Effect of Alkali Salts in Soils on Crops 



37 



the height was much more affected by the salts than in loam. The rise 

 in the cur\^e at 10,000 p. p. m. is due to the fact that no plants grew at 

 this concentration in the more toxic salts and not to the actual increase 

 in height. 



Figure 42 shows the effect of each salt in the three soils on the height 

 of wheat. The same general results which have already been pointed 

 out in connection with germination and dry -matter production are noted 

 here. Potassium nitrate produced the shortest plants in the loams, 





Fig. 3 7. — Curve showing the nutaber of days for wheat plants to come up in College loam, Greenville loam, 

 and sand containing various salts. Average for all concentrations. 



while sodium chlorid and sodium carbonate produced the shortest plants 

 in sand. 



Figure 43 shows the height of plants in soils to which three salts in 

 combinations of various kinds had been added. This diagram shows 

 that the chlorids and nitrates had a great effect on the height of plants, 

 while the carbonates and sulphates had less. 



The effect of the concentrations of sodium chlorid and sodium sulphate 

 on the height of different crops is showTi in figure 44. While the curves 

 are somewhat irregular, they show the same results that have already 

 been brought out regarding the shortening of plants by alkali. 



Figure 45 shows the effect of individual salts on the height of various 

 crops. It will be noted that in practically all cases the crops were 

 shorter where sodium chlorid was present than with the other salts; 

 also that sodium sulphate usually gave the highest plants. 



