602 



Journal of Agricultural Research 



Vol. VI, No. 16 



Plate LXXXIV shows the difference between some of the treatments 

 in series G. Observe the small growth of the wheat in the pot receiving 

 6 per cent of magnesium in magnesite. This is due to the physical con- 

 dition caused by applying the magnesite in a finely ground form, which 

 caused a setting that resembled cement, whereas in the pot with 10 per 

 cent of magnesium almost twice as much magnesite was applied, but 

 in a coarser form. For the ratios in these pots see Table VIII. 



Plate LXXXIV shows alfalfa growing under similar treatments. 



Table VIII. — Yields of wheat and alfalfa {in grams per pot on water-free basis) in soil, 

 dolomite, and magnesite — series G and H 



Treatment. 



None 



Percentage of magne- 

 sium in calcareous 

 soil: 



2.64 



1-328 



o. 672 



o. 344 



Percentage of magne- 

 sium in magnesite 

 plus calcium car- 

 bonate: 



2.0 



6.0 



10.0 



Percentage of magne- 

 sium in dolomite 

 Ci: 



12.7 



Molecular 

 ratio of 

 calcium 

 to mag- 

 nesium. 



5:3-8 

 5^3-8 

 5:3-8 

 5:3-8 

 5:3-8 

 5:3-8 

 5:3-0 

 5:3-9 



5:4 

 5=4 



5:75 

 5:75 



5 :i2 5 

 5:i 2 5 



5:5-2 

 5:5-2 



Wheat, series G. 



Pot 

 No. 



121 

 122 



123 



124 



125 

 126 

 127 

 128 

 129 

 130 



131 

 132 



*33 

 134 



135 

 136 



137 

 138 



Tops. 



15-4 

 I.08 



21.93 

 21. O 



26. 9 



2 7-3 



24- 5 

 28.62 



3 J -7 

 32.6 



35-5 

 35-8 

 9-7 

 30.8 

 18.2 

 17.4 



2. 17 

 3.26 



6-53 



15 



7 

 2 



4 

 4 

 25 

 14.4 

 10.32 



11.05 

 10.05 

 4. 26 

 1. 18 

 6. 25 

 6. 16 



Alfalfa, series H. 



First 

 crop. 



3-6 



2.28 



7. 22 

 7.04 

 9.41 



9-59 

 10. 11 

 10. 02 

 10. 28 



9.68 



9-15 

 10. 9 

 5.28 



5-9 



4.48 

 10. 11 



Second 

 crop. 



9-59 



7-47 

 7. 22 

 11. 7 



12.35 

 13. 72 

 12.3 

 9.68 

 10. 46 



8.97 

 9.86 



8-45 



10. 62 



5- 02 



9-77 



9-77 



Third 

 crop. 



5-63 



12. 6 



10. 02 



13.0 



10. 9 

 12.3 



9-59 

 10. 71 



7-8 3 



8.8 



8.88 



5-2 



3-69 



2.28 



9-59 



9-77 



Pot 

 No. 



147 

 148 



149 

 I50 

 151 

 152 

 153 

 154 

 155 

 156 



157 

 158 

 159 

 160 

 161 

 162 



163 

 164 



One of the most noticeable facts brought out in these series is the great 

 sensitiveness of the plants to small quantities of calcium and magnesium, 

 also their ability to utilize relatively insoluble forms of these two ma- 

 terials. In pots 121 and 122, Table IX, and pots 147 and 148, Table X, 

 the plants were grown in extracted sand receiving no calcium and mag- 

 nesium and were able to obtain considerable quantities that had not been 

 removed by the acid extractions. The alfalfa was even able to mature 

 a few seeds. 



