Feb. 17, 1919 Effect of Barium and Strontium on Plant Growth 193 

 TablB X. — Analyses of the corn fodder from the preceding experiments — Continued. 



The results of the analyses of the fodders that were produced in each 

 of the experiments show no very striking differences in the mineral com- 

 position of the fodders in any of the experiments (Table X). 



It will be obser\^ed that only very small amounts of barium and 

 strontium have been taken up by the plants growing in the presence 

 of compounds of each of these elements. 



SOYBEAN 



In Plate 24, C, are shown four jars of soybean {Soja max) plants that 

 were grown in cultural solutions. The plants in the jars on each end 

 have been grown in a cultural solution containing no barium compound, 

 whereas the two pots in the center have been grown in a similar solution 

 containing barium nitrate. The plants in the two jars in the center 

 received their sulphur from a solution containing taurin, while the 

 plants in the end jars received their sulphur from a solution of mag- 

 nesium and potassium sulphates. The differences to be observed in 

 the growth of the two sets of plants is attributed to the presence of the 

 barium nitrate v/hich appears to have retarded the growth of the roots, 

 stems, and foliage of the two sets of plants in the center. 



When the very small amounts of the barium compounds that occur 

 in the soil and the relatively insoluble state in which they occur are 

 taken into consideration, one is led to wonder how it is that plants are 

 able to extract even as much barium as can be determined in the ash 

 of normal plants. Since no barium was found by careful examination 

 of the residue from the evaporation of 25 liters of water flowing from 

 a tile drain on the Station farm, although the presence of barium in 

 the soil of the area drained had been proved by extracting 0.0508 gm. 

 of barium sulphate from the hydrochloric-acid solution from 500 gm. 

 of an average sample representing the first foot of soil from this field, 

 it would appear that the roots of plants do not obtain their barium 

 from the percolating soil water, but rather by some kind of selective 



