The Elements of Agriculture A Book for Young Farmers, with Questions Prepared for the Use of Schools - George E. Waring (bill gates books to read txt) 📗

 

The stems, roots, branches, etc., of most plants consist principally of woody fibre.

Their seeds, and sometimes their roots, contain considerable quantities of starch.

[Name the parts of the plant in which the different proximates exist.

State what you know about flour.

Do we know that different plants have ashes of different composition?]

The protein and the oils of most plants exist most largely in the seeds.

The location of the proximates, as well as of the inorganic parts of the plant, show a remarkable reference to the purposes of growth, and to the wants of the animal world, as is noticed in the difference between the construction of the straw and that of the kernel of wheat.

The reason why the fine flour now made is not so healthfully nutritious as that which contained more of the coarse portions, is that it is robbed of a large proportion of protein and phosphate of lime, while it contains an undue amount of starch, which is available only to form fat, and to supply fuel to the lungs.

SECTION 1 (THE PLANT) CHAPTER VIII (RECAPITULATION) Pg 55

Different plants have ashes of different composition. Thus--one may take from the soil large quantities of potash, another of phosphoric acid, and another of lime.

By understanding these differences, we shall be able so to regulate our rotations, that the soil may not be called on to supply more of one ingredient than of another, and thus it may be kept in balance.

[How are farmers to be benefited by such knowledge?]

The facts contained in this chapter are the alphabet of agriculture, and the learner should not only become perfectly familiar with them, but should also clearly understand the reasons why they are true, before proceeding further.

SECTION 2 (THE SOIL) CHAPTER I (FORMATION AND CHARACTER OF THE SOIL) Pg 56

[What is a necessary condition of growth?]

In the foregoing section, we have studied the character of plants and the laws which govern their growth. We learned that one necessary condition for growth is a fertile soil, and therefore we will examine the nature of different soils, in order that we may understand the relations between them and plants.

[What is a fixed character of soils?

How is the chemical character of the soil to be ascertained?

What do we first learn in analyzing a soil?

How do the proportions of organic or inorganic parts of soils compare with those of plants?

Of what does the organic part of soils consist?]

The soil is not to be regarded as a mysterious mass of dirt, whereon crops are produced by a mysterious process. Well ascertained scientific knowledge has proved beyond question that all soils, whether in America or Asia, whether in Maine or California, have certain fixed properties, which render them fertile or barren, and the science of agriculture is able to point out these characteristics in all cases, so that we can ascertain from a scientific investigation what would be the chances for success in cultivating any soil which we examine.

The soil is a great chemical compound, and its chemical character is ascertained (as in the case of plants) by analyzing it, or taking it apart.

We first learn that fertile soils contain both organic and inorganic matter; but, unlike the plant, they usually possess much more of the latter than of the former.

In the plant, the organic matter constitutes the most considerable portion of the whole. In the soil, on the contrary, it usually exists in very small quantities, while the inorganic portions constitute nearly the whole bulk.

SECTION 2 (THE SOIL) CHAPTER I (FORMATION AND CHARACTER OF THE SOIL) Pg 57

 

[Can the required proportion be definitely indicated?

From what source is the inorganic part of soils derived?

Do all soils decompose with equal facility?

How does frost affect rocks?

Does it affect soils in the same way?]

The organic part of soils consists of the same materials that constitute the organic part of the plants, and it is in reality decayed vegetable and animal matter. It is not necessary that this organic part of the soil should form any particular proportion of the whole, and indeed we find it varying from one and a half to fifty, and sometimes, in peaty soils, to over seventy per cent. All fertile soils contain some organic matter, although it seems to make but little difference in fertility, whether it be ten or fifty per cent.

The inorganic part of soils is derived from the crumbling of rocks. Some rocks (such as the slates in Central New York) decompose, and crumble rapidly on being exposed to the weather; while granite, marble, and other rocks will last for a long time without perceptible change. The causes of this crumbling are various, and are not unimportant to the agriculturist; as by the same processes by which his soil was formed, he can increase its depth, or otherwise improve it. This being the case, we will in a few words explain some of the principal pulverizing agents.

SECTION 2 (THE SOIL) CHAPTER I (FORMATION AND CHARACTER OF THE SOIL) Pg 58

 

The action of frost. When water lodges in the crevices of rocks, and freezes, it expands, and bursts the rock, on the same principle as causes it to break a pitcher in winter. This power is very great, and by its assistance, large cannon may be burst. Of course the action of frost is the same on a small scale as when applied to large masses of matter, and, therefore, we find that when water freezes in the pores[M] of rocks or stones, it separates their particles and causes them to crumble. The same rule holds true with regard to stiff clay soils. If they are ridged in autumn, and left with a rough surface exposed to the frosts of winter, they will become much lighter, and can afterwards be worked with less difficulty.

[What is the effect of water on certain rocks?

How are some rocks affected by exposure to the atmosphere? Give an instance of this.]

The action of water. Many kinds of rock become so soft on being soaked with water, that they readily crumble. The chemical changes of the constituents of the rock. Many kinds of rock are affected by exposure to the atmosphere, in such a manner, that changes take place in their chemical character, and cause them to fall to pieces. The red kellis of New Jersey (a species of sandstone), is, when first quarried, a very hard stone, but on exposure to the influences of the atmosphere, it becomes so soft that it may be easily crushed between the thumb and finger. SECTION 2 (THE SOIL) CHAPTER I (FORMATION AND CHARACTER OF THE SOIL) Pg 59

 

[What is the similarity between the composition of soils and the rocks from which they were formed?

What does feldspar rock yield? Talcose slate? Marls?

Does a soil formed entirely from rock contain organic matter?

How is it affected by the growth of plants?]

Other actions, of a less simple kind, exert an influence on the stubbornness of rocks, and cause them to be resolved into soils.[N] Of course, the composition of the soil must be similar to that of the rock from which it was formed; and, consequently, if we know the chemical character of the rock, we can tell whether the soil formed from it can be brought under profitable cultivation. Thus feldspar, on being pulverized, yields potash; talcose slate yields magnesia; marls yield lime, etc.

The soil formed entirely from rock, contains, of course, no organic matter.[O] Still it is capable of bearing plants of a certain class, and when these die, they are deposited in the soil, and thus form its organic portions, rendering it capable of supporting those plants which furnish food for animals. Thousands of years must have been occupied in preparing the earth for habitation by man.

As the inorganic or mineral part of the soil is usually the largest, we will consider it first.

As we have stated that this portion is formed from rocks, we will examine their character, with a view to showing the different qualities of soils.