6io 



Journal of Agricultural Research 



Vol. VI, No. 16 



EFFECT OF MAGNESIUM AND CALCIUM IN CALCAREOUS SOIL, DOLOMITE, 

 AND MAGNESITE, AFTER ALFALFA, UPON SOYBEANS (SERIES N) 



The soybeans in series N were grown after three crops of alfalfa had 

 been removed and the roots turned under. Pots 239 and 240 showed 

 but a small amount of growth. Pots 251, 252, and 253 showed consider- 

 able organic growth, but the plants were sickly and did not yield much 

 seed. The yields are reported in Table XVII. Analyses of the plants, 

 Table XVIII, show treatments with the largest quantities of magne- 

 sium in magnesite, giving the plants with the greatest magnesium con- 

 tent and containing as much as 29.92 pounds of magnesium per ton. 

 Also proportionately the highest amount of calcium and magnesium 

 were found in these pots. The check pots, 239 and 240, showed the 

 lowest percentage of calcium and magnesium in the plants grown. 



Table XVII. — Yields of soybeans {in grams per pot on the water-free basis) grown after 

 alfalfa in soil, magnesite, and sand — series N 



Pots 240, 242, 244, 245, 247, 249, and 253 were harvested at maturity, 

 or 80 days after planting. 



The plants used in the experiments in Table XVIII were 53 days old. 



Table XIX shows the differences in composition of wheat grown under 

 the same treatment but harvested at different periods of growth. The 

 first plants were harvested 53 days after being planted. It was the 

 original plan to allow the duplicates to mature, but owing to attacks of 

 mildew they were harvested 1 2 days later. 



