1916] SOILS FERTILIZERS. 809 



northern parts of the country from 15 to 30 days earlier than the average date, 

 but a thorough study of all the available data shows that the probability of 

 a killing frost occurring earlier than 10 days before the average date is only 

 about one in ten. 



" In the northern part of the cotton region the average date of the first fall 

 frost is between October 20 and October 25, and in the southern part of the 

 area the average date is about one month later. A killing frost has occurred 

 in the northern part of the area as early as October 1 and in the southern part 

 as early as November 10. The same rule applies, however, in this section of 

 the country as in the Northern States, that the probability of a frost occurring 

 earlier than 10 days befoi*e the average killing date is only about one in ten." 



Clim.atolog'ical data for the Uriited States by sections {U. S. Dcpt. Agr., 

 Weather Bur. Cliinat. Data, 3 {1916), Nos. 7, pp. 286, i^ls. 2, firjs. 8; 8, pp. 22^, 

 pis. 2, figs. 4)- — These numbers contain brief summaries and detailed tabular 

 statements of climatological data for each State for July and August, 1916, 

 respectively. 



[The climate of Pavlovsk], A.. V. Shipchinskii (A. Shipchinski) {Zap. 

 Selsk. Ehoz. hist. Imp. Petra I {Hem. Inst. Agron. Emp. Pierre I), 1 {1916), 

 pp. 52-69). — This is a summary of ten years' observations (1897-1904 and 1911- 

 1913). The average annual temperature was 6.9° C. (44.4° F.) ; the precipita- 

 tion, 500.3 mm. (19.7 in.). The prevailing wind was southeast. 



SOILS— FERTILIZERS. 



The loess soils of the Nebraska portion of the transition region. — ^III, 

 Potash, soda, and phosphoric acid, F. J. Alway and K. M. Isham {Soil Sci., 1 

 {1916), No. //, pp. 299-316, figs. 2).— This is a third report of studies conducted 

 at the Nebraska Experiment Station (E. S. R., 35, p. 510). 



It was found that " the total potash is very uniform in distribution both 

 from east to west and from the first to the sixth foot. While, on the whole, it 

 is slightly lower in the eastern areas and in the higher levels, the variations 

 are small and irregular. The proportion soluble in hot, strong hydrochloric 

 acid seems largely dependent upon the amount of silt present, it being lowest in 

 the most westerly area, in which, while the total potash is highest, the propor- 

 tion of very fine sand also reaches its maximum. 



" The total soda shows somewhat more variation. In the western four areas 

 it is quite uniformly distributed, both from area to area and from the surface 

 downward, amounting, in general, to a little more than half as much as the total 

 potash. In the two eastern areas it is distinctly lower; less is found in the 

 upper than in the lower 3 ft., and in general it amounts to a little less than half 

 as much as the total potash. The proportion of soda soluble in strong hydro- 

 chloric acid is lower than in the case of potash and is quite uniform. 



" The total phosphoric acid is still less evenly distributed. In the first 2 ft. 

 it seems much the same from east to west, while in the two eastern areas it is 

 higher in amount in the lower than in the upper sections. Most of it is soluble 

 in strong hydrochloric acid, neither location nor depth seeming to influence in 

 the proportion. . . . 



" Determinations were made of the total potash, soda, and phosphoric acid, 

 as well as of the portions of these soluble in cold 1 per cent hydrochloric acid, 

 in foiir separates — clay, silt, very fine sand, and coarser particles — from typical 

 humid and semiarid siibsoils. In the very fine sand from the humid subsoil 

 the amount of potash was found to be about the same as in the clay, but dis- 

 tinctly lov«er than in the silt. In the semiarid subsoil it was similar in the 

 Bilt and very fine sand, in both of which it was only very slightly higher than 



