How may it obtain heat?What is the use of the air circulating among its particles?Could most soils be brought to the highest state of fertility?What is the first thing to be done?Should its color be darkened?
How may it obtain heat?
What is the use of the air circulating among its particles?
Could most soils be brought to the highest state of fertility?
What is the first thing to be done?
Should its color be darkened?
4. It absorbs heat from the sun's rays to assist in the process of growth.
5. It admits air to circulate among roots, and supply them with a part of their food, while the oxygen of that air renders available the minerals of the soil; and its carbonic acid, being absorbed by the water in the soil, gives it the power of dissolving, and carrying into roots more inorganic matter than would be contained in purer water.
6. It allows the excrementitious matter thrown out by roots to be carried out of their reach.
All of these actions the soil must be capable of performing, before it can be in its highest state of fertility. There are comparatively few soils now in this condition, but there are also few which could not be profitably rendered so, by a judicious application of the modes of cultivation to be described in the following chapters.
The three great objects to be accomplished are:—
1. To adopt such a system of drainage as will cause all of the water of rains to passthroughthe soil, instead of evaporating from the surface.
2. To pulverize the soil to a considerable depth.
3. To darken its color, and render it capable of absorbing atmospheric fertilizers.
Name some of the means used to secure these effects.Why are under-drains superior to open drains?
Name some of the means used to secure these effects.
Why are under-drains superior to open drains?
The means used to secure these effects areunder-draining, sub-soil and surface-plowing, digging, applying muck, etc.
The advantages ofunder-drains overopendrains are very great.
When open drains are used, much water passes into them immediately from the surface, and carries with it fertilizing parts of the soil, while their beds are often compacted by the running water and the heat of the sun, so that they become water tight, and do not admit water from the lower parts of the soil.
The sides of these drains are often covered with weeds, which spread their seeds throughout the whole field. Open drains are not only a great obstruction to the proper cultivation of the land, but they cause much waste of room, as we can rarely plow nearer than within six or eight feet of them.
There are none of these objections to the use of under-drains, as these are completely covered, anddo not at all interfere with the cultivation of the surface.
With what materials may under-drains be constructed?Describe the tile.
With what materials may under-drains be constructed?
Describe the tile.
Under drains may be made with brush, stones, or tiles. Brush is a very poor material, and its use is hardly to be recommended. Small stones are better, and if these be placed in the bottoms of the trenches, to a depth of eight or ten inches, and covered with sods turned upside down, having the earth packed well down on to them, they make very good drains.
The best under-drains are those made with tiles, or burnt clay pipes. The first form of these used was that called thehorse-shoe tile, which was in two distinct pieces; this was superseded by a round pipe, and we have now what is called thesole tile, which is much better than either of the others.
Fig. 4-Sole Tile.Fig. 4—Sole Tile.
Why is the sole tile superior to those of previous construction?How are these tiles laid?How may the trenches be dug?
Why is the sole tile superior to those of previous construction?
How are these tiles laid?
How may the trenches be dug?
This tile is made (like the horse-shoe and pipe tile) of common brick clay, and is burned the same as bricks. It is about one half or three quarters of an inch thick, and is so porous that water passes directly through it. It has a flat bottom on which to stand, and this enables it to retain its position, while making the drain, better than would be done by the round pipe. The orifice through which the water passes is egg-shaped, having its smallest curve at the bottom. This shape is the one most easily kept clear, as any particles of dirt which get into the drain must fall immediately to the point where even the smallest stream of water runs, and are thus removed. An orifice of about two inches is sufficient for the smaller drains, while the main drains require larger tiles.
These tiles are laid, so that their ends will touch each other, on the bottoms of the trenches, and are kept in position by having the earth tightly packed around them. Care must be taken that no space is left between the ends of the tiles, as dirt would be liable to get in and choke the drain. It is advisable to place a sod—grass side down—over each joint, before filling the trench, as this more effectually protects them against the entrance of dirt. There is no danger of keeping the water out by this operation, as it will readily pass through any part of the tiles.
Fig. 5.Upton tool. Spade and hoe.Upton tool.Spade and hoe.
