1918.] SOILS — FERTILIZERS. 817 



improving crops. Improved cropping systems are outlined, and the results 

 obtained from system.s followed on some of the more successful farms of the 

 region are described. 



Our mineral supplies. — Nitrates, H. S. Gale {U. S. Geol. Survey Bui. 666-Z 

 {1917), pp. 4). — This is a brief review of the nitrate situation in the United 

 States, it being pointed out that there is in the Unitfcd States no known natu- 

 ral source of nitrates that can be counted on to furnish any considerable supply 

 of the refined nitrate salts. Imports and consumption in the United States for 

 various puiiDOses, including fertilizers and explosives from 1912 to 1916, are 

 summarized and artificial nitrogen fixation processes reviewed. It is stated 

 that while the electric arc fixation proces.ses are fundamentally the simplest, 

 a great amount of electric power is required. " It seems doubtful if the power 

 available in this country could be spared for use in this way. . . . 



" By-product ammonia, derived from the production of coke and of illuminat- 

 ing gas, is an important source of combined nitrogen and is an available source 

 for the production of nitric acid or nitrates. Such ammonia can be practically 

 oxidized to nitrates, and the supply of this material is therefore available to 

 relieve emergencj' requirements should other sources fail." 



Sulphate of ammonia: Its source, production, and use {Nciv Yoj'k: The 

 Barrett Co., 1917, pp. 23, figs. 19). — Tliis is a brief practical treatise on the 

 sources, production, and use of ammonium sulphate, with particular reference 

 to its u.se as a fertilizer. 



Veg'etation experiments on th.e availability of treated phosphates, J. G. 

 LiPMAN and H. G. McLean {Soil Sci., 4 {1917), No. 4, pp. SS7-343, fig. 1).— 

 Vegetation experiments on the availability of untreated ground rock phosphate, 

 ground phosphate rock previously composted with sulphur, and acid phosphate 

 are reported. 



It was found that " some crops can utilize the phosphorus in floats to good 

 advantage. This is particularly true of buckwheat. The ability of buckwheat 

 to use effectively the phosphorus of ground, but otherwise untreated, phosphate 

 rock suggests that this crop may be made a valuable green manure and em- 

 ployed to increase the content in the soil of organic matter and of available 

 phosphorus. Ground rock phosphate properly composted with ground sulphur 

 becomes a source of available phosphorus and may be employed to advantage 

 as a substitute for acid phosphate." 



Sixteen per cent acid phosphate, M. A. Bachtell {Agr. Col. Ext. Bui. [Ohio 

 State Univ.] 13 {1917-18). fig. 4, pp. 15, figs. 7). — This bulletin, summarizing ex- 

 perimental work at the Ohio Experiment Station, states that from 600 to 1,000 

 lbs. of acid phosphate per acre can be used with profit during a rotation of three 

 or four years on most Ohio soils, and that 16 per cent acid phosphate should 

 not cost over $16 a ton. Other practical information on the subject is given. 



Explorations and studies of the beds of phosphorites in Russia, 1914, 

 lA. V. Samoilov {Otchet Geol. Izsliedov. Fosfor. Zalezhei, 7 {1915), pp. 25 + 

 591, pis. 8, figs. 71; abs. in Intcriiat. Inst. Agr. [Rome], Internat. Rev. Sci. and 

 Pract. Agr., 8 {1917), No. 4, pp. 5G1, 562).— This report for the year 1914 of the 

 Commission for the Study of Phosphorite Beds (of the Agricultural Institute 

 of Moscow), contains twelve detailed accounts of the phosphorite beds of 

 many districts of Russia, made by various authors and enlarged with numerous 

 figures, plates, and maps. An introduction by Samoilov summarizes the gen- 

 eral results of the researches and exiilorations of 1914. The principal facts 

 are summarized as follows : 



In 1914 research work and explorations were carried out in the Provinces of 

 Samara, Tambov, Kur.sk, Orel, and Kaluga, and in the districts of Turgaish 

 and the Ural Mountains. In each di.strict the productivity of the beds, their 



