334 GRAZING INDICATORS. 



expended, for the payment of expenses necessary to execute the provisions of 

 this Act. 



Sec. 8. That the President is hereby authorized to modify any proclamation 

 establishing any grazing district, but not oftener than once in five years, to 

 take effect in not less than one year thereafter, and by such modification may 

 reduce the area or change the boundary lines of each grazing district. 



Classification and range surveys. — The necessity of a classification survey 

 to determine the primary division of the public domain into agricultural, 

 grazing, and forest lands has been discussed in the preceding chapter. Here 

 it will suffice to emphasize the importance of classifying as grazing land all 

 areas in which there is not convincing evidence of permanently successful 

 agricultural production. In view of the fact that dry-farming in many 

 regions is largely confined to forage production, by far the best plan would 

 be to treat the remainder of the public domain as grazing land and to organize 

 it into districts and units in such a way that the forage areas could be in- 

 tensively utilized. 



The primary task of a range survey is to determine the grazing types and 

 subtypes of a region and to approximate the carrying capacity of each. It 

 must ascertain the character, composition, extent, and value of each type, as 

 well as its present condition and its future development. It is essentially 

 ecological in nature, and hence must be based upon the climax formations and 

 their subdivisions, and upon their successional development. The most 

 important unit is the grouping or faciation, which represents the local type 

 with which an individual range must deal, though the larger ranches might 

 have a number of different types. A range survey will necessarily devote 

 much time to the need and the possibility of range improvement in the 

 different types. It will pay especial attention to the indicators of overgraz- 

 ing, and to the successional evidences of the best method of regeneration. It 

 will locate the areas infested with rodents or with poisonous plants, and will 

 suggest the most promising methods of eradication. It should likewise 

 take note of all areas in which there is actual or potential development of hay 

 and forage, and of the location and extent of communities of emergency 

 forage plants. It must also deal with the possibilities of water development, 

 by means of mills as well as by tanks. Finally, it will take account of sand- 

 hill, bad land, and other areas in which some form of grazing reclamation is 

 possible. In its complete expression the range survey should lead to the 

 production of ecologic sheets and folios which would do for the range what 

 topographic sheets and geologic folios do for the topography and geology of a 

 quadrangle. 



Production cycles. — The recurrence of wet and dry periods in general 

 harmony with the sun-spot cycle has already been shown to have a profound 

 effect upon the carrying capacity and water supply of the range. As a con- 

 sequence, the climatic cycle is clearly reflected by a corresponding grazing 

 cycle. The carrying capacity and water supply are high during wet periods, 

 and they are at a minimum during drought periods. For successful ranch 

 practice in the drier regions especially, the grazing cycle must be made the 

 basis of a production cycle. In fact, it is already the basis of such a cycle, 

 owing to the fact that production is necessarily reduced to the minimum dur- 

 ing a drought period. It is imperative that the actual existence of such a 





