30 



BULLETIN 1405, U. S. DEPARTMENT OF AGRICULTURE 



and three times at monthly intervals, and finally at the end of the 

 growing season. All cuttings were made 1 inch above the ground. 



Table 6. — Comparative yields of plots harvested five times and twice, respec- 

 tively, each season 



Plots Harvested Five Times at Monthly Intervals, the First Harvesting Being Made Two 

 Weeks After Inception of Growth and the Last Monthly Harvesting by Removal of the 

 Aftermath at the Close of Growing Season 



Plot No. 



Plant 



Zone 1 



Number 

 of plants 2 



Yield per plant 

 (grams) 



Total yield per plot (grams) 





1920 



1921 



1922 



1920 



1921 



1922 



1920 



1921 



1922 



S-l-8.... 



SL-1-10 . 

 C-4 



Letterman needle 



grass. 

 do 



Mountain brome 



Wild geranium 



do 



Mountain dandelion . 



Total... 



S-F 



O-B 



A-F 

 O-B 



S-F 



S-F 



8 



10 



29 



5 



8 

 8 



8 



10 

 

 5 

 7 

 6 



7 



6 

 

 1 

 2 



4 



1.40 



6.32 



30.56 

 3.84 



16.03 

 2.03 



0.36 

 1.60 



0.24 



.84 



11.21 



63.15 



886.20 

 19.19 



128. 21 

 16.23 



2.86 

 16.04 



1.65 

 5.02 



G-l-5.... 

 G-l-8.... 



A-l-8— . 



.37 



4.52 

 1.00 



.13 



1.36 

 .96 



1.87 



31.64 



5.99 



.ia 



2.71 

 3.83 





68 



36 



20 









1, 124. 19 



58.40 



13.34 

















Plots Harvested Just Before Seed Maturity and Again at Close of Growing Season 



S-25-32.. 



SL-41-50 



C-5 



G-16-20 - 

 G-25-32 . 

 A-25-32 . 



Letterman needle 

 grass. 



do 



Mountain brome 



Wild geranium. 



do 



Mountain dandelion- 

 Total 



S-F 



O-B 

 A-F 

 O-B 



S-F 

 S-F 



8 



10 



29 



5 



8 

 8 



8 



10 



28 



5 



8 



8 



8 



10 



25 



5 



8 



2 



2.09 



12.36 

 157. 97 

 13.39 

 13.13 

 1.06 



4.43 



4.47 

 77.42 

 11.80 

 18.32 

 .71 



5.00 



3.82 

 58.71 

 16.44 

 16.67 



1.45 



16.70 



123.64 



4, 581. 12 



66.94 



105.00 



8.44 



35.41 



44.67 



2, 167. 80 



58.99 



146. 52 



5.71 



39.98 



38.18 



1, 467. 68 



82.21 



133. 36 



2.90 





68 



67 



58 









4, 901. 84 



2, 459. 10 



1, 764. 31 

















i Zones: S-F=Spruce-fir; 0-B= Oak-brush; A-F= Aspen-fir. 



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

 ment. 



Table 7. — Effect of frequency of harvesting on yield 



Plant 



Yield 



per plot (grams) 



1917 



1918 



1919 



Plots harvested four times each season: 



Violet wheat grass 



65.9 

 755.4 



85.9 

 405.7 



69.8 



Mountain brome 



90.8 







Total ._ _ 



821.3 



491.6 



160.6 







Plots harvested twice each season: 



Violet wheat grass... .. 



285.9 

 1, 674. 9 



538.4 

 1,506.6 



789.4 



Mountain brome . 



1, 453. 6 







Total... ... . 



1,960.8 



2, 045. 



2, 243. 







Plots harvested once each season: 



Violet wheat grass. 



351.8 

 1, 058. 9 



552.5 

 943.3 



910.0 



Mountain brome . 



1,110.0 







Total 



1, 410. 7 



1, 495. 8 



2, 020. 







The fewer specimens killed and the greater maintenance of vigor 

 of the plants harvested only at seed maturity and at the close of 

 the growing season, as compared with those harvested five times, is 

 clearly indicated by the data. Table 6 indicates the decline in the 

 number of plants and the diminution in the yield per plant result- 



