326 EXPERIMENT STATION EECOBD. [Vol.35 



Certain factors which influence the ferti li zi n g action of the slightly 

 soluble phosphates, H. G. Sodekbaum (K. Landtbr. Akad. Eandl. och Tidskr., 

 54 (1915), No. 5, pp. 448-477, figs. 7 ; Meddel. Centralanst. Forsoksv. Jordbruk- 

 somrddet, No. 112 (1915), pp. 35, figs. 7 ; abs. in Chem. Abs., 9 (1915), No. 23, 

 p. 3319). — Pot cultui-e experiments with oats, barley, rye, and wheat on soils 

 deficient in both nitrogen and phosphoric acid to determine the influence of 

 the carbonate and sulphate of magnesium, sodium nitrate, ammonium sulphate, 

 and organic nitrogen on the fertilizing action of superphosphate, Thomas slag, 

 dicalcium phosphate, tricalcium phosphate, bone meal, Algerian phosphate, 

 and apatite are reported. 



Previous experiments on the influence of lime on the slightly soluble phos- 

 phates are reviewed, which showed that while the addition of lime to the 

 readily soluble phosphates had no marked influence upon their fertilizing 

 action, that of the less soluble phosphates was inhibited. With a low lime 

 content in the soil either type of phosphate was used to advantage, but with a 

 high lime content the insoluble phosphates gave no favorable results. 



In the present experiments it was found that when using superphosphate a 

 larger crop yield was obtained with ammonium sulphate than with sodium 

 nitrate, but when using tricalcium phosphate the opposite was true. The 

 results varied with the crops, wheat being more sensitive than the others. 

 When using dicalcium phosphate little difference was observed in the action 

 of the two nitrogen compounds. With the less soluble phosphates ammonium 

 sulphate and organic nitrogen proved superior to sodium nitrate, except with 

 barley, with which ammonium sulphate and organic nitrogen always gave a 

 poorer crop than sodium nitrate, regardless of the type of phosphate used. 

 When magnesium sulphate was used with the readily soluble phosphates, 

 little influence was observed on crop growth, regardless of the form of nitrogen 

 used, but when magnesium carbonate and ammonium sulphate were used with 

 readily soluble phosphates a distinctly increased yield was obtained. With the 

 less soluble phosphates, magnesium sulphate gave slight and conflicting results, 

 and the results obtained with magnesium carbonate varied with the plant, the 

 yield of rye and wheat being increased and that of barley and oats slightly 

 decreased. 



Displacement of the potash and phosphoric-acid contents of certain rocks 

 by some fertilizers, G. AndeiS (Compt. Rend. Acad. Sci. [Paris], 162 (1916), 

 No. 3, pp. 133-136; abs. in Rev. Sci. [Paris], 54 (1916), I, No. 3, p. 94).— Experi- 

 ments conducted along lines similar to those with feldspar, previously noted 

 (E. S. R., 30, p. 126), are reported in which glauconite containing 7.08 per cent 

 potash was subjected to the action of calcium carbonate, sodium chlorid, 

 sodium carbonate, ammonium sulphate, and calcium sulphate in the presence 

 of water, using 1 gm. of the salts to 10 gm. of glauconite. It was found that 

 the salts in the order mentioned dissolved 3.24, 5.67, 5.62, 7.17, 9.97, and 5.56 

 per cent of the total potash content of the glauconite. These results are said 

 to be greater than those obtained with feldspar. 



In further experiments with apatite, using ammonium carbonate, sodium 

 nitrate, potassium nitrate, and potassium carbonate, it was found that ammo- 

 nium carbonate and the nitrates failed to displace any appreciable amount of 

 phosphoric acid. Potassium carbonate displaced about 0.35 per cent of the 

 phosphoric-acid content of the apatite. 



Feldspar as a possible source of American potash, A. S. Cushman and 

 G. W. CoGGEHHAi.i, (Trans. A)ner. Inst. Chem. Engin., 7 (1914), PP- 184-202). — 

 In a second contribution to the subject (E. S. R„ 27, p. 724), the authors report 

 additional investigations which were conducted with the idea of separating and 