Upton tool.
Spade and hoe.
Indigging the trenchesit is not necessary (except in very stony ground) to dig out a place wide enough for a man to stand in, as there are tools made expressly for the purpose, by which a trench may bedug six or seven inches wide, and to any required depth. One set of these implements consists of a long narrow spade and a hoe to correspond, such as are represented in the accompanying figure.
With these tools, and a long light crowbar, for hard soils, trenches may be dug much more cheaply than with the common spade and pickaxe. Where there are large boulders in the soil, these draining tools may dig under them so that they will not have to be removed.
When the trenches are dug to a sufficient depth, the bottoms must be made perfectly smooth, with the required descent (from six inches to a few feet in one hundred feet). Then the tiles may be laid in, so that their ends will correspond, be packed down, and the trenches filled up. Such a drain, if properly constructed, may last for ages. Unlike the stone drain, it is not liable to be frequented by rats, nor choked up by the soil working into it.
The position of the tile may be best represented by a figure, also the mode of constructing stone drains.
Why are small stones better than large stones in the construction of drains?On what must the depth of under-drains depend?
Why are small stones better than large stones in the construction of drains?
On what must the depth of under-drains depend?
It will be seen that the tile drain is made with much less labor than the stone drain, as it requires less digging, while the breaking up of the stone for the stone drain will be nearly, or quite as expensive as the tiles. Drains made with large stones are not nearly so good as with small ones, because they are more liable to be choked up by animals working in them.[AK]
Fig. 6.a-Tile drain trench. b-Stone drain trench. c-Sod laid on the stone.a—Tile drain trench.b—Stone drain trench.c—Sod laid on the stone.
Describe the principle which regulates these relative depths and distances. (Blackboard.)Which is usually the cheaper plan of constructing drains?
Describe the principle which regulates these relative depths and distances. (Blackboard.)
Which is usually the cheaper plan of constructing drains?
Thedepthof the drains must depend on the distances at which they are placed. If buttwentyfeet apart, they need be butthreefeet deep; while, if they areeightyfeet apart, they must befivefeet deep, to produce the same effect. The reason for this is, that the water in the drained soil is not level, but is higher midway between the drains, than at any other point. It is necessary that this highest point should be sufficiently far from the surface not to interfere with the roots of plants, consequently, as the water line between two drains iscurved, themost distant drains must be the deepest. This will be understood by referring to the following diagram.
Fig. 7.aa-5 feet drains, 80 ft. apart. bb-3 feet drains, 20 ft. apart.aa—5 feet drains, 80 ft. apart. bb—3 feet drains, 20 ft. apart.
The curved line represents the position of the water.
In most soils it will be easier to dig one trench five feet deep, than four trenches three feet deep, and the deep trenches will be equally beneficial; but where the soil is very hard below a depth of three feet, the shallow trenches will be the cheapest, and in such soils they will often be better, as the hard mass might not allow the water to pass down to enter the deeper drains.
By following out these instructions, land may be cheaply, thoroughly, and permanently drained.
FOOTNOTES:[AK]It is probable that a composition of hydraulic cement and some soluble material will be invented, by which a continuous pipe may be laid in the bottoms of trenches, becoming porous as the soluble material is removed by water.
[AK]It is probable that a composition of hydraulic cement and some soluble material will be invented, by which a continuous pipe may be laid in the bottoms of trenches, becoming porous as the soluble material is removed by water.
[AK]It is probable that a composition of hydraulic cement and some soluble material will be invented, by which a continuous pipe may be laid in the bottoms of trenches, becoming porous as the soluble material is removed by water.
The advantages of under-draining are many and important.
