Food for potash salts and nitrate were added to the dressing of barn- 

 1 yard manure, the gross profits amounted to $22.93. When 



171 only basic slag and potash were added, and Nitrate of Soda 

 omitted, the gross profits amounted to $11.28. Abundant 

 evidence then is given that the land must be fertilized with 

 barnyard manure, but also with potash salts and phosphoric 

 acid, and in addition, and above all, with nitrogen. 



The Amount of Nitrogen Supplied by 16 Tons 

 of Manure. 



This result is not surprising, when we consider the 

 amount of nitrogen supplied in the barnyard manure. If we 

 take the nitrogen content of barnyard manure at 0.5 per cent, 

 which is the average, we give to the soil in 16 tons of dung, 

 1 60 pounds of nitrogen per acre, and if the field is to give 

 heavy yields, it has to supply the plants in four years 320 

 pounds of nitrogen, or twice as much as the barnyard manure 

 contains. In addition to this, it has to be borne in mind that 

 the greater part of the nitrogen of the barnyard manure is 

 contained in the straw and excrement, or in substances which 

 decompose slowly in the soil, and in great part are converted 

 into humus, which feeds the plants with nitrogen very slowly. 



The results thus far have been expressed in terms of 

 gross profits. The important question is, however, whether 

 the addition of chemical fertilizers, the phosphates, potash 

 salts and Nitrate of Soda, has resulted in a net profit, and 

 whether, because nitrogen has become more expensive, it is 

 desirable to use Nitrate of Soda at the high prices now asked 

 for it? 



Does It Pay to Use Nitrate of Soda at High Prices? 



In order to answer this question, we must refer to the 

 series of experiments conducted for many years to determine 

 how much nitrogen in the form of Nitrate of Soda, is re- 

 quired to produce a given quantity of grain, roots and pota- 

 toes. 



As an example, we have ascertained that we may 

 expect from each one hundred pounds of Nitrate of Soda, an 



