12 BULLETIN 1405, U. S. DEPARTMENT OF AGRICULTUEE 



The results of the experiment show that the early yield is com- 

 paratively small if the herbage is cropped when its average height 

 is 4 inches or less. The feed is too scanty for grazing animals to 

 satisfy their hunger in the usual period and the succulent short 

 herbage is "washy" and comparatively low in feed value, as is at- 

 tested by the restless and usually poor condition of animals when 

 they must subsist upon it. (PL I.) 



Moreover, when the plants are at this early stage of development 

 the soil on mountain range is almost invariably wet, or at least very 

 high in moisture content, so that trampling by stock injures the 

 plant roots and seriously packs the soil, causing it to harden and 

 bake badly when it dries. This condition of the surface soil pro- 

 motes erratic run-off, so that relatively little water is absorbed from 

 normal rains, and water is badly needed for the later plant growth 

 and for seed formation. 



When grazing is delayed until the important forage plants have 

 reached a height of 6 inches, there is less danger of injury to the 

 vegetation, the ground has usually dried out to the extent that 

 trampling does not damage it, and the stock are able to obtain a 

 sufficient quantity of more nutritious and substantial feed. 



Where wheat grasses, bromes, and needle grasses are the main 

 forage plants, they should have developed to 6 or 8 inches in height 

 before being grazed. The necessary development of other plants will 

 vary. Ordinarily valuable herbaceous species should have made a 

 growth of at least 6 to 8 inches before being considered ready for 

 grazing. In some cases it will be necessary to include consideration 

 of the stage of development of certain portions of the plants. Where 

 June grasses, blue grasses, and fescues are important, at least 25 per 

 cent of the heads of these earlier forage grasses should be showing 

 or the leaf sheaths enveloping the heads should be swollen and con- 

 spicuous (^, pp. 11, 12)? 



PLANT DEVELOPMENT THAT INDICATES RANGE READINESS OR UNREADINESS 



The determination of the opening date of the grazing season on 

 a given range should be based upon the condition of the soil and the 

 development of all the important forage species present rather than 

 upon the condition of a few " indicator " plants. Certain conditions 

 of the habitat may stimulate the growth of one species more than 

 another, so that the development of a few might be in advance of 

 that of the forage cover as a whole. Consequently the larger the 

 list of plants used as indicators the more reliable the result. In 

 fact, it is well to consider the development of all the important 

 plants, since there is one early maturing group of plants whose 

 development clearly indicates that the range is not ready for graz- 

 ing, and another later-maturing group which serves as a reliable 

 indication of range readiness and the possibility of continued vig- 

 orous forage production. The first group includes herbaceous spe- 

 cies, which reach maturity very early in the spring, and which, 

 being exceptionally high in water content and usually of low palata- 

 bility, have little value as forage. The plants of the second group 

 are herbaceous and browse species which mature their herbage and 

 seeds later in the season and which are highly important, because 



3 Figures in italic in parenthesis refer to " Literature cited," p. 54. 



