14 Journal of Agricultural Research voi. vi, no. i 



It is clear from the data that carbon bisulphid does not materially 

 benefit corn. An exception to this was seen in the case of Sparta sand; 

 in this instance the treated series showed a slight improvement. 



A comparison of the growth of mustard in acid and in neutral soil 

 shows that this crop grows best in a neutral soil. In Sparta sand and 

 Colby silt loam the yield of mustard in the treated soil was below that 

 of the control, while in the peat soil it failed entirely. It seems very 

 probable that the acid reaction of the soil inhibits the growth of mus- 

 tard. For instance, Kossovich (7) reports that mustard is sensitive to 

 acidity. The addition of 2 per cent of carbon bisulphid to Miami soil 

 stimulated the growth of mustard. This agrees with the results of pre- 

 vious tests. An increase in the growth of mustard has been noted in all 

 four experiments with carbon bisulphid in Miami soil. 



One series of jars, corn on Miami silt loam, was replanted to buck- 

 wheat. As previously reported, buckwheat showed a distinct improve- 

 ment in the carbon-bisulphid soil. If the control weights are taken as 

 100, the treated series is equal to 115. 



A review of all the data on the effect of carbon bisulphid on higher 

 plants shows very clearly that carbon bisulphid does not produce the 

 same effect on all plants. In almost every case (except acid soils) the 

 carbon bisulphid favors in a decisive way the growth of mustard. Next 

 in order of their response to carbon bisulphid come rape, red clover, 

 buckwheat, oats, and com. In acid soils, especially those rich in organic 

 matter, the growth of clover is greatly favored by the carbon-bisulphid 

 treatment. 



The majority of the evidence indicates that carbon bisulphid is most 

 beneficial to the growth of higher plants in peat or in open, sandy soils. 



EFl^ECT OF CARBON BISULPHID ON THE GROWTH OF PLANTS IN SILICA 



SAND 



If carbon bisulphid is a plant stimulant, then the addition of the proper 

 amount to a nutrient solution for plants should exert a beneficial effect 

 on the growth of higher plants. To test this a series of experiments was 

 performed on different plants. 



BUCKWHEAT AND OATS 



Eight jars were filled with pure silica sand (99 per cent pure quartz), 

 and the following ingredients added to each jar : 



Water (HgO) 500 c.c. 



Potassium nitrate (KNO3) 5 g™- 



Ferrous phosphate (Fe3(P04)2) 1.25 gm. 



Calcium phosphate (Ca3(P04)2) i. 25 gm. 



Calcium sulphate (CaS04) i. 25 gm. 



Magnesium sulphate (MgS04) i. 25 gm. 



