B60 



experience and is based largely upon the results of field fertilizer tests. 

 However, a chemical analysis of a soil is often of great benefit in studying 

 problems of soil fertility. 



It is generally recognized that the removal of plant food by crops is 

 not the only factor which may change the composition of a cultivated soil. 

 The agencies of wind and water play a very great part in effecting changes. 

 Insects, worms and animals often work through the soil and subsoil, caus- 

 ing variations and intermixtures. The crops themselves bring up from 

 below quite a little plant food and deposit it near the surface in the decay- 

 ing roots and stubble. In spite of the fact that the tendency of nature is 

 to build up and replenish the fertiliy of soil, there is no question but that 

 the destructive system of cultivation that has been followed by the farm- 

 ers of this country has more than counter-balanced nature's tendency to 

 upbuild, and as a consequence the soil has become more or less depleted. 

 It is believed that the analyses presented in this paper show what chemical 

 changes have been effected in the average soil of Indiana by cropping it 

 for from sixty to eighty years. 



TABLE I. 



Analysis of Corny oshe (31) Virgin and Cropped Soils. 



Material. 



Virgin 

 Soil. 



Virgin 

 Subsoil. 



Cropped 

 Soil. 



Cropped 



Subsoil. 



Insoluble silica, etc 



Potash (K 2 0) (Acid soluble) 



Soda (NajO) (Acid soluble) 



Lime (CaO) (Acid soluble) 



Magnesia (MgO) (Acid soluble) 



Manganese oxid (Mn.-j04) (Acid soluble) 



Ferric oxid (FeaOs) (Acid soluble). Alumina (AI2O3) 



(Acid soluble) 



Phosphoric acid (P2O5) (Acid soluble) 



Sulphur trioxid (SO3) (Acid soluble) 



Volatile matter 



Total 



Total nitrogen 



Total potash (K-.O) 



Total humus 



Acid humus 



88.49% 

 .26 

 .20 

 .43 

 .41 

 .14 



5.03 



.12 



.06 

 5.28 



100.42 



.18 

 1.83 

 1.98 

 1.16 



87.30% 

 .36 

 .20 

 .34 

 .60 

 .08 



8.01 



.07 



.05 

 3.20 



100.21 

 .07 



1. 



89.59% 

 .23 

 .17 

 .43 

 .40 

 .07 



5.31 



.11 



.06 

 3.88 



100.22 



.13 

 1.94 

 1.04 



.84 



86.37% 

 .34 

 .21 

 .51 

 .60 

 .09 



8.60 



.07 



.04 

 3.25 



100.08 



.06 



1.92 



.40 



