Natural Fertility of the Soil 11 



the great wheat fields in the Northwest, there were but 

 24.5 pounds of nitrogen removed in the crop harvested, 

 while the total loss to the acre was 171 pounds, or an 

 excess of 146 pounds, a large part of which loss was cer- 

 tainly due to the rapid using up of the vegetable matter 

 by this improvident method of practice. Whereas, on 

 the other hand, when wheat was grown in a rotation with 

 clover, the gain in soil nitrogen far exceeded that lost or 

 carried away by the crop. The continuous wheat- and 

 corn-growing in the West, and of cotton and tobacco 

 in the southern states, are responsible for untold losses 

 in this expensive element of fertility, while in nearly 

 every state of the Union, soils both rich and poor are 

 suffering more or less from the effect of natural losses in 

 this direction. 



THE NATURAL LOSS OF THE MINERAL ELEMENTS 



In the case of the minerals, phosphoric acid and potash, 

 which exist in fixed compounds in the soil, the actual 

 losses are undoubtedly very much less than is the case 

 with nitrogen, since only traces of these constituents 

 are ever found in solution in the drainage waters under 

 ordinary circumstances; yet, because of the large quan- 

 tity of water that passes through many of our soils, the 

 total amount of these rendered soluble and carried away 

 by this means is very great. Our great rivers carry in 

 solution into the ocean tons upon tons annually of these 

 elements of fertility, and it is an absolute loss, as there is 

 no natural means by which these may be returned to the 

 soil, as is the case with nitrogen ; and it is true, as in the 

 case of the former, that the soil is not only absolutely 

 poorer by virtue of the loss of its elements of fertility, 



