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Elements of soil physics
Soil & Tillage Research, 4 ( 1 9 8 4 ) 4 8 5 - 4 8 8
485
Elsevier Science P u b l i s h e r s B.V., A m s t e r d a m - - P r i n t e d in T h e N e t h e r l a n d s
Book Reviews SOIL PHYSICS
Elements of Soil Physics. P. Koorevaar, G. Menelik and C. Dirksen. Developments in Soil Science 13, Elsevier Science Publishers, Amsterdam and New York. 1983. xiv + 228 pages. Price: US$32.00 (in U.S.A. and Canada}, Dfl. 75.00 (rest of World). ISBN: 0-444-42242-0. This t e x t b o o k on Soil Physics has its origins in the lecture courses given in the Department of Soil Science and Plant Nutrition of the Agricultural University, Wageningen, The Netherlands. Its aim is to give students an introduction to basic principles. A novel feature of this b o o k is the inclusion of questions after each paragraph with answers at the end of each chapter for the student to check his progress in understanding the subject. The authors claim that students learning soil physics from the b o o k find it unnecessary to attend lectures or even tutorial classes, although one feels that generally most students would have difficulty in maintaining their interest in the subject with only the rather unexciting presentation of material and without being stimulated from other sources. The b o o k is divided into 8 chapters. The first deals with the composition and physical properties of soils, describing the 3-phase composition of soils and giving an introduction to the interaction between the solid and liquid phases in clays. The second chapter on the equilibrium in force fields and the theory of potentials expects the student to have a grounding in mechanics, outlining (often inadequately as in the case of summing v e c t o r s ) t h o s e aspects that are required for a discussion on soil-water equilibria. The authors do not help students in their understanding of h o w to apply basic principles by implying that the definition of physical laws are restricted to particular units, instead of emphasising that equations should balance dimensionally. For example, N e w t o n certainly did not use the units stated in the text when he formulated his second law. The discussion in this chapter is generally pedantic and does not make it easy for the student to have a physical feeling for the concept of potential, although the aim is that the theoretical discussion should help the student understand the practical situation of static equilibria in soils, the subject of the third chapter. The fourth chapter gives a generalised treatment of transport phenomena in soils on the basis that the flow can be considered as occurring in a continuum in response to a potential gradient. This chapter aims at giving the student a theoretical basis for describing the different transport phenomena in soils. It leads on to separate chapters on water flow, gas transport and heat flow in soils. However, the introduction to the subject through continuum physics does not bring out the physical differences in the mechanisms of the different flow phenomena in porous media.
486 The last chapter is in the form of an epilogue by Professor G.H. Bolt, in which attention is drawn to the additional understanding required for applying soil physics in the analysis and management of the soil behaviour in the real world. Professor Bolt points to developments in simulation modelling in complex soil studies, in the consideration of the spatial variability of soils and in the use of remote sensing in field measurements, that may lead to a predictive insight into physical processes on a field scale. The authors' treatment of soil physics is limited to a consideration of the physics of the soil environment and does not touch on the mechanical properties of soils that are of prime importance in tillage research. Their theoretical approach to the subject does not adequately bring o u t the empirical foundations of much of soil physics which is concerned with macroscopic soil phenomena. For many students wishing to get acquainted with soil physics their approach will be off-putting, although it could well be right for students with a previous training in pure science. E.G. YOUNGS (Rothamsted Experimental Station, Harpenden, Herts., AL5 2JQ, Great Britain)
SOIL Ken Simpson, Longman Group, Harlow, Essex, Gt. Britain, 1983, Price: £ 6 . 9 5 , 2 3 8 pp., ISBN: 0-582-44641-4.
Soil.
