102 
Joumal of Agricultural Research voi. xxviii, no. 2 
tered more or less equally over grama grass in this type. Match weed is espe¬ 
cially abundant in rocky or shallow soils. It also comes in on the better lands 
when the natural vegetation is weakened by overgrazing, or continued drought, 
or is destroyed by plowing. This type is rather common throughout the central 
and southern Great Plains. The carrying capacity is low, from 5 to 15 head of 
cattle per section, and the land is of doubtful agricultural value. 
(11) Grama Grass and Valley Sage ( Artemisia nana Nutt.).—This type, 
illustrated by Plate 2, B, is limited largely to the plains region of Montana, grow¬ 
ing in a rich deep loam soil in swales and in small valleys. It consists of a scat¬ 
tered growth of valley sage over a grass sod composed mainly of grama grass. 
Agriculturally, the land will produce during years of more than average moisture 
supply. The grazing capacity is good, ranging from 30 to 60 head of cattle 
per section, the number being dependent upon the density of the vegetation. 
(12 ) Grama Grass and Western Needlegrass ( Stipa comata Trin. & 
Rupr.).—A mixed stand of grama grass and needlegrass, with niggerwool, 
wheatgrass, and mountain sage, comprise this type. During dry seasons it 
appears to be composed mainly of grama grass, but during wet seasons the 
needlegrass is more conspicuous. By overgrazing, the mountain sage comes in 
and in time will become one of the dominant species of the type. This type is 
most important in portions of North and South Dakota and eastern Montana, 
on level land having a rather loose sandy black loam soil. The rainfall over the 
area occupied by this type ranges from 15 to 18 inches and moistens the soil to 
a depth of 14 to 18 inches. Agriculturally, lands of this character usually pro¬ 
duce good crops of grains except during years of less than average moisture sup¬ 
ply. They also afford very good grazing, ranging from 40 to 80 head of cattle 
per section in most areas. The western needlegrass, however, is not readily 
grazed after it matures, owing to its tough texture. 
(13) Grama-Buffalo Grass ( Bulbilis dactyloides ( Nutt.) Raf.).—The grama- 
buffalo grass type, shown by Plate 3, A, which is composed of a mixture of grama 
and buffalo grasses, is one of the most extensive types on the Great Plains south 
of the Montana line. It grows on hard or tight land where the soil moisture 
only rarely penetrates below the second foot and crop failures are sure during 
years of less than average moisture supply. Corn and wheat are the chief 
crops in the North, while the grain sorghums are ever present in the South. The 
carrying capacity over most of the lands supporting this type ranges from 25 to 
50 head of cattle per section. 
(14) Grama-Buffalo Grass, and Western Needlegrass. —A mixed 
stand of grama grass, buffalo grass, and needlegrass makes up this type. The 
needlegrass is taller than the other grasses and is more conspicuous, especially 
in wet years. The type also usually contains a scattering of Psoralea (P. argo - 
phylla ), cone flower (Echinacea) , and other flowering plants. Its soil and range 
are similar to Type (13). It is productive for wheat and corn in the North 
$nd grain sorghums in the South during years of average or more than average 
moisture supply. The carrying capacity of this type ranges from 35 to 75 
head of cattle per section. 
(15) Grama-Buffalo, and Wire Needlegrass (Aristida longiseta Steud.).— 
This type, illustrated by Plate 3, B, is composed of an even cover of grama and 
buffalo grass, with scattered bunches of wire needlegrass. This is a common type 
on loose, sandy loam soils .throughout the western Great Plains region. On 
heavy land this type occurs on the eastern edge of the high plains. Agricul¬ 
turally, this land is productive of wheat, corn, and grain sorghums during years 
of average or more than average moisture supply. As grazing land, it will carry 
from 20 to 40 head of cattle per square mile. The wire needlegrass is too 
tough to be palatable when it matures. 
(16) Grama-Buffalo, and Wheatgrass. —Large areas of rather heavy 
soils, mostly clays and clay loams throughout the Great Plains region, especially 
