CORN GKOWERS ASSOCIATION. 591 



the ledger. At the Illinois Experiment Station corn has been grown year 

 after year on a field of the college farm without any application of 

 manm'es or fertilizers of any kind. This experiment was begun twenty- 

 four years ago, and the best kind of cultivation and method of preparing 

 the seed bed have been used in the growing of the crops. The crop has 

 been carefully weighed from year to year. The yields have been kept 

 since 1888, but previous to the establishment of the experiment station 

 at this time no authoritative records were kejjt. The records since 1888 

 Are as follows: 



Ear Corn, Stover, 



Bushels Per Acre. Tons Per Acre. 



1888 (50.1.3 1.26 



1889 47.15 1.21 



1890 41.87 1.19 



1891 26.67 1.23 



1892 . 30.92 75 



1893 21.73 1.04 



1894 . 34.83 1.26 



1895 63.81 1.51 



1896 62.31 . 1.74 



1897 40.10 1.61 



1898 18.11 1.39 



1899 50.09 .' 1.61 



1900 48.03 1.29 



1901 23.65 1.14 



In other words, in 1901 it cost 50.6 cents per bushel to raise the crop. 

 It is a noticeable fact that the yield per acre has decreased gi'adually 

 on this field. The appearance of the soil has been changed. It is a 

 clayish-white color compared to the rich black color of the adjoining 

 rotated fields. The yield varies with the season, but is less than half 

 that of rotated fields or the ordinary fields of the station farm with 

 similar original conditions of soil fertility. There is a marked similarity 

 between these results and the results of continuous wheat growing for 

 fifty years on the Roodbulk fields of the Lawes and Gilbert experimental 

 farm in England. Continuous cropping and taking the crop off the field 

 exhausts the fertility of the soil, and it has been found that soils so 

 treated are very difficult to bring back to their original state of fertility. 

 The mechanical, as well as the chemical, condition of the soil is changed, 

 and it requires many years of careful and expensive treatment to renew 

 soil productiveness. 



This is found to be the case in ordinary practice, and the problem 

 before every corn grower is to keep up the fertility of the soil so that 

 it will continue to produce profitable corn crops. Here are several prac- 

 tical methods for accomplishing the desired results, which will be treated 

 briefly in this discussion: 



