THE PHYSICO-CHEMICAL INVESTIGATION OF SOILS. 



335 



N 

 Chile Saltpeter. 



Superphosphate, 



N 

 Tankage. 



Blank. 



P + N 



Superphosphate 

 and Chile 

 Saltpeter. 



Blank. 



P + K. 



Superphosphate 



and sulfate of 



Potash. 



Blank. 



P + N + K 



Superphosphate 



Chile Saltpeter and 



Sulfate of Potash. 



Blank. 



P 



Bone meal. 



K. 



Sulfate of 

 Potash. 



Thomas Phosphate 

 Slag. 



Scheme for Plot-tests of Fertilizers. 



