SOILS FERTILIZERS. 421 



when dry. The less i)l;istic clays may be classed with the heavier loams and 

 may be tilled with a water content of from 5 to 13 per cent, but require rela- 

 tively more power than the loams. The highly plastic clays can be tilled only 

 with high water content and in that condition are too soft to permit good 

 work. 



It is further pointed out that the knee of the curve corresponds to the 

 shrinking limit of soils on drying. 



Further studies of consistency curves with reference to soil classification 

 are to be made. 



Some dynamic processes in soils in the region of the distribution of frozen 

 soils, K. NiKiFOROv (Pochvoriedi^nic (PMologie), No. 2 {1912); ahs. in Zhur. 

 Opytn. Agron. (Rms. Jour. Expt. Landw.), 14 (1913), No. 5, pp. 456, 457). — 

 This article describes certain peculiar phenomena connected with the escape 

 of water resulting from summer thawing. This water accumulates between 

 different layers of the soil, and when the winter freezing begins the increased 

 pressure upon the localized water-bearing areas forces the water to the surface 

 either gradually through outcropping of ice or rapidly with the bursting of the 

 upper frozen layer. In either case the properties of the soil are more or less 

 profoundly affected. 



Soil analysis, C. T. Gimingham (Jour. Bath and West and South. Counties 

 Sac, 5. ser., 8 (1913-14), pp. 142-147; Univ. Bristol, Ann. Rpt. Agr. and Hort. 

 Research Sta., 1913, pp. 103-107). — This article discusses the practical value of 

 soil analysis to the agriculturist and horticulturist and indicates some of the 

 considerations which must be taken into account by the analyst. 



Relation of chemical composition to soil fertility, G. S. Feaps (Jour. Amer. 

 8oc. Agron., 7 (1915), No. 1, pp. 33-36).— It is stated that experiments at the 

 Texas Experiment Station indicate that there is a relation between the total 

 nitrogen and the active (soluble in fifth-normal nitric acid) phosphoric acid 

 and potash of the soil and the soil deficiencies as shown in pot experiments. 



Alkali in soils, J. W. Paterson (Jour. Dept. Agr. Victoria, 11 (1913), No. 5, 

 pp. 288-299, figs. 6). — The common alkali salts occurring in soils are described 

 and remedial measures discussed, particularly the use of gypsum for black 

 alkali and proper land drainage for white alkali. 



Organic matter in soils (Indian Tea Assoc, Sci. Dept. Quart. Jour., No. 2 

 (1914), pp. 55-64)- — In this article the changes undergone by organic matter 

 in the soil and the effects produced in the soil by these changes are discussed. 



With reference to tea culture it is stated that fine textured soils containing 

 over 50 per cent of silt, fine silt, and clay should contain about 10 per cent 

 of organic matter. Coarser textured soils containing over 50 per cent of coarse 

 and fine sand require not less than 5 per cent of organic matter. 



It is also stated that an abundance of organic matter in a soil is likely to 

 prevent attacks of white ants. 



On nitrification: Preliminary observations, E. R. Allen and A. Bonazzi 

 (Ohio Sta. Tech. Bui. 7 (1915)., pp. 42, figs. 6).— So-called physiological studies 

 of the nitrifying bacteria of soils are reported, together with brief reviews of 

 the work of others bearing on the subject. A bibliography is appended. 



In experiments on the nitrifying power of soils taken from representative 

 plats at the station to determine the effect of soil treatments in cropping, it 

 was found that the nitrifying power of naturally noncalcareous soils was 

 rather feeble as compared with naturally calcareous soils, even after receiving 

 moderate applications of ground limestone, but that very heavy applications of 

 ground limestone imparted a high nitrifying power. The results of these ex- 

 periments are also taken to indicate that the nitrifying power of the soil may 

 or may not correlate with its crop-producing power, it being considered pos- 



