764 EXPERIMENT STATION RECORD. 



If the effectiveness of water-soluble phosphoric acid be taken as 100, 

 that of the citrate- soluble phosphoric acid in case of alfalfa was 90.9 

 and in case of oats 82.4. The after effect of the slag on white mustard 

 was much greater than that of the water-soluble phosphoric acid, being 

 as 151.0:100. The after effect of the slag was greater the higher the 

 percentage of citrate-soluble phosphoric acid which it contained. 



Slags fi"om which the citrate-soluble phosphoric acid had been 

 removed were com^iared in the same manner. The effect on the first 

 crop of oats was practically insignificant, but the after effect on the fol- 

 lowing crop of mustard was more marked, although much inferior to 

 that of slags containing citrate-soluble i)hosphoric acid, 



Thomas slag, in which 12.8 per cent of phosphoric acid was citrate 

 soluble, was comi)ared on alfalfa and oats, followed by mustard with 

 the same slag so treated, by fusion with quartz, that 89.2 per cent of 

 its phosphoric acid had been rendered citrate soluble. The resalts 

 show clearly that not only the citrate solubility, but to an equal degree 

 the fertilizing effect of the phosphoric acid had been increased by fusion 

 with quartz. 



The effectiveness of partially dissolved bone meal, M. Maercker 

 {Jahrh. agr. chem. Vers. Stat. Halle, 1895, i)p. 22, 23). — To steamed bone 

 meal was added the amount of sulphuric acid which it was calculated 

 would convert the phosphate into dicalcium plios})hate. The prepara- 

 tion, however, contained 3.5 per cent of water-soluble phosphoric acid 

 and 19.5 jier cent of total phosphoric acid, a part of the phosphoric acid 

 remaining in the tricalcium form. This material was compared with 

 Thomas slag on oats, white mustard, and alfalfa, grown in pots on 

 sandy soil. On the oats the 2 phosphates produced practically iden- 

 tical results. On mustard following oats the prepared bone meal was 

 much more effective* than the Thomas slag, although the amount of 

 phosphoric acid utilized by the crop in each case was practically iden- 

 tical. In the case of alfalfa the prepared bone meal was slightly more 

 effective in increasing the yield and was utilized to a much greater 

 extent than the Thomas slag. 



Vegetation experiments on the fertilizing effect of various pot- 

 ash salts, M. Maercker {Jahrh. agr. chem. Yerfi. Stat. Halle, 181)5, pp. 

 8-15). — The fertilizing effect of kaiuit, carnallit, hartsalz (Schonit),^ 

 carbonate of potash, sodium chlorid, and magnesium chlorid, applied 

 at rates of 445 and 890 lbs. per acre, was tested on alfalfa, white mustard, 

 and potatoes, grown in pots containing light sandy soils. 



In the case of alfalfa, kainit and carnallit produced about the same 

 effect. The hartsalz gave a much larger increase in yield than the 

 other Stassfurt potash salts used, although it proved inferior in this 

 respect to the potassium carbonate.. 



' This is a salt similar to sylvinit, and contained potash, 14.91 per cent; lime, 3 per 

 cent; magnesia, 6.62 per cent; sulphuric acid, 15.11 per cent; and chlorin, 39.33 per 

 cent. 



