1S1I7.] PUBLIC DOCUMENT — No. 33. 175 



The mechanical preparation of the soil, the incorporation 

 of the manurial substances, the seeding, cultivating and 

 harvesting, were carried on year after year in a like manner, 

 and as far as practicable on the same day in case of every 

 plat during the same year. 



Kind of Cro2)s raised. 



Corn (maize), in 1889. 



Oats, in 1890. 



Rye, in 1891. 



Soy bean, in 1892. 



The annual yield of the various crops upon the different 

 plats showed, as a rule, that those plats (4, 7, 9) which had 

 not received in any form nitrogen for manurial purposes 

 yielded much smaller crops than those that annually received 

 in some form or other an addition of a corresponding amount 

 of available nitrogen. 



The total yield of croj)s on the plats receiving wo nitror/en 

 supply was, during the succeeding years, as follows : — 



With corn in 1889, one-fifth less. 



With oats in 1890, one-fifth to one-sixth less. 



With rye in 1891, one-fifth to one-sixth less. 



With soy bean in 1892, one-third to one-fourth less. 



The results of four years (1889 to 1892) of observations 

 were expressed in the following conclusions : — 



The experiments carried on upon Field A. during the years 

 1889, 1890, 1891 and 1892 shoiv conclusively the impor- 

 tance of a liberal supply to the soil of an available form of 

 nitrogen to secure a successful and remunerative cultivation 

 of farm crops under otherwise corresponding favorable condi- 

 tions. For even a leguminous crop, the soy bean, ivhen for 

 the first time raised upon Field A, did not furnish an excep- 

 tion to our observation (1892). (^For details, see report for 

 1892.) 



1893-97. — Subsequent to the year 1892, when for the 

 first time in the more recent history of the field under dis- 

 cussion an annual leguminous crop, a late-maturing variety'- 

 of soy bean, had been raised upon it, it seemed of interest to 

 ascertain whether the raising of the soy bean upon Field A 

 had increased the amount of available nitrogen stored up in 



