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E. J. RUSSELL. Phosphorus Compounds in Soils. - - The Stan- 

 dard Cyclopedia of Modern Agriculture and Rural Economy, edited 

 by Professor R. P. Wright. Vol. IX, The Gresham Publ. Cy., 

 p. 210. London, 1910. 



"Large quantities of organic phosphorus compounds occur in 

 peaty and moorland soils, but they are of little value as plant 

 food. Thus the Swedish moorland soils contain 0.15 per cent of 

 phosphorus (as P a O s ), and the fen soils of the Isle of Ely contain 

 0.3 or 0.4 per cent, soluble in hydrochloric acid, and 0.03 to 0.077 

 soluble in i per cent citric acid, yet all these soils give consider- 

 able returns for phosphatic manures. When these soils are burned 

 a certain amount of calcium phosphate is formed, and there is a 

 marked gain in fertility." 



J. M. HECTOR. Nitrogen, the Plant and the Farmer. Scot. 

 Farmer, 18, 1910, No. 891-894. 



A review of investigations on the fixation of free nitrogen by 

 plants. 



Prof. W. B. BOTTOMLEY. The fixation of Nitrogen by free living 

 soil Bacteria. Paper read at the Sheffield Meeting of the Brit. 

 Assoc. 1910. The Chemical News and Journal of Physical 

 Science, p. 155. Sept. 23rd, 1910. 



Since the discovery of the Azotobacter group of nitrogen-fixing 

 organism by Beijerinck in 1901 numerous attempts have been made, 

 but with little success, to utilise these organisms for increasing the 

 store of soil nitrogen. Gerlach and Vogel (1902) and Freuden- 

 reich (1903) obtained negative results in soil experiments. Lip- 

 man (1904), experimenting with Az. Beijerincki and Az. Vinelandii, 

 found that out of ten experiments there was a loss of nitrogen in 

 every case but one, and this showed a gain of only 4 mgrms. 



Certain results from inoculation experiments on clover with oats 

 in 1907, and the discovery that species of Azotobacter and Pseu- 

 domonas are always found in association in the algal zone of the 

 root-tubercles of Cycas, suggested that a mixed culture of these 

 organisms might be effective in fixing nitrogen in the soil. 



Pure cultures of the organisms obtained from Cycas root-tuber- 

 cles incubated for fifteen days at 24 C., gave the following results: 



