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 
4to5 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 or 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 
