150 AGRICULTURAL EXPERIMENT STATION. [Jan. 



phoric acid and of potassium oxide. The phosphoric acid 

 was supplied in form of dissolved bone-black, and the 

 potassium oxide either in form of muriate of potash or of 

 potash-magnesia sulphate. From 120 to 130 pounds of 

 potassium oxide, from 80 to 85 pounds of available phos- 

 phoric acid, and from 40 to 50 pounds of available nitrogen, 

 were supplied per acre. 



One plat, marked 0, received its main supply of phos- 

 phoric acid, potassium oxide and nitrogen in form of barn- 

 yard manure ; the latter was carefully analyzed before being 

 applied, to determine the amount required to secure, as 

 far as practicable, the desired corresponding proportion of 

 essential fertilizing constituents . The deficiency in potassium 

 oxide and phosphoric acid was supplied by potash-magnesia 

 sulphate and dissolved bone-black. The fertilizer for this 

 plat consisted of 800 pounds of barn-yard manure, 32 pounds 

 of potash-magnesia sulphate, and 18 pounds of dissolved 

 bone-black. 



Plats 4, 7 and 9 received no nitrogen-containing manurial 

 substance ; plats 1 and 2 received nitrogen in form of sodium 

 nitrate ; plats 5, 6 and 8 received nitrogen in form of ammo- 

 nium sulphate ; plats 3 and 10 received nitrogen in form of 

 dried blood ; plat received nitrogen in form of barn-yard 

 manure. 



The entire field, eleven plats, was ploughed April 9. The 

 fertilizer was applied broadcast to each plat, and subse- 

 quently slightly harrowed under, April 27. The final prepa- 

 ration of the soil for seeding, by ploughing and harrowing, 

 took place May 9. The same variety of corn (Clark), a 

 flint corn, was planted in drills in a similar manner as during 

 preceding years, May 10. The crop on all plats was kept 

 clean by means of the cultivator and hoe ; it was cut Sep- 

 tember 3, when the kernels were fairly glazed over. 



