142 ROOTS 



plant is mature. In the Irish Potato the roots may reach a depth 

 of 3 feet after extending laterally 2 or 3 feet, but for most of their 

 length they are within a few inches of the surface. It may now 

 be seen that deep cultivation may injure Corn, Potatoes, and 

 other plants with a similar root habit by tearing away the roots. 

 In Wheat, Oats, and Barley, the root systems do not extend so 

 far laterally as in Corn but deeper into the soil, reaching a depth of 

 4 to 5 feet. Flax and Kafir Corn have fibrous root systems which 

 feed mainly from the surface soil. Plants with shallow roots are 

 called surface feeders, and are considered " hard on the land," be- 

 cause they exhaust the moisture and mineral matter in the sur- 

 face soil. 



In trees, although the lateral roots may reach a length of nearly 

 100 feet, they still remain near the surface. In the Soft Maple, 

 lateral roots 80 feet in length have been found to range in depth 

 from 8 inches to 2 feet. In old Apple trees the lateral roots, 

 which may be 60 feet of more in length, usually have a depth 

 ranging from 2 to 5 feet. Since trees by the surface habit of their 

 roots take the moisture and mineral matter from near the surface, 

 it is clear why crops do not grow well around them even when 

 not affected by their shade. 



Some fruit trees, such as the Cherry and Pear, send their roots 

 several feet into the soil and, therefore, require a deeper soil than 

 some other kinds of fruit trees. The Quince, commonly used as 

 a stock on which to graft Pears, has a shallow root system, and so 

 has the ' ' Paradise ' ' Apple on which Apples are often grafted. The 

 fact that Pears grafted on Quinces or Common Apples grafted on 

 the "Paradise/' Apple bear younger than they do when grown on 

 their own roots, shows that the shoot and root system are very 

 closely related in their activities. The deep root systems occur 

 generally in connection with tap-roots, which sometimes reach 

 extraordinary depths. Also the lateral roots in a tap-root system 

 are usually well under the surface. For example, in Sugar Beets 

 the lateral roots are 6 inches or more under the surface, and, 

 therefore, not usually disturbed by deep cultivation. On account 

 of having a deep root system, Beets require a deep and well 

 loosened soil. 



As to the depth reached by tap-roots, 5 or 6 feet is common in 

 Alfalfa, and a depth of 31 feet has been recorded. The tap-root 

 of the Mesquite, which is a native of desert regions, has been 



