6 



LEAFLET 215, U. S. DEPARTMENT OF AGRICULTURE 



snakeweed, ring muhly, and three-awns, utilization should be judged 

 partly from the remaining blue grama and partly from the present 

 dominant vegetation. On such range the ultimate objective of good 

 management should be to hasten natural revegetation of the blue 

 grama. Grazing use should therefore be more conservative than on 

 good blue grama range. About 40 percent of the blue grama flower 

 stalks should be left standing instead of 25 percent. Where this is 

 accomplished, the stubble of the cropped plants will average about 

 2% inches above the ground and some 30 percent of the blue grama 

 forage will have been taken. The light grazing on the less palatable 

 associated plants will not prevent a steady increase in the volume of 

 blue grama in successive seasons. 



On deteriorated ponderosa pine ranges, where bunchgrasses such as 

 mountain muhly and Arizona fescue are the natural dominants and 



Stem 



height 



(percent) 



50 



70-- 



88-- 



Foroge 

 volume 

 (percent) 



2-inch 

 stubble 



Figure 3. — A blue grama plant illustrating proper utilization; 25 percent of the 

 stems should be left and nearly half the forage volume of the cropped stems. 

 Usually the upper half of a blue grama plant contains about 12 percent of the 

 volume, and half the volume is in the lower 12 percent of the height. 



blue grama is the invader, utilization should be judged on the basis 

 of the remaining bunchgrasses. If the bunchgrasses are properly 

 utilized, blue grama will usually have been grazed but lightly. 



The degree of use at any time prior to the end of the grazing season 

 should be roughly proportional to the period of grazing. If 40 per- 

 cent of the volume may properly be taken by the end of the season, 

 about 20 percent should have been taken when the season is half over. 

 On yearlong ranges with a 12-month grazing season ending in June 

 approximately one-fourth of the season has passed by the end of the 

 summer-growth period (the end of September) and proper use at this 

 time would take about 10 percent of the volume. Such use is very 

 light and so hard to see that close range inspection is needed to de- 

 termine it. 



