People's Pilot, Volume 4, Number 33, Rensselaer, Jasper County, 2 February 1895 — PROF. A. H. PURDUE, [ARTICLE]

PROF. A. H. PURDUE,

Principal of tire Rentt><dacr High School, Presen U a Thoroughly Interesting; SCIENTIFIC PAPER IN COMMON WORDS, ! That is of Inestimable Vain*? to the Bro’iressire Farmer Who ised Both Brain ana Brawn. “ORIGIN OF SOIL.” To those who are interested in the greatest possible development of the natural resources of our state, the movement on foot to improve its present methods of farming and all that pertains thereto, is extremely gratifying. In a very large degree’ the present prosperity of our country as well as its future condition. depends upon the manner in which farming is carried on. The mines yield to man their rich treasures of both the preprecious and the useful metals, the seas in abundance producer their fishes, but the race alwayshas. and of necessity always will, depend for its existence and. progress in civilization mainly upon the products of the soil. The soil produces plants which the animal feeds upon, and man depends for food, clothing, and shelter upon both plants and animals. The clothing upon our bodies, the shoes upon our feet: the shingles* of the roof, the brick of the hearth; the bread upon the table, and the plates we eat from; all these and. , thousands of other things, cornel either directly or indirectly from the soil. What a heritage the ( soil is to us, and how it devolves! upon us to see to it that the wanton manner in which it has in many cases been thoughtlessly destroyed by our fathers be, .substituted by such methods’ bf agriculture as I will constantly improve it! The most comprehensive! knowledge, of the treatment of soils, whether it be to cause them to yield their largest crops or for their preservation, includes some notion at least, of their origin. ‘ This is the apology I offer, if any is necessary, for addressing yon as farmers upon the subject of origin and nature of soils.

The term soil as I shall use it includes all that portion of the land areas that is not solid rock. It will readily be seen that in this sense it embraces a great variety of material, such as sand, clay, hardpan, etc. As you know, these materials at their greatest depth reach only a few hundred feet from its surface; and when we consider the great size of the earth, we readily see that the soil forms only a thin covering of the continents. But however small the amount of soil as compared with the solid portion of the earth, it is found almost everywhere on land areas. Small surfaces exposed to stormy winds or swift waters are sometimes destitute of soil, as are. also steep mountain slopes and limited areas from which moving ice has scraped it away. Because of the fact that the soil is so widely distributed, it usually escapes our notice except when we happen in those localities when there is none of it to be seen.

This universal distribution of the soil is no matter of chance, nor has it always existed as we now know it. or come into this existence by any agency acting suddenly, but is the result of thousands, nay I may say millions of years, bf the slow but sure work of many of nature's forces. With the exception of the relatively small amount of material produced from the decay of plants and animals, all soil material has originated from the breaking up of rook. Granting this to be true, it is plain that the chrracter of the soil, (that is whether it is sandy, clayey, or limey, etc.) of any locality, depends upon the kind of rock from which ’it was formed. Sandstone alone, when disintegrated, forms a sandy soil; limestone a limey soil; shales a clayey soil. We often find beds of sandstone and limestone overlying each other. In cases of this kind the disintegration of both together, forms a mixed soil of lime and sand. Beds of

sandstone, limestone, and shale, may overlie each other on a | hillside and disintegrate and be carried to the low ground below’, forming a mixed soil of lime, sand, aiid clay. Without stopping to consider how* the vast amount and great variety of rock of the continents was formed and came to be where it is, let us take it as we find it. and proceed to notice some of the ways in which it has been, and is being, changed from its solid form to tillable land. You have all observed in passing through railroad cuts, in digging wells and cellars, and in making other excavations, that there is often a gradual transition from the soil at the top, | through rotten, broken rock that can be easily worked with the pick and shovel, to hard rock beneath. Frequently in such cases as this a careful examination will show* without doubt that what is now soil was once stone, ami that the soil has been produced by the rotting, so to speak, of the stone. Observation will also prove to us that in such cases the process of soil formation is not only a thing of the past, but that it is now slowly but none the less surely going on.

