlay required for
irrigation? In a very interesting paper read before the Massachusetts
Horticultural Society, Mr. W. D. Philbrick gives much information on
the subject of artificial watering, and its need in our latitude and
section, and I quote from him freely:
"The amount of water required will depend largely on the rainfall,
velocity of the wind, atmospheric humidity, soil, etc. A loose, sandy
soil will require much more water than a retentive clay. In general,
however, it may be assumed that in the warm, growing months of May,
June, July, August and September, most vegetation requires an inch in
depth over the entire surface of the land every five days. This is, of
course, only an _average_. This quantity, estimated as needed by our
gardens, would be equivalent to six inches per month of rainfall. If we
compare this amount with the actual rainfall, we shall arrive at an
idea of what is to be supplied artificially.
"The rainfall at Boston for the past six years (to 1878), for the five
growing months named, varies from a maximum of 10.5 inches, in August,
1872, to a minimum of 0.65 inch, in June, 1873. During these six years
there was not a single season when we did not suffer more or less from
drought during some portion of the summer. Twenty-one of the thirty
months in question had less rainfall than six inches per month, and the
average of these twenty-one months was about 3.02 inches per month, or
only about half of what was needed. Some of the protracted seasons of
drought were almost entirely rainless for six weeks, during which the
weather was excessively hot and windy, and vegetation suffered
extremely in consequence."
Mr. Philbrick estimates that 27,000 gallons, or 108 tons, of water are
needed per acre at each watering, which, in a dry period, should be
repeated every five days. This enormous quantity leads him to suggest
that--
"before embarking in an enterprise of irrigation, it would be best to
make sure that the source can be depended upon for a sufficient supply
of water in the driest seasons; for it is precisely at such times that
the most water is needed. Ordinary springs and wells, therefore, are
entirely inadequate to furnish water for anything more than a small
patch or garden. The only sources to be depended upon for large areas
are unfailing streams, lakes, and ponds. There are few gardens so
favorably situated that the water can be drawn from canals and ditches
directly from some pond or stream. When this can be done it is by far
the cheapest method; and it is in this way that the extensive
irrigating works of Lombardy, Spain, France, California, and Colorado
are constructed. Where this system is adopted, considerable expense is
required to grade the land into inclined beds, so as to distribute the
water easily and evenly; but, once done, the water is applied at a very
trifling cost--so cheaply that it is used for farm crops in Lombardy
and the South of France."
In most instances, however, our land is so located that we cannot
irrigate it by a natural flow and fall of water. In this case, it may
be distributed by water-carts and by hand. This can be done only on a
very small scale. The cost in time and labor would be much too great
for profitable returns, and the ground would be so beaten and trampled
as to cause much injury. Such methods may answer very well for small
and well-mulched fruit gardens, making the home supply certain and
large, but it is inadequate from a business point of view. Distributing
water through pipes laid underground, beneath the plow, does not work
well at all, practically, and is not in accordance with nature. Most of
the water is wasted.
Mr. Phil brick continues:
"The only method of distributing water much used in gardens where
pumping is practiced is the system of iron pipes laid underground, with
hydrants distant 200 feet asunder, from which the water is distributed
by 100 feet of India rubber hose. This is also the plan adopted by
gardeners who make use of the public water supply."
When practicable, such iron pipes should be carried along ridges and
headlands, so as to let the water flow where we wish it by gravity as
far as possible.
"Where the water has to be distributed by hose and sprinkler it will be
found good economy to use a powerful pump, that will give a head of at
least thirty feet, and to use for distribution pipes of not less than
one and a half inches in diameter; provided, of course, that any
considerable area--an acre or more--is to be watered. Thus, for
example, we will suppose that it is required to water five acres of
land, and that we have near by a never-failing pond or river; we can
locate a steam pump near the river, and, while at work watering, we
load the safety-valve upon the delivering water pipe at fifteen pounds
per square inch, which corresponds to a head of about thirty feet of
water. We have 300 feet of iron pipe, two inches in diameter, and 100
feet of India rubber hose, one and a half inches in diameter, for the
delivery of the water. This apparatus would be capable of delivering 45
gallons per minute, or 27,000 gallons per day of ten hours--enough for
the thorough wetting of one acre per day, or every acre of the five
once in five days; by running nights, ten acres could be watered.
