September i, 192 i] 



NATURE 



Soil and Soil Management, 

 (i) Agnculiural Geology. By Dr. F. V. Emer- 

 son. Pp. xviii4-3i9- (New York: John 

 Wiley and Sons, Inc. ; London : Chapman and 

 Hall, Ltd., 1920.) 165. 6d. net. 



(2) The Soils and Agriculture of the Southern 

 States. By H. H. Bennett. Pp. xviii + 399 

 + plates. (New York : The Macmillan Co. ; 

 London: Macmillan and Co., Ltd., 1921.) 

 i8s. net. 



(3) Productive Soils: The Fundamentals of Suc- 

 ' cessfkil Soil Management and Profitable Crop 



Production. By W. W. Weir. (Lippincott's 

 Farm Manuals.) Pp. xvi + 398. (Phila- 

 delphia and London: J. B. Lippincott Co., 

 1920.) los. 6d. net. 



(4) Soil Alkali: Its Origin, Nature and treatment. 

 By Prof. F. S. Harris. (Wiley Agricultural 

 Series.) Pp. xvi + 258. (New York: John 

 Wiley and Sons, Inc. ; London : Chapman and 

 Hall, Ltd., 1920.) 135. 6d. net. 



(5) Text-hook of Land Drainage. By J. A. 

 Jeffery. (The Rural Text-book Series.) Pp. xx 

 + 256. (New York: The Macmillan Co.; 

 London: Macmillan and Co., Ltd., 192 1.) 

 los. 6d. net. 



(6) Agriculture and Irrigation in Continental and 

 Tropical Climates. By K. D. Doyle. Pp. xv 

 + 268. (London: Constable and Co., Ltd., 

 1921.) 195. net. 



THE output of books on the soil is now con- 

 siderable, especially in the United States, 

 and it is gratifying to find that the number of 

 agricultural students is so large as to justify an 

 array of volumes such as now exists. 



(i) Prof. Emerson deals with the subject funda- 

 mental to a large part of the work — the geological 

 processes by which the mineral particles of the 

 soil came to have their present properties, com- 

 position, and position. It is no longer supposed 

 that the study of soil is simply a branch of geo- 

 logy, because the vital part played by biological 

 factors is fully recognised. Nevertheless the fact 

 remains that geological factors determine the 

 whole structure of the soil, on which its agricul- 

 tural value largely depends. 



The book deals exclusively with United States 

 conditions, but it is of more than local interest. 

 The method of handling the subject may be com- 

 mended to teachers in this country who have no 

 book on similar lines dealing with Great Britain. 

 In particular the illustrations and the models are 

 distinctly helpful in character. 



Good use is made of the material collected by 

 the U.S. Soil and Geological Surveys, and there 



NO. 2705, VOL. 108] 



are sketch maps to show the broad outlines of the 

 soil regions and the main types of soil. One of 

 the most important soil regions is the coastal 

 plain, extending from New Jersey through Texas 

 and on to the south, which consists mainly of 

 sands or light loams. West and north of this 

 region is the Piedmont Plateau, the soils of which 

 are in the main rather heavy. A third highly 

 important group contains the glacial and loessial 

 soils, which include much of the wheat and corn 

 belt. 



In addition to the account of soils there is a 

 useful survey of the phosphate deposits of the 

 States. It is not generally realised that the 

 United States is by far the leading producer of 

 rock phosphate, and claims to be able to maintain 

 this position in virtue of its epormous untouched 

 reserves. Tennessee and Florida are the most 

 important sources. 



Altogether the book is one which cannot fail to 

 interest the teacher in this country, while the 

 serious agricultural student will welcome it as a 

 concise statement of the origin of the soils of the 

 United States and will wish he knew of as good 

 an account of British soils. 



(2) Dr. Bennett starts where Prof. Emerson 

 leaves off, and, assuming the soils already formed, 

 proceeds to describe them in detail and to show 

 what agricultural systems have grown up on 

 them. As an illustration : the coastal plains soil 

 mentioned above is here subdivided into eighteen 

 divisions, of which by far the largest is the Nor- 

 folk soil. General farming predominates over the 

 whole area, the particular crops being determined 

 by the climate, which varies from subtropical to 

 moderate conditions not far removed from our 

 own. The main crops, however, are cotton, 

 maize, and tobacco ; about 70 per cent, of the 

 United States cotton is produced on these soils. 

 There are also many specialised areas and 

 instances of crops or products which, at first sub- 

 sidiary, have gradually assumed more and more 

 importance, until finally they dominate a district 

 or formation. The data are well collected, and 

 there are many tables of statistics, both in the 

 main part of the book and in the appendix, which 

 the reader will not easily find elsewhere. There 

 are numerous illustrations of normal agricultural 

 practices and novel features which possess suffi- 

 cient interest to justify special description. 



W^e know of no better account of the soil and 

 agriculture of the Southern States, and, as in the 

 case of Prof. Emerson's work, the British teacher 

 will certainly wish he had as good an account of 

 the uses to which British soils are put. 



(3) Prof. Weir's book deals with the subject of 



