724 EXPEEIMENT STATION KECOKD. 



rate of nitrification of dried blood, ground bone, leather, oat straw, and alfalfa 

 hay, each added at the rate of 0.1 gm. of nitrogen with 0.75 gm. of calcium 

 carbonate to 300 gm. of sandy soil. 



Two rates of moistui*e were maintained in different series, (1) 5.35 i>er cent 

 calculated on the dry soil, or 20 per cent of the water-holding capacity of the 

 soil, and (2) 16.05 per cent, or 60 per cent of the water capacity. The soils 

 were placed in bottles which were kept in a dark cupboard. They were corked 

 to prevent evaporation but were aspirated twice weekly to renew the air. 



Determinations of ammonia and nitrate nitrogen were made at the beginning 

 of the experiments and at the end of 34 and 123 days. The mean temperature 

 of incubation was about 70° F. 



The results showed that in the case of the more active fertilizers the nitro- 

 gen was promptly ammonified and passed readily into the form of nitrates. 

 Taking the sum of the ammonia and nitrate nitrogen to represent available 

 nitrogen, it was found that four-fifths of the nitrogen of blood and bone was 

 converted into available form within four months under suitable conditions of 

 moisture and temperature. About 50 per cent of the nitrogen of alfalfa was also 

 made available in four months. Only 1.36 i>er cent of the nitrogen of leather 

 became available in that time, and this occurred only under the more moist con- 

 ditions of soil. There was an actual loss of available nitrogen in the case of 

 oat straw. 



On the composition and value of bat guano, C. F. Miller {Jour. Indus, and 

 Engin. Chem., 6 (19 H), No. 8, pp. 664, 665). — Analyses of samples of bat guano 

 from various sources are reported and discussed. 



In these samples the nitrogen varied from 0.5 to 11.84 per cent, phosphoric 

 acid from 1.08 to 4.8, and potash from 0.21 to 1.61. The results show wide 

 variations not only in the percentages of the fertilizer constituents but also in 

 their ratios to one another. In general, in the more recent deposits nitrogen is 

 the most valuable constituent, phosphoric acid and potash following in the 

 order given, but on aging the nitrogen content decreases very rapidly. Over 

 90 per cent of the phosphoric acid present was found to be water soluble, as 

 was also the greater part of the potash. 



The origin of nitrate deposits, W. H. Ross {Pop. 8ci. Mo., 85 {1914), No. 2, 

 pp. 134-145; Ainer. Fert. 41 {1914), No. 6, pp. 40-46).— The occurrence of 

 nitrate depo.sits in different parts of the world is described and the various 

 theories which have been advanced to explain their origin, particularly as found 

 in Chile, are reviewed. 



Among the theories to which attention is called are (1) that the nitrates have 

 resulted from electric storms, (2) that the atmospheric nitrogen has been fixed 

 by alkali carbonates in the presence of oxidizable matter, (3) that the nitrates 

 have resulted from the action of radio-active emanations from the soil, (4) that 

 the nitrates have been derived from seaweed, bird guano, or the manure of 

 vicufias and llamas, (5) that the deposits represent accumulations of nitrate 

 formed by the oxidation of organic matter in the soil of the great plain lying 

 between the nitrate beds and the Andes and washed down to their present loca- 

 tion by periodic fioods, and (6) that the nitrates have been formed by the direct 

 fixation of the nitrogen of the air by Azotobacter and like organisms as sug- 

 gested by Headden. 



The author concludes, however, that not one of these theories " is adequate to 

 account for all the conditions under which the deposits are found, and it seems 

 most i^robable, as some have suggested, that instead of being formed in one way 

 only, the nitrates owe their origin to several sources." 



Growth in Chilean nitrate industry, A. A. Winslow {Daily Cum. and 

 Trade Kpts. [U. &'.], 17 {1914), No. 165, p. 305).— The industry is stated to be 

 growing and prosperous. 



