WONDERS OF THE SOIL (C. 1958)

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Excerpted from The Evidence of God in an Expanding Universe, edited by John Clover Monsma. New York: G.P. Putman’s Sons, 1958

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WONDERS OF THE SOIL (C. 1958)

By Dale Swartzendruber, Soil Physicist

Af.Sc, Ph.D., Iowa State College. Formerly Assistant Soil Scientist, University of California, Los Angeles; presently Associate Professor of Soils, Purdue University. Member of Soil Science Society of America, American Geophysical Union, American Society of Agronomists. Specialist in soil structure and soil water movement.

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City dwellers driving their cars through the country­side admire the field crops, and know that these crops spring from the soil, but generally pay very little attention to the soil itself. Good farmers, on the other hand, pay very close attention to the different types and qualities of soil, although it cannot be expected of the general run of them that they make thoroughgoing scientific studies of the substance that means so much for their income and livelihood.

The soil is a world of wonders all by itself, but only scien­tific study brings that out. I shall invite the reader to follow me as I make some very brief, cursory comments. He may not, without further study, understand every phrase or bit of chemical nomenclature, but he should understand enough to agree with me that the soil is a world of wonders, and he should also come to see something of the network of design in this wonderworld—a network of design that inevitably will lead him to think of the Great Designer.

Let us take a look at soil as a weathering product. The products of geologic weathering have been listed as (1) residual mantle, (2) residual boulders, and (3) soil. All are the result of the disintegration and breakdown involved in weathering, but by virtue of its role in the maintenance of life on land areas soil stands in sharp contrast with the other two categories. Soil—here considered simply as the mineral mixture at the earth’s surface in which plants grow—is the source of important plant nutrients, and is necessary for the physical support of land plants.

As igneous rocks (intense-heat-produced) weather, the soluble bases such as calcium, magnesium and potassium are removed preferentially, leaving behind the oxides of silicon, aluminum and iron to comprise the bulk of the soil material. The phosphorus content is not greatly reduced, whereas the nitrogen content is generally increased.

The weathering of the original silicate minerals leads to the formation of clays. The clay fraction of soils, in temperate and cold regions, consists largely of crystalline silicates, with smaller quantities of nonsilicates. In the tropics free oxides and hydrous oxides of iron and aluminum may predominate.

An important property, or characteristic, of clay is the cation exchange capacity (electrical action). This property enables the holding of the soluble bases by exchange reac­tions, thus preventing the relatively low content of these bases from being reduced to zero. Cations held by exchange are available for plant use. So, the weathering process which causes loss of the plant-available soluble bases also provides an inorganic mechanism which retains them. Lack of space prevents a discussion of other plant nutrient elements. Let us, instead, ask the interesting question how the Great Designer arranged for the growth and survival of the first plants in geologic time. Presuming those plants to have had nutritional requirements similar to those of present day plants, it would seem that the soluble bases and phos­phorus should have been ample. With nitrogen the situation was different. Relatively large quantities are used by plants, and inorganic retention by the soil was poor. How could the first plants have obtained their nitrogen?

There is evidence that unaltered igneous rocks may contain ammoniacal nitrogen to the extent of 80 p.p.m. In the absence of prior oxidative reactions, this nitrogen might have been utilized by the first plants. But there are other sources, too. There is, for instance, lightning. Many people think of light­ning only as an instrument of destruction. But it is known that discharges of lightning form oxides of nitrogen which are brought down to the soil in rain or snow. The readily avail­able nitrate nitrogen thus added has been conservatively estimated as 5 pounds per acre per year, the equivalent of 30 pounds of sodium nitrate (Lyon, Buckman, and Brady, The Nature and Properties of Soils, Fifth Edition). Since the same authors report that such an addition will more than supply the nitrogen requirements of a continuous sod crop, it seems reasonable to assume that the same additions to primordial soil materials would have been sufficient to initiate plant growth.

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A further feature of lightning fixation is that the nitrogen fixed in tropical regions is greater than that fixed in humid-temperate regions, which in turn is greater than that fixed in semi-arid regions. Geographic regions are thus being served variously, according to their needs, by the Great Designer.

Speaking of the Great Designer—can the soil-plant inter­relationships just discussed really be taken as evidence of the existence of purposive design in Nature? This question can­not be answered apart from its implications for science in general.

It is doubtful that scientists would generally concur on a single definition of scientific method, but most would likely agree with Turner (editorial in Science, Sept. 6, 1957), that in broad outline science has as its purpose the discovery of generalizations (hereafter called laws) of Nature. To be logically consistent, a scientist who searches for such laws needs to believe that they exist, and it is impossible to deny their existence in view of the imposing array of laws already developed by the totality of science. In the spirit of free inquiry it also is logically consistent to ask why these laws exist, and why it is, as in soil-plant and numerous other scientific interrelationships, that the laws fit together in such a beneficial pattern.

At this stage it is recognized that we are approaching the border region between science and philosophy. How can we account for this pattern or order? It would seem that, basic­ally, there are just two alternatives. One would be the assertion that the order observed is merely an expression of the direction in which development has taken place, starting from an initially random state. But such a proposition is com­pletely at odds with common-sense experience, and is refuted scientifically by Boltzmann‘s “second law of thermodynam­ics,” which all modern scientists recognize. So this author accepts the second alternative, which is simply that Nature exhibits order by virtue of having been designed that way. The existence of a transcendent Intelligence is admittedly implied, but it is felt that this is far more reasonable and satisfying than concluding that order developed spontane­ously from disorder. Hence, it is felt that the soil-plant inter­relationships discussed heretofore are evidence of design in Nature.

The author recognizes that any design interpretation will immediately draw criticism from anti-teleologists (those who deny an intelligent purpose in creation). This is understand­able if we realize that most scientists of today, by virtue of their training, are not only steeped in mechanistic tradition but in many cases consider their scientific theories as practi­cally synonymous with reality. On this latter point Conant (Science and Common Sense) has written cogently, pointing out that one is well justified in treating scientific theories and explanations as highly provisional. Considered from such a vantage point, the violation of the anti-teleological dictums of a mechanistic scientific mentality does not seem forbid­dingly serious.

As a matter of fact, there is teleology, purpose, design “all over the place.” One cannot escape it, in the heavens above or on the earth below.

To deny a Great Designer is quite as illogical as to admire a magnificent field of yellow, waving grain and at the same time to deny the existence of the farmer in the farmhouse by the roadside.

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