512 EXPERIMENT STATION RECORD. [Vol.40 



the region of Paris, including a summary of observations on pressure; tempera- 

 ture of the air, soil, and subterranean waters; precipitation; humidity; and 

 sunshine, is reviewed. A comparison is made of the character of the seasons in 

 different years from 1891 to 1917, inclusive. A similar comparison is made of 

 the winters of 45 years, 1873-1918. A special article on a remarkable hailstorm, 

 which occurred July 29, 1917, in the region of Proving, is included. It is shown 

 that the winter of 1880 was extremely cold, those of 1891 and 1895 were very 

 cold, and those of 1888 and 1917 were also below the normal in temperature. 

 The winter of 1877 was extremely warm and those of 1883, 1S84, 1897, 1899, 

 1910, 1912, 1913, 1915, and 1916 were very warm. The summers of 1891, 1903, 

 1907, 1909, 1910, 1912, 1913, and 191G were cold, while those of 1S93, 1901. 1904, 

 and especially 1899, 1900, and 1911 were very hot. The summer of 1911 was the 

 hottest recorded. The summer of 1917 was cooL 



SOILS— FERTILIZERS. 



Soluble salt content of soils and some factors affecting it, M. M. McCool 

 and C. E. .Mhi.au {Michigan sta. Tech. Bui. J,d {1918), i>p. -J7. figs. !,). — Investi- 

 gations embracing several classes of soils ale described in which a study was 

 made of salt movements, rainfall, and the soluble salt content of soils, the 

 effect of crops on salt movement, the effect of plant growth on the soluble salt 

 content of soils, the Influence of different conditions of moisture and tempera- 

 ture on the rate of formation of soluble salts in cropped and virgin soils, and 

 the soluble salt content of field soils at different seasons of tin- year. Consid- 

 erable tabulated data are presented and fully discussed, The conclusions 

 reached may be summarized as follows: 



The translocation of salts is said to be due mainly to water movements. In 

 the presence of large quantities of salt a movement to areas of lower concen- 

 tration was observed even when water movements were prevented, higher soil 

 moisture contents aiding tliis movement. Since the soluble salt content of field 

 soils was found to be relatively low. it is deemed probable that plants are sup- 

 plied with food elements by diffusion from local areas around the roots only. 



The accumulation of soluble salts on the surface of oncropped areas is held 

 to indicate thai when water movements occur in the soil the salts are carried 

 along with it. That these movements do not occur at any great depth was 

 indicated by observations which revealed but little movement of water from 



the subsoil to the feeding I >f the roots. It appeared to be unlikely that 



any considerable Quantity of soluble material was supplied to plants from 

 depths below those of root penetration. It was found that the quantity of 

 soluble salts in greenhouse soils might become too great for proper plant de- 

 velopment, and that plant growth might be inhibited in muck soils by an accu- 

 mulation of soluble substances in the upper layers. 



Data obtained in these investigations are idso said to show that plants may 

 materially reduce the soluble salt content of the soil. Laboratory studies indi- 

 cated that the constituents of cropped soils went into solution at a somewhat 

 slower rate than those of corresponding virgin soils. The rate of solution of 



the soils Studied was found to be governed to some extent by temperature, being 

 more rapid at 25° C. than at temperatures approaching 0° C. The moisture 

 content of the soil appeared to have a marked effect on the rate of solubility. 

 It is believed, too, that biological activities play an Important part in these 

 phenomena. Under laboratory conditions the concentration of the soil solutions 

 at all moisture contents was usually lower after o<> days than after in days, 

 thought to be due possibly to the reabsorption of the soluble material by the 



