2                     FARMERS' BULLETIN 1611
and intermountain area there are dry-land and irrigated sections.
The Great Plains and Pacific areas each contain a rather definite section
in which the red-oat varieties are grown almost exclusively. In
the Pacific area there are sections in which oats are grown fromI both
fall and spring seeding.
THE GREAT PLAINS AREA
The Great Plains area is that territory lying between the ninetyeighth
meridian and the foothills of the Rocky Mountains and extending
from   Canada to southern Texas.      This outlines the territory
only in a general way but with reasonable accuracy.     This area comprises
the western parts of the Dakotas, Nebraska, Kansas, Oklahoma,
and Texas, and the eastern portions of Montana, Wyoming,
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GRE4AT PLAINS
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FIGURE 1.-Outline map of the United States, showing the general oat areas. In
the southern and Pacific areas the crop is grown from both fall and spring
seeding. In all other areas the crop is grown from spring seeding only. The
southern area is known also as the winter or fall-sown area. Likewise the
central area is often designated as the spring-sown red-oat area
Colorado, and New Mexico. The altitude ranges from slightly below
1,500 to more than 5,000 feet. The topography for the most part is
slightly  rolling, although great sections are comparatively level.
The general outline of the area is shown in Figure 1.
The climate of the Great Plains area is widely fluctuating and
rigorous. Crop production in this entire territory is more or less
hazardous, and crop failures frequently occur.     The rainfall varies
widely from season to season, btlt averages less than 20 inches annually
over the greater portion of the area. ITe distribution of the
seasonal precipitation is more often the determining factor in oat
production than is total annual precipitation.
The oat crop uses water rather freely and often fails because of
drought.   In the northern section frosts and even snowstorms occur
occasionally early enough in the fall to damage oats before they are
harvested, sometimes resulting in severe crop losses. Hailstorms