1. It entirely prevents drought.
2. It furnishes an increased supply of atmospheric fertilizers.
3. It warms the lower portions of the soil.
4. It hastens the decomposition of roots and other organic matter.
5. It accelerates the disintegration of the mineral matters in the soil.
6. It causes a more even distribution of nutritious matters among those parts of soil traversed by roots.
7. It improves the mechanical texture of the soil.
8. It causes the poisonous excrementitious matter of plants to be carried out of the reach of their roots.
9. It prevents grasses from running out.
10. It enables us to deepen the surface soil.
By removing excess of water—
11. It renders soils earlier in the spring.
12. It prevents the throwing out of grain in winter.
13. It allows us to work sooner after rains.
14. It keeps off the effects of cold weather longer in the fall.
15. It prevents the formation ofaceticand other organic acids, which induce the growth of sorrel and similar weeds.
16. It hastens the decay of vegetable matter, and the finer comminution of the earthy parts of the soil.
17. It prevents, in a great measure, the evaporation of water, and the consequent abstraction of heat from the soil.
18. It admits fresh quantities of water from rains, etc., which are always more or less imbued with the fertilizing gases of the atmosphere, to be deposited among the absorbent parts of soil, and given up to the necessities of plants.
19. It prevents the formation of so hard a crust on the surface of the soil as is customary on heavy lands.
How does under-draining prevent drought?
How does under-draining prevent drought?
1. Under-drainingprevents drought, because it gives a better circulation of air in the soil; (it does so by making it more open). There is always the same amount of waterinandaboutthe surface of the earth. In winter, there is more in the soil than in summer, while in summer, that which has been driedout of the soil exists in the atmosphere in the form of avapor. It is held in the vapory form byheat, which acts asbracesto keep it distended. When vapor comes in contact with substances sufficiently colder than itself, it gives up its heat—thus losing its braces—contracts, and becomes liquid water.
This may be observed in hundreds of common operations.
Why is there less water in the soil in summer than in winter, and where does it exist?What holds it in its vapory form?How is it affected by cold substances?Describe the deposit of moisture on the outside of a pitcher in summer.What other instances of the same action can be named?
Why is there less water in the soil in summer than in winter, and where does it exist?
What holds it in its vapory form?
How is it affected by cold substances?
Describe the deposit of moisture on the outside of a pitcher in summer.
What other instances of the same action can be named?
It is well known that a cold pitcher in summer robs the vapor in the atmosphere of its heat, and causes it to be deposited on its own surface. It looks as though the pitcher weresweating, but the water all comes from the atmosphere, not, of course, through the sides of the pitcher.
If we breathe on a knife-blade, it condenses in the same manner the moisture of the breath, and becomes covered with a film of water.
Stone houses are damp in summer, because the inner surfaces of the walls, being cooler than the atmosphere, cause its moisture to be deposited in the manner described. By leaving a space, however, between the walls and the plaster, this moisture is prevented from being troublesome.
How does this principle affect the soil?Explain the experiment with the two boxes of soil.
How does this principle affect the soil?
Explain the experiment with the two boxes of soil.
Nearly every night in the summer season, the coldearth receives moisture from the atmosphere in the form of dew.
A cabbage, which at night is very cold, condenses water to the amount of a gill or more.
The same operation takes place in the soil. When the air is allowed to circulate among its lower andcoolerparticles, they receive moisture from the same process of condensation. Therefore, when, by the aid of under-drains, the lower soil becomes sufficiently open to admit of a circulation of air, the deposit of atmospheric moisture will keep the soil supplied with water at a point easily accessible to the roots of plants.
If we wish to satisfy ourselves that this ispracticallycorrect, we have only to prepare two boxes of finely pulverized soil, one, five or six inches deep, and the other fifteen or twenty inches deep, and place them in the sun at mid-day in summer. The thinner soil will be completely dried, while the deeper one, though it may have been perfectly dry at first, will soon accumulate a large amount of water on those particles which, being lower and more sheltered from the sun's heat than the particles of the thin soil, are made cooler.
With an open condition of subsoil, then, such as may be secured by under-draining, we entirely overcome drought.
How does under-draining supply to the soil an increased amount of atmospheric fertilizers?How does it warm the lower parts of the soil?
How does under-draining supply to the soil an increased amount of atmospheric fertilizers?
How does it warm the lower parts of the soil?
