WSP11679

• File Number: 8101
• Description: Arkansas River Basin Description
• State: CO
• Basin: Arkansas
• Water Division: 2
• Date: 1/1/1944
• Author: USDA - SCS
• Title: Physical Land Conditions in the Western and Southwestern Baca County Soil Conservation Districts - Colorado
• Water Supply Pro - Doc Type: Report/Study

002362,

Slope classes are chosen to give an
exprcssion of the slope factor as it affccts
capability of the land. Since wind
erosion occurs on all slopes, slope classes
in this arca are particularly useful in
devising moisture-conservation treat-
ments. Each soil group occurs on a
characteristic range of slopcs. For
example, groups 3 and 4 arc on nearly
smooth areas; group 9 occurs over a
wide slope range, from gentle to steep
and precipitous; and groups 5 and 55
occur on smooth to fairly stcep slopes.
Slope classcs are designated by lcttcrs.
A slopcs arc less than 2 percent, that is,
they have a fall of less than 2 feet in 100
feet of horizontal distance. B slopes
are dominantly from 2 to 5 perccnt;
C, 5 to 10; D, 10 to 20; and DD, 20 per-
cent 01' more. The slope factor for
dunelike arcas, on which dominant slope
cannot be determined, is dcsignated
byX.
The. type and degrce of erosion were
mapped in detail, using the symbols
given on pages 41-42 and on the backs of
the maps. The erosion classcs arc grouped
as shown in table 11 (p. 42) into no ap-
parent, slight, moderate, severe, and
very severe erosion. .
The kind and d',gree of crosion and
the susceptibility of the soil to erosion
affect the capability of the land for use.
Ninety-eight pcrcent of the cultivated
land has lost from 4 to 6 inchcs of top-
soil and almost all has beml affected to
some degrec by wind erosion. Some
ficlds have becn seriously damaged,
whercas ncarby fields of the same soil
type havc been.but littlc crodcd. Anad-
jaccnt blowirlg field is a serious menace
to one that is protectcd, and erosion
may spread unless both are in their
proper use. Susceptibility to erosion as

well as the degree of erosion is closely
related to soil-group classification.
Erosion tends to accelerate erosion,
since drifting soil gradually be-
comes lightcr (sandier) in texture and
consequently more subject to wind
action. A more complete discussion of
erosion is given on pages 51-53.
The land-capability classification of
the soil groups, slope classes, and ero-
sion classes, ana also a list of the soil
types in each group are shown in table 1.
Only two classcs of land suitable for
cultivation, classes III and IV, and two
classcs of land suitable only for grazing,
classes VI and VII, are recognizcd in
Baca County. Class VIII, wasteland,
is confined to stream channels and lake
beds and is of little significance owing
to the small acrcage.
There is abundant evidence that marc
than simple practices are required to
maintain and conserve the soil even
under thc best-known methods of
cultivation today. Some measures,
though simple of performance, must be
very carefully timed. Continuous and
intensive application of tbe most com-
plex practices now known is rtecessary
for permanent cultivation of the highly
crodible soils in the semiarid climate of
Baca County. Tbe thousands of
scverely eroded idle acres within the
county today bear witness to the errors
of those who gave little thought to the
future of thcir land.

Choosing' Practices and Measures

The management and conservation
practices recommended for cultivation
of land in classes III and IV and for
range land in all capability classes are
summarized in table 2.

Western and Southeastern Baca County Soil Conservation Districts, Colorado

II