Oct. 4. igis 



Effect of Alkali Salts in Soils on Crops 



29 



even more so than with sodium carbonate. This affirms the well-known 

 toxicity of magnesium salts to roots when used alone. The various salts 

 in solution cultures did not act at all in the same manner as in soils, 

 which shows the inadvisability of applying too widely to the soil the 

 results obtained with solution cultures of alkali. 



RESULTS OF STUDIES 

 NUMBER OF SEEDS GERMINATED 



In the five graphs which follow (fig. 26-30) the eflfects of various 

 factors on the number of seeds germinating in each glass are given. 

 These are all summaries and each one represents a great many figures. 

 It will be remembered that 10 seeds were planted in each glass. 





 ^ 6 





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. 26. — Curve showing the number of wheat plants germinating in College loam, Greenville loam, and 

 sand with different concentrations. Average of 13 salts. 



Figure 26 shows the effect of the concentration of salts in sand, Green- 

 ville loam, and College loam on the number of seeds germinating. Each 

 curv'e represents the average of 13 salts in various combinations. In all 

 of the soils there was an average of about 8>2 plants coming up in each 

 glass to which no salt was added. In sand the germination rapidly 

 decreased with the concentration of salt, especially above 3^000 p. p. m. 

 In College loam and Greenville loam there was but little falling off in 

 germination until a concentration of over 4,000 p. p. m. had been 

 reached. 



Figure 27 shows the effect of the various salts on the germination of 

 wheat in the three kinds of soil. Each salt represents the average of 10 

 concentrations ranging from 1,000 to 10,000 p. p. m. In sand there 



