The First Book of Farming | Page 6

it in a warm room. Observe it from day to day as it puts out new shoots bearing leaves and roots (see Fig. 7). Break these off and plant them in soil and you have a number of new plants. If you can get the material, repeat this experiment with roots of horse-radish, raspberry, blackberry or dahlia. From this we see that it is the work of some roots to produce new plants. This function of roots is made use of in propagating or obtaining new plants of the sweet potato, horse-radish, blackberry, raspberry, dahlia and other plants.
[Illustration: FIG. 4. To show that plant-roots take water from the soil, the plants in A are suffering from thirst. B has sufficient water.]
[Illustration: FIG. 5. To show that plant roots take food from the soil. Both boxes were planted at the same time.]
[Illustration: FIG. 6. A radish root, from which the stored food has been used to help produce a crop of seeds. Notice the spindle shaded seed-vessels.]
[Illustration: FIG. 7. A sweet-potato root producing new plants.]
We have now learned five important things that roots do for plants, namely:
Roots hold plants firmly in place.
They absorb water from the soil for the plants.
They absorb food from the soil for the plants.
Some roots store food for the future use of the plant.
Some roots produce new plants.
How do the roots do this work? To answer this question it will be necessary to study the habit of growth of the roots of our plants.
HABIT OF GROWTH OF ROOTS
The proper place to begin this study is in the field or garden. So we will make another excursion, and this time we will take with us a pick-axe or mattock, a shovel or two, a sharp stick, a quart or half-gallon pitcher, and several buckets of water. Arrived in the field, we will select a well-developed plant, say, of corn, potato or cotton. Then we will dig a hole about six feet long, three feet wide, and five or six feet deep, close to the plant, letting one side come about four or five inches from the base of the plant. It will be well to have this hole 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