Photo by G. W. Groff 

 A TRKADMILL PUMP, VERY COMMON IN CHINA (SEE PAGE 945) 



above flood plain the lands of the delta 

 which are subject to overflow or are 

 too low to permit adequate drainage. 



But the conservation and utilization of 

 the wastes of the soil erosion, as applied 

 in the delta plain of China, stupendous 

 as this work has been, is nevertheless 

 small when measured by the savings 

 which accrue from the careful and ex- 

 tensive fitting of fields so largely prac- 

 ticed, which both lessens soil erosion and 

 permits a large amount of soluble and 

 suspended matter in the run-ofif to be 

 applied to and retained upon the fields 

 through their extensive system of irri- 

 gation. 



Mountainous and hilly as are the lands 

 of Japan, ii,ooo square miles of her cul- 

 tivated fields in the main islands of Hon- 

 shu, Kyushu, and Shikoku have been care- 

 fully graded to water-level areas, bounded 

 by narrow raised rims, upon which i6 or 

 more inches of run-off water, with its 

 suspended and soluble matter, may be ap- 

 plied, a large part of which is retained 



on the fields or utilized by the crop, 

 while surface erosion is almost com- 

 pletely prevented. 



The total area thus surface-fitted in 

 China must be 90,000 or 100,000 square 

 miles. Such enormous field erosion as is 

 tolerated at the present time in our South- 

 ern and South Atlantic States is permitted 

 nowhere in the Far East, so far as we 

 observed, not even where the topography 

 is much steeper. 



CONSERVATION, AN ENDURING ASSET 



One of the most remarkable agricult- 

 ural practices adopted by any civilized 

 people is the centuries-long and well nigh 

 universal conservation and utilization of 

 all human waste in China, Korea, and 

 Japan, turning it to marvelous account 

 in the maintenance of soil fertility and in 

 the production of food. 



To understand this evolution, it must 

 be recognized that mineral fertilizers so 

 extensively employed in modern western 

 asfriculture, like the extensive use of min- 



944 