"Soil" is a concise text dealing with the science and management of our basic agricultural resource. The author, a former vice-principal of the East of Scotland School of Agriculture, has drawn the material from his practical experience, his lecture notes as well as various published works. The text is clearly written and illustrated by easily understood figures and tables. It is divided for convenience into theoretical and practical sections, the latter being divided into separate discussions on identification and correction of, first, soil physical problems and, second, soil chemical problems. Its immediate area of application is the British Isles. The approach taken by the author is valid; that soils are inherently different from place to place, even in the same field, that they are vulnerable to maltreatment by the producer, and also that they are amenable to improvement by appropriate practices. In this connection he endeavours to point o u t vulnerable features of different soils with a view to avoiding problems before they develop. The principles and practices described are not necessarily new, but some new approaches are suggested, primarily for
485
Elsevier Science P u b l i s h e r s B.V., A m s t e r d a m - - P r i n t e d in T h e N e t h e r l a n d s
Book Reviews SOIL PHYSICS
Elements of Soil Physics. P. Koorevaar, G. Menelik and C. Dirksen. Developments in Soil Science 13, Elsevier Science Publishers, Amsterdam and New York. 1983. xiv + 228 pages. Price: US$32.00 (in U.S.A. and Canada}, Dfl. 75.00 (rest of World). ISBN: 0-444-42242-0. This t e x t b o o k on Soil Physics has its origins in the lecture courses given in the Department of Soil Science and Plant Nutrition of the Agricultural University, Wageningen, The Netherlands. Its aim is to give students an introduction to basic principles. A novel feature of this b o o k is the inclusion of questions after each paragraph with answers at the end of each chapter for the student to check his progress in understanding the subject. The authors claim that students learning soil physics from the b o o k find it unnecessary to attend lectures or even tutorial classes, although one feels that generally most students would have difficulty in maintaining their interest in the subject with only the rather unexciting presentation of material and without being stimulated from other sources. The b o o k is divided into 8 chapters. The first deals with the composition and physical properties of soils, describing the 3-phase composition of soils and giving an introduction to the interaction between the solid and liquid phases in clays. The second chapter on the equilibrium in force fields and the theory of potentials expects the student to have a grounding in mechanics, outlining (often inadequately as in the case of summing v e c t o r s ) t h o s e aspects that are required for a discussion on soil-water equilibria. The authors do not help students in their understanding of h o w to apply basic principles by implying that the definition of physical laws are restricted to particular units, instead of emphasising that equations should balance dimensionally. For example, N e w t o n certainly did not use the units stated in the text when he formulated his second law. The discussion in this chapter is generally pedantic and does not make it easy for the student to have a physical feeling for the concept of potential, although the aim is that the theoretical discussion should help the student understand the practical situation of static equilibria in soils, the subject of the third chapter. The fourth chapter gives a generalised treatment of transport phenomena in soils on the basis that the flow can be considered as occurring in a continuum in response to a potential gradient. This chapter aims at giving the student a theoretical basis for describing the different transport phenomena in soils. It leads on to separate chapters on water flow, gas transport and heat flow in soils. However, the introduction to the subject through continuum physics does not bring out the physical differences in the mechanisms of the different flow phenomena in porous media.
486 The last chapter is in the form of an epilogue by Professor G.H. Bolt, in which attention is drawn to the additional understanding required for applying soil physics in the analysis and management of the soil behaviour in the real world. Professor Bolt points to developments in simulation modelling in complex soil studies, in the consideration of the spatial variability of soils and in the use of remote sensing in field measurements, that may lead to a predictive insight into physical processes on a field scale. The authors' treatment of soil physics is limited to a consideration of the physics of the soil environment and does not touch on the mechanical properties of soils that are of prime importance in tillage research. Their theoretical approach to the subject does not adequately bring o u t the empirical foundations of much of soil physics which is concerned with macroscopic soil phenomena. For many students wishing to get acquainted with soil physics their approach will be off-putting, although it could well be right for students with a previous training in pure science. E.G. YOUNGS (Rothamsted Experimental Station, Harpenden, Herts., AL5 2JQ, Great Britain)
SOIL Ken Simpson, Longman Group, Harlow, Essex, Gt. Britain, 1983, Price: £ 6 . 9 5 , 2 3 8 pp., ISBN: 0-582-44641-4.
Soil.
"Soil" is a concise text dealing with the science and management of our basic agricultural resource. The author, a former vice-principal of the East of Scotland School of Agriculture, has drawn the material from his practical experience, his lecture notes as well as various published works. The text is clearly written and illustrated by easily understood figures and tables. It is divided for convenience into theoretical and practical sections, the latter being divided into separate discussions on identification and correction of, first, soil physical problems and, second, soil chemical problems. Its immediate area of application is the British Isles. The approach taken by the author is valid; that soils are inherently different from place to place, even in the same field, that they are vulnerable to maltreatment by the producer, and also that they are amenable to improvement by appropriate practices. In this connection he endeavours to point o u t vulnerable features of different soils with a view to avoiding problems before they develop. The principles and practices described are not necessarily new, but some new approaches are suggested, primarily for