Abstract

                                In the opening chapter of this book. Mr. G. V. Jacks, the Deputy Director of the Imperial Bureau of Soil Science at the Rothamsted Agricultural Experimen- tal Station, England, gives a very readable account of the modern aspects of soil erosion. in which he particularly stresses the broad economic relationships of the problems of land maintenance. "As the result solely of buman mismanage ment, the soils upon which men have attempted to found new civilizations, are disappearing, washed away by water and blown away by wind... Already...nearly a million square miles of new desert have heen formed, and a far larger area is approaching desert conditions". Despite the invention of efficient agricultural implements, the introduction of better varieties of crops, and the increased use of manures, the average output of the land per unit area taken the world over, is rapidly diminishing this is mainly attributed to the ravages of soil erosion which" is altering the course of world history more radically than any war or revolution". Nevertheless, soil erosion is a beneficient process without which the world would long ago have died, being Nature's way of discarding its old worn-out skin and renewing its living sheath of soil from the dead rock beneath" In Nature, it takes place slowly, so that equilibrium is always maintained bet- ween soil removal and soil formation under particular conditions of climate. It is the great acceleration of erosion through human mismanagement that has changed the process into one of the most vicions and destructive forces thuit hava ever been released by man". Deforestation, the destruction of natural herbage by over. grazing and excessive cultivation may so nasten soil removal that fertile land. taking centuries to form, may be entirely lost within a year or even a few days.

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