FIELD EXPERIMENTS IN THE SOUTH 



483 



Table 96 gives the yields of corn, wheat, and clover obtained 

 in 1907 on the Vienna soil experiment field in Johnson County, 

 Illinois, located on the less rolling phase of yellow silt loam in the 

 unglaciated area, and typical of more extensive areas of this type 

 in other Southern states. (It should be remembered that geo- 

 graphically and agriculturally one third of Illinois belongs with the 

 South Central states. A straight line from the north point of 

 Kentucky to the northeast corner of Missouri divides Illinois into 

 two practically equal parts.) 



The land on which the Vienna field is located has been cropped 

 for about seventy-five years. It had never had any soil treatment, 

 so far as can be determined, and was badly run down when the 

 Experiment Station came into possession of it in 1902. 



The field is divided into three series of five fifth-acre plots. 

 A three-year rotation of corn, cowpeas, and wheat was followed for 

 four years, then changed to corn, wheat, and clover, but, excepting 

 the 1907 crop, the clover has failed. Cowpeas have been substi- 

 tuted and the crop harvested or plowed under, as seemed practical, 

 according to the yield and weather conditions. In 1902, oats were 

 grown in the place of wheat. 



The soil treatment has been as follows: 



Plot i of each series, no treatment except as the cowpea stubble or the 

 second growth of clover has been plowed under in the regular course of the 

 rotation. 



Plot 2, legume crops and catch crops plowed under, except in 1905-1906-1907. 



Plot 3, legumes plowed under and lime applied. 



Plot 4, legume, lime, and phosphorus. 



Plot 5, legume, lime, phosphorus, and potassium. 



TABLE 96. CROP YIELDS IN ILLINOIS SOIL EXPERIMENTS: VIENNA FIELD 



