144 



CORN CROPS 



102. As soils are continuously cropped, progressive 

 changes take place. A suggested method of adapting the 

 fertilizer to conditions is given by C. E. Thome of the 

 Ohio Agricultural Experiment Station, as indicated by 

 experience on rather poor glacial soil at that station : ^ — 



TABLE XXXII 

 Fertilizers suggested for Different Conditions 



WHEN IT PAYS TO FERTILIZE FOR CORN 



103. The gross income per acre from cereal crops is low, 

 and their extensive culture can be carried on only where 

 the soil naturally furnishes most of the mineral elements 

 without excessive cost. In the past, cereal culture has 

 largely followed the opening up of new lands, while it has 

 declined on old soils when extensive use of commercial 

 fertilizers has become necessary. 



From the foregoing discussion it seems that the use of 

 mineral fertilizers for corn can be applied at a profit only 

 as a supplement to soils already well supplied with avail- 

 able minerals. In many cases when a single mineral 

 1 Ohio Agr. Exp. Sta., Bui. 141. 1903. 



