190 AGRICULTURAL EXPERIMENT STATION. [Jan. 



1. Field Experiments for the Purpose of studying 

 THE Economy of raising Leguminous Crops 

 (Clovers, etc.) as a Means of enriching the 

 Soil in Nitrogen in the Interest of the Sub- 

 sequent raising of Grain Crops. 



Field A. 



The systematic treatment of the field here under con- 

 sideration, as far as suitable 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-tenth of an acre each) of a uniform size and 

 shape, one hundred and thirty-two feet long and thirty-three 

 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 observations ujoon the same 

 field has been to study the infiuence of an entire 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 combination^ on the 

 character and yield of the croj) selected for the trial. 



Several plats which for five preceding years did not receive 

 any nitrogen compound for manurial purposes were retained 

 in that state, to studj' the effect of an entire exclusion of 

 nitrogen-containing manurial substances on the crop under 

 cultivation, while the remaining ones received, as l^efore, a 

 definite amount of nitrogen in the same form in which they 

 had received it in preceding years ; namely, either as sodium 

 nitrate or as ammonium sulphate, or as organic nitrogenous 

 matter in form of dried blood or of barn-yard manure. A 

 corresponding amount of available nitrogen was applied in 

 all these cases. 



