SOILS FERTILIZERS. 



19 



bearing upon the economic problems of the region," and is based upon informa- 

 tion obtained in soil surveys in different parts of the region as well as upon 

 special studies of the soil conditions in parts of the region where soil surveys 

 have not been undertaken. 



The general conclusion reached is that "the soils of the Volusia series are 

 not ' Avorn out ' in any proper sense of the word, but, so far as the mineral mat- 

 ter of the soil is concerned, are abundantly supplied with the plant-food ele- 

 ments for the production of good crops. The difficulties encountered in crop 

 production upon the Volusia soils arise chiefly from lack of drainage, poor phys- 

 ical condition, and a depletion of organic matter." 



Methods of management and cropping adapted to the imi)rovement of condi- 

 tions are discussed. 



The minus quantity in California soils, G. W. Shaw (Cal. Cult., 32 (1909), 

 No. 10, 1)1). 275, 29 Jf, 295). — The cause of decline in fertility of California soils 

 and practical methods of restoring their productiveness are discussed. The 

 decline in productiveness is attributed to poor physical condition and deficiency 

 of humus, and the method of improvement proposed is based upon the belief 

 that " the maintenance of fertility or i)roductiveuess of soils is very largely a 

 matter of the upkeep of the humus content." 



The agricultural soils of Cape Colony, C. F. Jubitz (Agr. Jour. Cape Good 

 Hope, S-'t {1909), Nos. h, pp. Ji22-',36; 5, pp. 550-567, flg.s. 2, dgm.'i. 2; 6, pp. 675- 

 697, figs. S, dgms. 2). — This series of articles discusses the geological relations 

 and plant food, alkalinity, and physical composition of Cape Colony soils in a 

 stunming up of the results of a rather comprehensive and systematic study of 

 these soils. See also a previous note (E. S. R., 20, p. 1014). 



The average composition of the various types of soil examined is as follows: 



Geological origin and average conipo.'iition of types i>f Cape Colony noil. 



The methods and results of special studies of the amount and character of 

 the soluble salts in different groups of soils as affected by irrigation, rainfall, 

 and other conditions are reported and discussed. Sodium chlorid and sulphate 

 were often found to be dominant constituents of the soluble salts, sodium car- 

 bonate less frequently. The soils are classified with reference to mechanical 

 composition, especially the percentage of fine earth, which varied from 56.3 per 

 cent in one group to 100 per cent in another. 



