19161 SOILS — FERTILIZERS. 21 



sterilization of soils by antiseptics and heating. It is thought that the benefits 

 which result from heating the soil are partly biological and partly chemical. 



The influence of nitrification upon soil fertility, W. L. Owkn (ib'Mf/or [Chi- 

 cago}, 17 (1015), No. 11, pp. 30, 31). — From a review of work bearing on the sub- 

 ject conducted at some of the state experiment stations and at foreign experi- 

 ment stations, the author concludes that cotton-seed meal is superior to ammo- 

 nium sulphate, due to the neutralization of the soil acidity in the former case 

 by the formation of annnonia. 



Physical-chemical studies of soil. — III, The conditions of humidity of 

 soils and the absence of veg'etation, U. Pbatolongo (Sta:;. Sper. Agr. Ital., ^8 

 (li)15), No. 1, pp. 44-56; ahs. in Intcrnat. Inst. Agr. [Rome,], Mo. Bui. Agr. 

 Intel, and Plant Diseafics, 6 {1915), No. 5, p. GOO). — Experiments, based in part 

 on work previously noted (E. S. R., 30, p. 215), with rye, oats, clover, vetch, 

 mustard, and flax, on four different arable soils of alluvial origin, and one clay 

 soil, are reported. The purpose was to determine the relation between the 

 initial wilting point of the plant on the one hand and the water content of the 

 soil at the initial wilting point and the chemical and physical properties of the 

 soil on the other. In the experiments normal conditions were maintained during 

 the germination and growth of the crops until a height of from 10 to 12 cm. 

 (3.94 to 4.73 in.) was reached, after which all conditions were maintained 

 normal except moisture, the content of which was gradually decreased. 



It was found that a constant relation existed between the water contents of 

 the different soils at the initial wilting point of vegetation and the so-called 

 " deviation " in the Van Bemmelen water vapor tension curve for the same 

 soils, the average coefficient of proportionality being 5.06±0.08. No essential 

 difference was observed in the different crops in regard to their resistance to 

 the gradually increasing aridity of the soils. 



Effect of vanillin as a soil constituent, J. J. Skinner (Plant World, IS 

 (1915), No. 12, pp. 321-330, figs. 5).— The substance of this paper has been 

 previously noted from another source (E. S, R., 32, p. 619). 



Experiments on lime determination in agricultural soil by more recent 

 methods, W. Bandi (Jahresber. Landw. Schule RUtti, 1912-1914, PP- 149-154) • — 

 Experiments with 130 samples of soils of varying textures are reported, in 

 which the extent of effervescence with hydrochloric acid, the amount of calcium 

 oxid soluble in ammonium chlorid, the reaction to litmus, and the power of 

 sustaining the development of Azotobacter in a nutritive medium were observed 

 for each sample. 



The results are taken to indicate that the simple hydrochloric acid test for 

 the lime requirement of soil is in general sufficient. If a soil effervesces with 

 hydrochloric acid it is considered to need no lime. A quantitative determina- 

 tion of carbon dioxid is considered superfluous on the grounds that the hydro- 

 chloric acid test is equally effective within practical limits. On the other hand, 

 if there is no effervescence with hydrochloric acid the reaction toward litmus 

 should be determined. If alkaline, this indicates that no lime is needed, but if 

 acid, shows a need for lime. If the reaction toward litmus is neutral the power 

 of supporting a growth of Azotobacter should be tested. 



See also previous notes by Christensen (E. S. R., 24, p. 527; 34, p. 813). 



Plant foods for crops in 1916, L. L. Van Slyke (New York State Sta. Circ. 

 47 (1916), pp. 8). — This circular presents the consensus of opinion of the mem- 

 bers of a (Conference of representatives of the agricultural experiment stations 

 of the New England States, New Jersey, and New York called for the purpose 

 of discussing the effects of the war upon the cost of plant-food materials and 

 furnishing suggestions to farmers as to practical methods to adopt during 1916 

 under present conditions. 



