32 



BULLETIN 1405, U. S. DEPARTMENT OF AGRICULTURE 



starting one month after the beginning of growth, though much 

 weakened, lived through the three years of treatment. 



With most species a system of grazing which would result in 

 removal of the herbage four or five times in a season should by all 

 means be avoided. A grazing practice based on cropping at or a 

 few days before seed maturity and again at the close of the grazing 

 season, however, would not generally be detrimental to the vigor 

 of established plants. It would leave the plants physiologically 

 strong, though it would prevent any seed from reaching maturity 

 unless the grazing was by sheep. If not in too great numbers, 



7bto/ye/d of ' p/ots harvested 'four times //? o reason 



y e 



r eor 

 JS/7 



/9/d 

 J9JS 



J9t7 

 /9/8 

 /9/9 



/9/7 

 /9/6 

 /S/9 



suo- 



Tbfo/ y/e/c/ cf p/ots harvested Twice //> oseoson 



/OOO 



75UV 



Toto/y/e/d of p/ots horr zsted once //? o season 



2QOO 



~Z500 



Fig. 12. — Effect of frequency of harvesting on yield 



sheep usually graze only a portion of the near-ripe seed crop of 

 the grasses. 



Table 8. — Results of early and late harvestings in alternate years 



Plot No. 



Plant 



Zonei 



Number of 

 plants 2 



Yield per plant 

 (grams) 



Total yield per plot 

 (grams) 





1920 



1921 



1922 



1920 



1921 



1922 



1920 



1921 



1922 



S-17-24.. 

 B-4__ 



Letterman needle grass... 

 Mountain brome 



S-F 

 A-F 

 S-F 

 O-B 

 A-F 



8 

 23 



8 

 5 

 10 



8 

 22 

 8 

 5 

 10 



8 

 21 

 7 

 5 

 10 



1.38 

 8.04 



17.99 

 8.98 



10.37 



2.56 

 28.79 

 20.75 



3.97 

 19.05 



1.42 

 18.13 

 12.40 



7.34 

 19.65 



11.06 

 185. 00 

 143. 88 



44.88 

 103. 69 



20.49 

 633.40 

 166. 00 



19.84 

 190.48 



11.34 

 380. 71 



G-17-24 





86.80 



G-ll-15.. 

 E-4 



do 



Violet wheat grass 



Total 



36.68 

 196. 48 





54 



53 



51 









488.51 



1, 030. 21 



712. 01 

















i Zones: S-F= Spruce-fir; A-F = Aspen-fir; O-B = Oak-brush. 



2 The number of plants shown in this table represents those living at the beginning of each year's 

 treatment. 



