that the blight which has smitten the fairest and most fertile provinces 

 of Imperial Rome, has spared Britannia (and other northern areas of 

 Europe). 9 



Much of the area of the United States may be classified as 

 belonging to the second type. Generally its climate is such 

 that there are wet and dry seasons, approximately at any 

 rate; in many parts the rains are heavy and at times torren- 

 tial; and a large proportion of the country 75 to 80 percent 

 is mountainous or sloping. Even a moderately rolling terrain, 

 when the vegetative cover has been removed and the top 

 soil pulverized by cultivation, is susceptible to erosion, as 

 in many parts of the Mississippi Valley. However, as Bennett 

 has told us, slope is not the most potent factor affecting ero- 

 sion and run-off. Available data indicate that the most im- 

 portant factor is the character of the vegetative cover, and 

 after that the character and condition of the soil. 10 



The fertile top soils of many of the best agricultural lands 

 of the United States have been or are being washed out of 

 the reach of service to Man as a result of the removal of 

 vegetative cover and the manner in which tilled lands are 

 cropped. 11 



This wastage of the most basic and indispensable resource of the 

 country the soil has become one of the most important problems 

 confronting the Nation. From a country with a large proportional area 

 of rich agricultural land we are plunging, almost heedlessly, in the 

 direction of a nation of predominantly poor agricultural land, as the 

 result of unrestrained erosion. 



The economic and social aspects of this tragic transformation have 

 been tremendous. The acceleration of erosion * * * has reached 

 an enormous annual cost to the Nation, as measured by soil depreciation 

 and reduced yields alone; and has carried with it consequences of first 

 importance to the permanence of investments in the billions of dollars in 

 navigation, water-power sites, municipal water-supply reservoirs, irriga- 

 tion developments, agriculture, and grazing. 12 



If we should will to do something designed to arrest this 

 "plunging, almost heedlessly, in the direction of a nation of 



9 George P. Marsh, Man and Nature, New York, 1864, p. 49. 



10 H. H. Bennett, Dynamic Action of Rains in Relation to Erosion in the Humid Region, 

 Transactions, American Geophysical Union, 1934, pp. 481-482. 



11 See Foreword, p. 2. 



12 Report of National Resources Board, 1934, p. 161. 



