INCREASING FORAGE YIELDS ON INTERMOUNTAIN WINTER RANGES 90 
The following minimum stubble heights and twig lengths are char- 
acteristic of moderately grazed winter range. Indian ricegrass will 
have an average of 2 to 3 inches of stubble remaining at the end of the 
grazing season. Although all plants are usually grazed, a few of the 
larger, more robust ones will usually have as much as 5 or 6 inches 
of stubble. On galleta an average stubble height of 1 to 11% inches 
will remain and 5 to 10 percent of its ground area, usually toward 
the perimeter of stands, will be ungrazed. Black sagebrush will have 
an average of 11% to 2! inches of current twig growth remaining and 
in years when seed stalks are produced in abundance, 10 to 20 percent 
of these will be ungrazed. On winterfat 11% to 2% inches of current 
growth will remain and 10 to 15 percent of the plants will appear to 
be ungrazed. 
The percentages of utilization given in table 1 are useful utilization 
guides in subtypes where the species listed make up a large part of the 
plant cover or herbage production. These utilization guides should be 
adhered to rather closely in order to maintain a moderate grazing 
intensity. On range subtypes where winterfat, bud sagebrush, black 
sagebrush, Indian ricegrass, and galleta do not occur, or on ranges 
where they make up only a small proportion of the vegetation, it may 
be necessary to select other key forage species on which to base utiliza- 
tion guides. If scattered but choice forage species are to be maintained 
in the plant cover, it may be necessary to use some of these as key 
species and to reduce the grazing level enough to prevent grazing injury. 
Where ranges are in a deteriorated condition, utilization percentages 
must be adjusted to provide for range recovery. On ranges in poor 
condition it may be necessary to leave more than 50 percent of the 
herbage of the palatable species during 2 or 3 years while the vigor of 
the plants is being restored. This will allow them to compete more 
successfully with invading species or species of low palatability such 
as Russian-thistle, shadscale, or small rabbitbrush. On ranges in very 
poor condition it may be desirable to suspend grazing for as long as 
2 years or to allow grazing only every other year. Within the experi- 
mental range, a severely depleted winterfat subtype made satisfactory 
improvement when grazed moderately in alternate years. 
STOCKING RATES 
Stocking rates for winter ranges should be in balance with the 
capacity of grazing areas to produce forage. This is. necessary for 
efficient production of sheep. To adjust stocking rates annually to 
meet the wide fluctuations in forage production due to variations in 
precipitation is obviously impracticable, because flocks are primarily 
composed of breeding ewes which are grazed on other seasonal ranges 
to round out the yearlong range livestock operation. A more work- 
able procedure is to adjust the numbers of sheep so that they will be 
in balance with the forage yield over a fairly long period of time. 
The term “forage” is used to denote the amount of herbage which 
can be grazed or used by sheep under moderate grazing without 
injuring the range or impairing future production. The average stock- 
ing rate should take into account differences in productive capacity 
of different plant subtypes on the grazing area. Provision should also 
be made for recurrent drought periods. 
