142 BOARD OF AGRICULTURE. [Pub. Doc. 



solved phosphate rock (acid phosphate), 11,254 pounds. 

 The great superiority of the basic slag was unquestionably 

 due in this instance to the favorable action of the lime upon 

 the crop, — a function which the lime of the superphosphate, 

 which is largely changed to land plaster (gypsum) in the 

 process of manufacture, cannot effectually perform. In fact, 

 the Kingston experiments bear out this conclusion most 

 fully, as shown by the close proximity of the results secured 

 with superphosphate to those with basic slag upon the limed 

 soil, where of course the additional lime contained in the 

 slag meal could not prove as effective in its influence upon 

 the crop as upon the unlimed land. The basic slag pro- 

 duced 20,400 pounds of hay, while the results with super- 

 phosphate were as follows: dissolved bone-black, 19,838 

 pounds ; dissolved bone, 19,281 pounds ; and dissolved phos- 

 phate rock, 20,205 pounds. From this it will be seen that 

 there was a total difierence of crop, as compared with the 

 dissolved phosphate rock, amounting on the limed land, in 

 four years, to but 195 pounds of hay per acre in favor 

 of the basic slag, while on the unlimed soil it amounted to 

 4,242 pounds, or over 2 tons, of hay. This not only illus- 

 trates in the most striking manner the point aimed at, but 

 shows that upon acid soils where lime is deficient the lime of 

 basic slag in its corrective influence upon the soil is a source 

 of great material value to the farmer, amounting in this in- 

 stance to over 2 tons of hay to the acre in the course of the 

 four years. 



Iron and alumina phosphate is probably but little known 

 to the farming community, though, if the truth were known, 

 there are many who use it as a constituent of certain brands 

 of commercial fertilizer. This is the material known in 

 Europe as redonda phosphate, where it is considered by 

 many, even when treated so as to show by analysis much 

 reverted phosphoric acid, as practically worthless, and a 

 most dangerous adulterant of other phosphates. It is 

 sometimes referred to as redondite. This phosphate is 

 usually subjected in this country to a patented process, 

 which renders a large portion of it soluble in ammonium 

 citrate solution, as a result of which it is determined and 

 classed chemically as reverted acid. After subjection to 



