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Managed grasslands — Analytical studies
350
of utilizing lignocellulosic wastes, other than through the ubiquitous ruminant. The book concludes with a brief summary of the discussions which took place after each of the three main sessions. Emphasis is placed on the limitations of the various approaches to greater utilization of lignocellulosic wastes, either untreated or after some form of chemical/physical treatment, the problems of scaling up and the competition from easily fermentable starch sources, which are now also in surplus in Europe. This book is warmly recommended to agricultural postgraduates, lecturers, advisers and researchers, as well as being required reading for administrators who seek the "philosopher's stone" of solving the problem of just one of Europe's surpluses. G. ALDERMAN
Department of Agriculture University o[ Reading Earby Gate Whiteknights Reading Berks, RG6 2AT Gt. Britain
GRASSLANDS
Managed Grasslands - - Analytical studies. R.W. Snaydon (Editor). Ecosystems o[ the World, Volume 17B. Elsevier, Amsterdam, The Netherlands, 1987, xiv+ 285 pp., illus. Dfl. 300, ISBN: 0-444-42565-9. The series Ecosystems of the World will consist of 29 volumes. Volume 17 deals with managed grasslands. It is divided into two parts. The book under review is a sequel to the part which describes managed grasslands of temperate and mediterranean regions. Volume 17B takes an analytical approach. The preceding volume, as well as the present one, ignores managed grasslands in the tropics. The publisher or the editors must have considered t h e m unimportant, although reference is occasionally made to the tropics in examples. It is indeed a fact that probably only about 5% of tropical grasslands can be termed as managed, but that is still a large area, and in some tropical regions managed grasslands play an important role-in the production of beef and milk. Furthermore, their development can contribute much to the production of food in areas which are greatly in need of better h u m a n nutrition. It is not as if there is no research on managed grasslandS in the tropics. In Australia, South America and Africa, large organisations staffed with reputable scientists are engaged
351 in serious research into the development of managed grasslands. There is no doubt in my mind that managed grasslands in the tropics should have been included in this series of studies on world ecosystems. This book consists of 26 chapters divided into four sections: primary production, secondary production, nutrient cycling and systems management. It presents quite good reviews of knowledge up to 1983. There are, however, only a few references dated 1984 and none more recent. Yet the book was published in 1987. Science develops fast and, therefore, reviews and books should be published without delay after the material has been written, otherwise they are out of date before they appear. Of the eight chapters on primary production, two deal with the productivity of grasslands in Great Britain, New Zealand and in Mediterranean and semiarid regions. These chapters are still descriptive despite the intention of an analytical approach. It is not clear why .only these regions were selected. Perhaps it would have been better to omit this kind of description altogether, and to have concentrated on the physiological aspects and effects of fertilizers and utilization on yield and botanical composition. It is not clear why there is a chapter on botanical composition in this part of the book and another one by the same author in the last part on systems management, particularly when the last chapter only covers six pages. Another example of a more logical approach that could have been followed is the combination of the chapters "effects of nitrogen fertilizer", "nitrogen cycling" and "nitrogen losses". This would have meant longer chapters by fewer authors or more joint authorships, but it would have benefitted the lay-out of the book. Although many chapters are very well written and relevant to present day grassland science, the choice of chapter titles and their placing in various parts of the book does not seem to follow a clear pattern. Modelling is a powerful research technique and the book contains a chapter on it, but only in relation to pasture growth. There are also models on pasture utilization and systems management, which are not dealt with. The part on secondary productivity has a logical sequence of chapters on beef, milk and sheep production, but then another 4-page chapter on "other domesticated animals". The contents of the short chapter on "reproduction, lifespan and efficiency of production" could easily have been incorporated in the chapters on the animal species. The part dealing with nutrient cycling contains chapters on nitrogen fixation and water run-off and drainage, which appear out of place. With chapters on nitrogen and phosphorus cycling, why is there a separate chapter on "return of nutrients by animals", in which the same elements are dealt with? The final part, systems management, contains chapters on economics, stocking rate, fertilization and conservation, but not on grazing systems. A great deal of effort has gone into the writing of this book and the contents
