STOCKING NORTHERN GREAT PLAINS SHEEP RANGE 27 



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••&v ''4 tl fc « 



.,,,.,. 



Figure 10. — Six years of heavy sheep grazing and trampling changed the vege- 

 tative composition of typical northern Great Plains range to a dense stand of 

 low-value annual plants mostly woolly Indianwheat except in the protection 

 of pricklypear clumps. 



tion of plants producing seedstalks was very similar in the ungrazed 

 areas and the conservatively stocked pasture. In the heavily stocked 

 pasture, however, about 10 percent more of the plants produced seed 

 stalks than in the conservatively stocked pasture and 5 percent more 

 than in the ungrazed areas. Although heavy stocking retarded 

 height growth, it stimulated the production of seedstalks in blue 



Table 8.- — Average maximum length of leaves and height of seedstalks, 

 and proportion of plants that produced seedstalks, by rate of stocking 

 and species, 19^2 



Stocking rate and species 



Heavy : 



Blue grama 



Bluestem wheatgrass 



Conservative: 



Blue grama 



Bluestem wheatgrass 



Ungrazed : 



Blue grama 



Bluestem wheatgrass 



Length 

 of leaves 



Cm. 



9 

 28 



11 

 30 



14 

 35 



Height of 



seedstalk- 



Cm. 



30 

 56 



31 

 60 



33 



61 



Plants 

 with 



seedstalks 



Percent 



91 



17 



83 

 13 



87 

 15 



