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The Beginning Of Soil

Soil beginnings come from rock together with animal and vegetable decay during long stretches or periods of time when great rock masses were crumbling and breaking up due to external forces. Heat, water and wind action, and friction were largely responsible for this. By friction here is meant the rubbing and grinding of rock mass against rock mass at plate boundaries. Plates sit on the molten earth core and contain this molten material until a weak spot in the earth's crust develops such as a volcano. These huge rock boundaries are bumping, scraping, grinding and settling against one another. This is what happens: bits of rock are worn off due to this scraping and are moved by wind or water action. This ground up rock material is then blended with decaying organic material and forms soil.

Changes in temperature over millions of years added to the cracking, the crumbling, the upheavals that help produce soil. You know some of the effects in winter of sudden freezes and thaws. Small examples of bursting water pipes and broken pitchers are like nothing to what was happening in the world during those days. The water and the wind in the atmosphere helped along this crumbling work.

From all this action of rubbing, which action mechanism we'll call mechanical, it is easy enough to understand how sand was formed. This represents one of the great divisions of sandy soil. The sea shores are great masses of pure sand. If soil were nothing but broken rock masses then indeed it would be very poor and unproductive. But the early forms of animal and vegetable life decaying became a part of the rock mass and a soil useful for growing plants and vegetables resulted. So the soils we speak of as sandy soils have mixed with the sand other matter, sometimes clay, sometimes vegetable matter or humus, and often animal waste.

Clay brings us right to a second class of soils - clayey soils. It happens that certain portions of rock masses became dissolved when water trickled over them and heat was plentiful. This dissolution took place largely because there is in the air a certain gas called carbon dioxide or carbonic acid gas. This gas attacks and changes certain substances in rocks. It changes this rock substance into something else which we call clay. This is not a mechanical change, but a chemical one instead. The difference in the two kinds of change is just this: in the one case of sand, where a mechanical change went on, you still have the same material that you started with, except that the size of the mass is smaller. You started with a large rock, and ended with little particles of sand. But you had no different variety of rock in the end. Mechanical action may be illustrated with a piece of lump sugar with the sugar representing a big mass of rock. Pulverize the sugar, and even the smallest bit is sugar. It is the same with the rock mass; but in the case of a chemical change you start with one material and end with another. You started with a mass of rock which had in it a portion that became changed by the acid acting on it. It ended in being an entirely different material which we call clay. So in the case of chemical change a certain material is started with and in the end we have an entirely different item. The clay soils are often called mud soils because of the amount of water used in their formation.

The third type soil that people wanting to farm have to deal with is lime soil. We are thinking of soils from the farming point of view. This soil was naturally formed from limestone. Ages ago the lower animal and plant forms picked up particles of lime from the water . They used the lime to form skeletons or shells about themselves as protection from larger animals. Coral is an example of this class of skeleton-forming animal.

As the animal died the skeleton remained. Great masses of this living matter pressed all together, after ages, formed limestone. Some limestones are still in such shape that the shelly formation is still visible. Marble, another limestone, is somewhat crystalline in character. Another well-known limestone is chalk. Perhaps you'd like to know a way of always being able to tell limestone. Drop a little bit of an acid on some lime. See how it bubbles and fizzles. Then drop some on the chalk and on the marble, also. The same bubbling takes place. So lime must be in these three different material structures. You do not have to buy a special acid for this work, for even household acids like vinegar will cause the same result.

Then these are the three primary types of soil with which the farmer has to deal with. When you know your garden soil by studying it, you will learn how to prepare it properly for the type of plants that you intend to grow.