352
are worth reading, but the final result leaves a feeling of dissatisfaction, which is not improved by the high price of the book. L. 'T MANNETJE
Agricultural University Department of Field Crops and Grassland Science Wageningen The Netherlands
GRASSLAND SYSTEMS
Agronomy of Grassland Systems. C.J. Pearson and R.L. Ison. Cambridge University Press, Cambridge, Gt. Britain, 1987, v ÷ 169 pp., paperback, £9.95/ US$16.95, ISBN: 0-521-31009-1. This is yet another book on grasslands, but this one differs from others on this subject in having a truely analytical approach emphasizing systems concepts and biological principles. It will find good use in all kinds of climatic and economic situations, although the authors work in Australia and, in consequence, many of the examples are from that part of the world and New Zealand. The first chapter gives an overview of what to expect in the other seven chapters. One deals with generation from seeds, including seed bank dynamics, which is so important in understanding persistency of pasture species, particularly legumes. Forage production in terms of emergence and establishment, differentiation into plant parts, the physiology of growth and regrowth, and competition are covered in another chapter; not in great detail, but with sufficient depth and literature references to guide the student into further study. Particularly well treated are flowering and seed production, the specialty of the junior author. Mineral nutrition is dealt with from the point of view of plant needs for growth as well as that of nutrient recycling. The little and inadequate attention paid to the principles of nitrogen fixation by legumes is disappointing. The authors cannot be forgiven for once again listing the cross inoculation groups of host plant genera and Rhizobium, a concept which was already pointed out as useless in 1940 and, I had hoped, was killed in the sixties. However, herbage quality, animal intake, and also grassland-animal interactions and management have been done justice in two chapters. The final chapter is about grasslands in farming systems including a section on economics. There are three appendices; one with details on the derivation of climatic data for the calculation of grassland growth, one on calculating the feed demands of animals and one on investment analysis using discount cash flow. The book contains a large literature references section and a useful index. The book is well presented, full of formulae and diagrams, but, nearly un-
of utilizing lignocellulosic wastes, other than through the ubiquitous ruminant. The book concludes with a brief summary of the discussions which took place after each of the three main sessions. Emphasis is placed on the limitations of the various approaches to greater utilization of lignocellulosic wastes, either untreated or after some form of chemical/physical treatment, the problems of scaling up and the competition from easily fermentable starch sources, which are now also in surplus in Europe. This book is warmly recommended to agricultural postgraduates, lecturers, advisers and researchers, as well as being required reading for administrators who seek the "philosopher's stone" of solving the problem of just one of Europe's surpluses. G. ALDERMAN
Department of Agriculture University o[ Reading Earby Gate Whiteknights Reading Berks, RG6 2AT Gt. Britain
GRASSLANDS
Managed Grasslands - - Analytical studies. R.W. Snaydon (Editor). Ecosystems o[ the World, Volume 17B. Elsevier, Amsterdam, The Netherlands, 1987, xiv+ 285 pp., illus. Dfl. 300, ISBN: 0-444-42565-9. The series Ecosystems of the World will consist of 29 volumes. Volume 17 deals with managed grasslands. It is divided into two parts. The book under review is a sequel to the part which describes managed grasslands of temperate and mediterranean regions. Volume 17B takes an analytical approach. The preceding volume, as well as the present one, ignores managed grasslands in the tropics. The publisher or the editors must have considered t h e m unimportant, although reference is occasionally made to the tropics in examples. It is indeed a fact that probably only about 5% of tropical grasslands can be termed as managed, but that is still a large area, and in some tropical regions managed grasslands play an important role-in the production of beef and milk. Furthermore, their development can contribute much to the production of food in areas which are greatly in need of better h u m a n nutrition. It is not as if there is no research on managed grasslandS in the tropics. In Australia, South America and Africa, large organisations staffed with reputable scientists are engaged
