812 EXPERIMENT STATION RECORD. [Vol. 85 



the North Carolina Department of Agriculture and issued August 31, 1916, 

 deals with the soils of a fairly well-drained area of 354,560 acres in east-central 

 North Carolina, the topography of which includes broad, gently rolling inter- 

 stream areas, which become more rolling as the larger streams are approached. 

 The county lies wholly within the Costal Plain soil province. 



" The soils of Wayne County are derived from the unconsolidated sands, 

 clays, and gravel of sedimentary origin." They include both upland and bottom 

 land types. Including swamp, 23 soil types of 11 series are mapped, of which 

 the Norfolk fine sandy loam, sandy loam, and sand cover 22.4, 21.4, and 13.4 per 

 cent of the area, respectively. 



Study of an exact classification of soils with reference to climate and 

 geology, R. Lang {Internat. Mitt. Bodenk., 5 (1915), No. J,, pp. 312-346, fig. 1).— 

 The work of others bearing on the subject is briefly reviewed, and a study of 

 soil classification is reported in which, first, the influence of the main climatic 

 factors in soil formation, such as temperature and humidity, and the remaining 

 soil forming factors are dealt with. Finally, the changes produced are described 

 by which the development of soils under special climatic conditions can take 

 place. 



It is concluded that the rain factor, computed from the average annual rain- 

 fall and the average temperature, is very important in determining the limits 

 of the extent and conditions of the formation of a soil type. 



Use of the moisture equivalent for the indirect determination of the 

 hygroscopic coefllcient, F. J. Alway and J. C. Russel ([/. S. Dept. Agr., Jour. 

 Agr. Research, 6 {1916), No. 22, pp. 833-846).— In this contribution from the 

 Minnesota Experiment Station, experiments with silt loam soils collected from 

 30 virgin prairie fields in Nebraska are reported, the purpose of which was to 

 determine the reliability of the use of the moisture equivalent for the indirect 

 determination of the hygroscopic coeflicient in soils. 



It was found that " the hygroscopic coefficient may in most cases be calcu- 

 lated from the moisture equivalent with sufficient accuracy to permit its use 

 in soil-moisture studies. For certain types of soil, however, the ratio departs so 

 widely from that assigned by Briggs and Shantz (E. S. R., 26, p. 628) that the 

 indiscriminate use of the latter value does not seem permissible. Before em- 

 ploying this indirect method for the determination of the hygroscopic coeffi- 

 cient in connection with soil-moisture studies the ratio should be experimentally 

 established for each of the particular types of soil involved. 



" The effect of considerable quantities of organic matter is, in general, to 

 give the ratio of the moisture equivalent to the hygroscopic coefficient a higher 

 value. In the case of any extensive study of soil moisture involving many soil 

 types, the same general conclusions as to the relation of the nonavailable mois- 

 ture to the hygroscopic coefficient are to be expected, no matter whether the 

 latter value be directly determined or be calculated from the moisture equiva- 

 lent by the Briggs-Shantz formula. For the calculation of the moisture equiva- 

 lent from the mechanical analysis no general formula appears universally 

 applicable, the formula needing modification according to the soil type to which 

 it is to be applied." 



Soil tank investigations, S. E. Collison {Florida Sta. Rpt. 1915, pp. CII- 

 CV). — ^A continuation of the investigation on the lo.sses of fertilizing constitu- 

 ents in the drainage water from soil (E. S. R., 33, p. 24) is reported. 



" The loss of nitrogen has increased somewhat over that for last year. The 

 loss of potash has increased in two of the tanks and decreased slightly in the 

 other two. . . . The loss of nitrogen was very large in the earlier periods but 

 has decreased notably in the later ones, reaching the lowest figure in 1914, and 

 increasing somewhat for 1915. . . . The losses of potash have increased from 



