subject to any sort of treatment with impunity. Chem- 

 ically, it contains elements which must be present in 

 certain proportions for the support of vegetation. 

 Physically, it is made up of matter which supplies the 

 principal plant food. This food, with its chemical con- 

 stituents in proper admixture, is furnished by the de- 

 composition of organic matter and the disintegration of 

 mineral matter that proceed together. Whatever dis- 

 turbs either factor of the process, whatever takes out of 

 the soil an excessive amount of one or more of the 

 chemical elements upon which plant growth depends, 

 ends in sterility. Any agricultural methods that move 

 in this direction mean soil impoverishment; present re- 

 turns at the cost of future loss ; the exhaustion of the 

 land exactly as the animal system is enfeebled by lack 

 of proper nourishment. 



Our agricultural lands have been abused in two 

 principal ways ; first, by single cropping, and, second, by 

 neglecting fertilization. It is fortunate for us that 

 nature is slow to anger, and that we may arrest the 

 consequence of this ruinous policy before it is too late. 

 In all parts of the United States, with only isolated ex- 

 ceptions, the system of tillage has been to select the crop 

 which would bring in most money at the current market 

 rate, to plant that year after year, and to move on to 

 virgin fields as soon as the old farm rebelled by lower- 

 ing the quality and quantity of its return. It is still 

 the practice, although diversification of industry and 

 the rotation of crops have been urged for nearly a cen- 

 tury and are to-day taught in every agricultural college 



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