351 in serious research into the development of managed grasslands. There is no doubt in my mind that managed grasslands in the tropics should have been included in this series of studies on world ecosystems. This book consists of 26 chapters divided into four sections: primary production, secondary production, nutrient cycling and systems management. It presents quite good reviews of knowledge up to 1983. There are, however, only a few references dated 1984 and none more recent. Yet the book was published in 1987. Science develops fast and, therefore, reviews and books should be published without delay after the material has been written, otherwise they are out of date before they appear. Of the eight chapters on primary production, two deal with the productivity of grasslands in Great Britain, New Zealand and in Mediterranean and semiarid regions. These chapters are still descriptive despite the intention of an analytical approach. It is not clear why .only these regions were selected. Perhaps it would have been better to omit this kind of description altogether, and to have concentrated on the physiological aspects and effects of fertilizers and utilization on yield and botanical composition. It is not clear why there is a chapter on botanical composition in this part of the book and another one by the same author in the last part on systems management, particularly when the last chapter only covers six pages. Another example of a more logical approach that could have been followed is the combination of the chapters "effects of nitrogen fertilizer", "nitrogen cycling" and "nitrogen losses". This would have meant longer chapters by fewer authors or more joint authorships, but it would have benefitted the lay-out of the book. Although many chapters are very well written and relevant to present day grassland science, the choice of chapter titles and their placing in various parts of the book does not seem to follow a clear pattern. Modelling is a powerful research technique and the book contains a chapter on it, but only in relation to pasture growth. There are also models on pasture utilization and systems management, which are not dealt with. The part on secondary productivity has a logical sequence of chapters on beef, milk and sheep production, but then another 4-page chapter on "other domesticated animals". The contents of the short chapter on "reproduction, lifespan and efficiency of production" could easily have been incorporated in the chapters on the animal species. The part dealing with nutrient cycling contains chapters on nitrogen fixation and water run-off and drainage, which appear out of place. With chapters on nitrogen and phosphorus cycling, why is there a separate chapter on "return of nutrients by animals", in which the same elements are dealt with? The final part, systems management, contains chapters on economics, stocking rate, fertilization and conservation, but not on grazing systems. A great deal of effort has gone into the writing of this book and the contents
352
are worth reading, but the final result leaves a feeling of dissatisfaction, which is not improved by the high price of the book. L. 'T MANNETJE
Agricultural University Department of Field Crops and Grassland Science Wageningen The Netherlands
GRASSLAND SYSTEMS
Agronomy of Grassland Systems. C.J. Pearson and R.L. Ison. Cambridge University Press, Cambridge, Gt. Britain, 1987, v ÷ 169 pp., paperback, £9.95/ US$16.95, ISBN: 0-521-31009-1. This is yet another book on grasslands, but this one differs from others on this subject in having a truely analytical approach emphasizing systems concepts and biological principles. It will find good use in all kinds of climatic and economic situations, although the authors work in Australia and, in consequence, many of the examples are from that part of the world and New Zealand. The first chapter gives an overview of what to expect in the other seven chapters. One deals with generation from seeds, including seed bank dynamics, which is so important in understanding persistency of pasture species, particularly legumes. Forage production in terms of emergence and establishment, differentiation into plant parts, the physiology of growth and regrowth, and competition are covered in another chapter; not in great detail, but with sufficient depth and literature references to guide the student into further study. Particularly well treated are flowering and seed production, the specialty of the junior author. Mineral nutrition is dealt with from the point of view of plant needs for growth as well as that of nutrient recycling. The little and inadequate attention paid to the principles of nitrogen fixation by legumes is disappointing. The authors cannot be forgiven for once again listing the cross inoculation groups of host plant genera and Rhizobium, a concept which was already pointed out as useless in 1940 and, I had hoped, was killed in the sixties. However, herbage quality, animal intake, and also grassland-animal interactions and management have been done justice in two chapters. The final chapter is about grasslands in farming systems including a section on economics. There are three appendices; one with details on the derivation of climatic data for the calculation of grassland growth, one on calculating the feed demands of animals and one on investment analysis using discount cash flow. The book contains a large literature references section and a useful index. The book is well presented, full of formulae and diagrams, but, nearly un-