Results 



As expected, increasing the severity of clipping and of 

 competition successively decreased the growth and vigor of 

 Idaho fescue during the year following treatment (figures 1 

 and 2). 



Subjecting Idaho fescue to extreme clipping while under 

 full competition reduced herbage volume the following year 

 by 84 percent. Extreme clipping under both partial and no 

 competition reduced herbage volume 66 and 47 percent, re- 

 spectively, when compared with the undipped plants under 

 both partial competition and no competition. Thus, the rela- 

 tive depressant effects of clipping were lessened when com- 

 petition was reduced. 



The normally suppressing effect of competition on indi- 

 vidual plants of Idaho fescue is clearly shown by the volume 



800 



700 



^ 600 - 



500 



400 



300 



200 



100 



Competition 



z~7\ 



None 



Partial 



Full 



No clipping 



Heavy clipping 



Extreme clipping 



Figure 1. Herbage volume production of Idaho fescue the year follow- 

 ing clipping under different levels of competition. (The col- 

 umn third from the left represents volume of check plants — 

 no clipping, full competition.) 



5 



