SOILS FERTILIZERS. 15 



him that he can forward to the station such definite statements of facts, and 

 samples properly taken, as will convey the data needfnl for a full luiderstand- 

 ing of the situation." 



Illinois soils in relation to systems of permanent agriculture, C. G. Hop- 

 kins (Illinois Sta. Circ. 108, pp. 26). — In this circular the author amplifies his 

 well-known views regarding the maintenance of soil fertility by utilization of 

 the nitrogen of the air through leguminous crops, the liberation of potassium 

 from the soil suijply, and the return to the soil of the phos]ihorus removed by 

 crops, ])referably in the form of insoluble phosphates, and explains in some 

 detail the systems of soil management and cropping most likely to secure these 

 results. 



Soil surveys, F. B. Guthrie (Agr. Gaz. A'. /S. Wales, IS (1907), Xo. J, pp. 

 438-.'i43). — This paper discusses briefly the use of soil analysis and more fully 

 " the best means for carrying out a systematic examination of the soils of Aus- 

 tralasia, on the lines on which such work is being carried out in other countries, 

 or with such modifications as ma.v be found most suitable to our conditions." 



I'articular emphasis is laid upon the importance of determining those prop- 

 ex'ties which depend upon the physical character and texture of the soil. The 

 purely chemical analysis is assigned a subordinate ])ositi()n and is limited to 

 determinations of humus, total nitrogen, and of lime, potash, and phosphoric 

 acid soluble in hydrochloric acid, and in special cases in other solvents. It is 

 held that a determination of the rate of nitrification is of the greatest impor- 

 tance, and the method worked out by Ashby (E. S. R., K!. j). 452) and the oxida- 

 tion method by Russell (E. S. R., 17, p. 53(5) are suggested for trial in the 

 absence of any well-estal»lished method for this purpose. 



Agricultural charts and the analysis of soils, A. Gregoire (Bui. Soc. Chini. 

 Bchj., 21 (1901). Xo. .'/. pp. l-l.i-Kil)). — The autlior lays great stress upon the 

 importance of the study of geological conditions and processes, and much less 

 upon chemical analysis. 



The agricultural value of the soils of central and western Africa, A. 

 Hebert (Quill-. Colon., 11 (1901), No. 4, pp. 1S1-1S5). — The soils of this region 

 are described on the basis of data secured by examinations of representative 

 samples collected by Chevalier in his expeditions to the Lake Tchad region, 

 French Guiana (E. S. R., 18, p. 426), the Island of St. Thomas, and the Gold 

 Coast (E. S. R., 18, p. 532). 



The soils of the Lake Tchad region are shown to be in general very sandy, 

 very poor in phosphoric acid and potash, and particularly deficient in lime, but 

 rich in sodium salts. The similarity in essential characteristics of the soils 

 from different parts of the region indicates that they are of common origin and 

 that the region was originally the bed of an inland sea, all of which, except 

 Lake Tchad, has disappeared b.v evaporation. 



The soils of the other regions show the siime deficiencies as those of the Lake 

 Tchad region. 



In spite of the great deficiency, and in some cases almost total lack of potash, 

 phosphoric acid, and lime in the soils of central and western Africa, the in- 

 digenous plants, including among others coffee (Coffea e.TCelsa), cotton (Gos- 

 sypimn anomalum), and cacao, are able to assimilate the considerable amounts 

 of these constituents needful for their vigorous growth. A direct connection 

 between the deficiency of lime and the characteristic desert conditions of Sahara 

 is traced. 



The fertility of some colonial soils, as influenced by geological conditions, 

 C. F. .TiKiTz (.4i'/;'. Jour. Cape dooil Hope, So (1901), Xo. .'/, jip. -J.) J-.J77)). — 

 Studies which have been carried on during the past 7 years in the government 



