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Soil science
Soil& Tillage Research, 21 (1991) 153-154 Elsevier Science Publishers B.V., Amsterdam
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Book Review SOIL SCIENCE Advances in Soil Science, Volume 9, by B.A. Stewart (Editor). Springer-Verlag, New York, 1989, 215 pp., hardcover, price DM 154, ISBN: 3-540-96781-8.
Volume 9 of this series offers four contributions in the fields of soil chemistry and physics, environmental science and soil survey. Each one combines a review of the state on present knowledge, some comments on practical applications and some guidelines on necessary further research work. The first and largest contribution reviews the use of gypsum on soils. The product is described in terms of availability and aqueous chemistry. Possible uses of gypsum concern mainly dispersive and acid soils. After a few introductory remarks on dispersive soils and their physicochemical behaviour, the response of soil to gypsum is described. Gypsum dissolves slowly in soils, thus releasing Ca-ions that counteract the effect of Naions. The influence of electrolyte concentration and exchangeable sodium percentage on the dispersive behaviour of the soil is described as well as the improvements in hydraulic conductivity or infiltration rate brought about by a gypsum application. Broadcasting techniques and possible uses on natural soils for conservation purposes or erosion control complete this well-docum e n t e d section. Soils with acid subsoils offer a second field for gypsum application. Unlike lime, gypsum dissolves rapidly enough to produce a calcium concentration increase down the profile and to reduce the concentration of free aluminum. The authors present several examples of positive gypsum effects on acid subsoils, but they also show that many aspects remain obscure at the present time. Gypsum appears to have a wide potential for use on dispersive a n d / o r acid soils, but a good deal of additional research and development is still needed. The second contribution summarizes our present knowledge on heavy metals and their environmental significance. After some introductory comments on the detrimental and nutritional aspects, the natural and anthropogenic occurrence of heavy metals, the author focuses on their more or less labile forms in the soil, and the lack of generally accepted methods of form identification. The analysis of plants grown in pot trials may not always reflect the real availability of heavy metals. A better understanding of the role of soil pH and of
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possible consequences following changes in soil management will have to be considered in future legislative approaches to the problem. The third contribution concerns the use of extractants in studies of trace metals in soils and sludges. A comprehensive list of extracting agents is proposed with some comments on their mode of action. The first and least agressive agent - - organic solvents - - might remove some oily and waxy components protecting metals in sludges and soils; the author is surprised that it is so rarely included in extraction sequences. There is still some uncertainty about the precise mode of action of several extracting agents, as well as about some "secondary" aspects of the sample preparation such as drying and grinding. The author presses for a rapid and urgent clarification of those problems. The last contribution refers to the use of soil survey data for quantitative land evaluation. Soil survey has achieved several important goals. Actual qualitative and quantitative procedures, lab and field data, allow a quality soil survey. On the other hand, the users of pedological information have changed; they would like to be able to select different land use options and to include the environmental protection dimension in their evaluations. As large scale maps cannot possibly be drawn for all the areas, the relevance of an observation made on a small scale m a p is discussed. Pedotransfer functions are helpful in order to obtain the information needed from an existing set of other data. The author proposes an interesting approach to future developments in land evaluation. Summarizing Volume 9, one can say that the four contributions manage to combine the presentation of actual scientific knowledge, possible practical applications and expected trends for future works successfully. A rich bibliography allows rapid access to the original literature. J.A. NEYROUD
Station fbdbrale de recherches agronomiques de Changins CH 1260 Nyon Switzerland
153
Book Review SOIL SCIENCE Advances in Soil Science, Volume 9, by B.A. Stewart (Editor). Springer-Verlag, New York, 1989, 215 pp., hardcover, price DM 154, ISBN: 3-540-96781-8.
Volume 9 of this series offers four contributions in the fields of soil chemistry and physics, environmental science and soil survey. Each one combines a review of the state on present knowledge, some comments on practical applications and some guidelines on necessary further research work. The first and largest contribution reviews the use of gypsum on soils. The product is described in terms of availability and aqueous chemistry. Possible uses of gypsum concern mainly dispersive and acid soils. After a few introductory remarks on dispersive soils and their physicochemical behaviour, the response of soil to gypsum is described. Gypsum dissolves slowly in soils, thus releasing Ca-ions that counteract the effect of Naions. The influence of electrolyte concentration and exchangeable sodium percentage on the dispersive behaviour of the soil is described as well as the improvements in hydraulic conductivity or infiltration rate brought about by a gypsum application. Broadcasting techniques and possible uses on natural soils for conservation purposes or erosion control complete this well-docum e n t e d section. Soils with acid subsoils offer a second field for gypsum application. Unlike lime, gypsum dissolves rapidly enough to produce a calcium concentration increase down the profile and to reduce the concentration of free aluminum. The authors present several examples of positive gypsum effects on acid subsoils, but they also show that many aspects remain obscure at the present time. Gypsum appears to have a wide potential for use on dispersive a n d / o r acid soils, but a good deal of additional research and development is still needed. The second contribution summarizes our present knowledge on heavy metals and their environmental significance. After some introductory comments on the detrimental and nutritional aspects, the natural and anthropogenic occurrence of heavy metals, the author focuses on their more or less labile forms in the soil, and the lack of generally accepted methods of form identification. The analysis of plants grown in pot trials may not always reflect the real availability of heavy metals. A better understanding of the role of soil pH and of
154
possible consequences following changes in soil management will have to be considered in future legislative approaches to the problem. The third contribution concerns the use of extractants in studies of trace metals in soils and sludges. A comprehensive list of extracting agents is proposed with some comments on their mode of action. The first and least agressive agent - - organic solvents - - might remove some oily and waxy components protecting metals in sludges and soils; the author is surprised that it is so rarely included in extraction sequences. There is still some uncertainty about the precise mode of action of several extracting agents, as well as about some "secondary" aspects of the sample preparation such as drying and grinding. The author presses for a rapid and urgent clarification of those problems. The last contribution refers to the use of soil survey data for quantitative land evaluation. Soil survey has achieved several important goals. Actual qualitative and quantitative procedures, lab and field data, allow a quality soil survey. On the other hand, the users of pedological information have changed; they would like to be able to select different land use options and to include the environmental protection dimension in their evaluations. As large scale maps cannot possibly be drawn for all the areas, the relevance of an observation made on a small scale m a p is discussed. Pedotransfer functions are helpful in order to obtain the information needed from an existing set of other data. The author proposes an interesting approach to future developments in land evaluation. Summarizing Volume 9, one can say that the four contributions manage to combine the presentation of actual scientific knowledge, possible practical applications and expected trends for future works successfully. A rich bibliography allows rapid access to the original literature. J.A. NEYROUD
Station fbdbrale de recherches agronomiques de Changins CH 1260 Nyon Switzerland