The herald., 1893-10-10
4 San Ga1riel ralleu reservoir and tountain.


lower side of its circuit, as it passes
back to the river. The second set, being
at lower level than the first, serve as
drains, conveying the water that over
flows from the first to the main channel,
which IN the latter part of its course is
no longer feeder but drain.
The water is allowed to flow through
this system as often as required, care
being taken that it shall not lie at rest
Mt any time, the effect OF which is found
to be tendency to cause the growth of
coarse grass. This method is called
bed work irrigation, from the gronnd
being laid out in nearly regular beds by
the channels. 1t is applicable only to
tolerably level land.
By another method called catch
work, irrigation is conveniently applied
to uneven ground. One set of channels
follow the contour lines of the ground,
each retaining its own level. These are
crossed nearly at right angles by nu-
merous other small channels, which
are fed at their upper ends by the main
gutter, and the water is directed by
stops of clods of earth into the level
side channels, which are filed as may
be desired.
The laying out of the work and the
management of the operation, so as to
| distribute the water uniformly. in the
proper quantities, and at the right
times, reqnire good judgment, close at
| tention, and much experience.
The irrigating season in England ia
the colder portion OF the year, com.
mencing in October and November, and
terminating in March or April. The
letting the water on or of during frosty
weather is to be avoided, as crust OF
ice may root out the grass as il thews
As nearly as may be, with reference to
this danger, the water is allowed to
flow through the channels for two or
three weeks at a time, and is then
drawn completely off, so that the ground
may become as thoroughly dry as posi-
BILE. In this condition it is left for five
or six days, when if there is no fear of
freezing the operation ia repeated; and
80 on through the winter.
When the grass begins to vegetate,
the periods OF irrigation should be
shortened, and cease entirely when it ia
sufficiently forward to make good past
ure. The effect of this practice is often
very striking; the grass is brought for
ward very early in the spring. After
feeding off one crop or moving the grass,
the land ia sometimes again irrigated for
q short time to great advantage. A
second crop is ready to be cut by the
time the first has ripened on the dry
meadows. Three OF four crops of grass
are thus obtained in each season.
But the perfection of irrigation is wher
it is combined with thorough under
draining. The water flowing in bring
x-.sk ~,
ouH mineral and organic substances suit
able for the good of plants. By evapora
tiou and by various chemical reaction
the soluble ingredient may be set free
when they become entangled with TIN
other foreign matters in the grass and il
the soil beneath, both OF which act a
filters.
Thus the finely comminuted sediment
and the soluble salts are equally dis
tributed among the rootlets, and thest
are refreshed by the new supplies fur
nished by each repetition of the process
By the drains the excess of moisture
is soon removed, stsgnation, 30 injurious
to vegetation, is prevented, and the ele
ments that feed the plants below the
surface are kept in similar condition
of healthy renewal with those of the ali
circulating among the branches ant
adding to the vegetable growth by
assimilation going on through tht
leaves. The benefits derived from thu
process vary of course with the quality
of the ingredients brought in by the
water, according as these are more Of
less suited to the requirements of tht
soil and OF the crops.
The hard water, charged with carbon
ate of lime, which it has gathered il
flowing through a limestone region
brings a valuable fertilizing ingredien
to ailIcious soils deficient in lime anC
the clayey sediment washed out of allu-
vial bottoms ia spread with the mos
beneficial effect over loose sandy soils
Sometimes organic liquid manure, sucf
as the drainage OF farmyards and leach
ings OF compost heaps, are supplied tt
the soil by being mingled with the
water used in irrigating but the princi
pal object of irrigation is to supply
moisture, as it is always easy to ado
manure in a solid form.
Much attention is now given to the
subject of irrigation in that portion O
abe United States lying between the
Mississippi river and the Rocky noun
tains 80 that vast region, some O.
which was long known as the great
American desert, bids fair in time to bt
Tor the most part brought under fail
cultivation.
The Mormons in Utah by means O.
irrigation render their barren country
fertile. The general plan with them
and also in California, is to lead the
water in canals from the rivers or tine
mountains, and 20 allow it to flow ovel
tine heids, either through small chan
nes made in the soil or over the ever
surface.