2. Under-drainingfurnishes an increased supply of atmospheric fertilizers, because it secures a change of air in the soil. This change is produced whenever the soil becomes filled with water, and then dried; when the air above the earth is in rapid motion, and when the comparative temperature of the upper and lower soils changes. It causes new quantities of the ammonia and carbonic acid which it contains to be presented to the absorbent parts of the soil.
3. Under-drainingwarms the lower parts of the soil, because the deposit of moisture (1) is necessarily accompanied by an abstraction of heat from the atmospheric vapor, and because heat is withdrawn from the whole amount of air circulating through the cooler soil.
When rain falls on the parched surface soil, it robs it of a portion of its heat, which is carried down to equalize the temperature for the whole depth. The heat of the rain-water itself is given up to the soil, leaving the water from one to ten degrees cooler, when it passes out of the drains, than when received by the earth.
There is always a current of air passing from the lower to the upper end of a well constructed drain; and this air is always cooler in warm weather, when it issues from, than when it enters the drain. Its lost heat is imparted to the soil.
How does it hasten the decomposition of roots and other organic matter in the soil?How does it accelerate the disintegration of its mineral parts?Why is this disintegration necessary to fertility?
How does it hasten the decomposition of roots and other organic matter in the soil?
How does it accelerate the disintegration of its mineral parts?
Why is this disintegration necessary to fertility?
This heating of the lower soil renders it more favorable to vegetation, partially by expanding the spongioles at the end of the roots, thus enabling them to absorb larger quantities of nutritious matters.
4. Under-draininghastens the decomposition of roots and other organic matters in the soil, by admitting increased quantities of air, thus supplyingoxygen, which is as essential in decay as it is in combustion. It also allows the resultant gases of decomposition to pass away, leaving the air around the decaying substances in a condition to continue the process.
This organic decay, besides its other benefits, produces an amount of heat perfectly perceptible to the smaller roots of plants, though not so to us.
5. Drainingaccelerates the disintegration of the mineral matters in the soil, by admitting water and oxygen to keep up the process. This disintegration is necessary to fertility, because the roots of plants can feed only on matters dissolved fromsurfaces; and the more finely we pulverize the soil, the more surface we expose. For instance, the interior of a stone can furnish no food for plants; while, if it were finely crushed, it might make a fertile soil.
Any thing, tending to open the soil to exposure, facilitates the disintegration of its particles, and thereby increases its fertility.
How does under-draining equalize the distribution of the fertilizing parts of the soil?Why does this distribution lessen the impoverishment of the soil?How does under-draining improve the mechanical texture of the soil?How do drains affect the excrementitious matter of plants?
How does under-draining equalize the distribution of the fertilizing parts of the soil?
Why does this distribution lessen the impoverishment of the soil?
How does under-draining improve the mechanical texture of the soil?
How do drains affect the excrementitious matter of plants?
6. Drainingcauses a more even distribution of nutritious matters among those parts of soil traversed by roots, because it increases the ease with which water travels around, descending by its own weight, moving sideways by a desire to find its level, or carried upward by attraction to supply the evaporation at the surface. By this continued motion of the water, soluble matter of one part of the soil may be carried to some other part; and another constituent from this latter position may be carried back to the former. Thus the food of vegetables is continually circulating around among their roots, ready for absorption at any point where it is needed, while the more open character of the soil enables roots to occupy larger portions, making a more even drain on the whole, and preventing the undue impoverishment of any part.
7. Under-drainsimprove the mechanical texture of the soil; because, by the decomposition of its parts, as previously described (4 and 5), it is rendered of a character to be more easily worked; while smooth round particles, which have a tendency to pack, are roughened by the oxidation of their surfaces, and move less easily among each other.
8. Drainscause the excrementitious matter ofplants to be carried out of the reach of their roots. Nearly all plants return to the soil those parts of their food, which are not adapted to their necessities, and usually in a form that is poisonous to plants of the same kind. In an open soil, this matter may be carried by rains to a point where roots cannot reach it, and where it may undergo such changes as will fit it to be again taken up.
Why do they prevent grasses from running out?
Why do they prevent grasses from running out?