In cases of this kind, if the rock lies in such a position as not to permit of “washing,” the soil remains where it was ormed; but if the rock be on a •slope, the soil is, liable to be carried away by the rains as fast as formed, to the bottom lands below’, or to streams, by which it may be. earned long distances oeiore it is dropped. In this •vay/“the flood plains of our rivers, both large and small, are composed of material brought logetheß from very distant parts. For example, any acre of land inlndiana subject to the annual overflow or the Ohio river, may be, and doubtless is, composed of material from Kenlucky, Ohio, West Virgiipaj;and Pennsylvania. Likewise. * the soil at New* Orleans, La., is composed of material from every state and territory between the Rocky Mountains and the Appalachian Mountains, brought down by the Mississippi and its tributaries. Remembering what was said above, we see that the soil at New’ Orlesns originated from the rocks of Montana, Colorado, Tennessee, New York, and all the other states of the Mississippi Valley. The process of the slow decomposition of rock can be seen also in old stone quarries that have for a long time been abandoned. in the foundations of bmildmgs, stone steps, steep cliffs, in fact in all places where rock is exposed to the w’eather. This decay is sometimes comparatively rapid, and sometimes very slow, depending largely upon the character of the stone, but it is only a question of time when the most durable stone, exposed to the W’eather. will be broken up and scattered as the sands of the sea.

But it is not alone by the process of “rotting” that sriones are changed to soil. Though this immediate locality is not a fitplace for observing it, none of you have failed to notice in other ' localities where the streams are swifter than here, the large amount of gravel earned by thestreams. This gravel, whici now has round. smooth surfaces, consisted of angular pieces o’’ stone. When picked up by the water, these sharp cornerea pieces of stone have teen robed along the bed of the stream and knocked against each other until their corners have worn off to the present form. Much of this gravel will coiitin-; ue to wear till it finally entirely, disappears. Meanwhile, each' grain of sand, as it is worn from the pebble, is picked up by the stream and carried to quiet water somewhere along its course and dropped, where it contributes its mite to the formation of soil, when we consider the great amount of this kind of work almost everywhere being done by streams, we realize that the quantity of soil each year produced in this way must be enormous; and when we remembered that this work has continued through the tens of thousands of years that have oas»sed, we must admit that a very- large portion oX our soil has been

j formed by the grinding up of rock by streams. Another manner in which rock is worn away, though of little importance in this locality, is by wind action. This is noth; able in the western states where there are strong winds and but | little vegetation to bold the sand. In such places the strong winds pick up the loose sand and dash it with great force against the exposed faces of rocks and cliffs, in that way rapidly wearing them off. This, continued through past ages has had much to do with producing the western soils. Let us consider another agen cy. formerly very active in this locality, by which rock is ground to sand. viz., thegla-iei In any region where more snov. falls during the winter than melts dur : ng the summer season, there is necessarially an accuinu kition of that material. Bach year it becomes deeper, and would eventually read) a very great, height, did not the force of gravity, acting upon it as up on all other matter, pull it down to a lower level. As each year’s snowfall adds its weight to the hignest part, the pressure from that point in all directions pro duces an actual, though slow movement of the snow (which has become compressed into ice) from the high level to a lower one. This moving body of ice,, we call a glacier. It is plain to be seen that a mass of ice of very great depth, moving in this way. would act as a scraper, and gather up all loose material along its route, such as soil, gravel and loose stone, and would shove this material along in front of, and beneath it. The material at the base of the ice, consisting of angular stones, gravel, sand, etc., in passingover beds of rocks, would wear them off and grind them into sand. This sand would be pushed along with the bowlders, gravel, and other debris, to the edge of the glacier where all of the maiferiai.would b.e dropped by th** mel|jhg Ice. i. The deposition of material along the edge of the glacier, continued througn a long period of time, would result in a ridge. An example of this kind of work is seen in the ridge which runs in a north easterly direction across Jasper county a mile and a half north of this place. While the glacier is building up at one place, it is scooping out in another, in that way producing depressions, which after its disappearance becomes swamps and lakes. Now it is known that during a former period of the earth’s history. a large body of ice with one of its centeres north of the Great Lakes, covered a large portion of North America. From its centre this body of ice moved southward, covering Michigan, a large portion of Ohio, must of Indiana and Illinois, much of the territory west of the Mississippi, and New York and the New England states. In places, this great ice sea is said to have been two miles thick. It doubtless continued for a vdry long time, so that the rock beneath, in man y places, may have had hundreds of feet worn off. Evidence of this wearing is found in different parts of Jaspercounty, where the surface of the rock is worn off smooth, and is as level as a floor. It is not at all improbable that a large portion of the sand of this locality owes its origin to this grinding away of the rock during the glacial period. As the ice melted and disappeared. the rock and other material with which it was loaded, were dropped and left scattered nwer the surface. This, as you Imow. accounts for the great number of boulders in parts of this county and the state. These boulders disintergating, add their material to the soil. It is thus seen that glaciers, as well -is rivers, are great agents in the distribution of soil material to distant parts. Another agent in rock disintgeneration is frost. Every one knows that the expansive force of water in freezing is very great. A small amount of water left in a strong iron pipe, will in freezing. burst it. All rock is more or l°ss porous, and sn contains water. This water, in freezing, will break the rock up. It may be that only a very small portion of the outside will be broken off

