SOILS — FEETILIZEES. 



419 



ported sodium bisulphate was substituted for sulphuric acid. A Russian rock 

 phosphate was treated with the bisulphate, the product obtained dissolved m 

 water and the solution evaporated until sodium sulphate crystallized out 

 When the solution was concentrated to 45° Baume it contained from 20 to 22 

 gm of phosphoric acid per liter, and this solution readily attacked steamed 

 bone meal and yielded a double superphosphate of good physical quality, but 

 which contained only from 24 to 25 per cent of phosphoric acid, from 92 to 98 

 per cent of which was soluble in water. 



The action of iron sulphid and its oxidation products in combination witH 

 phosphorite P. E. Gal'tsev and I. V. aKUSHKiN {Izv. Moskov. Selsk. Khoz. 

 Inst (Ann. Inst. Agron. Moscou), 19 {1913), No. 1, pp. 223-232, figs- 2).-ln pot 

 experiments the use of iron sulphid in combination with rock phosphate did not 

 increase the assimilation of phosphoric acid. The use of a modified pyrite, 

 containing sulphate and sulphuric acid, however, produced a beneficial effect m 



tbis rcsoGct 



Possible sources of potash in the United States, F. K. Cameron (U. 8. Dept. 

 Agr Yearbook 1912, pp. 523-536) .—The results of special investigations made 

 by the Bureau of Soils and the U. S. Geological Survey on this subject are 

 briefly summarized. The minor sources of potash discussed are wood ashes, 

 wool washings, pomace and vinasse, artificial niter, sunflowers and desert 

 plants carbonate ponds of Nebraska and vicinity, rock salt and brines; the 

 major sources, alunite, feldspar, and potash silicates, desert basins, and giant 

 kelps The general conclusion is " that the United States has at hand known 

 possible sources of potash suflicient to supply its present and prospective needs. 

 It has possiblv. but not yet proved, sources sufficient to supply many times its 

 own needs Some of these have apparently so much promise, commercially, as 

 to justify the expectation that potash salts of American origin may be a factor 

 in the market in the near future." 



The effect of sodium manuring on the composition of plants, B. L. Haet- 

 WELL and P H. Wessels {Rhode Island Sta. Bui. 153, pp. S9-118).-The results 

 of investigations which have been carried on at the station for a number of 

 years are summarized as follows : 



■ " The field experiment, involving 48 plats, was begun in 1894. The soil was 

 kept supplied with liberal amounts of nitrogen and phosphorus. Different 

 relative quantities of potassium and sodium in chlorids and carbonates were 

 applied to separate plats. Two different amounts of lime were used, but m 

 all cases the soil still reacted somewhat acid to litmus paper. During the 

 early part of the experiment the average maximum applications per year of 

 the potassium and sodium salts were from about 250 to 420 lbs. per acre; but 

 during the years 1907 to 1910, in which was undertaken the work not hereto- 

 fore published, the applications of potassium and sodium were reduced to about 

 one-third of these amounts. 



" Earlier published determinatiops of the plant-food materials m the crops 

 showed that an increase in the sodium manures increased the percentage of 

 phosphorus, but not of nitrogen, in the crops. The percentage of sodium was 

 likewise increased, but that of potassium was decreased in the majority of cases. 

 " The results with onions in a single year, 1908, showed that the addition of 

 the full ration of sodium to the full ration of potassium affected uniformly 

 neither the size of the crop nor the percentage of total and reducing sugars. 

 Furthermore, although in the presence of the full ration of sodium the reduc- 

 tion in the amount of potassium to one-half and one-fourth rations resulted m 

 successive decreases in the crop, the percentage of sugar was not universally 

 changed. Incidentally it was shown that ordinary drying of onions reduces 

 the amount of total sugar and increases the proportion of reducing sugar. 



