FARMING INDICATORS. 255 



the increasing rainfall of the wet phase. This would not only permit the tak- 

 ing of the necessary precautions against the disasters due to drought, but it 

 would also make possible the development of an optimum system of manage- 

 ment. This would enable the farmer to fit his crops and methods of tillage 

 to the variations in rainfall and would permit the stockman to increase or 

 decrease his herds or to vary his supplies of forage with the wet and dry phases 

 of the cycle. In short, the cycle management of all the basic practices of the 

 West would provide the maximum insurance against loss or disaster and would 

 afford the greatest possible annual returns. _^ It is further discussed in con- 

 nection with agricultural and forest indicators, but its value is especially 

 emphasized under grazing, since the latter and the related dry-farming are 

 most dependent upon climatic conditions. 



FARMING INDICATORS. 



Types of farming. With reference to indicators, types of farming may 

 be based upon conditions or upon crops. Since the former determines the 

 methods and return (and often the crop as well), it seems to afford the better 

 basis. Accordingly, the usual division into humid and arid farming is em- 

 ployed here, with a further division of the latter into dry-farming and irrigation 

 farming. It is clear that no sharp line exists between the types of agriculture 

 in humid and arid regions. Between the two lies a broad belt of semi-arid 

 country in which there is a gradual adjustment of methods and crops to 

 increasingly arid conditions. The distinction is further obscured by the 

 variation in rainfall from the wet to the dry phase of the climatic cycle. Dur- 

 ing the wet period humid farming is possible through most or all of the semi- 

 arid belt and the need of drainage becomes felt over a much wider area. 

 During the dry period arid conditions are pushed across much of the semi-arid 

 country and semi-arid conditions develop in the outlying humid areas. How- 

 ever, practices change much less than conditions; the general area of the humid, 

 semi-arid, and arid regions remains essentially the same, with their mutual 

 relations identical. 



The humid region is regarded as possessing a lower limit of 25 inches of 

 rainfall, while the semi-arid has a range of 15 to 25 inches, and the arid from 2 to 

 15 inches. As would be expected from variations in the annual amount and 

 distribution of the rainfall, semi-arid areas with 20 to 25 inches of rain are 

 characterized by the humid type of farming, and those with 15 to 20 inches 

 by dry-farming. The latter type usually reaches its lower limit at 12 inches, 

 or at 10 inches where the rainfall is largely of the winter type. Below 10 

 inches, farming is profitable only by means of irrigation. Naturally, the 

 latter is also extensively practiced in regions with 10 to 20 inches of rain, and 

 to some degree under even higher rainfall. As Briggs and Belz (1911) have 

 shown, the eflficiency of rainfall depends upon the amount of evaporation, and 

 hence decreases more or less regularly from the northeast to the southwest in 

 the western United States. 



Relation of types of farming to indicators. Because of the control made 

 possible by irrigation, methods of tillage, and variation in crop or variety, 

 indicator values are less definite in the case of types of farming than in grazing 

 or forestry. Their significance is further reduced by the possibility of irri- 



