206 



DRY-FARMING 



ditions are all favorable, seeds cannot germinate 

 properly. The first requisite for successful seed 

 germination is a proper degree of heat. For every 

 kind of seed there is a temperature below which 

 germination does not occur ; another, above which it 

 does not occur, and another, the best, at which, pro- 

 viding the other factors are favorable, germination 

 will go on most rapidly. The following table, con- 

 structed by Goodale, shows the latest, highest, and 

 best germination temperatures for wheat, barley, and 

 corn. Other seeds germinate approximate!}' within 

 the same ranges of temj^erature : — 



Germination Temperatures (Degrees Fahrenheit). - 



Germination occurs within the considerable range 

 between the highest and lowest temperatures of this 

 table, though the rapidity of germination decreases 

 as the temperature recedes from the best. This ex- 

 ]ilains the early spring and late fall germination when 

 the temperature is comparatively low. If the tem- 

 perature falls below the lowest required for germina- 

 tion, dry seeds are not injured, and even a tempera- 

 ture far below the freezing p(jint of water will not 



