Soil Conservation in Perspective

R. Burnell Held, Marion Clawson

• Publisher: RFF Press
• Year: 2013
• Print ISBN: 9781617260124
• eBook ISBN: 9781135983857
• Topic: Biological Sciences
• Subtopic: Ecology
• Index: Biological Sciences

This book reviews and evaluates the nationwide soil conservation effort in the United States and suggests broad outlines of a future conservation program.

Originally published in 1965

PART I

BACKGROUND AND SETTING

Chapter 1

MAN AND RESOURCES

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FROM prehistorical times to the present, man has been concerned with his future food supply. Primitive men learned to store some of the seeds they gathered for the lean seasons and years, and hunters learned to dry meat for future use. A modest store of food provided a reserve which might mean the difference between life and death. The margin between food supply and food need was often close and precarious and the balance had to be struck in a very small area because of the lack of transport. The seven fat and seven lean years of ancient Egypt as related in the Bible became the base for an ever-normal granary several thousand years later. The ancient problem of food supply has become the classic problem of the relation between resources and population, which concerns most of the world today in terms of present needs, and all of it in terms of the long-range future.

Within the period of modern history, this classic problem had its most forceful original statement by Malthus. There were, of course, forerunners of Malthus—Adam Smith, among others—and there were later doctrines, but his statement was so directly to the issue, and so forceful, that it has long stood as the prototype.¹ Malthus took as accepted the facts that resources were limited and that population would multiply continuously unless it was restrained either voluntarily or by various checks such as disease and lack of food. He not only believed there was an eventual physical limit to the quantity of agricultural land, but also that its quality was uniform. And he anticipated no increase in production costs until all land had been employed. Beyond that point, output could be increased from the same area of land, but only at rising cost, thus introducing (in other terms) the principle of diminishing marginal output.

Figure 1. The availability of agricultural land: Malthus vs. Ricardo. (Chart from Harold J. Barnett and Chandler Morse, Scarcity and Growth: The Economics of Natural Resource Availability, The Johns Hopkins Press, 1963, p. 60.)

Ricardo was shortly to introduce variations and changes in the Malthusian model. As shown in Figures 1 and 2, he agreed with Malthus on a limit to the quantity of land, but, in particular, he made much of variations in the quality of land. The second part of Figure 1 puts Ricardo’s views on land scarcity and quality of land in modern graphic form. Under his formulation the best land is used first, with increasingly poorer land used as needed. As a result, the cost of output rises long before the final margin of cultivation is reached, as shown in Figure 2. How soon and how sharply costs rise depend upon the area of land of different qualities, on the one hand, and upon the size of the population—hence, upon the demand—on the other.

Malthus, Ricardo, and later writers applied their theories of resource scarcity to other resources than agricultural land. In particular, they applied them to minerals. It was nearly always assumed that the total quantity of mineral was absolutely limited, although differences in grade of deposit were accepted, and that each pound or ton mined meant that much smaller volume remaining for later extraction. Thus, the problem of using such fixed and irreplaceable resources was different from that of using soil, which could be maintained productively forever.

Malthus and Ricardo have left an enormous legacy of conviction in modern conservationists, even among those who never heard of, or never read, either. The idea that men shall some day “run out” of minerals, and perhaps other resources, or that population increase will outrun agricultural output, is deeply ingrained in much popular thinking.

Figure 2. Malthusian and Ricardian economic scarcity effects. (Chart from Harold J. Bamett and Chandler Morse, Scarcity and Growth: The Economics of Natural Resource Availability, The Johns Hopkins Press, 1963, p. 61.)

These theories were essentially static in nature. While population increase was basic to the theoretical structure, other change was largely ignored or brushed aside. The possibility of technological advance was recognized, but it was believed that at best this would only postpone the ultimate day of reckoning. According to these views, such advance could not be counted upon to solve the resource problem, much less was it in any way directly related to resource consumption.

In their recent reconsideration of the whole subject, Barnett and Morse make technological change the center of their concern.² They view the use of natural resources in a complex modern society and economy as part of a larger process that necessarily includes forces of technological change, which in turn have profound repercussions upon resource use itself. The mining of metals is part of such an economy, but the technological changes arising out of a metal-using economy make the supply of metals that is economically available vastly greater than before. It is true, in a strict physical sense, that each pound or ton of metal mined means one pound or ton less in the ground. However, the total supply in the ground is so vast, if the lowest concentrations are included, as to be nearly inexhaustible. And that which is mined is not destroyed in any absolute sense, but becomes useful economically for other purposes or is ultimately recycled through various natural processes of diffusion and concentration. Under the dynamic theoretical structure erected by these two authors, resource scarcity is no longer inevitable or probable; on the contrary, it is most unlikely.

