run across the row rather than lengthwise with it.  Then with the pitcher pour water about the base of the plant and wash the soil away from the roots.  Gently loosening the soil with the sharpened stick will hasten this work.  In this way carefully expose the roots along the side of the hole, tracing them as far as possible laterally and as deep as possible, taking care to loosen them as little as possible from their natural position. (See Figs. 8 and 9.) Having exposed the roots of one kind of plant to a width and depth of five or six feet, expose the roots of six or eight plants of different kinds to a depth of about eighteen inches.  As this may require more time than we can take for it in one day, it will be well to cover the exposed roots with some old burlaps or other material until we have them all ready, in order to keep them from drying and from injury.

When all is ready we will study the root system of each plant and answer these four questions: 

In what part of the soil are most of the roots?

How deep do they penetrate the soil?

How near do they come to the surface of the soil?

How far do they reach out sidewise or laterally from the plant?

To the first question, “In what part of the soil are most of the roots?” you will give the following answers:  “In the upper layer.”  “In the surface soil.”  “In the softer soil.”  “In the darker soil.”  “In the plowed soil.”

These are all correct, but the last is the important one.  Most of the roots will be formed in that part of the soil that has been plowed or spaded.

The second question, “How deep do the roots penetrate the soil?” is easily answered.  Roots will be found penetrating the soil to depths of from two to six feet or more. (See Fig. 8.) The author has traced the roots of cowpea and soy bean plants to depths of five and six feet, corn roots four and five feet, parsnips over six feet.  The sweet-potato roots illustrated in Fig. 8 penetrated the soil to a depth of over five feet.  The roots of alfalfa or lucern have been traced to depths of from thirteen to sixteen feet or more.

How near to the surface of the soil do you find roots?  Main side or lateral roots will be found within two or three inches of the surface, and little rootlets from these will be found reaching up as near the surface as there is a supply of moisture.  After a continued period of wet weather, if the soil has not been disturbed, roots will be found coming to the very surface and even running along the top of the soil.

As to the fourth question, How far do roots reach out sidewise or laterally from the plant? you will find roots extending three, four, five and even six or more feet from the plant.  They have numerous branches and rootlets, which fill all parts of the upper soil.  Tree roots have been found thirty or forty feet in length.