26 



Journal of Agricultural Research 



Vol. V, No. I 



concentrations ranged from i,ooo parts of anhydrous salt for each 

 1,000,000 parts of water up to 10,000 p. p. m. of salt.. The seedlings 

 were allowed to grow 21 days before being harvested. At harvest the 

 following determinations were made of the plants in each glass: (i) 

 Plants still alive, (2) average height of plants, (3) average length of roots, 

 (4) average number of leaves per plant, (5) dry weight of tops, (6) dry 

 weight of roots, (7) ratio of length of tops to length of roots, (8) ratio of 

 weight of tops to weight of roots. 



In the first test sodium chlorid, sodium carbonate, and sodium sulphate, 

 were used; in the second, potassium chlorid, calcium chlorid, and mag- 

 nesium chlorid; and in the third, sodium nitrate, potassium nitrate, and 

 magnesium nitrate. Figures 23, 24, and 25 show in detail the number of 



KaCl 



Check.^ No-Salt 



t.oooppm. 



Mooppm. loooppm. aoooppm. aoooppm. lo.oooppm 



, = One plant. — = 0.1 gm. dry matter; tops \ = 0.1 gm. dry matter; roots. 



Fig. 23.— Diagram showing the number of seedlings alive and dry matter produced in tops and roots in 

 21 days with solutions of sodium chlorid, sodium sulphate, and sodium carbonate in different combina- 

 tions and concentrations. 



plants alive at the end of three weeks, as well as the weight of tops and 

 roots in each glass. 



An examination of the figures shows a gradual decrease in growth 

 as the concentration of salts increased. Plants were able to endure 

 much stronger chlorids and nitrates in solution culture than in the 

 soil, while the carbonate retarded growth more in the solution than in 

 the loam, but not as much as in the sand. The plants growing in the 

 distilled water without any salts had no food except that stored in the 

 seed and that dissolved from the glass, and, as a result, they produced 

 less growth than plants growing in the dilute solutions. 



The results showing the effect of concentration of the various salts 

 are summarized in Table XI. Each figure represents the average of 

 nine different salts of a given concentration. An examination of the 

 table shows that the number of plants alive at the end of three weeks 



