Agriculture for Beginners | Page 6

fine, loose dirt stirred by the cultivating-plow will make a mulch that serves to keep water in the soil in the same way that the plank kept moisture under it. The mulch also helps to absorb the rains and prevents the water from running off the surface. Frequent cultivation, then, is one of the best possible ways of saving moisture. Hence the farmer who most frequently stirs his soil in the growing season, and especially in seasons of drought, reaps, other things being equal, a more abundant harvest than if tillage were neglected.
=EXERCISE=
1. Why is the soil wet under a board or under straw?
2. Will a soil that is fine and compact produce better crops than one that is loose and cloddy? Why?
3. Since the water which a plant uses comes through the roots, can the morning dew afford any assistance?
4. Why are weeds objectionable in a growing crop?
5. Why does the farmer cultivate growing corn and cotton?
SECTION IV. HOW THE WATER RISES IN THE SOIL
[Illustration: FIG. 8. USING LAMP-CHIMNEYS TO SHOW THE RISE OF WATER IN SOIL]
When the hot, dry days of summer come, the soil depends upon the subsoil, or undersoil, for the moisture that it must furnish its growing plants. The water was stored in the soil during the fall, winter, and spring months when there was plenty of rain. If you dig down into the soil when everything is dry and hot, you will soon reach a cool, moist undersoil. The moisture increases as you dig deeper into the soil.
Now the roots of plants go down into the soil for this moisture, because they need the water to carry the plant food up into the stems and leaves.
You can see how the water rises in the soil by performing a simple experiment.
=EXPERIMENT=
Take a lamp-chimney and fill it with fine, dry dirt. The dirt from a road or a field will do. Tie over the smaller end of the lamp-chimney a piece of cloth or a pocket handkerchief, and place this end in a shallow pan of water. If the soil in the lamp-chimney is clay and well packed, the water will quickly rise to the top.
By filling three or four lamp-chimneys with as many different soils, the pupil will see that the water rises more slowly in some than in others.
Now take the water pan away, and the water in the lamp-chimneys will gradually evaporate. Study for a few days the effect of evaporation on the several soils.
SECTION V. DRAINING THE SOIL
A wise man was once asked, "What is the most valuable improvement ever made in agriculture?" He answered, "Drainage." Often soils unfit for crop-production because they contain too much water are by drainage rendered the most valuable of farming lands.
Drainage benefits land in the following ways:
1. It deepens the subsoil by removing unnecessary water from the spaces between the soil particles. This admits air. Then the oxygen which is in the air, by aiding decay, prepares plant food for vegetation.
2. It makes the surface soil, or topsoil, deeper. It stands to reason that the deeper the soil the more plant food becomes available for plant use.
3. It improves the texture of the soil. Wet soil is sticky. Drainage makes this sticky soil crumble and fall apart.
4. It prevents washing.
5. It increases the porosity of soils and permits roots to go deeper into the soil for food and moisture.
6. It increases the warmth of the soil.
7. It permits earlier working in spring and after rains.
[Illustration: FIG. 9. LAYING A TILE DRAIN]
8. It favors the growth of germs which change the unavailable nitrogen of the soil into nitrates; that is, into the form of nitrogen most useful to plants.
9. It enables plants to resist drought better because the roots go into the ground deeper early in the season.
A soil that is hard and wet will not grow good crops. The nitrogen-gathering crops will store the greatest quantity of nitrogen in the soil when the soil is open to the free circulation of the air. These valuable crops cannot do this when the soil is wet and cold.
Sandy soils with sandy subsoils do not often need drainage; such soils are naturally drained. With clay soils it is different. It is very important to remove the stagnant water in them and to let the air in.
When land has been properly drained the other steps in improvement are easily taken. After soil has been dried and mellowed by proper drainage, then commercial fertilizers, barnyard manure, cowpeas, and clover can most readily do their great work of improving the texture of the soil and of making it fitter for plant growth.
[Illustration: FIG. 10. A TILE IN POSITION]
=Tile Drains.= Tile drains are the best and cheapest that can be used. It would not be too strong to say that draining by tiles