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

water. Swamps often receive the washings of adjacent hills; and, in these cases, their soil is derived from a foreign source.

We might continue to enumerate instances of the relations between soils and the sources whence they originated, thus demonstrating more fully the importance of geology to the farmer; but it would be beyond the scope of this work, and should be investigated by scholars more advanced than those who are studying merely the elements of agricultural science.

SECTION 2 (THE SOIL) CHAPTER I (FORMATION AND CHARACTER OF THE SOIL) Pg 65

 

The mind, in its early application to any branch of study, should not be charged with intricate subjects. It should master well the rudiments, before investigating those matters which should follow such understanding.

[In what light will plants and soils be regarded by those who understand them?]

By pursuing the proper course, it is easy to learn all that is necessary to form a good foundation for a thorough acquaintance with the subject. If this foundation is laid thoroughly, the learner will regard plants and soils as old acquaintances, with whose formation and properties he is as familiar as with the construction of a building or simple machine. A simple spear of grass will become an object of interest, forming itself into a perfect plant, with full development of roots, stem, leaves, and seeds, by processes with which he feels acquainted. The soil will cease to be mere dirt; it will be viewed as a compound substance, whose composition is a matter of interest, and whose care is productive of intellectual pleasure. The commencement of study in any science must necessarily be wearisome to the young mind, but its more advanced stages amply repay the trouble of early exertions.

FOOTNOTES Pg 66

 

[M] The spaces between the particles.

[N] In very many instances the crevices and seams of rocks are permeated by roots, which, by decaying and thus inducing the growth of other roots, cause these crevices to become filled with organic matter. This, by the absorption of moisture, may expand with sufficient power to burst the rock.

[O] Some rocks contain sulphur, phosphorus, etc., and these may, perhaps, be considered as organic matter.

[P] These distinctions are not essential to be learned, but are often convenient.

SECTION 2 (THE SOIL) CHAPTER II (USES OF ORGANIC MATTER) Pg 67

 

[What proportion of organic matter is required for fertility?

How does the soil obtain its organic matter?

How does the growth of clover, etc., affect the soil?]

It will be recollected that, in addition to its mineral portions, the soil contains organic matter in varied quantities. It may be fertile with but one and a half per cent. of organic matter, and some peaty soils contain more than fifty per cent. or more than one half of the whole.

The precise amount necessary cannot be fixed at any particular sum; perhaps five parts in a hundred would be as good a quantity as could be recommended.

The soil obtains its organic matter in two ways. First, by the decay of roots and dead plants, also of leaves, which have been brought to it by wind, etc. Second, by the application of organic manures.

[When organic matter decays in the soil, what becomes of it?

Is charcoal taken up by plants?

Are humus and humic acid of great practical importance?]

When a crop of clover is raised, it obtains its carbon from the atmosphere; and, if it be plowed under, and allowed to decay, a portion of this carbon is deposited in the soil. Carbon constitutes nearly the whole of the dry weight of the clover, aside from the constituents of water; and, when we calculate the immense quantity of hay, and roots grown on an acre of soil in a single season, we shall find that the amount of carbon thus deposited is immense. If the clover had been removed, and the roots only left to decay, the amount of carbon deposited would still have been very great. The same is true in all cases where the crop is removed, and the roots remain to form the organic or vegetable part of the soil. While undergoing decomposition, a portion of this matter escapes in the form of gas, and the remainder chiefly assumes the form of carbon (or charcoal), in which form it will always remain, without loss, unless driven out by fire. If a bushel of charcoal be mixed with the soil now, it will be the same bushel of charcoal, neither more nor less, a thousand years hence, unless some influence is brought to bear on it aside from the growth of plants.

SECTION 2 (THE SOIL) CHAPTER II (USES OF ORGANIC MATTER) Pg 68

 

It is true that, in the case of the decomposition of organic matter in the soil, certain compounds are formed, known under the general names of humus and humic acid, which may, in a slight degree, affect the growth of plants, but their practical importance is of too doubtful a character to justify us in considering them. The application of manures, containing organic matter, such as peat, muck, animal manure, etc., supplies the soil with carbon on the same principle, and the decomposing matters also generate[Q] carbonic acid gas while being decomposed. The agricultural value of carbon in the soil depends (as we have stated), not on the fact that it enters into the composition of plants, but on certain other important offices which it performs, as follows:--

[On what does the agricultural value of the carbon in the soil depend?

Why does it make the soil more retentive of manure?

What is the experiment with the barrels of sand?]

It makes the soil more retentive of manures. It causes it to appropriate larger quantities of the fertilizing gases of the atmosphere. It gives it greater power to absorb moisture. It renders it warmer. Carbon (or charcoal) makes the soil retentive of manures, because it has in itself a strong power to absorb, and retain[R] fertilizing matters. There is a simple experiment by which this power can be shown. SECTION 2 (THE SOIL) CHAPTER II (USES OF ORGANIC MATTER) Pg 69

 

Ex.--Take two barrels of pure beach sand, and mix with the sand in one barrel a few handfuls of charcoal dust, leaving that in the other pure. Pour the brown liquor of the barn-yard through the pure sand, and it will pass out at the bottom unaltered. Pour the same liquor through the barrel, containing the charcoal, and pure water will be obtained as a result. The reason for this is that the charcoal retains all of the impurities of the liquor, and allows only the water to pass through. Charcoal is often employed to purify water for drinking, or for manufacturing purposes.

[Will charcoal purify water?

If a piece of tainted meat, or a fishy duck be buried in a rich garden soil, what takes place?

What is the reason of this?

How does charcoal overcome offensive odors?

How can you prove that charcoal absorbs the mineral impurities of water?]

A rich garden-soil contains large quantities of carbonaceous matter; and, if we bury in such a soil a piece of tainted meat or a fishy duck, it will, in a short time, be deprived of its odor, because the charcoal in the soil will entirely absorb it.

Carbon absorbs gases as well as the impurities of water; and, if a little charcoal be sprinkled over manure, or any other substance, emitting offensive odors, the gases escaping will be taken up by the charcoal, and the odor will cease.

SECTION 2 (THE SOIL) CHAPTER II (USES OF ORGANIC MATTER) Pg 70

 

It has also the power of absorbing