NEW OR SCIENTIFIC METHOD 105 



recognized by such general observations. Until the carrying 

 capacity of a pasture has been materially reduced, the animals 

 grazed generally come through the season in fair flesh. Like- 

 wise, until the plant cover as a whole has been opened up, or a 

 large proportion of the more palatable plants actually killed, 

 the factors responsible for the injury are not recognized. After 

 such serious depletion many seasons of skillful management are 

 required to reestablish the original forage cover. 



New or Scientific Method. — Because of the serious loss to 

 the stockman and the usual injury to important watersheds 

 resulting from destructive grazing, a finer measure than merely 

 observing the density of the plant cover and the condition of the 

 stock pastured must govern the grazing plans. From the view- 

 point of proper utilization, the margin between what clearly 

 constitutes overgrazing and what is clearly undergrazing must 

 be reduced to a minimum. 



The one reliable, indeed the only direct, scientific way of 

 detecting pasture depletion in its early stages is by observing 

 the succession of the conspicuous vegetation, that is, the replace- 

 ment of one set or type of plants by another.^ 



Quite different plants occupy soils in the various stages of 

 formation or depletion. Plant hfe began on the earth with 

 very simple forms. In the early geological ages, largely because 

 of the absence of a deep layer of soil, only simple plant forms or 

 those of low development were in evidence. These forms, 

 through the disintegration of the once consolidated rock, and 

 the gradual accumulation of humus, in the course of time were 

 supplanted by the more specialized forms of plant life. This 

 process continued until the highest kinds of seed-bearing plants 

 came to predominate. Generally it does not require much 

 misuse of grazing lands to deplete the soil, expose the underlying 

 rock, and degrade the vegetation to such an extent that only the 

 lower uneconomical forms of plant life can exist. 



If the highly palatable plants on pasture lands are so closely 

 or repeatedly cropped as to weaken or actually kill them, they 



1 Sampson, Arthur W., "Plant Succession in Relation to Range Management." 

 U. S. Dept. of Agr. Bui. 791, pp. 1-7, 1919 