Not all economists will accept the Barnett-Morse formulation, even for technologically advanced countries; and it may not be applicable to poor countries which lack capital, trained manpower, and technological capacity. Nevertheless, the role of technology in making available resources which otherwise would be unusable is very great, and widely acknowledged. Certainly, we include technological change as one of the major variables in our consideration of soils and their use.

Concepts of Resources

The term “natural resources” has different meanings for different persons. Our definition, stated briefly is: “A natural resource is any quality or characteristic of nature which man knows how to use economically to ends which he desires.”³

The qualities and characteristics of nature are almost limitless—soils, climate, vegetation, minerals, animals, and many others—and the range within each is very great. Some are important at one stage in human development, while others are useless or even unknown. There is much interest, from time to time, in resource inventories; but any resource inventory is useless except as directed to a specific kind of use and a known technology. The mild climates of Florida, Arizona, and Southern California are extremely valuable assets in a modern industrial economy where attractions to a skilled labor force may far outweigh a local availability of coal and iron, for example.

The role of technology in making qualities or characteristics of nature useful for man’s needs is well known. Until men knew how to get petroleum out of the ground, and to use it once it was out, it did not exist in any economic sense. Uranium, once a chemical curiosity, became an international strategic material overnight, when the first atomic bomb was exploded; when discoveries so far outran earlier estimates, it became a glut on the market.

But neither technology nor extraction of earth’s qualities is costless; many things are possible which are not currently economic. The United States possesses great deposits of oil shale and Canada has great deposits of tar sands. From both it is wholly possible to extract enormous quantities of petroleum, but thus far it has not proved economic to use either. Salt water can be converted to fresh “to make the deserts bloom,” but thus far the costs have been prohibitive for any but limited special uses. Power from atomic sources is technically feasible, and seems to be on the verge of becoming economically feasible—at least under some circumstances. Caution is required in speaking of economic feasibility, however, because history shows how much it has changed in the past. Yet, at any given time, certain qualities of nature, such as the oil shale deposits, can be evaluated on the assumption that some day they will become economically usable, even though they are not today. They are part of potential resources, but not part of presently usable ones.

The goals that men seek in resource use are equally important, and sometimes overlooked or inadequately considered. The attainment of the greatest possible income, measured in conventional dollar terms, may be sought for many purposes. This is an appropriate goal, and one for which the tools of economic analysis are well suited. But it is not the only goal, as most economists realize. Resources may be used for some ends which are not easily measured, or measurable at all, in monetary terms. One practical example of considerable quantitative importance today is the use of forests and other land areas for recreation. Others are the use of large quantities of minerals, labor, and capital for defense purposes; and the shipment abroad of wheat and other foods not needed at home to relieve distress and to assist in the economic growth of developing areas. It may be argued that, in each of these cases, the aim is to maximize something—whether personal satisfactions not easily measurable in money terms, or national security, or something else. But, in some cases patterns of resource use seem scarcely to maximize anything, unless it be conformance with long-established prejudices. To stretch the interpretation of income maximization to fit all these cases resembles the efforts of an old hen to spread out and cover an overly large setting of eggs—something is likely to be left in the cold. The problem of goals becomes especially difficult when resource use in many countries and cultures is considered. What may seem irrational to Americans may be the height of rationality to the people of the other culture.

These considerations about resources in general apply equally to soil. And, even in the United States, the objectives of soil conservation programs are not identical for everyone. Elaborate procedures have been developed for measuring the physical characteristics of soils—their depth, geologic history, size of constituent particles, slope, availability of plant nutrients, and many other features. Through practical experience and scientific research, a rich technology also has been developed for their use. Soils are used primarily by farmers and other private landowners, who seek maximum incomes as at least one goal, and who are thus highly responsive to economic considerations.

Each aspect of our definition of natural resources as applied to soils has undergone substantial change in the United States over the past three hundred years. Through erosion, different hydrologic relationships caused by forest clearing and other practices, irrigation, continued cropping, and so on, the basic characteristics of the soil have been changed in many areas. The enormous advances in technology, from hand tools in the colonial era through animal power during the nineteenth century to mechanical power today—and equally dramatic changes in other aspects of farm technology—have been described many times. Growth of large cities, development of transportation networks, creation of marketing institutions, and many other economic changes have affected the economics of agriculture in still other ways. The goal of farming has changed to some degree, from provision of food and fiber for the farm family on a largely self-sufficient base to the production of commodities for sale in the expectation, or hope, of a profit.

