720 EXPERIMENT STATION RECORD. 



It was found that, although the percentage of nitrogen remained practically 

 constant under continued cropping for, in extreme cases, 25 years, there was a 

 marked decrease in the carbon content. 



" The loss of humus from these soils under the wheat-fallow system Is a 

 matter of serious imi)ort, and it would seem that methods for conserving this 

 organic matter must be adopted if these soils are to maintain their productive- 

 ness." 



Sandy soils of western and northern Michigan, J. A. Jeffeey ( Michigan 

 Sta. Circ. 16, <pp. 101-105). — These soils range from the coarser dune sands, 

 which possess little or no agi'icultural value, to the finer Miami sands. 



" The Miami sands vary from soils that possess much intrinsic agricultural 

 value to soils that can never be made profitably productive under ordinary 

 methods of management." The possible cropping value is indicated by the 

 original vegetation which the soils are supi)orting or have supported. Potatoes, 

 clover, rye, buckwheat, and in some cases wheat, oats, and barley are the crops 

 best suited to the soils. " Truck crops do well, corn and beans do fairly well. 

 Alfalfa promises to prove a very valuable crop for these soils. They are not 

 adapted to the growing of sugar beets." 



Results of chemical studies of the cane soils of Java, T. Mark (Arch. 

 Suikerindus. Ncderland. Indie, 20 {1912), No. 32, pp. 1251-131 Jf, pis. 11, fig. 1; 

 Meded. Proefstat. Java-Huikerindus., 1912, No. 23, pp. 653-1 Ut, pis, 11, fig. 1).— 

 This is a compilation of physical and chemical analyses, made by different 

 investigators during the last 25 years, of a large number of samples of cane 

 soils from various districts of Java. See also a note by Mohr (E. S. R., 25, p. 

 512). The report includes a discussion of the topographical features of the 

 various districts, the character and distribution of the soil types, and the 

 amount of plant -food constituents of the soils. 



Soil mapping and geological-agronomic maps, W. Koehne {Landw. Ilefte, 

 1912, No. 5, pp. 32). — This is a general discussion of the scope and purix)se of 

 geological-agronomic soil maps, with particular reference to their practical 

 value and interpretiition by the farmer. 



The Mangum terrace in its relation to efficient farm management, J. S. 

 Gates (U. 8. Dept. Agr., Bur. Plant Indus. Circ. 9Jt, pp. 11, figs. 9). — The advan- 

 tages and construction of the Mangum terrace worked out by P. H. Mangum of 

 Wake Forest, N. C, are briefly described. It is a broad bank of earth contour- 

 ing the field at a grade of aiJiiroximately 1^ in. to 14 ft. Under ordinary farm 

 conditions, the most practical way of constructing the terrace is by back 

 furrowing along the grade line. 



The advantages of this system are stated to be its adaptation to all types of 

 soil, especially to moderately rolling lauds, the possibility of using extensive 

 cultivation machinery and cultivating across the terrace, the saving of labor 

 and laud, and the ease of preserving the terrace when once constructed. 



Bacteriological studies of field soils. — I, The effects of lime, P. E. Brown 

 {Iowa 8ta. Research Bui. 5, pp. 189-210). — Previous experiments (E. S. R., 26, 

 p. 428) having dealt with the effects of ground limestone on certain groups of 

 soil bacteria under greenhouse conditions, similar experiments were conducted 

 under field conditions. The results of the work in general were similar to those 

 already noted. 



Bacteriological studies of field soils. — I, The effects of liming, P. E. Brown 

 {Centhl. Bakt. [etc.], 2. AM., 35 {1912), No. 11-13, pp. 2Si-2J,8) .—This is an 

 abridged account of investigations noted above. 



Bacterial activities in frozen soils, P. E. Brown and R. E. Smith {Iowa Sta. 

 Research Bui. 4, PP- 157-184; CentU. Bakt. [etc.], 2. AM., 3Jt {1912), No. 14-17, 



