10 



PROFITABLE MANURING. 



fertilized with potash and phosphoric acid, the remaining 

 two (marked N) also received potash and phosphoric acid 

 and in addition nitrogen in the form of nitrate of soda. 

 The increase of growth in the pots where nitrate of soda was 

 used, shows the effect of nitrogen. Stated in figures, the 

 gain was three to one. This experiment was made with soil 

 known to be deficient in nitrogen, and serves to show 



FIG. 2. LEGUMES NEED LITTLE NITROGEN FERTILIZER. 



beyond doubt that these two crops cannot be grown to 

 advantage unless there is enough nitrogen supplied to 

 balance properly the potash and phosphoric acid. 



Figure 2 shows the same treatment, the plants in this 

 case being Vetches. The results show that some plants, at 



