NEWER PROBLEMS IN SOIL TREATMENT 



FRANK I. MANN, Oilman 



HE GREATEST asset any nation ever had is that which 

 the United States had in the fertility of her soils ; it is the 

 basis on which rest all other assets, whether of bank, of 

 railroad or of manufacture. The importance of this asset, 

 and the rate at which it is being exhausted, entitles it to 

 consideration as a national problem, not only for agriculture 

 but for all industries. We are now drawing on this asset and have 

 done so for many years ; we have sold the products, for domestic con- 

 sumption and for export, for less than any reasonable cost of replace- 

 ment. This is a wanton waste, which must some time be reflected in 

 the decreasing prosperity and happiness of the people. The value of 

 this asset is largely expressed in the organic matter of the soils ; and that 

 which is of greatest value in the organic matter is the element of nitro- 

 gen. The ultimate problem in food production is the fixation of at- 

 mospheric carbon by the plants, and when we remember that, as a 

 broad proposition, nitrogen, with a small amount of minerals, is the 

 usual measure of the fixation of carbon, we can realize the great im- 

 portance of its maintenance. 



It has been estimated that the virgin soils of the United States 

 contained about 550 million tons of the element nitrogen; and they 

 are now estimated to contain about 275 million tons, which is a re- 

 duction to one-half the original amount. When we spread this present 

 total over all the cropping land in the country, it gives an average of 

 about 2,000 pounds per acre; and when we make allowance for the 

 larger amounts in the richer soils of what is termed the corn belt, the 

 northwestern wheat belt, and the alluvial soils variously distributed, 

 it gives about 1,500 pounds per acre for the remaining land, which con- 

 stitutes by far the largest area. This area largely comprizes the 

 Eastern states, the country south of the Ohio and Missouri rivers, and 

 parts of the states bounding these rivers on the north. This means 

 that the lands in this large area do not now contain enough nitrogen 

 to give fair returns from their operation. These figures indicate that 

 we have already exhausted about one-half of our greatest national 

 asset. 



If we take the total crops produced each year and calculate the 

 total amount of nitrogen required to form the finished product, we 

 have a total of about three million tons ; that is, there is annually re- 

 moved from the soils about this amount of nitrogen. If we calculate, 



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