34 



March 27 — All plants sprayed with potassium sulfide solution for 



mildew. 

 March 29 — Mildew mostly disappeared. 

 April 5 — Crop again sprayed for mildew. 

 April 24 — Almost no mildew present. 



May 8 — Crop growing well and a few heads are beginning to show. 

 Ma}^ 24 — Heads out on nearly all plants. 



June 5 — Most of the heads in milk and ready to harvest. The 

 oats have made a good growth in spite of the check re- 

 ceived from mildew. There were 10 plants in all the 

 pots except in 12 cases, where only 9 were present. 

 June 7 — The crop was harvested. 



The yield from each pot was placed in a separate cloth bag and 

 suspended in the greenhouse until thoroughly air dried, when it was 

 carefully weighed in the laboratory. Each lot was then ground and 

 dry matter and nitrogen tests made. Table No. 1 shows the yield 

 obtained from each nitrogen source expressed in grams of dry matter, 

 also the total amount of nitrogen recovered by the dry matter yield, 

 exclusive of roots. In studying this table it should be borne in mind 

 that pots 1 A, B, C, D, E, F, G, H; 2 A, B, C, D, and 4 A, B received 

 their nitrogen from unwashed dried blood. Those receiving .42 

 gram of nitrogen constituted the standard. Pots 62 A, B (garbage 

 tankage) and 15 A, B (castor pomace) received their nitrogen from 

 unwashed material. The results on these tests show the activity of 

 the total nitrogen. In all other cases the activities refer to the water 

 insoluble organic nitrogen. 



Table No. 2 shows the comparison in nitrogen activity between 

 the alkaline permanganate method used in the laboratory and the 

 vegetation experim.ent. The nitrogen activities in the vegetation 

 tests have been calculated from two points of view : (1) From the 

 increase in yield of dry matter over the no nitrogen pots, assum- 

 ing unwashed blood (the standard) to have a total nitrogen activity 

 of SO per cent. (2) From the increase in yield of nitrogen recovered 

 in the dry matter over the no nitrogen pots. It would appear that 

 this latter method would be a more just comparison as it shows the 

 actual amount of nitrogen taken up by the plant from each nitrogen 

 source. In computing the percentages of activity by this method 

 the nitrogen recovered by the unwashed blood is placed at SO (both 

 laboratory and field experiments show good red blood to have a nitro- 

 gen activity of about SO per cent). For comparison this table also 

 shows both the increase in yield of dry matter and the increase in 

 yield of nitrogen over the no nitrogen pots. 



