Field Experiments with Fertilizers. 145 



ground blood and meat ; the former is a little cheaper. Either of 

 them can be mixed with the phosphate and the potash and applied 

 at the time when the seed is put in the ground, or earlier. 



The quantity of the fertilizer to be applied. — A liberal dressing 

 will be more likely to give a decisive answer to the question put 

 by the experiment than a scanty dressing will. I would recom- 

 mend the following quantities per acre : of nitrate of soda, 400 

 pounds, or of tankage or dried blood used instead of nitrate of soda^ 

 600 pounds ; of plain superphosphate, 800 pounds ; of muriate 

 of potash, 800 pounds. The fertilizers should be dry and finely 

 powdered, and if applied together should be first very thoroughly 

 mixed. 



The cultivation of all the plots of the same set should be as nearly 

 alike as possible. Therefore the whole of that portion of the field 

 selected for any one set of experiments should be plowed and other- 

 wise prepared for fertilizing and seeding on the same da}'^ ; all the 

 fertilizer that is to be applied and the seed should be put 

 in on the same day. If nitrate is to be used as a top dressing 

 it should be applied on all the plots of a set on the same day 

 E ach cultivating or hoeing of the plots of one set should be done. 

 and the crop of all the plots of a set should be harvested, on the 

 same day. As soon as practicable after every rain, every plat 

 should be surface stirred to the depth of two or three inches, in 

 order to conserve the moisture. 



All these directions being followed, differences between the 

 yields of different plats, due to any other causes than differences 

 in the fertilizing, will be reduced to a minimum, and the results 

 due to differences in fertilizing will be likely to come out more 

 clearly. 



The number of plats for one complete set of experiments and 

 the manner of fertilizing them is shown in the diagram at the 

 beginning of this bulletin ; the size of the plat is supposed to be 

 one- tenth of an acre. The abbreviations used are K for potash, 

 P for phosphoric acid, N for nitrogen, O for no fertilizer, and 

 S for stable manure, if it is desired to have a plat so ferti- 

 lized in order to show whether there is profit in using any com- 

 bination of commercial manures instead of the home -made product. 



For the sake of economy in cost of fertilizers and labor, the 



