after the 1902 wheat crop and turned under later in the fall, pro- 

 duced a marked effect upon the 1903 wheat crop. This effect be- 

 came more marked in 1904 and 1905, when every pot receiving 

 legume treatment outyielded the pot receiving lime-nitrogen 

 treatment. 



The last line in the table gives the yields from a pot of virgin 

 soil collected from a piece of unbroken virgin sod land adjoining 

 the cultivated field from which the soil in all the other pots was 

 taken. It is seen that the yields from this pot are gradually de- 

 creasing, doubtless due to the exhaustion of the more active or- 

 ganic matter in the soil. 



TABLE 98. CROP YIELDS FROM PULASKI COUNTY (ILLINOIS) SOIL 

 Pot-culture Experiments 



The results from the pot cultures bear out very conclusively the 

 results obtained from the field tests; namely, that marked improve- 

 ment can be made on this soil by turning under legume crops where 

 lime has been applied. Very striking results appear in the oat 

 crop in 1907. 



Of interest in this connection is another series of pot-culture 

 experiments, with soil from the worn hill lands of Henry County, 



