SOILS — FERTILIZERS. 25 



with soils of different types. It was found tliat the different sludges behaved 

 differently in any one soil, and that the different soils showed decidedly differ- 

 ent capacities for rendering the nitrogen of the sludge available as measured 

 by nitrates formed. The rate of nitrification, however, was generally higher 

 than that of such high-grade materials as dried blood, tankage, fish guano, 

 and cotton-seed meal. 



The economic importance of utilizing sludge is discussed and suggestions as to 

 the best methods of using it alone and with other fertilizers are given. 



Peat, C. A. Davis (U. S. Oeol. Survey, Mineral Resources of the United 

 States Calendar Year 19 IS, pt. 2, pp. 383-392).— This is a review for 1913 of 

 data relating to the production and use of peat in the United States and abroad. 



[Utilization of prickly pear as a fertilizer], T. H. Johnston and H. Tryon 

 (Rpt. Prickly-Pear Travel. Com., Qtieensland, 1912-1914, pp. 25, 26). — The 

 use of prickly pear as a fertilizer as practiced in Madras, Mysore, and the Bom- 

 bay Presidency, of India, is briefly described. 



The action of liquid manure as a nitrogenous fertilizer, B. Schulze {Ztschr. 

 Landw. Kammer Schlesien, 18 {1914), No. 44, p. 1630). — Comparative tests on 

 potatoes, beets, and oats of equal amounts of nitrogen in the form of nitrate 

 and of liquid manure are briefly reported, indicating that the utilization of 

 the nitrogen of the nitrate was about 60 per cent, while that of the liquid 

 manure was about 41 per cent. 



The manufacture of nitrates from the atmosphere, E. K. Scott (Ann. Rpt. 

 Smithsn. Inst., 1913, pp. 359-384, pis. 3, figs. 7). — This is a reprint of an aiticle 

 which has already been noted from another source (E. S. R.. 27. p. 420). 



The action of certain new nitrogenous fertilizers on sandy and upland 

 moor soils, B. Tacke (Mitt. Ver. Ford. Moorkultur Deut. Reiche, 32 (1914), 

 No. 23, pp. 4^^-424)- — Comparative field tests on oats, rye, and potatoes grown 

 on sandy and moor soils of diffei*ent kinds showed that ammonium nitrate, 

 calcium nitrate, urea, and superphosphate prepared with synthetic nitric acid 

 were, as a rule, as effective as sodium nitrate and ammonium sulphate and 

 may be substituted for them if the price permits this to be profitably done. 

 The Schloesing nitrate was apparently less effective on the well-limed moor 

 soils than the other fertilizing materials tested. 



[Some chemical and agricultural effects of fertilizer mixtures containing 

 calcium cyanamid], C. J. King (Com. Pert., 10 (1915), No. 1, pp. 14-16).— 

 Continuing previous work by Brackett (E. S. R., 30, p. 26), the author studied 

 changes in the soluble phosphoric acid and nitrogen content in mixtures of 

 acid phosphate, calcium cyanamid, and muriate of potash, and also the effect 

 of such mixtures on the growth of cotton. 



The results confirm those of previous experiments in showing that there 

 was a considerable reversion of phosphoric acid in the mixtures after standing 

 a few months. After six months of storage the amount of insoluble phosphoric 

 acid had increased from 0.4 to 2.01 per cent. There was no appreciable loss of 

 nitrogen in that time. The field tests of the mixtures on cotton indicated a 

 depreciation in their fertilizing effect within one month after the mixtures were 

 made. 



The kelp industry {Rpt. Bd. Agr. Scot., Home Indus. Highlands and Islands, 

 1913, pp. 118-131; ahs. in Jour. Franklin Inst., 179 (1915), No. 2, p. 260).— 

 Attention is called to the marked increase in the production of kelp in the 

 British Isles since 1905 and a brief account is given of methods of utilization 

 employed, especially in Scotland, and of the products which may be obtained. 



It is stated that Scotch seaweed is much richer in iodin than Pacific coast 

 kelps or Japanese seaweeds and is, therefore, especially valuable as a source 

 of supply of this substance, particularly in view of the present shortage of the 



