Agricultural Systems 20 (1986) 313-3 t 9
Book Reviews
Frank M. D'Itri (Ed.). A Systems Approach to Conservation Tillage. Institute of Water Research and Department of Fisheries and Wildlife, Michigan State University, USA. Lewis Publishers Inc., Michigan, USA, 1985. 384 pp. Price: £36.75. 'Conservation tillage' is stated by the author of the first chapter of this book to be 'a complex, multi-faceted subject'. The remaining twenty-five chapters, each based on a paper presented at a conference at Michigan State University, seek to explore this complexity in every relevant detail. Two definitions of conservation tillage, selected from many alternatives, are offered. In the first, it is suggested that all tillage practices that conserve soil and water can be regarded as conservation tillage. In Chapter 3, three kinds of conservation tillage are identified, based on the amount of soil disturbance involved. These are: (a) no-tillage, zero tillage or slot planting; (b) strip tillage, including till planting and rotary strip tillage and (c) non-inversion tillage, including chisel tillage, disk tillage and rotary tillage. In general, the benefits claimed for conservation tillage, in addition to conservation of soil and water, include savings in energy, time and the use of tillage equipment. The additional costs include greater inputs of chemicals and of management expertise. The first eight chapters review the development of specialised equipment and crop and soil management systems. The next section describes methods of controlling weeds, insects and plant diseases and three further chapters deal with the economics and energy requirements 313
Agricultural Systems (20) (1986)---© Elsevier Applied Science Publishers Ltd, England, 1986. Printed in Great Britain
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Book reviews
of some selected systems, with particular reference to the conditions applicable to the mid-West of the USA, and to the state of Michigan. In the last ten chapters a range of environmental, sociological and public policy considerations are discussed, reflecting the many interacting aspects of a topic which now features prominently in the United States, and increasingly in many other countries. The effects of conservation tillage on farm profit are discussed, including comparison of the effectiveness of a range of systems and practices and their applicability to a variety of types of soil. The need for additional herbicides and pesticides, and for greater use of fertilisers, and the techniques of using these agrochemicals in no-tillage situations, are also discussed. Under the heading of environmental effects, the consequences of conservation tillage practices are considered in relation to topics such as surface hydrology, water quality and wind and water erosion, and the ecological implications for weed, microbial and animal populations are reviewed. Books which are based on conference proceedings are not always easily readable, but this is an exception. The style appropriate to verbal delivery has been successfully adapted to give an unusually fresh approach to the written word--at least in the majority of chapters. For a relatively expensive hardback book the print style gives a rather unsophisticated appearance, lacking in variety of typeface and with emphasis given solely by somewhat obtrusive underlining. Nevertheless, the final result is a book that is clearly readable, both in terms of its presentation and content. Conservation tillage is undoubtedly a subject of great importance in a world that is now more than ever conscious of the energy cost, financial cost and potential environmental cost of conventional farming cultivation systems. The wide range of topics presented in this book cannot fail to be of interest and value to all who are seriously concerned, from the farming or non-farming points of view. Although much of the subject matter is drawn from experience and research in Michigan, the lessons to be learned are applicable far beyond the boundaries either of that state or of North America. 3. A. C. Gibb
Vera, Rafit R. & Carlos Sergt, R. (Eds). Sistemas de Produccirn Pecuaria Extensiva (Extensive Systems of Animal Production), Brasil, Colombia,