Depth of Root Penetration 



233 



laid under tribute by them, and 

 this makes it clear that the stor- 

 age room for water in the soil for 

 many of the fruits may be much 

 greater than we have pointed out 

 above. 



In the case of the strawberry, 

 however, the figure shows that it 

 is a particularly shallow feeder, 

 and, therefore, is certain to suffer 

 severely in dry times if not irri- 

 gated. 



In Fig. 42 are shown the roots 

 of alfalfa only 174 days from 

 seeding. These had forged their 

 way through so close a clay su bsoil 

 that more than four days of con- 

 tinuous washing were required to 

 dissolve away a cylinder of soil 1 

 foot in diameter and 4 feet long. 

 The roots, however, had penetrated 

 this soil to a depth exceeding four 

 feet, and the nitrogen-fixing tuber- 

 cles were already developed 22 

 inches below the surface. 



In the rigid data here pre- 

 sented, combined with that shown 

 in Figs. 10 and 11, we have a 

 rational basis upon which to build 

 a practice of irrigation, so far as 

 that relates t<? the depth of soil 



m 



f-:l!l-M 



Fig. 42. Roots of alfalfa 

 in Wisconsin 174 days 

 from seeding. 