9. By under-draining,grasses are prevented from running out, partly by preventing the accumulation of the poisonous excrementitious matter, and partly because these grasses usually consist oftilleringplants.
These plants continually reproduce themselves in sprouts from the upper parts of their roots. These sprouts become independent plants, and continue to tiller (thus keeping the land supplied with a full growth), until the roots of thestools(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.
10. Drainingenables us to deepen the surface-soil, because the admission of air and the decay of rootsrender the condition of the subsoil such that it may be brought up and mixed with the surface-soil, without injuringits 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.
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?
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?
11.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.
12.The throwing out of grain in winteris 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.
13.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.
14.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?
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 theantiseptic(preserving) powers of water. 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.
16.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 thecomminution of mattersnecessary 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?
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?
17.The evaporation of water, and the consequent abstraction of heat from the soil, is in a great measure preventedby draining the water out at thebottomofthe soil, instead of leaving it to be dried off from the surface.
When water assumes the gaseous (or vapory) form, it takes up 1723 times as muchheatas 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 aswetas 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.
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 toenterthe soil, how do they benefit it?How do under-drains prevent the formation of a crust on the surface of a soil?
When rains are allowed toenterthe soil, how do they benefit it?
How do under-drains prevent the formation of a crust on the surface of a soil?
18. When not saturated with water the soil admits the water of rains, etc., which bring with themfertilizing 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 soilis due to the evaporation of water, which isdrawn 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. 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?
What kinds of soil are benefited by under-draining?
Thekinds of soil benefited by under-drainingare 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 istoo dry, is as much a reason why it should be drained, as that it istoo 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 a depth of at leastthirty inches, should be under-drained, and the operation, if carried on with judgment, would invariably result in profit.
What do English farmers name as the profits of under-draining?What stand has been taken by the English government with regard to under-draining?
What do English farmers name as the profits of under-draining?
What stand has been taken by the English government with regard to under-draining?
Of the preciseprofitsof under-draining this is not the place to speak: many of the agricultural papers contain numerous accounts of its success. It may be well to remark here, that many English farmers give it, as their experience, that under-drains pay for themselves every three years, or that they produce a perpetual profit of 33⅓ per cent., or their original cost. This is not the opinion oftheoristsandbook farmers. It is the conviction of practical men, who know,from experience, that under-drains are beneficial.
The best evidence of the utility of under-draining is the position, with regard to it, which has been taken by the English national government, which affords much protection to the agricultural interests of her people—a protection which in this country is unwisely and unjustly withheld.
In England a very large sum from the public treasury has been appropriated as a fund for loans, on under-drains, which is lent to farmers for the purpose of under-draining their estates, the only security given being the increased value of the soil. The time allowed for payments is twenty years, and only five per cent. interest is charged. By the influenceof this patronage, the actual wealth of the kingdom is being rapidly increased, while the farmers themselves, can raise their farms to any desired state of fertility, without immediate investment.
How does under-draining affect the healthfulness of marshy countries?Describe the sub-soil plow.
How does under-draining affect the healthfulness of marshy countries?
Describe the sub-soil plow.
The best proof that the government has not acted injudiciously in this matter is, that private capitalists are fast employing their money in the same manner, and loans on under-drains are considered a very safe investment.
There is no doubt that we may soon have similar facilities for improving our farms, and when we do, we shall find that it is unnecessary to move West to find good soil. The districts nearer market, where the expense of transportation is much less, may, by the aid of under-drains, and a judicious system of cultivation, be made equally fertile.
One very important, though not strictly agricultural, effect of thorough drainage is its removal of certain local diseases, peculiar to the vicinity of marshy or low moist soils. The health-reports in several places in England, show that wherefever and aguewas once common, it has almost entirely disappeared since the general use of under-drains in those localities.
Describe the Mapes plow.Why is the motion in the soil of one and a half inches sufficient?How does the oxidation of the particles of the soil resemble the rusting of cannon balls in a pile?
Describe the Mapes plow.
Why is the motion in the soil of one and a half inches sufficient?
How does the oxidation of the particles of the soil resemble the rusting of cannon balls in a pile?
