8 BULLETIN .'54, U. S. DEPARTMENT OF AGRICULTURE. 



ally in localities where the stand has previously been weakened 

 through drought, is an important factor in connection with reproduc- 

 tion. The injury to seedlings due to grazing depends primarily upon 

 the class of stock grazed, the season of grazing, and the way in which 

 the stock is handled. It can therefore best be discussed in connection 

 with the different systems of grazing the range, the relation of each 

 system to the maintenance of the stand, and the revegetation of the 

 range with the most valuable plants. 



EFFECT OF GRAZING ON THE FORAGE CROP. 



From what has been said about the growth requirements of the 

 principal forage plants, it is plain that the most effective system of 

 range management from the standpoint of the vegetation alone will 

 be the one that interferes least with the growth of the plant up to the 

 time of seed maturity, and then aids in planting the seed. Any 

 system adopted must be practicable from the standpoint of the stock- 

 man. 



Grazing on western range lands may be divided into three more 

 or less distinct systems: (1) Yearlong or season-long grazing year 

 after year; (2) yearlong or season-long grazing with occasional total 

 exclusion of stock during the entire year to give the forage a chance 

 to reproduce; and (3) deferred grazing, which aims at a rotation in 

 the time of using each portion of the range, allowing the plants on 

 one portion to mature their seed each year before they are cropped, 

 and then grazing it to avoid loss of forage through nonuse, and to 

 assist reproduction by trampling in the seed. 



The following discussion aims to show the comparative merits of 

 the three grazing systems from the standpoint of the range plants' 

 requirements for growth and reproduction, and to outline the system 

 which promises the best results to both the range and the stock 

 industry. 



YEARLONG GRAZING. 



Prior to the inclusion of lands in the National Forests stock 

 usually had access to the range before snow was entirely off it, and 

 therefore when the earliest growth was appearing in the lower eleva- 

 tions. As the season advanced the stock drifted or were driven to 

 the highest portions, reaching each portion soon after growth had 

 begun. In many localities the range was so crowded that it was 

 grazed continuously throughout the season; the only period of rest 

 Avas during the time required for the herbage to grow enough after 

 being closely cropped to again permit grazing. Results from such 

 practices were directly comparable to those from the monthly clip- 

 ping experiments cited, and, in addition, the range was damaged a 



