170 AGEICULTURAL EXPERIMENT STATION. [Jan. 



1. Field Experiments carried on for the Purpose of 



ASCERTAINING THE EfFECT OF THE EXCLUSION OF 



Every Form of Nitrogen-containing Manurial 

 Matter from the Fertilizer applied for the 

 Production of a Leguminous Crop (Clover-like 

 Plants) on the Yield, as compared with the 

 Results obtained when a Liberal Amount of 

 Various Nitrogen - containing Manurial Sub- 

 stances is applied under Otherwise Corre- 

 sponding Circumstances for the Same Purpose.* 



Field A. 



The unbroken record of this field extends over more than 

 twenty years. The systematic treatment of the soil, as far 

 as modes of cultivation and of manuring are concerned, was 

 introduced during the season of 1883-84. The subdivision 

 of the entire area into eleven plats (one-eighth of an acre 

 each), of a uniform size and shape, one hundred and thirty 

 feet long and thirty feet wide, with an unoccupied and 

 unmanured space of five feet in width between adjoining 

 plats, has been retained unaltered since 1884. A detailed 

 statement of the particular aim and general management of 

 our experiments, as well as of the results obtained in that 

 connection from year to year, forms a prominent part of our 

 contemporary printed annual reports, to which I have to 

 refer for details. 



Since 1889 the main object of obser^vations upon the same 

 field has been to study the influence of an entii'e exclusion 

 of any additional nitrogen-containing manurial substance 

 from the soil under cultivation^ as well as of a definite 

 additional supply of nitrogen in different forms of combi- 

 natio7i, on the character and yield of the crop selected for the 

 trial. The treatment of the soil adopted in preceding years 

 favored this new project for field ol)servations. 



Several plats wliich for five preceding years did not receive 

 any nitrogen compound for manurial purposes were retained 

 in that state, to study the eft'ect of an entire exclusion of 



* Soja bean served for the observation. 



