28 



CIRCULAR SO 4, U. S. DEPARTMENT OF AGRICULTURE 



grama. It is not inferred that greater seedstalk production as a 

 result of heavy stocking means greater production of viable seed. 

 Although data are not available, heavy grazing may have actually 

 reduced the quantity of good seed produced even though more seed- 

 stalks appeared on the heavily than on lighter stocked areas. 



Leaves of bluestem grew taller on the conservatively stocked pas- 

 ture and the ungrazed areas in 1942 by 7 and 25 percent, respectively, 

 than on the heavily stocked pasture, and seedstalks were 7 and 9 

 percent taller (table 8). However, the plants on the heavily stocked 

 pasture produced more seedstalks that year by 31 and 13 percent 

 than plants on the conservatively stocked and ungrazed areas. Thus, 

 as with blue grama, heavy stocking retarded the height growth but 

 stimulated seedstalk production. Again, however, the effect on pro- 

 duction of viable seed is not known, but heavy stocking may well 

 have caused the production to decline. 



Effects ox Herbage Production 



Where intensive use of range vegetation retards its recovery from 

 drought, the result is less herbage production, less usable forage, and 

 lower grazing capacity. 



Table 9. — Production of air-dry herbage per acre and estimated usable 

 forage per acre l under various stocking rates, by species, 191$ 



Species 



Heavily 



stocked 



Perennial grasses: 



Blue grama 



Bluestem wheat grass. 



Threadleaf sedge 



Other perennial 

 grasses 



Lbs. 

 149 



110 

 124 



Total. _. 

 Perennial forbs. 

 Browse 



Total. 



Annuals 



Conserva- 

 tively 

 stocked 



Lbs. 



66 

 50 

 43 



M 

 42 



03 M 

 x 



Lightly 

 stocked 



Ungrazed 



c3 

 Si. 



- 



— c 



b3 bC 



d S3 



- - 



Lbs. Lbs. Lbs. I Lbs. j Lbs. 



250 73 279 59 I 515 



245 49 445 98 653 



365 69 204 24 39 



— e 



Lbs. 

 149 

 131 



7 



87 



52 



198 



119 



109 



65 



108 



65 



470 

 143 



( 2 ) 



211 

 29 



1,058 



94 



1 



310 

 19 



( 2 ) 



1,037 

 93 

 45 



246 



19 



2 



1,315 

 40 

 33 



352 

 8 

 2 



613 

 815 



240 



163 



1, 153 

 79 



329 



16 



1. 175 

 306 



267 

 61 



1. 38S 

 437 



362 



S7 



Total, all species 1. 42S 403 1.232 345 1,481 328 1,825 



449 



1 Estimates of usable forage for blue grama, bluestem. and threadleaf sedge 

 derived by applying utilization figures in table 4 to pounds of air-dry herbage per 

 acre. For other species the following factors were used for all stocking intensities: 

 other perennial grasses, 60 percent; perennial forbs, 20 percent; browse, 5 percent; 

 annuals. 20 percent. 



2 Less than 1 pound. 



