28 



Journal of Agricultural Research 



Table XI. — Effect of concentration of salts in solution cultures on the growth of wheat 

 seedlings. Average of 45 glasses for each concentration, with sodium sulphate, sodium 

 carbonate, sodium chlorid, calcium chlorid, potassium chlorid, potassium nitrate, 

 magnesium nitrate, and sodium nitrate in various combinations 



Concentration of 

 salts in solution. 



Ratio of 

 weight 

 of tops 



to roots. 



P.p, 

 None 



1,000. .. . 



2,000. .. . 



3,000.... 



4,000. .. . 



S.ooo. ... 



6,000. .. . 



7,000. .. . 



8,000. .. . 



9,000. .. . 

 10,000. .. . 



2.36:1 

 3-37:1 

 3.04:1 

 3.08:1 

 2.83:1 

 2. 40:1 

 2. 67:1 

 2. 43 : 1 

 2. 46:1 

 2.58:1 

 2-37:1 



Table XII shows the efifect of the individual salts when used alone. 

 The results given in this table are the averages of various concentrations, 

 from 1,000 to 10,000 p. p. m. In interpreting these figures it must be 

 remembered that no nutrient solution was added where the single salt 

 was present. Using the average height of plants as an index, the toxicity 

 of the salts was in the following order: Sodium carbonate, sodium 

 chlorid, magnesium nitrate, sodium sulphate, magnesium chlorid, sodium 

 nitrate, potassium nitrate, potassium chlorid, and calcium chlorid. 



Table XII. — Growth of wheat seedlings in solution cultures of various salts. Average 

 of 10 concentrations of each salt 



A rather conspicuous point in the table is the high ratio of tops to 

 roots, both as to length and weight, in the cultures containing mag- 

 nesium chlorid. The roots were also very short wath magnesium nitrate, 



