PLATE 4 
A. —A field of Johnson County White Dent in Sullivan County, Ind., in 1919. 
The soil was acid and had a high available aluminum and iron content. Three tons 
of ground limestone applied in 1920 corrected this condition, and the plants in the 
treated areas grew better and were more resistant to the rootrots. 
B. —A field of Country Gentleman Sweetcom in Shelby County, Ind., in 1919. 
The plants in the foreground showed abundant rootrot at this stage of development. 
In the background in a heavier soil the plants were in tassel and were markedly less 
affected. The soil when tested showed large quantities of available aluminum and 
iron salts. It was deficient in lime and available phosphates. This type of soil was 
used in the pot cultures shown in Plate 14, A, 