Thesub-soil plowis an implement differing in figure from the surface plow. It does not turn a furrow, but merely runs through the subsoil like a mole—loosening and making it finer by lifting, but allowing it to fall back and occupy its former place. It usually follows the surface plow, entering the soil to the depth of from twelve to eighteen inches below the bottom of the surface furrow.
The best pattern now made (the Mapes plow) is represented in the following figure.
Fig. 8.The Mapes plow and its mode of action. a-Shape of the foot of the plow, b-Its effect on the soil.The Mapes plow and its mode of action.a—Shape of the foot of the plow,b—Its effect on the soil.
The sub-soil plows first made raised the whole soil about eight inches, and required very great power in their use often six, eight, or even ten oxen. The Mapes plow, raising the soil but slightly, may be worked with much less power, and produces equally good results. It may be run to its full depth in most soils by a single yoke of oxen.
Of course a motion in the soil of but one and a half inches is very slight, but it is sufficient to move each particle from the one next to it which, in dry soils, is all that is necessary. Whoever has examined a pile of cannon-balls must have observed that at the points where they touch each other, there is a little rust. In the soil, the same is often the case. Where the particles touch each other, there is such a chemical change produced as renders them fit for the use of plants. While these particles remain in their first position, the changed portions are out of the reach of roots; but, if, by the aid of the sub-soil plow, their position is altered, these parts are exposed for the uses of plants. If we hold in the hand a ball of dry clay, and press it hard enough to produce the least motion among its particles, the whole mass becomes pulverized. On the same principle, the sub-soil plow renders the compact lower soil sufficiently fine for the requirements of fertility.
Why are the benefits of sub-soiling not permanent on wet lands?Does sub-soiling overcome drought?How does it deepen the surface soil?
Why are the benefits of sub-soiling not permanent on wet lands?
Does sub-soiling overcome drought?
How does it deepen the surface soil?
Notwithstanding its great benefits on land, which is sufficiently dry, sub-soiling cannot be recommended for wet lands; for, in such case, the rains of a single season would often be sufficient to entirely overcome its effects by packing the subsoil down to its former hardness.
On lands not overcharged with water, it is productive of the best results, it being often sufficient to turn the balance between a gaining and a losing business in farming.
It increases nearly every effect of under-draining; especially does it overcome drought, by loosening the soil, and admitting air to circulate among the particles of the subsoil and deposit its moisture on the principle described in the chapter on under-draining.
It deepens the surface-soil, because it admits roots into the subsoil where they decay and leave carbon, while the circulation of air so affects the mineral parts, that they become of a fertilizing character. The deposit of carbon gives to the subsoil the power of absorbing, and retaining the atmospheric fertilizers, which are more freely presented, owing to the fact that the air is allowed to circulate with greater freedom. As a majority of roots decay in the surface-soil, they there deposit much mineral matter obtained from the subsoil.
Why is the retention of atmospheric manures ensured by sub-soiling?Why are organic manures plowed deeply under the soil, less liable to evaporation than when deposited near the surface?How does sub-soiling resemble under-draining in relation to the tillering of grasses?When the subsoil consists of a thin layer of clay on a sandy bed, what use may be made of the sub-soil plow?
Why is the retention of atmospheric manures ensured by sub-soiling?
Why are organic manures plowed deeply under the soil, less liable to evaporation than when deposited near the surface?
How does sub-soiling resemble under-draining in relation to the tillering of grasses?
When the subsoil consists of a thin layer of clay on a sandy bed, what use may be made of the sub-soil plow?
The retention of atmospheric manures is morefully ensured by the better exposure of the clayey portions of the soil.
Those manures which are artificially applied, by being plowed under to greater depths, are less liable to evaporation, as, from the greater amount of soil above them, their escape will more probably be arrested; and, from the greater prevalence of roots, they are more liable to be taken up by plants.
The subsoil often contains matters which are deficient in the surface-soil. By the use of the sub-soil plow, they are rendered available.
Sub-soiling is similar to under-draining in continuing the tillering of grasses, and in getting rid of the poisonous excrementitious matter of plants.
