1919] SOILS FERTILIZERS. 425 



phate, calcium nitrate, and commercial calcium cyanamid as a source of 

 nitrogen, are reported. 



It was found as a general result of these experiments that " nitrate of am- 

 monia may be expected to give, at least as great increases of crop, weight for 

 weight of nitrogen, as any of the other concentrated nitrogenous manures 

 in use." 



Ammonium nitrate showed the best average results with both oats 

 and hay. This result is considered unusual and possibly due to accidental 

 causes. " If it is confirmed that nitrogen in nitrate of ammonia is more 

 effective as a fertilizer than an equal weight of nitrogen in nitrate of soda, 

 nitrate of lime, or sulphate of ammonia, it will be necessary to seek for an 

 explanation of such an unexpected result." 



The setting of mixtures of superphosphate and ammonium sulphate, F. S. 

 FowwEATHER (JouT. Soc. Chevi. Indus., 38 (1919), No. 9, pp. 110R-112R).—Ex- 

 periments to determine the conditions that influence the setting into hard 

 lumps of mixtures of ammonium sulphate with superphosphate are reported, 

 in which mixtures of superphosphate, containing about 30 per cent soluble 

 phosphate and ammonium sulphate, were placed under a heavy weight to 

 bring the particles into intimate contact. 



The conclusions drawn are that the rate of setting of such mixtures is in- 

 creased by the reduction of free acid in the mixture. " The presence of 

 moisture also tends to increase the rate of setting, but this effect is not very 

 marked unless accompanied at the same time by reduction of free acid." 



A large scale test confirmed the above conclusions. " Thus a compound 

 fertilizer made from fairly fresh mineral superphosphate and ammonium 

 sulphate to which a small amount of limestone was added set very consider- 

 ably when stored in a heap for a few days, and after regrinding and putting 

 into bags, no further trouble was experienced as regards setting." 



Phosphate demonstration in Stevens County in 1918, P. R. McMillek, P. E. 

 MiLLEE, and G. H. Nesom (Univ. Minn. Agr. Ext. Div. Spec. Bui. SIf {1919), pp. 

 7, figs. 2). — Cooperative field experiments with acid phosphate on 25 farms in 

 the county are reported in which the phosphate was added to fields ranging in 

 size from 1 to 30 acres at the rate of 200 lbs. per acre. The soil in general is a 

 black silt loam with silt loam subsoil. Of the 14 farmers who tried the phosphate 

 on wheat nearly all secured a marked increase, ranging from 2.1 to as high as 

 10.5 bu. per acre. No increase was obtained with acid phosphate on oats, but 

 there was an increase in six cases out of seven with barley. 



" No heavy investments in phosphate are suggested, but the results of the ex- 

 perimental work in Stevens County to date make it appear a wise business 

 measure for those farmers of Stevens and the immediately surrounding 

 counties who have heavy soils on which some fields have received little or no 

 manure, to apply on one of these half a ton or more of acid phosphate at the 

 rate of 200 lbs. per acre, using wlieat or barley as the trial crop and preferably 

 seeding with clover." 



The phosphate industry, J. Hendrick (Jour. Soc. Chem. Indus., S8 (1919), 

 No. 9, pp. 155R-157R). — The author discusses the phosphate industry throughout 

 the world, with special reference to the United States and Great Britain, and 

 reports the average results of 66 field experiments with turnips covering four 

 years at the North of Scotland Agricultural College comparing soluble and in- 

 soluble phosphates. 



" The general result of the experiments is to show (1) that the average effect 

 of superphosphate is only slightly greater than that of insoluble phosphate, such 

 as basic slag or ground mineral phosphate, when equal weights of phosphoric 

 acid are applied, and (2) that if one-third of the phosphoric acid is given as 



