Dry-Farming | Page 6

and 30 inches, sub-humid, and those receiving over 30
inches, humid. It is admitted that even such a classification is arbitrary,
since aridity does not alone depend upon the rainfall, and even under
such a classification there is an unavoidable overlapping. However, no
one factor so fully represents varying degrees of aridity as the annual
precipitation, and there is a great need for concise definitions of the
terms used in describing the parts of the country that come under

dry-farming discussions. In this volume, the terms "arid," "semiarid,"
"sub-humid" and "humid" are used as above defined.
Precipitation over the dry-farm territory
Nearly one half of the United States receives 20 inches or less rainfall
annually; and that when the strip receiving between 20 and 30 inches is
added, the whole area directly subject to reclamation by irrigation or
dry-farming is considerably more than one half (63 per cent) of the
whole area of the United States.
Eighteen states are included in this area of low rainfall. The areas of
these, as given by the Census of 1900, grouped according to the annual
precipitation received, are shown below:--
Arid to Semi-arid Group Total Area Land Surface (Sq. Miles)
Arizona 112,920 California 156,172 Colorado 103,645 Idaho 84,290
Nevada 109,740 Utah 82,190 Wyoming 97,545 TOTAL 746,532
Semiarid to Sub-Humid Group
Montana 145,310 Nebraska 76,840 New Mexico 112,460 North Dakota
70,195 Oregon 94,560 South Dakota 76,850 Washington 66,880
TOTAL 653,095
Sub-Humid to Humid Group
Kansas 81,700 Minnesota 79,205 Oklahoma 38,830 Texas 262,290
TOTAL 462,025
GRAND TOTAL 1,861,652
The territory directly interested in the development of the methods of
dry-farming forms 63 per cent of the whole of the continental United
States, not including Alaska, and covers an area of 1,861,652 square
miles, or 1,191,457,280 acres. If any excuse were needed for the lively
interest taken in the subject of dry-farming, it is amply furnished by
these figures showing the vast extent of the country interested in the
reclamation of land by the methods of dry-farming. As will be shown
below, nearly every other large country possesses similar immense
areas under limited rainfall.
Of the one billion, one hundred and ninety-one million, four hundred
and fifty-seven thousand, two hundred and eighty acres (1,191,457,280)
representing the dry-farm territory of the United States, about 22 per
cent, or a little more than one fifth, is sub-humid and receives between
20 and 30 inches of rainfall, annually; 61 per cent, or a little more than
three fifths, is semiarid and receives between 10 and 20 inches,

annually, and about 17 per cent, or a little less than one fifth, is arid and
receives less than 10 inches of rainfall, annually.
These calculations are based upon the published average rainfall maps
of the United States Weather Bureau. In the far West, and especially
over the so-called "desert" regions, with their sparse population,
meteorological stations are not numerous, nor is it easy to secure
accurate data from them. It is strongly probable that as more stations
are established, it will be found that the area receiving less than 10
inches of rainfall annually is considerably smaller than above estimated.
In fact, the United States Reclamation Service states that there are only
70,000,000 acres of desert-like land; that is, land which does not
naturally support plants suitable for forage. This area is about one third
of the lands which, so far as known, at present receive less than 10
inches of rainfall, or only about 6 per cent of the total dry-farming
territory.
In any case, the semiarid area is at present most vitally interested in
dry-farming. The sub-humid area need seldom suffer from drouth, if
ordinary well-known methods are employed; the arid area, receiving
less than 10 inches of rainfall, in all probability, can be reclaimed
without irrigation only by the development of more suitable. methods
than are known to-day. The semiarid area, which is the special
consideration of present-day dry-farming represents an area of over
725,000,000 acres of land. Moreover, it must be remarked that the full
certainty of crops in the sub-humid regions will come only with the
adoption of dry-farming methods; and that results already obtained on
the edge of the "deserts" lead to the belief that a large portion of the
area receiving less than 10 inches of rainfall, annually, will ultimately
be reclaimed without irrigation.
Naturally, not the whole of the vast area just discussed could be
brought under cultivation, even under the most favorable conditions of
rainfall. A very large portion of the territory in question is mountainous
and often of so rugged a nature that to farm it would be an impossibility.
It must not be forgotten, however, that some of the best dry-farm lands
of the West are found in the small mountain valleys, which usually are
pockets of most fertile soil, under a