Effect of Alkali Salts in Soils on Crops 



31 



nesium chlorid retarded germination most of any of the salts that were 

 used together, while sodium sulphate, potassium sulphate, and mag- 

 nesium sulphate retarded it least. With the first three salts there was 

 no germination whatever above 9,000 p. p. m. and less than one-third 

 complete germination at a concentration of 5,000 p. p. m. 



In figure 29 the effect of the concentration of sodium chlorid, sodium 

 carbonate, and sodium sulphate on the different crops is shown. A strik- 

 ing feature of the table is the stimulating effect of these salts in low con- 

 centration on the germination of sugar beets. With the exception of 

 sugar beets, all the crops showed considerable similarity. One reason 

 for the high germination of beets is the number of germs in each seed 



a 12 



U 9 



o 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 

 Concentration of salts in p. p. m. 

 Fig. 29.— Curve showing the effect of concentration of salts on the number of seeds of various kinds ger- 

 minating. Average for sodium chlorid, sodium carbonate, and sodium sulphate. 



ball. Alfalfa and field peas were affected by the salts decidedly more 

 than the cereals. 



The individual effect of sodium chlorid, sodium carbonate, and sodium 

 sulphate on the different crops is shown in figure 30. Sodium chlorid is 

 seen to be rather uniformly toxic to all crops, while sodium carbonate 

 varies greatly. Sugar beets seem to be particularly resistant to sodium 

 sulphate. 



DRY MATTER PRODUCED 



The five curves which follow (fig. 31-35) show the same results for 



amounts of dry matter produced by each glass that were given for 



germination in the five preceding figures (fig. 25-30). The numbers 



given represent the dry weight of plant material produced in each glass. 



5770°— 15 3 



