6 CIRCULAR 925, U. S. DEPARTMENT OF AGRICULTURE 
x XxX x x x 
it 
MIDDLE | EARLY ** EARLY * EARLY : i) 
LATE | MIDDLE ,, MIDDLE , LATE | mipbLE | mippeE |! t 
WINTER | WINTER || WINTER | WINTER | WINTER | WINTER 
Sete ee se Oe ie oe See eee ee 
MODERATE | MODERATE ’* LIGHT { LIGHT * MODERATES HEAVY ** } 
k 4k ‘ ! k 1 ! 
| | | | | | 
ee eS SS = 
|| . 
* MIDDLE ¥f i | EARLY 7 
MIDDLE , LATE ji MIDDLE , EARLY { MIDDLE | LATE 
WINTER WINTER || WINTER WINTER | WINTER WINTER 
Hoe N08 Oe eee 
‘MODERATE’ HEAVY * HEAVY 7% LIGHT 
LIGHT | LIGHT 
MIDWINTER 
12 Uy 18 
HEAVY 
HE AVY 
EARLY, LATE | 
\ WINTER i LATE WINTER 
20 | 19 
MODERATE | MODERATE 
= _ 
MIDDLE LATE iE 
WINTER EARLY WINTER * 
14 
HEAVY 
EARLY, LATE 
WINTER 
EARLY WINTER 
16 
| 15 
| MODERATE | HEAVY 
bee ieee @ eee 
Figure 4.—Fenced range pastures at the Desert Experimental Range. Intensities 
of grazing in the pastures were light, moderate, or heavy during the various grazing 
periods, as indicated. 
method (12) for the same period with the exception of the first 3 years, 
1935-37, for which they were determined from the density estimates, 
using the calculated relation (regression) of density and yield for the 
period 1938-47. 
Estimates of herbage utilization were made at the end of grazing 
periods on the same plots that were used for obtaining plant density 
and herbage yield. Percentage utilization of individual shrubs and 
grasses was determined by the ocular-by-plot method described by 
Pechanec and Pickford (1/1). Percentage utilization of the current 
herbage of each species was obtained by averaging the estimates made 
on the plots. The weight of herbage utilized was computed by multi- 
plying the total yield of each species by the average percentage utiliza- 
tion. 
Herbage yields obtained at varying periods on the moderately and 
heavily grazed range and on the protected enclosures and heavily 
grazed range were compared and used to supplement information 
obtained in the experimental range pastures. 
