650 EXPERIMENT STATION RECORD. 



the Thomas slag (16 per cent citric acid soluble in phosphoric acid ) gave much better 

 results during the first year than agricultural phosphate (ground crude phosphate 

 containing 25 per cent total phosphoric acid). 



Sources of supply and methods of manufacture of phosphates and potash 

 salts, E. B. Yoorhees (Jour. Franklin Inst, 160 {1905), No. 3, pp. 211-215) .—Brief 

 accounts are given of the various sources of supply of natural phosphates, especially 

 in the United States, and of the Stassfurt potash dep< >sits. The condition of the phos- 

 phoric acid in different kinds of phosphates and their suitability for the manufacture 

 of fertilizers are discussed, as well as the manufacture of refined potash salts from the 

 crude salts and their use in the manufacture of fertilizers. 



Experiments with various potash fertilizers, E. Haselhoff (Landw. Jahrb., 

 34 (1905), No. 3-4, pp. 647-664, pi. 1). — An account is given of comparative pot tests 

 of potassium chlorid, potassium sulphid, potassium phosphate, potassium nitrate, 

 kainit, and 40 per cent potash salts, applied to potatoes followed by wheat. The 

 potash salts were used in connection with a basal fertilizer mixture containing the 

 necessary amounts of nitrogen and phosphoric acid. The fertilizers were applied 

 only to the potato crop, their after-effect being observed on the wheat. 



The data reported include yield and composition of the tubers and vines of the 

 potatoes and straw and grain of the wheat, the data for composition being used 

 especially as a basis for studying the relative rates of assimilation of potash and soda 

 in the different parts of the plants and with the different fertilizer combinations. 

 All of the potash fertilizers increased the yield of potatoes, but the results were not 

 conclusive as to the relative effectiveness of the different potash salts in this respect. 

 Two varieties of potatoes were used in the experiments, Gloria and Magnum bonum, 

 and the results show that the relative efficiency of the fertilizers varied with the 

 variety of the potato grown. 



A partial substitution of potassium chlorid by sodium chlorid resulted in a small 

 increase in yield, but when the amount of sodium chlorid was further increased 

 there was a decrease in yield. There was no after-effect of the potash salts on spring 

 wheat in one series of experiments and but a slight after-effect was observed in a 

 second series. The after-effects of substitution of sodium chlorid for potassium 

 chlorid were the same as with the first year's crop. The amount of potash taken 

 up by the plants varied with the different salts. The smallest amount of potash 

 was taken up by potatoes from the kainit, but during the following year the wheat 

 assimilated the largest amount of potash on the plat which had received kainit the 

 previous year. 



Sodium, whether applied in the form of sodium nitrate or sodium chlorid, was 

 taken up by both potatoes and wheat, and resulted in an increase of the sodium 

 content of both vines and straw and tubers and grain, the increase in case of the 

 grain being especially noticeable. The amount of soda assimilated varied with the 

 amount applied and its relation to the amount of potash present. It appears prob- 

 able that by -the application of sodium chlorid or potash salts containing sodium 

 chlorid the potash of the soil is rendered soluble and more easily assimilated by the 

 plants. 



The availability of mixed fertilizers, W. F. Sutherst (Chem. News, 92 (1905), 

 No. 2395, p. 185). — The solubility in 1 per cent citric acid of the phosphoric acid 

 of bone and various mixtures of bone and muriate of potash, kainit, nitrate of soda, 

 sulphate of ammonia, and salt is reported. The results show that the availability of 

 the phosphoric acid was increased in some cases and decreased in others by mixing 

 the bone with the chemicals. 



In case of bone meal containing a considerable amount of organic matter the solu- 

 bility of the phosphoric acid in 1 per cent citric acid was decreased by admixture 

 of muriate of potash, kainit, and salt. In case of bone flour containing a small 

 amount of organic matter the admixture of the chemicals in every case increased the 