When the subsoil is a thin layer of clay on a sandy bed (as in some plants of Cumberland Co. Maine), the sub-soil plow, by passing through it, opens a passage for water, and often affords a sufficient drainage.
To how great a depth will the roots of plants usually occupy the soil?What is the object of loosening the soil?How are these various effects better produced in deep than in shallow soils?
To how great a depth will the roots of plants usually occupy the soil?
What is the object of loosening the soil?
How are these various effects better produced in deep than in shallow soils?
If plants will grow better on a soil six inches deep than on one of three inches, there is no reason why they should not be benefited in proportion, by disturbing the soil to the whole depth to which roots will travel—which is usually more than two feet.The minute rootlets of corn and most other plants, will, if allowed by cultivation, occupy the soil to the depth or thirty-four inches, having a fibre in nearly every cubic inch of the soil for the whole distance. There are very few cultivated plants whose roots would not travel to a depth of thirty inches or more. Even the onion sends its roots to the depth of eighteen inches when the soil is well cultivated.
The object of loosening the soil is to admit roots to a sufficient depth to hold the plant in its position—to obtain the nutriment necessary to its growth—to receive moisture from the lower portions of the soil—and, if it be a bulb, tuber, or tap, to assume the form requisite for its largest development.
It must be evident that roots, penetrating the soil to a depth of two feet, anchor the plant with greater stability than those which are spread more thinly near the surface.
The roots of plants traversing the soil to such great distances, and being located in nearly every part, absorb mineral and other food, in solution in water, only through thespongioles at their ends. Consequently, by having these ends inevery partof the soil, it isallbrought under contribution, andthe amount supplied is greater, while the demand on any particular part may be less than when the whole requirements of plants have to be supplied from a depth of a few inches.
May garden soils be profitably imitated in field culture?
May garden soils be profitably imitated in field culture?
The ability of roots, to assume a natural shape in the soil, and grow to their largest sizes, must depend on the condition of the soil. If it is finely pulverized to the whole depth to which they ought to go, they will be fully developed; while, if the soil be too hard for penetration, they will be deformed or small. Thus a carrot may grow to the length of two and a half feet, and be of perfect shape, while, if it meet in its course at a depth of eight or ten inches acold, hardsubsoil, its growth must be arrested, or its form injured.
Roots are turned aside by a hard sub-soil, as they would be if received by the surface of a plate of glass.
Add to this the fact that cold, impenetrable subsoils arechemicallyuncongenial to vegetation, and we have sufficient evidence of the importance, and in many cases the absolute necessity of sub-soiling and under-draining.
It is unnecessary to urge the fact that a garden soil of two feet is more productive than a field soil of six inches; and it is certain that proper attention to these two modes of cultivation will in a majority of cases make a garden of the field—more than doublingits value in ease of working, increased produce, certain security against drought, and more even distribution of the demands on the soil—while the outlay will be immediately repaid by an increase of crops.
Is the use of the sub-soil plow increasing?Will its use ever injure crops?
Is the use of the sub-soil plow increasing?
Will its use ever injure crops?
The subsoil will be much improved in its character the first year, and a continual advancement renders it in time equal to the original surface-soil, and extending to a depth of two feet or more.
The sub-soil plow is coming rapidly into use. There are now in New Jersey more foundries casting sub-soil plows than there were sub-soil plows in the State six years ago. The implement has there, as well as in many other places, ceased to be a curiosity; and the man who now objects to its use, is classed with him who shells his corn on a shovel over a half-bushel, instead of employing an improved machine, which will enable him to do more in a day than he can do in the "good old way" in a week.
Had we space, we might give many instances of the success of sub-soiling, but the agricultural papers of the present day (at least one of which every farmer should take) have so repeatedly published its advantages, that we will not do so.
In no case will its use be found any thing but satisfactory, except in occasional instances where there is some chemical difficulty in the subsoil, which an analysis will tell us how to overcome.
As was before stated, its use on wet lands is not advisable until they have been under-drained, as excess of water prevents its effects from being permanent.