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lished (February, 1909), from which the following statements are 

 quoted : 



"The soil is the one indestructible, immutable asset that the nation possesses. 

 It is the one resource that cannot be exhausted; that cannot be used up. The 

 general conception of the exhaustion of soils is that the crop removes plant food, 

 and that unless we return some considerable portion of plant food to the soil it 

 eventually becomes incapable of longer producing adequate crops. We quote 

 from a recent article in one of the agricultural journals: 



" ' We have warned our readers for the last ten years of what is coming if 

 they continue to grow grain crops and sell them off the farm continuously from 

 year to year. . . . Don't imagine for one minute that your soils are of inexhaust- 

 ible fertility. No such soils were ever made in the Western Hemisphere, except, 

 perhaps, such as are enriched by overflow every three or four years.' 



"The impression prevails that our crops take out phosphoric acid, potash, 

 and nitrates to such an extent that the soil becomes incapable of longer supply- 

 ing these plant-food constituents for a satisfactory yield." 



"As we see it now, the main cause of infertile soils or the deterioration of 

 soils is the improper sanitary conditions originally present in the soil or arising 

 from our injudicious culture and rotation of crops. It is, of course, exceedingly 

 difficult to work out the principles which govern the proper rotation for any par- 

 ticular soil. 1 



"The important thing is that we now understand the nature of the soil; how 

 it supplies the nutrient constituents for the crops and how it maintains the supply ; 

 how crops may affect each other when grown in succession on the soil ; how cul- 

 tivation affects the conditions resulting from the crop, and, lastly, we are begin- 

 ning to understand how fertilizers come into this scheme and themselves act on 

 or change toxic conditions in the soil, rendering the soil again sweet and 

 healthy for the growing crop." 



"It has been shown that in southern Maryland and in middle Virginia the 

 cause of the recent depression in agriculture and of the low yield of crops is due 

 to methods which have prevailed rather than to any exhaustion of the soil, 

 and that with improved methods these areas are coming up and will again be 

 made to produce satisfactory crops. The soils are not wearing out in the sense 

 that they are unable longer to provide mineral nutrients, but the yields are low 

 because through the prevailing methods the soils have not been maintained in 

 proper condition. In these latter instances the yields have actually declined, 

 but not from the cause which has been generally ascribed. 



"It has been shown that from the modern conception of the nature and pur- 

 pose of the soil it is evident that it cannot wear out, that so far as the mineral 

 food is concerned, it will continue automatically to supply adequate quantities 

 of the mineral plant foods for crops, but it has also been shown that the soil 

 can be abused and its fertility temporarily impaired by improper methods of 

 handling. 



1 Italics mine. C. G. H. 



