The Elements of Agriculture A Book for Young Farmers, with Questions Prepared for the Use of Schools, George E. Waring [read aloud books TXT] 📗

the stools (or clumps of tillers), come in contact with an uncongenial part of the soil, when the tillering ceases; the stools become extinct on the death of their plants, and the grasses run out.

The open and healthy condition of soil produced by draining prevents the tillering from being stopped, and thus keeps up a full growth of grass until the nutriment of the soil is exhausted.

Draining enables us to deepen the surface-soil, because the admission of air and the decay of roots render the condition of the subsoil such that it may be brought up and mixed with the surface-soil, without injuring its quality.

The second class of advantages of under-draining, arising in the removal of the excess of water in the soil, are quite as important as those just described.

SECTION 4 (MECHANICAL CULTIVATION) CHAPTER III (ADVANTAGES OF UNDER-DRAINING) Pg 205

 

[How does the removal of water render soils earlier in spring?

Why does it prevent the throwing out of grain in winter?

Why does it enable us to work sooner after rains?

Why does it keep off the effects of cold weather longer in the fall?]

Soils are, thereby, rendered earlier in spring, because the water, which rendered them cold, heavy, and untillable, is earlier removed, leaving them earlier in a growing condition. The throwing out of grain in winter is prevented, because the water falling on the earth is immediately removed instead of remaining to throw up the soil by freezing, as it always does from the upright position taken by the particles of ice. We are enabled to work sooner after rains, because the water descends, and is immediately removed instead of lying to be taken off by the slow process of evaporation, and sinking through a heavy soil. The effects of cold weather are kept off longer in the fall, because the excess of water is removed, which would produce an unfertile condition on the first appearance of cold weather.

The drains also, from causes already named (3), keep the soil warmer than before being drained, thus actually lengthening the season, by making the soil warm enough for vegetable growth earlier in spring, and later in autumn.

[How does it prevent lands from becoming sour?

Why does it hasten the decay of roots, and the comminution of mineral matters?

How does it prevent the abstraction of heat from the soil?]

15. Lands are prevented from becoming sour by the formation of acetic acid, etc., because these acids are produced in the soil only when the decomposition of organic matter is arrested by the antiseptic (preserving) powers of water.

SECTION 4 (MECHANICAL CULTIVATION) CHAPTER III (ADVANTAGES OF UNDER-DRAINING) Pg 206

 

If the water is removed, the decomposition of the organic matter assumes a healthy form, while the acids already produced are neutralized by atmospheric influences, and the soil is restored from sorrel to a condition in which it is fitted for the growth of more valuable plants.

The decay of roots, etc., is allowed to proceed, because the preservative influence of too much water is removed. Wood, leaves, or other vegetable matter kept continually under water, will last for ages; while, if exposed to the action of the weather, as in under-drained soils, they soon decay.

The presence of too much water, by excluding the oxygen of the air, prevents the comminution of matters necessary to fertility.

[How much heat does water take up in becoming vapor?

Why does water sprinkled on a floor render it cooler?

Why is not a cubic inch of vapor warmer than a cubic inch of water?

Why does a wet cloth on the head make it cooler when fanned?

How does this principle apply to the soil?]

The evaporation of water, and the consequent abstraction of heat from the soil, is in a great measure prevented by draining the water out at the bottom of the soil, instead of leaving it to be dried off from the surface. SECTION 4 (MECHANICAL CULTIVATION) CHAPTER III (ADVANTAGES OF UNDER-DRAINING) Pg 207

 

When water assumes the gaseous (or vapory) form, it takes up 1723 times as much heat as it contained while a liquid. A large part of this heat is derived from surrounding substances. When water is sprinkled on the floor, it cools the room; because, as it becomes a vapor, it takes heat from the room. The reason why vapor does not feel hotter than liquid water is, that, while it contains 1723 times as much heat, it is 1723 as large. Hence, a cubic inch of vapor, into which we place the bulb of a thermometer, contains no more heat than a cubic inch of water. The principle is the same in some other cases. A sponge containing a table-spoonful of water is just as wet as one twice as large and containing two spoonsful.

If a wet cloth be placed on the head, and the evaporation of its water assisted by fanning, the head becomes cooler--a portion of its heat being taken to sustain the vapory condition of the water.

The same principle holds true with the soil. When the evaporation of water is rapidly going on, by the assistance of the sun, wind, etc., a large quantity of heat is abstracted, and the soil becomes cold.

When there is no evaporation taking place, except of water which has been deposited on the lower portions of soil, and carried to the surface by capillary attraction (as is nearly true on under-drained soils), the loss of heat is compensated by that taken from the moisture in the atmosphere by the soil, in the above-named manner.

SECTION 4 (MECHANICAL CULTIVATION) CHAPTER III (ADVANTAGES OF UNDER-DRAINING) Pg 208

 

This cooling of the soil by the evaporation of water, is of very great injury to its powers of producing crops, and the fact that under-drains avoid it, is one of the best arguments in favor of their use. Some idea may, perhaps, be formed of the amount of heat taken from the soil in this way, from the fact that, in midsummer, 25 hogsheads of water may be evaporated from a single acre in twelve hours.

[When rains are allowed to enter the soil, how do they benefit it?

How do under-drains prevent the formation of a crust on the surface of a soil?]

When not saturated with water the soil admits the water of rains, etc., which bring with them fertilizing gases from the atmosphere, to be deposited among the absorbent parts of soil, and given up to the necessities of the plant. When this rain falls on lands already saturated, it cannot enter the soil, but must run off from the surface, or be removed by evaporation, either of which is injurious. The first, because fertilizing matter is washed away. The second, because the soil is deprived of necessary heat.

19. The formation of crust on the surface of the soil is due to the evaporation of water, which is drawn up from below by capillary attraction. It arises from the fact that the water in the soil is saturated with mineral substances, which it leaves at its point of evaporation at the surface.

SECTION 4 (MECHANICAL CULTIVATION) CHAPTER III (ADVANTAGES OF UNDER-DRAINING) Pg 209

 

This soluble matter from below, often forms a very hard crust, which is a complete shield to prevent the admission of air with its ameliorating effects, and should, as far as possible, be avoided. Under-draining is the best means of doing this, as it is the best means of lessening the evaporation.

The foregoing are some of the more important reasons why under-draining is always beneficial. Thorough experiments have amply proved the truth of the theory.

[What kinds of soil are benefited by under-draining?]

The kinds of soil benefited by under-draining are nearly as unlimited as the kinds of soil in existence. It is a common opinion, among farmers, that the only soils which require draining are those which are at times covered with water, such as swamps and other low lands; but the facts stated in the early part of this chapter, show us that every kind of soil--wet, dry, compact, or light--receives benefit from the treatment. The fact that land is too dry, is as much a reason why it should be drained, as that it is too wet, as it overcomes drought as effectually as it removes the injurious effects of too much water.

All soils in which the water of heavy rains does not immediately pass down to