176 HATCH EXPERIMENT STATION. [.Ian. 



the soil to such an extent as to afi'ect the yield of succeed- 

 ing crops upon those plats (4, 7, 9) which, as a rule, had 

 not received at any time for eight successive years an 

 addition of available nitrogen from any other manurial 

 source but the atmospheric air and the roots left in the soil 

 after harvesting the crops raised. 



•A grain crop (oats) was selected as the crop suitable to 

 serve for that purpose. The general management of the 

 experiment, as far as the preparation of the soil, manuring 

 and seeding-down are concerned, was the same as in previous 

 years (see tenth annual report). 



An examination of the yield of the crop in 1893, secured 

 upon the different plats, showed that the total crop per acre 

 on those plats to which no nitrogen was applied (4, 7, 9) 

 averaged 800 pounds less than in case of the plats which 

 received their regular supply of nitrogen in some form or 

 other. The average yield of oats upon the plats (4, 7, 9) 

 which had received no nitrogen supply from any outside 

 source was from one-seventh to one-eirjhth less in iveight than 

 the average yield of the remaining plats, which received 

 annually additional nitrogen supply. 



From these results it appeared that the introduction of an 

 annual leguminous crop into our rotation had somewhat 

 reduced the difference in yield between the plats receiving 

 no nitrogen and those receiving it, yet had not entirely 

 obliterated it. It was decided to continue the observation 

 by repeating the raising of soy beans in 1894, oats in 1895 

 and soy beans in 1896. 



1894. — To secure, if possible, more decisive results 

 regarding the presence and absence of available nitrogen, 

 it was decided to use twice the amount of phosphoric acid 

 and potassium oxide, as compared with the preceding years. 



AmoiDit of Fertilizing Ingredients aj)pliedper Acre during 1894. 



( Nitrogen, .... 15 pounds. 



Plats 0, 1, 2, 3, 5, 6, 8, 10, «! Phosphoric add, , . . 160 pounds. 



[ Potassium oxidf, . . . 250 pounds. 



C Nitrogen, .... none. 



Plats 4, 7, n, . . . ■{ Phosplioric acid, . . . 160 jjounds. 



\^ Potassium o.vide, . . . 250 pounds. 