during any one freeze, but large stones are often cracked open in this way. When once broken open, more surface is exposed to the weather and disintegration becomes more rapid. It may be so slow r as not to be noticed, but it is nevertheless going on, and the most durable stone, even in climates no colder than this, must finally succumb to the action of frost ani lend their material to the soil. If a small piece of limestone be placed in muriatic acid, the stone will soon disappear. The acid dissolves it. If this acid be heated till it evaporates, the stone will be left in the bottom of the vessel as a tine powder. A process very similar to this is extensively carried on by nature. ' When wood or coal burns, a gas is formed called carbon dixoide, or carbonic acid, The same thing is formed when animals and plants decay. As the decay of animals and plants is always going on, this gas is always to be found in the soil. It is heavier than air, and consequently collects in low places, as the bottoms of wells and coal shafts, where it is known as choke-damp. It is soluble in water, and water charged -with it is a solvent of limestone, though not so rapid a solvent as muriatic acid. When rain water falls upon the parth and passes through the soil, it takes up this carbonic acid and in that way becomes capable of disolving the limestone beneath, if there should be any. Such water is liable to reappear somewhere on the surface as a "limestone spring,” or on a hillside as a "seep.” In either case, a portion of the limestone in solution is dropped, due either to the fact 1 hat the water evaporates .and leaves it, or that the pressure on the water is relieved on comiingtothe surface, and the gas esca]>es, just as the same kind of gas escapes from the "soda water” after it is drawn from the fountain. If the solution of the limestone is due to the presence oi the carbon dioxide, after this gas escapes the limestone must Ibe dropped. It is in this way Aha' lime has become mixed I through the soil. The dissolving power of water charged with ' jarbonie acid also accounts for tin caves always found in limestoneregions. Such waters, in constantly finding their way through the joints of the limestone, dissolve it out, carry it away in solution and deposit it somewhere on the surface. Many substances besides limestone are soluble'in the waters of

f the earth. The advantage cdtning from this fact is certainly very, great. When a substance is in solution, it is distributed throughout the dissolving liquid. After a heavy rain, the soil is completely saturated with water.. Some of the solid material in all portions of the soil is thrown into solution. and distributed by the wate r to. all; adjacent parts. In this, way the different constituents of the soil become thoroughly mixed. The water is the circulating medium by which different parts of the soil exchange material. After the rain, follows the drouth, during which the water near the surface is evaporated, and the solid matter held in solution is deposited at the surface. Of course evaporation is confined to the surface as only that portion is accessible to the air. As the surface soil dries it draws the waterup from the dam]) ground be low just as the wick of a lamp draws up the oil. This water, in turn, evaporates and leaves ; its solid matter deposited at and near the surface. In some places, as in the alkali regions of the west, material is left by evaporution in sufficient quantities to form a thick crust on the surface. By this means, the water is constantly carrying material from below and adding it to the upper portion of the soil, where it is ready to be taken up by the growing crop.

There is another manner 5 n 1 which seasons of wet and drouth contribute to soil formation. The air is a very active agent in charging soil and rock and fitting them for the use of plants. While the ground is saturated with water, most of the air is driven out; but as the water disappears by evaporation, the air follows it down, seeking every cavity, however small, causing the mineral mattei’ to change its form, and the organic matter to decay. Of course no portion of the soil becomes thoroughly dry. Enough water is left in it after the air enters, to facilitate the action of the air.

