July 17, 1916 Influence of Calcium and Magnesium on Plant Growth 599 



carbonates limestone was 1 .62 times as soluble as dolomite and more than 

 3 times as soluble as magnesite. 



Applications of dolomite Ci up to 40 per cent caused no injury to 

 either wheat or alfalfa. 



Table IV shows the treatments and yields of series C and D. Analyses 

 of these plants are reported in Table V. Series C (wheat) was harvested 

 83 days after planting and series D (alfalfa) was harvested 84 days after 

 planting. 



From Table V it can be seen that wheat grown in soil (pots 41 and 42) 

 shows 0.279 per cent of calcium and 0.256 per cent of magnesium, but 

 when grown in extracted sand (Table III, pots 1 and 2) it had only 0.187 

 per cent of calcium and 0.108 per cent of magnesium, showing that there 

 is a decided tolerance for these two elements. By comparing the wheat 

 with the alfalfa it can be seen that, while alfalfa is a heavier feeder than 

 wheat on calcium and magnesium, the proportional amounts of calcium 

 are greater in alfalfa than in wheat. 



Table V. — Analysis of wheat and alfalfa grown in brown silt loam — series C and D 



WHEAT STRAW 



Pot No. 



41 and 42. 

 43 and 44. 

 47 and 48. 

 55 and 56. 

 63 and 64. 



Substance added. 



Calcium. 



Per cent. 

 3°5 



5 2 7 

 971 



315 

 30 



Mag- 

 nesium. 



Per cent. 



°-35 2 

 .458 

 . 671 

 . 2 



4. o 



Composition of plants. 



Calcium. 



297 

 297 



35 2 

 353 

 43 



Magnesium. 



Mgm. 

 23-3I 

 5 2 -7 

 32.8 



33-8 

 31.0 



Per cent. 



0. 256 

 .467 



1. 19 

 •337 



• 45 6 



Molecular 

 ratio of 

 calcium 

 to mag- 

 nesium. 



5 : 7-2 



5 :i 3- 1 

 5:28. 1 



5: 7-9 

 5 8.8 



WHEAT ROOTS 



41 and 42. 

 43 and 44. 

 47 and 48. 

 55 and 56. 

 63 and 64. 



5: 7-5 

 5-" 7 

 5:14. 1 



5:6 



5: 5-7 



ALFALFA HAY 



65 and 66. 

 67 and 68. 

 71 and 72. 

 79 and 80. 

 87 and 88. 



•3°5 

 •5 2 7 

 .971 



•3i5 

 5.3o 



35 2 

 458 

 671 



71. o 

 78.4 

 11. 4 



85-5 

 98-5 



1-595 

 1.56 

 .86 

 1.684 

 1.84 



17. 7 



35-3 

 12. 82 

 25. o 

 27. 8 



398 



624 



96 



492 



521 



3-8 

 9-3 



2.4 



2-3 



ALFALFA ROOTS 



65 and 66. 

 67 and 68. 

 71 and 72. 

 79 and 80. 

 87 and 88. 



5:11.8 



5 :i 4 7 

 5 :i 3-3 

 5 :i ° 

 5 : 5- 1 



