32 BULLETIN 1031, U. S. DEPARTMENT OF AGRICULTURE. 
understocking with some loss of forage, or overstocking and conse- 
quent injury to the range. Although it would be far better and 
cause less loss of forage in the long run to understock slightly each 
year, the tendency in the past has been toward overstocking. Until 
the proper rate of stocking has been determined, however, careful 
observation of range and stock should make possible the detection 
of deterioration in time to provide for recuperation in a few seasons. 
Overgrazing on grama-grass range in the Southwest may be recog- 
nized to some extent in its first year by observations of the degree 
of cropping of the grass. Ordinarily grama grass should not be 
cropped closer in any year than will leave the lower joints of a few 
grass stalks on each tuft. This will provide a means of revegetation 
under favorable conditions the next year. 
Black grama grass reproduces mainly by stolons. A number of 
the mature fiower-stalks of each plant bend to the ground, sending 
forth a crown of leaves at each node or “joint” which takes root 
when it strikes the soil. Eventually as the little plants become es- 
tablished the connecting part dies and an independent plant is thus 
formed. If the grass is grazed so closely that no nodes are left 
there is no opportunity to revegetate by this method. 
In loose soil overstocking results in the trampling and loosening 
of the surface soil so that the roots of the grasses are exposed and 
wind erosion begins. If the stock grazing an area fall off in con- 
dition faster than other causes warrant. overstocking is no doubt 
occurring. 
Following the first year of overgrazing unpalatable annual grasses 
and weeds and short-lived perennial plants usually increase along 
with a reduction in number of leaves and height of the grass and in 
the number of flowering stalks and stolons. These secondary species 
increase with continued overgrazing and deterioration of the range 
until they are the only vegetation present. This is the case within a 
radius of one-half mile around some stock-watering places in the 
Southwest. The main plants indicating the first stages of deteriora- 
tion in the grama-grass range of southern New Mexico are such 
annuals and short-lived perennial plants as tall eriogonum, sixweeeks 
grasses, spectacle-pod, whitestem, and yellow caltrops. 
The best indicators of later stages of deterioration are dropseed 
grasses, leatherweed, silvery nightshade, and yellowbush, followed 
by snakeweed, and finally the mesquite-sandhill type if overgrazing 
and wind erosion is allowed to continue too long. 
Where overgrazing has reached the stage where mesquite sandhills 
are being formed it will be difficult to restore the range. Effort 
should be made to detect the breaking down of the range much 
earlier, or as soon as the annuals and short-lived perennials begin 
to increase and the good grasses to decrease. Figures 1 and 2, 
