THE PRESENT CIVILISATION-WILL IT FAIL?

Forest and Bird, Issue 53, 1 August 1939, Page 2

THE PRESENT CIVILISATION -WILL IT FAIL?

Extracted from The Rape of the Earth,” by Dr. G. V. Jacks, Assistant-Director, Imperial Bureau of Soil Science, Rothamstead Experimental Station, England.

AS the result solely of human mismanagement, the soils upon which men have attempted to found new civilizations are disappearing, washed away by water and blown away by wind. To-day, destruction of the earth’s thin living cover is proceeding at a rate and on a scale unparalleled in history, and when that thin cover the soil —is gone, the fertile regions where it formerly lay will be uninhabitable deserts. Already, indeed, probably nearly a million square miles of new desert have been formed, a far larger area is approaching desert conditions and throughout the New World erosion is taking its relentless toll of soil fertility with incredible and ever-increasing speed. Science produces new aids to agriculture—new machines that do the work of a score of men, new crop varieties that thrive in climates formerly considered too harsh for agriculture, new fertilizers that double and treble yields—yet taken the world over the average output per unit area of land is falling. There is a limit to the extent to which applied science can temporarily force up soil productivity, but there is no limit except zero to the extent to which erosion can permanently reduce it. A nation cannot survive in a desert, nor enjoy more than a hollow and short-lived prosperity if it exists by consuming its soil. That is what all the new lands of promise have been doing for the last hundred years, though few as yet realise the full consequences of their past action or that soil erosion is altering the course of world history more radically than any war or revolution. Erosion is humbling mighty nations, re-shaping their domestic and external policies and once and for all it has barred the way to the El Dorado that a few years ago seemed almost within reach. Erosion in Nature is a beneficent process without which the world would have died long ago. The same process, accelerated by human mismanagement, has become one of the most vicious and destructive forces that have ever been released by man. What is usually known as “geological erosion” or “denudation” is a universal phenomenon which through thousands of years has carved the earth into its present

shape. Denudation is an early and important process in soil formation, whereby the original rock material is continuously broken down and sorted out by wind and water until it becomes suitable for colonization by plants. Plants, by the binding effects of their roots, by the protection they afford against rain and wind and by the fertility they impart to the soil, bring denudation almost to a standstill. Everybody must have compared the rugged and irregular shape of bare mountain peaks where denudation is still active with the smooth and harmonious curves of slopes that have long been protected by a mantle of vegetation. Nevertheless, some slight denudation is always occurring. As each superficial film of plantcovered soil becomes exhausted it is removed by rain or wind, to be deposited mainly in the rivers and sea, and a corresponding thin layer of new soil forms by slow weathering of the underlying rock. The earth is continuously discarding its old, worn-out skin and renewing its living sheath of soil from the dead rock beneath. In this way an equilibrium is reached between denudation and soil formation so that, unless the equilibrium is disturbed, a mature soil preserves a more or less constant depth and character indefinitely. The depth is sometimes only a few inches, occasionally several feet, but within it lies the whole capacity of the earth to produce life. Below that thin layer comprising the delicate organism known as soil is a planet as lifeless as the moon. The equilibrium between denudation and soil formation is easily disturbed by the activities of man. Cultivation, deforestation or the destruction of the natural vegetation by grazing or other means, unless carried out according to certain immutable conditions imposed by each region, may so accelerate denudation that soil, which would normally be washed or blown away in a century, disappears within a year or even within a day. But no human ingenuity can accelerate the soil renewing process from lifeless rock to an extent at all comparable to the acceleration of denudation. This man-accelerated denudation is what is now known as soil erosion. It is the almost inevitable result of reducing

below a certain limit the natural fertility of the soilof man betraying his most sacred trust when he assumes dominion over the land. Man-induced soil erosion is taking place today in almost every country inhabited by civilized man, except north-western Europe. It is a disease to which any civilization founded on the European model seems liable when it attempts to grow outside Europe. Scarcely any climate or environment is immune from erosion, but it is most virulent in the semi-arid continental grasslandsthe steppes, prairies and veldts of North and South America, Australia, South Africa and Russia, which offer the greatest promise as future homes of civilization. It is also the gravest danger threatening the security of the white man and the well-being of the coloured man in the tropical and sub-tropical lands of Africa and India. Until quite recently erosion was regarded as a matter of merely local concern, ruining a few fields and farmsteads here and there, and compelling the occupiers to abandon their homes and move on to new land, but it is now recognized as a contagious disease spreading destruction far and wide irrespective of private, county, state, or national boundaries. Like other contagious diseases, erosion is most easily checked in its early stages; when it has advanced to the stage when it threatens the entire social structure, its control is extremely difficult. In the main, unimportant individuals have started erosion and been crushed by it, until the cumulative losses in property and widespread suffering and want have brought governments and nations, with their immense powers for good or evil, into the fray.

In the United States the problem of erosion has become a dominant factor in national life; in South Africa, according to General J. C. Smuts, “erosion is the biggest problem confronting the country, bigger than any politics.” In these two countries erosion has already assumed the proportions of a national disaster of the first magnitude, and has sapped their life blood to such a degree that only a tremendous and single-minded effort from a united nation can prevent a further rapid and irreparable decline. Fortunately, there are signs that the effort will be made in time. Elsewhere, the same destructive processes are at work, but owing to less intense exploitation in the past, they have not advanced so far as in the United States and South Africa. Nevertheless, governments, warned by the example of the United States in particular, are everywhere being compelled to take note of erosion, and when a government stirs it means that the question involved is no longer the concern of one section, but of the whole of the community. That the ultimate consequence of unchecked soil erosion, when it sweeps over whole countries as it is doing to-day, must be national extinction, is obvious, for whatever other essential raw material a nation may dispense with, it cannot exist without fertile soil. Nor is extinction of a nation by erosion merely a hypothetical occurrence that may occur at some future date; it has occurred several times in the past. Erosion has, indeed, been one of the most potent factors causing the downfall of former civilizations and empires whose ruined cities now lie amid barren wastes that once were the world’s most fertile lands.