12 

 Each pot received the following basic fertilizer application: — 



25 grams of fine ground limestone. 



5 grams of sulfate of potash-magnesia. 



5 grams of muriate of potash. 



9 grams of acid phosphate. 

 18 grams of basic slag phosphate. 

 Nitrogen Applications. 



Number 

 of Pots. 



Source of Nitrogen. 



Grams of 

 Nitrogen per Pot. 



None 



Nitrate of soda . 

 Dried red blood . 

 Dried red blood . 

 Washed dried red blood 

 Washed dried red blood 

 Washed fertilizer, grade 2-8-2 

 Washed fertilizer, grade 2-8-2 

 Washed fertilizer, grade 2-8-3 

 Washed fertilizer, grade 2-8-3 



.42 



.421 



.841 



.42 



.84 



.42 



.84 



.42 



.84 



1 .42 grams per pot equivalent to 59.5 lbs. nitrogen per acre. 

 .84 grams equivalent to 119 lbs. per acre. 



The commercial fertilizers and one series of the dried blood were washed with suc- 

 cessive portions of distilled water so as to remove all water soluble nitrogen. The 

 water insoluble portion, dried at a low temperature, was used in the vegetation pot 

 work. Each fertilizer residue was tested for nitrogen and also for nitrogen activity 

 by both the alkaline and neutral permanganate methods, in order to secure data for 

 comparison with the vegetation experiment. The various nitrogen products, as weU 

 as the basic fertilizer applications, were mixed with the whole volume of soil in each pot. 



Oats were selected as the crop to be grown. The crop was harvested when in milk 

 by cutting even with the ground, each pot having its full quota of plants (ten) at har- 

 vest time. Dry matter determinations were made on the air dried products. The 

 care of the experiment during the growing season was in charge of Mr. R. L. Coffin, 

 who has had many j^ears of experience in this line of work. 



Results are presented in the following table. The relative nitrogen availability is 

 calculated from the average increased yields over the no-nitrogen pots, the average 

 increase from the washed dried blood being placed arbitrarily at 80 for each quantity 

 of application. For the sake of comparison the activity of the nitrogen in each source 

 of organic nitrogen used, as determined by the two laboratory methods under discus- 

 sion, is included. In the case of the unwashed blood, this activity is calculated on the 

 total nitrogen basis, and includes water soluble organic as well as the active water 

 insoluble organic nitrogen. 



1 Diied blood 3 A to 4 C inclusive received their nitrogen from unwashed material. 



