CHAPTER IV.

THE SOIL.

INTRODUCTORY.

THE great prairie plow turns over the sod upon which the grass has grown and the wild flowers have bloomed for ages. The farmer plants the corn and sows the wheat, and receives rich returns for his labor. But as the seasons pass, the blades become slender and the stalks small; the ears are no longer large, nor the grains plump and round.

Let us reflect. The grass that waved in the sun of many summers fell each year upon the earth, and strengthened the bosom that nourished it. The flowers that nodded upon the plains, and gave their perfume to the soft air, perished only to give strength and beauty to others of fairer form and sweeter fragrance.

The generous soil has been giving to the farmer, in corn and cotton, the rich stores gathered from blade and flower. These rich gifts have been changed into ear and pod, that the farmer has been yearly gathering.

There is a great law that must be applied here.

It is called the law of compensation. Since the soil has given of her stored wealth, an equivalent must be given to her, or her storehouse becomes empty and her power exhausted.

It has taken much thought, and many years of experience, to learn what may be returned to the soil to repair the drain upon its natural supplies. The proper rotation of crops, the application of needed food supplies, the periods of rest and proper cultivation, are all subjects of the deepest interest, and are considered in the following lessons.

LESSON XV.

STORY OF THE SOIL.

I.

"Father, where did all the land come from?" Henry Patterson asked this question of his father, as they sat on the porch together one summer evening, after the day's work was done.

"Well, Henry," said Mr. Patterson, "that depends. It depends, in the first place, upon what you mean by 'land.' By the word 'land' do you mean all the earth's crust that is not water? You know that the earth's crust is said to be composed of land and water; but the word 'land' when thus used includes the rocky part of the earth's crust as well as the part that is often referred to as soil."

Henry said that by the word "land" he had meant the part that he supposed should be called earth. "Yes," said Mr. Patterson, "I understand now what you mean. By the word 'land' you mean the soil. I will tell you about it as well as I can. Much of the earth's surface that is now dry land was at one time covered with shallow waters-shallow seas. These shallow waters teemed with low forms of animal and vegetable life. As these animals, mosses, and sea-weeds died, their remains

sank -- built up from the bottom — and gradually the earth's crust became thicker in places.

"In time, mountain ranges were formed, and the action of the air and the rain, the sun and the frosts, caused the rocks thus exposed to crumble, and water carried the crumbled rocks from the high places down into the low places. Sea-weeds and sea-mosses grew and decayed with the mass thus deposited; then other plants grew as this mass became enriched by the decay of animal and vegetable life, and in time plants grew in great numbers. Vast forests were buried by floods, and these buried forests were burned into beds of coal by confined heat, just as a stick of wood is changed to charcoal in a stove or in a charcoal pit.

"The air and water, heat and cold, crumbled other rocks, and the crumbled particles, mingled with decayed vegetable and animal remains were carried down by water, and other layers of soil were formed on top of the coal beds and elsewhere. Largely in this way, as the ages have gone by, the layers of soil have been formed by time and tide, life and death, growth and decay.

"This work is still going on. Rocks crumble, or by friction are ground into fine particles; plants convert a portion of this mass into leaves, stems,

and fruit; animals eat the plants, and they are changed to flesh, and finally all these bodies go back to the soil, or to dust whence they came."

2.

Henry was much interested in all this, for he had not before thought much about it.

"You see, then," Mr. Patterson went on, "that soils are composed of two general classes of elements or matter, the one class being the rock materials, and often called inorganic; the other being the decayed remains of animal and plant life, often called organic matter."

To help Henry to get this information clearly fixed in his mind, Mr. Patterson made the following diagram:

1. Soil is composed of

1. Inorganic matter, such as

(a) Silicon, (b) aluminium, (c) lime, (d) sodium, (e) potassium, (ƒ) sulphur, (g) iron, (h) magnesia, etc.

2. Organic matter, as

(a) Remains of animals, (b) remains of plants.

"You have no doubt noticed," continued Mr. Patterson, "that the upper part of the soil in many

localities is dark in color. This dark soil is largely