re prepared, and immense sums were spent in carrying out these plans.
Enormous dams of cemented stone were thrown across the gorges in the
foothills of the mountains. Behind these solid dams the water from the
rains and the melting snow of the mountains was backed for miles, and
was at once ready to change barrenness into fruitfulness. The stored
water is led by means of main canals and cross ditches wherever it is
needed, and countless acres have been brought under cultivation.

Water is generally applied either by making furrows for its passage
through the fields or by flooding the land. The latter plan is the
cheaper, but it can be used only on level lands. Where the land is
somewhat irregular a checking system, as it is called, is used to
distribute the water. It is taken from check to check until the entire
field has been irrigated.

[Illustration: FIG. 288. THE PROCESS OF IRRIGATING CORN]

The furrow method is usually employed for fruits and for farm and garden
crops. In many places the grass and grain crops are now supplied with
water by furrows instead of by flooding.

Irrigated lands should be carefully and thoroughly tilled. The water for
irrigation is costly, and should be made to go as far as possible. Good
tillage saves the water. Moreover, all cultivated crops like corn,
potatoes, and orchard and truck crops ought to be cultivated frequently
to save the moisture, to keep the soil in fit condition, and to aid the
bacteria in the soil. It was a wise farmer who said, "One does not need
to grow crops many years in order to learn that nothing can take the
place of stirring the soil."

METHODS OF IRRIGATING CROPS

_Tree fruits._ Water is conducted through very narrow furrows from three
to five feet apart, and allowed to sink about four feet deep, and to
spread under the ground. Then the supply is cut off. The object is to
wet the soil deeply, and then by tillage to hold the moisture in the
soil.

_Small fruits._ The common practice is to run water on each side of the
row until the rows are soaked.

_Potatoes._ A thorough soaking is given the land before planting-time,
and then no more than is absolutely necessary until blossoming-time.
After the blossoms appear keep the soil moist until the crop ripens.

_Garden crops._ Any method may be employed, but the vital point is to
cultivate the ground as early as it can be worked after it has been
irrigated.

_Meadows and alfalfa._ Flooding is the most com