Resources are so enormously variable and diverse, in so many ways, that some grouping into broad classes seems essential. From a broad technological or management viewpoint, resources can be grouped as shown in Table 1. Some resources are “flow resources” with a stream of uses possible without loss of the resource itself. These, in turn, are divisible into nonstorable resources, of which sunlight is a good example, and storable ones, such as water from natural precipitation. In contrast are the “fund resources.” All of these are exhausted by use, but some can be renewed and some cannot. The “exhaustible but renewable” fund resources are typified by mature forests or soil fertility. Either can be used and renewed, at least under many circumstances. However, this is possible only within a range of reversibility. If all the trees of a species were cut, to use an extreme example, forests of the same species could not be re-established. Soil can be renewed when nutrients are used and even part of the soil itself washed away or otherwise destroyed; but if the process goes too far it will prove impossible to reverse. Still other resources—the extraction of petroleum and mining of minerals—for example, are “exhaustible and nonrenew-able,” at least within the span of human planning.

TABLE 1. General characteristics of natural resources

SOURCE: John F. Timmons, et al., Committee on Soil and Water Conservation of the Agricultural Board, Principles of Resource Conservation Policy, With Some Applications to Soil and Water Resources (Washington: National Academy of Sciences-National Research Council, 1961), Publication 885, p. 8.

Possibly we should add another class–”nonexhaustible resources.” For example, climatic factors, position on the earth’s surface, basic geology, and perhaps other aspects or characteristics are so permanent and so difficult or impossible for man to change that they are practically inexhaustible. The same might be said of the minerals dissolved in sea water. However, these can be considered, perhaps without too much violence, as flow resources of a nonstorable kind.

Wantrup uses a system of classification of natural resources (see Table 2) which is similar to the foregoing in some respects, but differs significantly from it in other ways.⁴ While his major breakdown is closely related, his secondary breakdown for the stock resources (or fund resources) is on the basis of absence or presence of natural deterioration, and for the flow resources is inability or ability of human action to affect the resources. Still other classifications are possible; the problem is not simple, and different considerations may loom larger in the minds of some students than in those of others.

TABLE 2. Wantrup’s classification of natural resources

I NONRENEWABLE OR STOCK RESOURCES.

1. Stock not significantly affected by natural deterioration: metal ores in situ; coal; stones; clays.

2. Stock significantly affected by natural deterioration: refined metals subject to oxidation; oil and gas in case of seepage and blowoff; plant nutrients subject to leaching; radioactive substances in process of nuclear disintegration; surface water reservoirs subject to evaporation.

II RENEWABLE OR FLOW RESOURCES.

1. Flow not significantly affected by human action: solar and other cosmic radiation; tides; winds.

2. Flow significantly affected by human action.

a) Reversibility of a decrease in flow not characterized by a critical zone: precipitation; special locations that form the basis of site value; services from a species of durable producer or consumer goods.

b) Reversibility of a decrease in flow characterized by a critical zone: animal and plant species; scenic resources; storage capacity of groundwater basins.

SOURCE: S. V. Ciriacy-Wantrup, Resource Conservation—Economics and Policies (rev. ed.; Berkeley University of California Press, 1963), p. 42.

In any event, such classifications, while logical and helpful in many ways, generally do not fit any particular resource exactly. Soils, which are our major concern, are complex physical combinations of resources. Some of their characteristics fit into one part of a general classification, others fit elsewhere. Basic position on the earth’s surface—with all that this means in terms of geologic origin and base for the soil, climate, and other features—is a stock or fund resource, not naturally changing, not storable, not exhaustible, and hardly subject at all to man’s control. Should major control over climate (or any aspect thereof) become practical, this classification would have to be changed accordingly; but that day is not yet. The soil particles themselves, above the basic bedrock, are a fund or stock resource, but are exhaustible; soil can be eroded away, right down to bare rock, and be irreplaceable within human lifetimes. Even short of such drastic destruction, soil can be damaged permanently, perhaps within a restorable range but subject to improvement only at considerable cost. The organic matter contained in the soil, the level of plant nutrients, and even, to an extent, the soil structure are stock in the sense that these properties were part of the soil before it was ever tilled. They are also flow resources in the sense that they change, either naturally or in response to man’s use. The changes brought about by man often cause significant shifts in the productivity of the soil, increasing or reducing it. Soil-moisture relationships often can be modified greatly, even ...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• CONTENTS
• Preface
• List of Figures
• PART I. BACKGROUND AND SETTING
• PART II. PERFORMANCE AND EVALUATION
• PART III. THE NEXT GENERATION
• SUBJECT INDEX
• AUTHOR INDEX