[Chap. XXX ROOTS: PROCESSES AND SOIL RELATIONS 



327 



'^^^ fCF': 



Fig. 138. Relative growth of plants in relation to the concentration of various 

 ions of inorganic salts: Upper — tomato plants; lower — a diagrammatic representa- 

 tion of the effects of ions on the yield of hay in an unplowed meadow in southern 

 Greenland. The ions added to different parts of the meadow are indicated on the 

 left. Each haystack represents a yield of 1,000 pounds. The yields indicated are 

 averages per acre of 8 successive harvests. Data from Danish Experiment Station 

 of south Greenland. 



