314 EXPERIMENT STATION RECORD, 



C'ouii)letely sterilized at a distance of 60 cm. in 80 seconds, at 40 cm. in 1.^) 

 seconds, iit 20 cm. in 4 seconds, and at 10 cm. in less than 1 second. The 

 sterilization was effected by an expenditure of 3.0 watt hours per cubic meter, 

 but it is thought that this can be considerably reduced. 



SOILS— FERTILIZERS. 



What is weathering? P. Treitz {Comiit. Rend. Conf. Internat. Agrng6ol. 

 [Budapest], 1 {IVO'J), pp. lSl-161). — Special emphasis is laid in this article upon 

 the controlling influence of moisture upon weathering, and soils are classified 

 witli reference to tlie character of the climate in which they have been formed. 



The principal soil zones described are (1) those in which the precipitation is 

 from 450 to 800 mm., (2) those with from 300 to 450 mm., and (3) those with 

 less than 300 mm. In the first is included the moist oceanic climate in which the 

 soil solutions are poor in bases and have an acid reaction, and the drier con- 

 tinental climate in which the soil solutions are rich in bases, especially lime, but 

 are also acid. The second zone includes semiarid climate in which the soil 

 moisture is a saline, alkaline humus solutiou. The third zone includes desert 

 climate and drifting sandy soils. 



In discussing weathering the author distinguishes between the surface crust 

 of the soil particle, consisting of products of weathering, and the inner unaltered 

 core. The former when separated from the particle and diffused through the 

 soil forms clay. The weathered soil is a mixture of silicates resulting from 

 the weatliering process with fragments of unaltered original minerals. The 

 weathering is more complete in humid regions tlian in dry regions. As regards 

 the composition of the products of weathering, the relation of bases to acids 

 varies slightly within each climatic zone. With a change of the climatic con- 

 ditions, however, this relation varies uniformly. The acid content (silicic and 

 humic acid) decreases with the humidity of the air, the content of bases increas- 

 ing with increasing aridity. Even forest soils contain from 10 to 20 times as 

 much bases in arid regions as in humid regions. Tlie separation of acids as 

 well as bases from the soil solution depends upon climatic conditions. With a 

 decrease in tlie intensity of solution greater amounts of easily soluble com- 

 pounds separate out. 



Soil types as determined by climatic zones, E. von Cholnoky {Conipt. 

 Rend. Conf. Internat. Agrogeol. [Budapest], 1 (lUO'J). pp. 103-176, chart 1). — 

 This article deals with desert, steppe, savanna, and forest soils, and shows the 

 relation of moisture to the character of the soil. 



Classification of soils according' to climates (Terre Vaud., 2 (1910), No. 16, 

 pp. 18]~1H3). — This is a review of papers by Treitz, Cholnoky. and Cornu on 

 the relation of soils to climate. 



Agrogeological field work, H. Horusitzky (Compt. Rend. Conf. Internat. 

 Agrogeol. [Budapest], 1 {1909), pp. 193-201).— The principal points which 

 should receive attention in such work are stated. 



What should be included in agrogeological reconnaissance and special 

 charts? E. Timko (Compt. Rend. Conf. Internat. Agrogeol. [Budapest], 1 

 (1909), pp. 208-205). — A brief statement of the requisites of such soil charts is 

 given. 



The preparation of agrogeological reconnaissance and special charts, W. 

 GiJLL (Compt. Rend. Conf. Internat. Agrogeol. [Budapest]. 1 (1909), pi). 201- 

 212).— A brief statement. 



The special value of soil analysis in intensive agriculture, E. Leplae 

 (Compt. Rend. Conf. Internat. Agrogeol. [Budapest], 1 (1909), pp. 177-187). — 

 This article maintains that chemical analysis is of great value in determining 



