260 DRY-FARMING 



is deeply modified by the arid conditions prevailing 

 in dry-farming. This shows itself first in the propor- 

 tion of the various plant parts, such as roots, stems, 

 leaves, and seeds. The root systems of dry-farm 

 crops are generally greatly developed, and it is a com- 

 mon ol^servation that in adverse seasons the plants 

 that possess the largest and most vigorous roots en- 

 dure best the drouth and burning heat. The first 

 function of the leaves is to gather materials for the 

 building and strengthening of the roots, and only after 

 this has been done do the stems lengthen and the 

 leaves thicken. Usual!}', the short seas(jn is largely 

 gone before the stem and leaf growth begins, and, 

 consequently, a somewhat dwarfed appearance is 

 characteristic of dr3--farm crops. The size of sugar 

 lieets, potato tubers, and such underground parts 

 depends upon the available water and food supply 

 when the jjlant has established a satisfactory root 

 and leaf system. If the water and food are scarce, 

 a thin beet results ; if abundant, a well-filled beet may 

 result. 



Dry-farming is characterized I33' a somewhat short 

 season. Even if good growing weather prevails, the 

 decrease of water in the soil has the effect of hastening 

 maturity. The formation of flowers and seed begins, 

 therefore, earlier and is completed more c[uickly under 

 arid than under humid conditions. Moreover, and 

 resulting ]5robal)ly from the greater abundance of 

 materials stored in the root system, the proportion 



