90
WALLACE H. FULLER
the Upper Snake River Plains in the states of Washington and Idaho on
the north. They extend through the Colorado Plateau of Northern Arizona,
Utah and Colorado to the Wyoming Basin of the Rocky Mountains along
the eastern border (Western Regional Soil Survey Work Group, 1964).
The basin and range area, which occupies parts of Arizona, California,
Nevada, and Utah, is the largest contiguous area. The Central and San
Joaquin Valleys of California and Williamette Valley of Oregon roughly
bound the desert region on the west.
A great variety of desert soils are mapped. They include the zonal Red
Desert, desert (gray), and Sierozem soils and small acreages of Brown and
Chestnut soils. Azonal Regosols (sandy outwashes and dunes) and Lithosols (shallow and rocky) are scattered throughout the zonal soils. Intrazonal Calcisols [lime accumulation (Cca layer)], Solonetz (sodic), and
Solonchak (salic) also are scattered throughout the desert areas. They appear in low localities and represent only a small total area. The general
topography of North American deserts changes abruptly from flat valleys to
rugged mountains and from level plateaus to deep river canyons. Elevations
range from below sea level to over 1800 meters and precipitation
from 7.5 to 25 cm. In the southern deserts creosotebush (Larrea divaricata), mesquite (Prosopis spp.), Yucca (Yucca spp.), cactus (Cactaceae
spp.), muhly grass (Muhlenbergia spp.), and annual grasses dominate. In
the northern deserts sagebrush (Artemisia spp.), shadscale (Atriplex confertifolia), hopsage (Grayia spinosa), needlegrass (Stipa spp.), and
Indian ricegrass (Oryzopsis hymenoides) dominate.
The chain of intermountain valleys and basins in the south that start
in the Sonoran Desert of Mexico, have deep medium to coarse-textured
red soils that extend north into the Desert soils of southern Nevada (Fuller,
1972). The Chihuahuan Desert of Mexico that crosses a part of Texas
and extends into New Mexico also has Red Desert soils. They form in the
hottest and most arid climate of the continent. The Red Desert soils are
well drained, fertile, and very productive under irrigated agriculture. World
record yields of crops have been grown on these soils under proper management (see Fig. 14). Water is an essential factor to this high productivity
and often must be brought from great distances (see, for example, Fig.
15).
Salty soils (Solonchak and Solonetz) intersperse with the Red Desert soils
in low-lying basin spots, flat bottoms and playas. Death Valley, for example, is a very hot interior basin with a high proportion of its soils as Calcisols, Solonetz, Solonchak, and Regosols. Calcisols and Regosols appear
in localized areas of the red desert. The rough, rocky mountain slopes of
thin soils support lithosols. Red Desert soils also develop in the Rio Grande
and Pecos River Valleys on alluvial-colluvial fans and stream terraces.
WALLACE H. FULLER
the Upper Snake River Plains in the states of Washington and Idaho on
the north. They extend through the Colorado Plateau of Northern Arizona,
Utah and Colorado to the Wyoming Basin of the Rocky Mountains along
the eastern border (Western Regional Soil Survey Work Group, 1964).
The basin and range area, which occupies parts of Arizona, California,
Nevada, and Utah, is the largest contiguous area. The Central and San
Joaquin Valleys of California and Williamette Valley of Oregon roughly
bound the desert region on the west.
A great variety of desert soils are mapped. They include the zonal Red
Desert, desert (gray), and Sierozem soils and small acreages of Brown and
Chestnut soils. Azonal Regosols (sandy outwashes and dunes) and Lithosols (shallow and rocky) are scattered throughout the zonal soils. Intrazonal Calcisols [lime accumulation (Cca layer)], Solonetz (sodic), and
Solonchak (salic) also are scattered throughout the desert areas. They appear in low localities and represent only a small total area. The general
topography of North American deserts changes abruptly from flat valleys to
rugged mountains and from level plateaus to deep river canyons. Elevations
range from below sea level to over 1800 meters and precipitation
from 7.5 to 25 cm. In the southern deserts creosotebush (Larrea divaricata), mesquite (Prosopis spp.), Yucca (Yucca spp.), cactus (Cactaceae
spp.), muhly grass (Muhlenbergia spp.), and annual grasses dominate. In
the northern deserts sagebrush (Artemisia spp.), shadscale (Atriplex confertifolia), hopsage (Grayia spinosa), needlegrass (Stipa spp.), and
Indian ricegrass (Oryzopsis hymenoides) dominate.
The chain of intermountain valleys and basins in the south that start
in the Sonoran Desert of Mexico, have deep medium to coarse-textured
red soils that extend north into the Desert soils of southern Nevada (Fuller,
1972). The Chihuahuan Desert of Mexico that crosses a part of Texas
and extends into New Mexico also has Red Desert soils. They form in the
hottest and most arid climate of the continent. The Red Desert soils are
well drained, fertile, and very productive under irrigated agriculture. World
record yields of crops have been grown on these soils under proper management (see Fig. 14). Water is an essential factor to this high productivity
and often must be brought from great distances (see, for example, Fig.
15).
Salty soils (Solonchak and Solonetz) intersperse with the Red Desert soils
in low-lying basin spots, flat bottoms and playas. Death Valley, for example, is a very hot interior basin with a high proportion of its soils as Calcisols, Solonetz, Solonchak, and Regosols. Calcisols and Regosols appear
in localized areas of the red desert. The rough, rocky mountain slopes of
thin soils support lithosols. Red Desert soils also develop in the Rio Grande
and Pecos River Valleys on alluvial-colluvial fans and stream terraces.