50 BULLETIN 1031, U. S. DEPARTMENT OF AGRICULTURE. 
usually dry, and stock, especially breeding cows, are in the most 
critical condition. 
SEASONAL USE OF RANGE. 
Where grama-grass or yearlong range and tobosa-grass or summer 
range occur together, as they do on the Jornada Range Reserve, 
management of the range is a comparatively simple matter. 
The chief requirement of grama-grass range, to obtain revegeta- 
tation and maintain it at its highest productivity, is protection or 
material reduction of grazing during the main growing season, July 
to September, inclusive. On the other hand, tobosa-grass or summer 
type of range, because of its growth habits and the character of the 
soil it occupies, does not suffer materially if grazed during the time 
it makes its main growth and must be grazed at this time if maxi- 
mum utilization is to be secured. Division of these two classes of 
range, using the tobosa-grass and similar types during summer and 
fall, and holding the grama grass and similar types for use during the 
winter and spring, will serve the several-fold purpose of securing the 
full use of each, giving the grama-grass range the protection. it 
requires during the growing season, and insuring a supply of winter 
and spring range for the stock. 
Figure 1 shows how the various types of range have been divided 
into the two classes on the Jornada range reserve. Pastures 2, 3, 
5,10, and 12 are chiefly valuable for winter or yearlong range. Pas- 
tures 7, 8, 9, and 13 are best adapted to summer grazing. Pasture 1 
contains both winter and summer range, but cattle are confined 
to the latter as much as possible by salting and closing waters on 
the former and later in the year opening these waters and salting 
on winter range. It was not always possible to put the fences di- 
rectly upon the boundary between the two classes of range, espe- 
cially where the types occurred more or less intermixed, without ex- 
cessive fencing and water development, but the aim was to divide 
the range as nearly as practicable in this manner. 
The plan has been to use pasture 13 as summer and fall range for 
a herd of 500 head and pasture 10 as winter range for this same 
herd each year. The more needy cows in pasture 10 during each 
spring were then separated and placed in pasture 7, a small reserve 
pasture. The larger breeding herd has been grazed in pasture 1 
yearlong, with effort to confine the stock to the proper range at 
the proper season, except that all needy cows were separated and 
grazed in pasture 2,or one of the various smaller pastures where there 
was reserve feed, when their condition required it. Using pasture 
1 as yearlong range with such control of stock as was possible by 
salting and riding has not been as satisfactory, however, as has been 
