July 17, 1916 Influence of Calcium and Magnesium on Plant Growth 603 



TABLE IX. Analysis of wheat grown in soil, dolomite, and magnesite series G 



WHEAT STRAW 



WHEAT ROOTS 



The high percentage of magnesium in the plants grown in pots receiv- 

 ing 35 per cent of magnesite is also characteristic of tolerance. Like- 

 wise a high magnesium content tends to accompany plant sickness. In 

 the case of wheat grown in dolomite, pots 137 and 138, there was a 

 higher percentage of calcium than in any other treatment. A ton of 

 water-free material contained 11.48 pounds of calcium and 14.6 pounds 

 of magnesium, but a ton of dry matter from the treatment with 25 per 

 cent of magnesite showed 7.5 pounds of calcium and 19.1 pounds of 

 magnesium per ton, as against the check in sand which contained 3.3 

 pounds of calcium and 2.64 pounds of magnesium. Alfalfa tends to show 

 the same thing, except that it is a decidedly heavier feeder upon these 

 two elements than is the wheat crop. 



The wheat, Table VIII, was planted on January 26, 1914, and harvested 

 on May 27, 1914, making 121 days of growth. The alfalfa was also planted 

 on the above date and the first crop harvested on May 27, 1914. The sec- 

 ond crop was harvested 127 days later, on October i, 1914, and the third 

 crop on November 12, 1914, after 42 days of additional growth. 



By comparing pot 147, Table X, for the three crops, it will be seen 

 that the second crop of alfalfa contained practically three times as much 

 calcium and magnesium per ton as did the first crop, while the time of 

 growth was about the same. The third crop contained about twice as 

 much calcium and magnesium per ton as did the first crop, and its period 



