620 EXPERIMENT STATION RECORD. 



this content is proportional to tlie ainonnt of plant food in the soil solnble in 

 carbon dioxid. The amount of plant food taken up is the same as that which 

 is soluble under like conditions in water containing carbon dioxid. Under vary- 

 ing conditions of growth, for example, in climate and soil, which affect the sohi- 

 bility, the percentage utilization of the given i)lant food is also changed, but 

 it is indei)endent of the amount of the plant food applied. 



To what extent can fertilizer action be replaced or streng'thened by the 

 work of bacteria? P. Ehrenberg (Jahrb. Dent. Landiv. Gesell., 2Jt (1909), 

 No. 4, pp. 915-926). — This is a popular review of investigations by the author 

 and others tending to show that the action of fertilizers may be materially 

 modified by bacterial activity in the soil. 



On the decomposition of stable manure, B. Heinze (Ahs. in Centbl. Bakt. 

 [etc], 2. Aht., 25 {1909), No. 19-25, pp. 503, 50/,).— It is stated that the thorough 

 decomposition of stable manures in the stall and in the heap greatly increases 

 its efficiency as a fertilizer. This decomposition not only increases the availa- 

 bility of the fertilizing constituents of the manure but also improves it as a 

 food for micro-organisms in the soil. 



The contents of the fertilizer sack, C. E. Thorne (Ohio Farmer, 125 (1910), 

 No. 6, pp. 1, 20). — The nature and sources of the principal constituents of fer- 

 tilizers and the mixing of fertilizers of desired composition are discussed. 



The use of commercial fertilizers as top-dressing, Bannert (JaJirb. Dent. 

 Landiv. Gesell., 2J, (1909), No. 4, PP- 926-934) ■ — The practical experience of a 

 number of farmers is summarized. 



The cost of available nitrogen, E. B. Voorhees (Netv Jersey Stas. Bui. 224,. 

 pp. 14-19). — This article discusses the relative availability of nitrate, am- 

 monical, and organic nitrogen with special reference to the commercial and 

 agricultural value of the principal materials furnishing these different forms 

 of nitrogen. It is shown that while the organic forms of nitrogen are less 

 available than the nitrate or ammonical nitrogen they at present cost more 

 in the market. 



The nitrate deposits of Chile, R. A. F. Penrose, Jr. {Jour. Geol., 18 (1910), 

 No. 1, pp. 1-32, figs. 7). — This article discusses the location and natural fea- 

 tures of the nitrate regions, the history of the nitrate mining industry, the 

 mode of occurrence and materials composing the nitrate deposits in the Tara- 

 paca region, industrial features in the Tarapaca nitrate region, other nitrate 

 I'egions in Chile and nitrate deposits elsewhere than in Chile, and the origin of 

 the Chilean deposits. 



It is stated that "almost all the nitrate of Chile is in the great arid basin 

 lying between the Andes and the coast ranges, in the provinces of Tarapaca and 

 Antofagasta." Smaller deposits ai'e found to the north and south of these 

 provinces. 



The author considers derivation from organic matter, and especially guano, 

 as the most probable hypothesis regarding the origin of these deposits. The 

 nitrate mining industry is comparatively recent in origin. In 1830 the pro- 

 duction was 8.348 long tons. During the year ended March 31, 1909, it was 

 about 1,808.986 long tons. It is stated that the nitrate being mined at present 

 is very wastefully treated and a large percentage of it is left in the refuse 

 material accumulating around the factories. " Thus low-grade nitrate ma- 

 terials are gradually accumulating in immense amounts, and may be used in 

 the future when more economical methods are introduced. These materials, 

 together with the possible new discoveries of nitrate, render the future of the 

 industry in Chile much more hopeful than some of the pessimistic prophets 

 would lead us to believe; and for very many years to come Chile will doubtless 

 be capable of supplying nitrate to the world." 



