220 EXPERIMENT STATION RECOED. 



The physiological role of nutrient salts in the soil, D. Dicenty (Resume [1], 

 pp. 23, 24). — The author discusses in this article the bearing on plant growth 

 of the concentration of the soil solution, with reference particularly to phos- 

 phoric acid. It is held that, other conditions being the same, the growth is 

 better the larger the amount of the nutrient salts in the soil solution, and this 

 in turn depends upon the amount of fine particles from which the nutrient salts 

 may be derived. 



The determination of the assimilable plant food in the soil, A. Rindell (Re- 

 sume [1], pp. 31-33). — This article deals mainly with the kind of solvent to be 

 used in determining the assimilable plant food in soils. The author favors a 

 water solution of carbon dioxid, which gives results comparable with those 

 obtained in vegetation experiments. The concentration of this solution is not 

 specifically stated. 



New principles of soil investigation, A. Atterberg (Resume [1], pp. 36-38). — 

 In this article the author expresses the opinion that the most important physical 

 properties of soils are firmness, watei--holding capacity, plasticity, and move- 

 ment of water, and that the two most important physiological properties are 

 the degree of fineness of soil particles at which the root hairs of legumes can 

 not penetrate the soil, and the degree at which bacterial life is impossible. 



The purpose and. fundamental principles of soil classification, E. W. Hilgard 

 and R. H. Loughridge (Resume [1], pp. 40). — The paper of which this is an 

 abstract discusses " first the objects to be attained by soil classification, whether 

 practical or theoretical. It then presents the various points of view from which 

 soils are and may be considered, and the inadequacy of any single one ; finally, 

 the possible agreement upon a common basis of classification and description." 



The nomenclature and the classiftcntion of soil types, B. de Inkey (Resume 

 [1], pp. 41. 42). — This is an abstract of a paper which deals with soil classifica- 

 tion on the basis of (1) soil components, (2) petrography of the subsoil, (3) 

 geographical and geological genesis of the soil, (4) physicochemical genesis, and 

 (5) relation to climate and vegetation. 



Plant food, especially phosphoric acid and nitrogen, in acid soils and their 

 detennination, M. Weibull (Resume [1], pp. 51-55). — This is an abstract of a 

 paper in which investigations are reported which show that acid soils responded 

 better to nitrogenous and phosphatic fertilizers than neutral or alkaline soils. 

 Acid soils yielded much less phosphoric acid to fifth-normal nitric acid by the 

 Stoddart method (E. S. R., 20, p. 1114) than alkaline soils, although containing 

 practically the same total phosphoric acid. The reaction of the soil depends 

 upon the lime and humus content and the presence of certain silicates. If the 

 first two are known the reaction may be reckoned. Soils showing assimilable 

 lime (by the Meyer method) and loss on ignition in the proportion of about 0.1 

 per cent of the former to 2 per cent of the latter are usually neutral. The 

 author proposes and has undertaken the mapping of soils on the basis of their 

 reaction. 



Some methods of analysis in soil investigations, A. Vesterberg (Resume [11, 

 pp. 56-58). — In this paper descriptions are given of a titration method for the 

 determination of carbonate, carbonic acid, and organic substances; a rapid field 

 method for the determination of calcium ; a titration method for humic acid 

 solutions ; and a method for determining the water-soluble salts by electrolytic 

 conductivity. 



Some notes on the mechanical analysis of soils, especially of those of arid 

 regions, W. Beam (Resume 2, pp. 1-3). — In this article the author objects to the 

 of acid to break up soil aggregates. He uses the classification of soil par- 

 ticles recommended by the Bureau of Soils of this Department and follows to 

 a large extent the methods proposed by that Bureau. In an attempt to substi- 



