Agricultural Yc~ter Management, 9 (1984) 79--84 79 Elsevier Science Publishers B.V., Amsterdam --Pr inted in The Netherlands

Book Reviews

ONE-DIMENSIONAL CONVECTIVE-DISPERSIVE SOLUTE TRANSPORT

Analytical Solutions of the One-Dimensional Convective-Dispersive Solute Transport Equation. M.Th. van Genuchten and W.J. Alves. Technical Bulletin No. 1661, U.S. Department of Agriculture, Washington, DC, 1982. 151 pp.

The intention of the authors is to present a compendium of analytical solutions for one-dimensional convective-dispersive solute transport in com- bination with linear instantaneous equilibrium adsorption and zero-order or first-order product ion or decay. These reactions are encountered in problems of simultaneous water and solute movement in soils or in open water courses.

The first chapter gives a brief theoretical discussion of the governing trans- port equation, the parameters appearing in this equation, and the different types of initial and boundary conditions. Not much attention is paid to the physical significance of the different mathematical expressions. In the second chapter, 16 known and 28 original analytical solutions for this solute transport equation are listed. These solutions are ordered according to the reactions involved; convective-dispersive transport with no production or decay, with zero-order production and with simultaneous zero-order produc- tion and first-order decay; and according to the boundary conditions: constant or exponential variation in time; flux or concentration type input, finite or semi-infinite media. Some of these solutions take two pages of equations, such that only about 10% of the book contains text while the remainder is made up of equations and tables. At the end a brief, but inter- esting, discussion on the effects of the different types of boundary condi- tions is presented.

The first appendix lists Laplace transforms which are used in the deriva- tion of the analytical solutions. The second appendix presents computer programs, written in Fortran IV, for some of the analytical solutions. These programs are well explained and documented with practical examples. It is a pity that every analytical solution requires its own computer program and that the authors did not succeed in writing one general program for all cases. However, the last computer program is a numerical solution, based upon finite elements. This program can handle most types of boundary conditions and the results are just as accurate as the analytical solutions.

The authors did not include more recent developments in the convective- dispersive transport theory such as non-linearity and effects of immobile water pockets. Probably these will be the subject of a sequel to this work.

This book is certainly not a t ex tbook or a general reference work. It is of a very specific nature, suitable for researchers dealing with problems on dispersive solute movement, who have no strong mathematical background

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and need analytical equations describing the solute concentration in time and space, in order to analyse experimental results, or for a quick verifica- tion of numerical solutions of more complicated systems.

F. De SMEDT Lab. Hydrology, Free University Brussels

Pleinlaan 2, 1050 Brussels, Belgium

SALINE AND SODIC SOILS

Sal ine and S o d i c Soi ls: Pr inc ip les - - D y n a m i c s - - Model ing . E. Bresler, B.L. McNeal, and D.L. Carter. Springer-Verlag, Berlin/Heidelberg/New York, 1982. x + 236 pp., US$43.00/DM98.00. ISBN 3-540-11120-4.

A tremendous amount of knowledge has been acquired during the past decade in soil physics and soil chemistry. This book reflects this progress pertaining to salt-affected soils. The latest research results are reported, with a large amount of material on modeling the transport of salts in soils and the application of these models to large-scale agricultural problems. This book is divided into three parts: (1) diagnosis and properties; (2) transportation and distribution of salts; and (3) management.

The 'Diagnosis and Properties' includes sections on sources of salts, water quality and soil solution parameters, surface phenomena of salt-affected soils, salt dissolution and precipitation, and diagnosis of salinity problems. Although the topics are familiar to readers in this subject area, most of the emphasis is on reporting the latest research findings regarding these topics. Also, modeling concepts are introduced.

The 'heart ' of this book is Part 2, 'Transportation and Distribution of Salts'. The topics are water movement processes, salt transport in soils, and modeling of salt-flow phenomena. This is an excellent presentation on the application of soil physics and soil chemistry to modeling of field situations. Again, most of the material has been developed during the past decade.

The last part of this book deals with 'Management'. The topics are crop salt tolerance, irrigation practice, reclamation of saline and sodic soils, solute flow models applied to irrigation management optimization, and specialized management practices. The application of models to optimizing irrigation management practices, including the economic evaluation of salinity, is the most useful information in this part of the text.

This is an excellent book! Anyone concerned with soil and water salinity will benefit by reading this text. Why? Because the latest research findings of the past decade are used in developing models that can be applied to solving large-scale field problems. Hopefully, the authors will seriously consider providing us with another edition before the end of this decade.

GAYLORD V. SKOGERBOE Department o f Agricultural and Chemical Engineering

Colorado State University Fort Collins, CO 80523, U.S.A.