Plot 3. The like complete dressing, but without potash. Food for 



Plot 4. The like complete dressing, but without nitrogen. 

 Plot 5. Is left without additional fertilizing; it received only 



barnyard manure, but no chemical fertilizers. 

 For control purposes this group of experiments is carried 

 out on four several parts of the field. Thus each fertilizing 

 is represented on four parallel plots, in the same experiment, 

 pursued on the same plots until a new dressing of fertilizer is 

 given. Experiments of this sort have been carried out, and 

 I am able to present the results of 10 such series of experi- 

 ments, which having been brought to a conclusion, the dress- 

 ings of barnyard manure amounted to 16 tons per acre in a 

 four years' rotation, which is a normal dressing, and the 

 question of whether the soil dressed with 16 tons of barnyard 

 manure per acre remained hungry for nitrogen? 



Results of Field Experiments. 



Average gross profit per annum and per acre from 

 fertilizing with : 



Barnyard Manure, 



Barnyard Barnyard Manure, Potash Potash, Phosphoric Acid, 



Manure. and Phosphoric Acid. and Nitrate of Soda. 



$8.57 $13-90 $30.38 



6.57 8.67 19.10 



6.00 7.52 17.33 



6.29 8.86 21.62 



5.90 6.48 17.19 



9.43 18.48 30.48 



6.38 14.86 20.29 



5.90 11.62 26.67 



4-57 8.77 21.52 



6.66 13.62 24.67 



$6.627 $11.278 $22.925 



It will be observed at once from an inspection of the 

 table that nitrogen in the form of barnyard manure has not 

 sufficed by a long way to meet the nitrogen requirements of 

 the plants. In each of the ten fields, the net profit had fallen 

 considerably when the Nitrate of Soda had been omitted 

 from the supplementary dressing. On the mean of all the 

 fields, and all the years of experiment, the gross profit per 

 acre per annum has amounted to $6.63. When basic slag, 



