only 70 pounds of barium sulfide would be applied per acre. Laboratory 

 experiments show that the Barium-Phosphate has about 1-20 the neutraliz- 

 ing effect of commercial hydrated or slaked lime, and about 1-15 that of fine 

 ground limestone. In other words, a soil that would require one ton, or 

 2,000 pounds of calcium hydrate to reduce soil acidity, would require 2,720 

 pounds of calcium carbonate, and 40,000 pounds, or 20 tons, of Barium- 

 Phosphate to produce the same effect; or stated in another way, 136 pounds 

 of ground limestone costing about 40 cents would be as effective a neutrali- 

 zer as a ton of Barium-Phosphate. 



CONCLUSIONS. 



From the results of experiments thus far conducted at this Station, we 

 have failed to observe any effect from the use of Barium-Phosphate that 

 would warrant us in recommending its use in place of the soluble phosphates. 



The manufacturers claim that to get the best results with this mate- 

 rial, it should be used in connection with stable manure or with green 

 crops plowed under, assuming that the bacteria in the manure will render 

 available the insoluble phosphates. This point we have not as yet 

 proved, and it is our purpose to conduct further experiments in order if 

 possible to solve the problem. 



*One exception was noted in one pot in the experiment conducted in 1916 witli Dwarf Essex 

 Rape. 



