THE FERTILITY OF THE SOIL 229 



found between the larder of poverty and the larder of 

 wealth. It is not even a question of age. Some of the 

 old fields on my farm are not too poor to grow luxuriant 

 oats on which a carelessly tossed hat finds a safe resting 

 place. This is the simple statement of facts established 

 by experience and investigation of the ages, and es- 

 pecially of modern scientific discoveries. 



THE BUBEAU OF SOILS. 



Various collateral theories have been urged in regard 

 to soil fertility by many different investigators. The 

 Bureau of Soils, of the Department of Agriculture, 

 some twenty years ago advanced the theory + hat all soils 

 without distinction contain an abundant quantity of 

 plant foods, and the soil solution must necessarily be- 

 come saturated with these constituents to the same de- 

 gree of concentration in all soils, irrespective of the 

 amounts of phosphoric acid and potash there may be 

 present. In speaking of this theory Mr. Alfred Daniel 

 Hall, of the Rothamsted Experimental Station, makes 

 the following observation : 



Little as this view would seem to square with our experi- 

 ence of the effects of phosphatic and potassic fertilizers on par- 

 ticular soils, the theory of a soil solution of constant composi- 

 tion must be valid if the conditions existing in the soil are 

 such as postulated. 



This theory of soil fertility is not accepted by soil 

 specialists such as King, Hilgard, Hall, Hopkins, nor 

 by any great number of agricultural chemists. 



In addition to the above theory the Bureau of Soils 

 has advanced the theory that lack of fertility in the 

 soil is due largely to the residual toxic substances which 

 are left in the soil from previous growth, and hence 



