FERTILIZERS. 733 



The average composition of the fertilizers is about the same as in 

 previous years except that there are slightly smaller percentages of 

 ammonia and potash. " One out of every 4 of the usual fertilizers fell 

 below the guaranty in some single ingredient and 1 out of 15 in its 

 valuation." 



Experiments on the action of phosphoric acid in bone meal and 

 Valserine phosphate as compared with that of superphosphate 

 and Thomas slag, P. Liechti (Landw. Jahrb. Schweiz, 11 (1897), pp. 

 378-389). — This is an account of comparative tests during 2 years 

 (1890-1897) of the above phosphates on oats growing in galvanized-iron 

 cylinders (20 cm. deep and 20 cm. in diameter) tilled with a sandy humus 

 soil containing a moderate supply of potash and phosphoric acid. 

 The phosphatic materials used were bone ash superphosphate contain- 

 ing 16.3 per cent of water-soluble phosphoric acid in 1890 and 17.5 per 

 cent in 1897; tine-ground Thomas slag containing 17.51 per cent total 

 phosphoric acid and 15.08 per cent of citrate-soluble phosphoric acid, 

 tine-ground Valserine phosphate containing 19.39 per cent total phos- 

 phoric acid and 1.44 per cent citrate-soluble phosphoric acid, raw bone 

 meal containing 19.02 per cent total phosphoric acid and 4.32 per cent 

 of nitrogen, fine-ground steamed bone meal containing 32.3 per cent 

 phosphoric acid and 1.3 per cent nitrogen, and coarse steamed bone 

 meal containing 32 per cent phosphoric acid and 1.4 per cent nitrogen. 

 Each year phosphoric acid was applied in the different forms at the rate 

 of 0.35 gm. per pot, or 111.40 kg. per hectare (99.3 lbs. per acre), 

 together with supplementary applications of the necessary amounts of 

 potash and nitrogen. The highest yields were obtained each year from 

 the pots to which superphosphate and slag were applied. The pots 

 receiving superphosphate yielded on the average in 1890 54.3 gm. 

 of grain and 112.7 gm. of straw, containing 0.271 gm. of phosphoric acid ; 

 in 1897 the corresponding figures were 54, 83.3, and 0.2057. The pot 

 receiving slag produced in 1890, G0.9 gm. of grain and 110.0 gm. of straw, 

 containing 0.271 gm. of phosphoric acid; the corresponding figures in 

 1897 were 48.0, 70.1, and 0.292. It is thus seen that in case of the super- 

 phosphate and slag the yields were somewhat lower in 1897 than in 

 1896. There was a small relative increase in yield in the pots which 

 had received insoluble phosphoric acid in the form of bone meal and 

 mineral phosphate, but when the large amount of phosphoric acid 

 actually applied in these cases is taken into account this increase is 

 insignificant. The proportion of phosphoric acid applied which was 

 recovered in the crops was as follows : 



Proportion of phosphoric acid recovered in the crop. 



Superphosphate 



Thomas slag 



Raw bone meal 



Steamed bone meal (fine) . . . 

 Steamed bone meal (coarse) 



