SOILS — FERTILIZERS. 809 



diaraino acid nitrogen was converted into ammonia more rapidly than tlie 

 nitrogen of other groups. With casein, soy-bean cake meal, and cotton-seed meal 

 the more rapid ammonification of the basic nitrogen was especially noticeable. 

 These results are taken to indicate that all portions of the organic nitrogen in 

 the different materials used as fertilizers and green manures are not equally 

 susceptible to ammonification. 



Further investigations, including a study of the decomposition of individual 

 amino acids and acid amids, are in progress. 



The loss of nitrogen and organic matter in cultivated Kansas soils and the 

 effect of this loss on the crop-producing power of the soil, C. O. Swanson 

 (Jour. Indus, and Engin. Chem., 7 (1915), No. 6, pp. 529-532).— With reference 

 to the average decrease in crop-producing power shown by Kansas soils in 

 spite of improved seeding and tillage methods, data previously reported by 

 the author on the chemical composition of representative Kansas soils (E. S. R., 

 32, p. 26) are cited to show that the elements nitrogen and carbon have 

 disappeared from the cultivated soils in proportionately larger quantities than 

 the other essential elements. These soils have lost in round numbers from 

 one-fifth to two-fifths of the nitrogen and from nearly one-fourth to one-half 

 of the organic matter. This loss of organic matter and nitrogen is considered 

 to be the most important cause of the decreased crop-producing power of the 

 soils. 



Protozoology applied to the soil, N. Kopeloff, H. C. LI^'T, and D. A. Coleman 

 (Trans. Amer. Micros. Soc, 34 (1915), No. 2, pp. 149-154). — A new method for 

 counting protozoa, consisting of an adaptation of the blood-counting apparatus 

 (Blutkorperziihlapparat) whereby the organisms may be counted directly, rap- 

 idly, and accurately is described, and experiments to determine the medium 

 best adapted for the large and rapid multiplication of the various kinds of 

 protozoa are reported. 



Ten per cent hay infusion proved to be the most favorable medium for the 

 development of large numbers of small flagellates, as well as small and large 

 ciliates. Hay infusion in various concentrations, with and without the addi- 

 tion of egg albumin, was well adapted to the development of the organisms. 

 Hay infusion plus 5 per cent egg albumin proved superior to all other media for 

 the development of ciliates. Soil extract was an excellent medium, though 

 somewhat inferior to hay infusion plus 5 per cent egg albumin, and. with the 

 soil used in the experiment lower concentrations than those recommended by 

 Cunningham and Lohnis (E. S. R., 31, p. 26) developed protozoa in a shorter 

 period of time. Three per cent chicken manure was an excellent medium for 

 the development of small ciliates. The general order of appearance of protozoa 

 was as follows: Small flagellates, small ciliates, large flagellates, and finally 

 large ciliates. " The numbers and species of protozoa which can be obtained 

 from a given soil are largely dependent upon the media employed [and] time 

 of incubation, as well as the kind of soil used." 



Radio-activity of soils and waters, A. Gockel (Die Radioaktivitdt von 

 Boden und Quellen. Brunsicick: Friedr. Vieweg d Son, 1914, PP- V+IOS, figs. 10; 

 rev. in Wasser u. Abwasser, 9 (1915), No. 5, p. 135). — This book summarizes the 

 present knowledge of the radio-activity of soils and waters and contains 

 the following chapters : The radio-activity of the rocks forming the earth's 

 crust, radio-active minerals, the radio-activity of the soil air, soil emanations, 

 the radio-activity of waters, radio-activity and soil heat, and methods of measure- 

 ment. Methods of procedure in studies of radio-activity are given particular 

 attention throughout the book. It is stated that so far as is now known most 

 soils show radium and thorium emanations. A bibliography is appended. 



