359 



The Chemical Composition of Virgin and Cropped 



Indiana Soils. 



S. D. Conner. 



In November, 1913, the Soils and Crops Department of the Purdue 

 Agricultural Experiment Station collected samples of a large number of 

 typical virgin and cropped soils, with a view to determine the chemical 

 composition, to see if there was any appreciable difference in them. The 

 samples were taken with an auger and each sample represented not less 

 than five borings to a depth of six and one-half inches. Subsoil samples 

 were taken at the same time and represented the layer from a depth of 12 

 to 18 inches. Great care was taken to select fields where uniform and 

 typical samples could be secured. The samples in each case represent a 

 heavily cropped soil and an adjacent virgin soil of the same type which 

 had never been cropped. The virgin soil samples were taken from a line 

 fence row, or from a woodlot which had never been cultivated. The sepa- 

 rate samples were properly prepared and analyzed for various elements. 

 Also composite samples were prepared from the virgin soils, the virgin 

 subsoils, the cropped soils and the cropped subsoils. The composites were 

 made by taking equal weights of the separate samples and thoroughly mix- 

 ing them. The analyses of the separate samples not being completed up 

 to the present time, the analyses of the composite samples only are given 

 in this paper. 



There is a rather widespread idea that the chemist can take a sample 

 of soil and by making a complete analysis, determine without any other 

 information just what element is deficient in the soil and needed as a 

 fertilizer. This is not true, and it is very seldom that an analysis alone 

 will indicate the needs of a soil. The chemist can tell with a fair degree 

 of accuracy just how much of each element is present in the soil, but he is 

 not able from a chemical analysis alone, to say what various crops are 

 able to extract from the soil. The ability to determine the fertilizer needs 

 of various crops on different types of soil is more or less a matter of 