The action of air on metals in the presence of water is shown in the rusting of a tin vessel put away wet, or of an unpainted iron fence; and that air and water act together in the decay of organic matter, is shown in the rotting in two of fence posts just beneath the surface of the ground. These posts do not rot so rapidly at the bottom because a less amount of air is accessible there. Closely connected with the work of the atmosphere in soil formation, is that of animals. All burrowing animals, such as moles, field mice, gophers, ants, earthworms and crawfish are active and useful agents in converting the material of the earth into productive soil. Moles and mice make small tunnels near the surface of the ground, and earthworms and crawfish dig vertical holes. Earthworms sometimes go to the depth of four feet from the surface. The holes of all animals that have taken on underground habits allow the water to enter freely and perform its work of disintegration. As the water evaporates, the air enters the holes and performs its work necessary, as we have seen, to the formation of soil, and also to the existence of plant life.

But animals themselves have a direct influence on soils. As stated above, the earthworm sometimes burrows to the depth of four feet. They find their way through the ground mainly by passing earthy matter through the alimentary canal as they move along. A small amount of this earth, in passing through the digestive track, is taken up as food for the animal, but the greater portion is ejected. In passing through the animal, the material is of necessity changed a great deal by the digestive fluid secreted and by the process of grinding. It is the habit of these worms to come to the surface during the night, thus carrying material from below and depositing it on the surface as excrement. Their chief value in soil formation probably consists in this. As there are thousands of these animals in any acre of clayey land, their combined work for a century must be very great. The gophers, prairie-dogs, and ground . squirrels of the western part of the United States have been very active in the formation of soils. Each colony of these animals will every year remove, tons of material to the surface, where it is readily disintegrated by air, water, and frost. By their death and decay, valuable ingredients are added to the soil, and carbonic acid is formed, which as above stated, is a valuable solvent in the presence of water.

It remains to consider, briefly, the part that plants play in soil formation. Plants, as well as animals,, contribute a great deal to the breaking up of rock. Many plants send their roots far into the earth, often penetrating the joints in the rock beneath, which they spread apart by growth. Besides being broken up by the roots of plants, the rock penetrated by them is slowly dissolved during the growing season by an acid which i the roots secrete. Trees, when blown down, often bring up great quantities of rock adhering to their roots. This, exposed to the weather, soon disintegrates into soil. That portion of plant remains which does not undergo complete decomposition is known as vegetable mould. This mould becomes mixed with the other ingredients of the soil, which is one of nature's methods of fertilization. It was by the decay of the vast amount of vegetation that has for centuries grown in the marshes of this portion of the state that the ’ black, low-ground soil was formed. For example, the peat and muck composing “Gifford Marsh” and the “Blue Sea.” and which is in places twenty feet deep, is the partly decayed vegetation which those swamps have produced in the centuries , past. After the water isdrained from their surface parts so that the air can enter and do its work in the decay of the vegetable matter, those swampy regions will soon be converted into valuable land. The above is a very brief statement of some of the ways in which nature has prepared that thing from which we sprang, by which we exist, and to which we must return, the soil. Permit me in closing to quote from Prof. Shaler of Harvard University: “When we perceive that civilization rests on the food-giving capacities of the

soil, when we perceive that all advance of our kind depends upon the preservation and enhancement of its fertility, we are in a position to consider the duty which we owe to it. This obligation bids us nurture and care for this part of the earth with an exceeding tenderness and affection. It bids us ever remember that it is enriched with the dust of our progenitors, and is teeming with the life which is to come. In shaping these motives to practice, it seems first necessary to clear away those crude and indeed painful notions which lead men to look with contempt and disgust upon the soil.' If there be any of the great truths of modern learning which more than any others deserve to be imprinted on the minds of our youth, it is these lessons as to the nature and function of this beneficent part of the earth. Only through knowledge can we hope to bring men to a proper understanding of the value of the trust which is in their keeping. Until by education w r e bring people to a consciousness that the w r anton neglect of their duty to their kind which an improvident use of the soil reveals, is a form of treason to mankind, we can not hope to implant in them a proper sense of responsibility in the management of their great inheritance.”