1894.] PUBLIC DOCUMENT — No. 33. 185 



cultivation, while the remaining ones received as before 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. 



Aside from the difference regarding the nitrogen supply, 

 all plats were treated alike. They each received without an 

 exception a corresponding amount of available phosphoric 

 acid and of potassium oxide. The phosphoric acid was sup- 

 plied in form of dissolved bone-black, and the potassium 

 oxide either in form of muriate of potash or of potash-mag- 

 nesia sulphate. 



Amount of Fertilizing Ingredients used Annually per Acre. 



C Nitrogen, 45 pounds. 



80 jiounds. 

 125 pounds. 



none. 



80 pounds. 



125 i^ounds. 



Plats 0, 1, 2, 3, 5, 6, 8, 10, -{ Phosphoric acid, 

 [ Potassium oxide, 



f Nitrogen, . 

 Plats 4, 7, 9, . . . ^ Phosi^hoi'ic acid, 

 ^^ Potassium oxide. 



One plat marked received its main supply of phosphoric 

 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 the 

 three essential fertilizing constituents. The deficiency in 

 potassium oxide and phosphoric acid was supplied l)y 

 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. 



The mechanical preparation of the soil, the incorporation 

 of the manurial substances, — the general character of the 

 latter being the same, — the seeding, cultivating and harvest- 

 ing 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. 



