Figure 11. — 



General view of part of the forage nursery where early studies of plant vigor were made. 



Development of desirable grazing technique 

 requires answers to such questions as: How 

 early can the range be grazed? How many times 

 within a growing season can it be grazed? How 

 completely may plants be utilized and still have 

 the range maintained and improved? 



The first plant vigor experiments were 

 started at the Station headquarters in the 

 autumn of 1916 (fig. 11). For one experiment, 

 three species that had produced well and had 

 recovered satisfactorily from grazing were 

 studied; namely, mountain brome, smooth 

 brome, and slender wheatgrass. The experi- 

 ment was designed to determine just how dif- 

 ferent intensities and different frequencies of 

 grazing affected the seasonlong growth and 

 vigor of these valuable grasses. Thirty speci- 

 mens of each species were planted in each of 

 four plots. Harvesting varied from one to four 

 times during the growing season. 



Plots where herbage was removed four times 

 during the season produced the least dry mat- 

 ter, and plants were seriously weakened; plots 

 harvested twice produced the second least 

 amount of dry matter, and plants were some- 



what weakened. Plots cut just before seed 

 maturity generally showed the greatest produc- 

 tion of dry matter and best plant survival. 



A companion project studied nine species: 

 five grasses, three forbs, and one shrub. To ob- 

 tain the most accurate data possible, the forage 

 removed from all plots was harvested with 

 shears "in a method simulating grazing as near- 

 ly as possible." The season and closeness of har- 

 vesting represented some 24 methods of har- 

 vest differing in date, frequency, and closeness 

 of cutting. 



In 1919 this project was expanded by plant- 

 ing numerous additional native forage species 

 in the nursery. The following year, many new 

 plots were set out on the range so that perform- 

 ance could be watched under actual range con- 

 ditions. Some of these plots were in the oak- 

 brush type (elevation 7,200 feet) and some in 

 the spruce-fir type (about 10,000 feet). 



These experiments and their results were re- 

 ported in detail by Director Sampson and 

 Harry E. Malmsten, Grazing Examiner, in a 

 "landmark" publication (Sampson and 

 Malmsten 1926). Published while the science of 



22 



