92 SCIENCE AND SOIL 



SOILS OF THE SOUTHERN STATES 



The average composition of twelve samples of soil from seven 

 different counties in Kentucky outside of the Blue Grass Region 

 shows 550 pounds of acid-soluble phosphorus in 2 million pounds 

 of surface soil; and within the famous Blue Grass Region the supply 

 of acid-soluble phosphorus amounts to 5200 pounds (nearly ten 

 times as much) in 2 million of soil, as the average of 30 soil analyses, 

 collected from five counties, these residual soils having been formed 

 in part at least from the weathering of phosphatic limestone. 



The state of Tennessee may be divided geologically into five 

 principal sections: 



(1) The great loess-covered undulating upland area of west 

 Tennessee, lying chiefly between the Mississippi and Tennessee 

 rivers. 



(2) The Central Basin, including most of ten counties (David- 

 son, Trousdale, Jackson, Smith, Wilson, Williamson, Rutherford, 

 Bedford, Marshall, andMaury) and parts of several adjoining coun- 

 ties. The Central Basin includes much of the great phosphate 

 beds of Tennessee. It resembles in some respects the Blue Grass 

 region of Kentucky, and by some the Central Basin of Tennessee 

 is claimed to be the original home of Kentucky blue grass. 



(3) The Highland Rim, surrounding the Central Basin. 



(4) The Cumberland Plateau, farther east. 



(5) The East Tennessee Valley, lying between the Cumberland 

 Plateau and the Unaka Mountains on the eastern border of the 

 state. 



Table 19 shows the plant food in representative soils of each of 

 these great sections, the averages of several soil analyses being 

 reported for the more important areas (Mooers, Tennessee Bulletin 

 78). 



The average composition of the yellow silt loam soil on the loess- 

 covered Ozark Hills of southern Illinois shows 1890 pounds of 

 nitrogen, 950 pounds of phosphorus, and 31,450 pounds of potas- 

 sium per acre in 2 million pounds of surface soil, which is practi- 

 cally the same as for the west Tennessee soil. It may be kept in 

 mind, too, that the north line of west Tennessee is only 35 miles 



