WHAT WE FIND IN SOILS 27 



MECHANICAL ANALYSES* OF TYPICAL AGRICULTURAL SOILS 



What does this table show? This in a most striking 

 way : that wheat soils, handled under certain conditions, 

 possess a moderate quantity of their soil grains in the form 

 of very fine sand, silt, fine silt, and clay ; that truck-crop 

 soils possess but a small quantity of the finest grains, 

 their characteristic lying in the great quantity of fine and 

 very fine sand ; that the bright tobacco soils possess a 

 limited quantity of the finer grains and most of the 

 coarser grains, while the heavy tobacco soils are largely 

 composed of the finer grains with a much lesser quantity 

 of the coarser materials ; that the grass lands possess a 

 very great quantity of clay and silt, but a relatively small 

 amount of the coarser sand grains. 



In this table two types of grass lands are shown : the 

 productive and the barren. The former is in good physi- 

 cal condition, that is, its texture is in good form : the soil 

 grains are reasonably well arranged, the humus content 



United States Department of Agriculture. 



