STORING WATER IN THE SOIL 95 



spring when plants are not growing. If the rains 

 that fall during the growing season are indispensable 

 in crop production, the possible area to be reclaimed 

 by dry-farming will be greatly limited. Even when 

 much of the total precipitation comes in summer, 

 the amount in dry-farm districts is seldom sufficient 

 for the proper maturing of crops. In fact, successful 

 dry-farming depends chiefly upon the success with 

 which the rains that fall during any season of the 

 year may be stored and kept in the soil until needed 

 by plants in their growth. The fundamental opera- 

 tions of dry-farming include a soil treatment which 

 enables the largest possible proportion of the annual 

 precipitation to be stored in the soil. For this pur- 

 pose, the deep, somewhat porous soils, characteristic 

 of arid regions, are unusually well adapted. 



Alway's demonstration 



An important and unique demonstration of the 

 possibility of bringing crops to maturity on the 

 moisture stored in the soil at the time of planting 

 has been made by Alway (Fig. 27). Cylinders of 

 galvanized iron, 6 feet long, were filled with soil 

 as nearly as possible in its natural position and con- 

 dition. Water was added until seepage began, after 

 which the excess was allowed to drain away. When 

 the seepage had closed, the cylinders were entirely 

 closed except at the surface. Sprouted grains of 