"When only a limited area is to be watered--less than an acre--the
wind-mill furnishes a cheaper source of power than the steam pump. To
make it available, large storage of water must be provided at a high
level, so that the mill may work during stormy weather and store the
water until needed. A wind-mill, costing with pump and tank about $500,
will furnish water enough for one or two acres of land, provided
storage can be provided for 200,000 gallons of water. To provide this
storage might cost as much as a steam pump. Where elevated reservoirs
can easily be made, and the amount of water needed is not over 10,000
gallons daily, the wind-mill is, without doubt, cheaper power than
steam."
Mr. Philbrick shows conclusively that where a gardener pays at the rate
of twenty-five cents per 1,000 gallons, or even much less, only crops
approaching $1,000 per acre in value will warrant the outlay. When land
can be easily graded, and irrigated through canals and ditches, the
yearly cost has been reduced, in some cases, as low as from one to
three dollars per acre per year.
"Wherever drainage is not perfect, it must be made so before irrigation
can be safely practiced; otherwise, if a heavy fall of rain should
occur just after application of water, the plants might suffer
seriously from being too wet."
In the discussion which followed the reading of this paper, Mr. John B.
Moore said, among other things: "No crop takes the moisture out of the
soil more quickly than strawberries, and, for these and other crops
which soon suffer from dryness, he lets the water run down the rows all
night from half a dozen large pipes."
Hon. Marshall T. Wilder then remarked that "the secret how Mr. Moore
produced his large strawberries had now come out."
(In a letter recently received, Mr. Moore further states: "In the
garden, I have had the best results where I have let the water run out
of open hose between the rows of raspberries, strawberries, etc.,
always making it a rule to wet the ground thoroughly, and then stop,
and not apply any more until there is good evidence of the soil needing
it again. A constant drizzle is detrimental to vegetation.")
Mr. W. C. Strong said that the "even distribution of water was very
important; otherwise, the ground became sodden in places, and other
parts received no benefit. He thought that considerable part of the
benefit of irrigation arose from showering the foliage, especially at
night, as in a green-house."
Mr. Philbrick said that he applied water in sunshine sometimes, but
that in general he did not like to do so. (I would caution the reader
to be very careful about wetting foliage under a hot sun, as it often
causes both leaves and fruit to scald. I once lost a crop of
gooseberries through a midday shower, followed by a hot afternoon.)
Mr. E. P. Richardson had found a hose perforated with holes an eighth
of an inch in diameter, and about three or four inches apart, very
convenient for applying water. It can be laid anywhere, in a straight
or crooked line, and under plants whose leaves are injured by watering
in the bright sun. Such a hose may be left for hours without attention.
In the garden at Kalamazoo already referred to, the water was obtained
by damming up a spring. "The water was conveyed in a wooden conduit,
made of two-inch plank, and rendered water-tight by coal tar." The
whole apparatus was very inexpensive, and proves that in many instances
the ingenious and enterprising horticulturist can work out a simple
system of his own that, at slight cost, will answer his purpose.
This chapter aims at little more than to put the reader on the right
track for further investigation, and to suggest a few of the first
principles and requirements of irrigation. The great majority have
little realization of the amount of water required, and very often much
loss is incurred and injury caused by attempting artificial watering
with an insufficient supply. Mr. Dunkley, at Kalamazoo, started with a
wind-mill, but found it wholly inadequate. Partial watering is worse
than useless. By liberal mulching, very much less water is required,
and much longer intervals between irrigation may elapse.
If one designs to undertake irrigation upon a large scale, he should
employ the services of an expert, and "make haste slowly." At the same
time, many fruit farms are so located, or might be, that the laborer
with a pick and shovel could solve the problem of an abundant supply of
water.
When unfailing moisture can be maintained, and plants are not permitted
to bear in June, nor to make runners, almost a full crop may be
obtained in the autumn.