1890.] PUBLIC DOCUMENT — No. 33. 149 



blood. 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 phos- 

 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 pound.s 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 w^as 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. 



For details, compare the following tables, containing the 

 history of Field A : — 



Composition of Manurial Stibstances appl 



Nitrate of soda :rz nitrogen, 



Sulphate of ammonia zz: nitrogen, .... 



Dried blood z:^ nitrogen, 



Muriate of potash =: potassium oxide. 



Sulphate of potash ^ potassium oxide. 



Dissolved bone-black := available phosi^horic acid, . 



Barn-yard manures moisture, 



phosphoric acid, 



potassium oxide, 



nitroffen 



ed. 



Per Cent. 



16.00 

 20.91 

 8.24 

 48.58 

 37.54 

 21.80 

 73.04 

 .688 

 .527 

 .568 



