Systems approaches for agricultural development are needed to determine rational strategies for the role of agriculture in national development. Mathematical models and computer simulation provide objective tools for applying science to determine and evaluate options for resource management at field, farm and regional scales. However, these tools would not be fully utilizable without incorporating social and economic dimensions into their application. The second international symposium, Systems Approaches for Agricultural Development (SAAD), held in Los Banos, 6-8 December 1995, fostered this link between the biophysical sciences and the social sciences in the selection of keynote papers and oral presentations, a selection of which are included in these books. The contents further reflect how systems approaches have definitely moved beyond the research mode into the application mode. The large number and high quality of interdisciplinary research projects reported from different parts of the globe, to determine land use options that will meet multiple goals and yet sustain natural resource bases, is a key indicator of this coming of age'. At the farm level, where trade-off decisions between processes and products (commodities) feature strongly, much progress is also evident in the development of systems-based tools for decision making. At the field level optimization of resource use and minimizing environmental effects has become of major concern for which systems approaches are indispensable. The books, of which Volume I deals with regional and farm studies level and Volume II with field level studies, will be of particular interest to all agricultural scientists and planners, as well as students interested in multidisciplinary and holistic approaches to agricultural development."

Systems approaches for agricultural development are needed to determine rational strategies for the role of agriculture in national development. Mathematical models and computer simulation provide objective tools for applying science to determine and evaluate options for resource management at field, farm and regional scales. However, these tools would not be fully utilizable without incorporating social and economic dimensions into their application. The second international symposium, Systems Approaches for Agricultural Development, held in Los BaAos, 6-8 December 1995, fostered this link between the bio-physical sciences and the social sciences in the choice of keynote papers and oral presentations, a selection of which is included in this book. The book's contents further reflect how systems approaches have definitely moved beyond the research mode into the application mode. The large number and high quality of interdisciplinary research projects reported from different parts of the globe, to determine land use options that will meet multiple goals and yet sustain natural resource bases, is a key indicator of this coming of age'. At the farm level, where trade-off decisions between processes and products (commodities) feature strongly, much progress is also evident in the development of systems-based tools for decision making. This book will be of particular interest to all agricultural scientists and planners, as well as students interested in multidisciplinary and holistic approaches for agricultural development.

Facing new challenges with respect to sustainable agriculture and rural development strategies for low-income countries, related to global environmental change and globalization of markets, an interdisciplinary Wageningen University and Research Centre group set out to draw lessons from the DLO-IC projects of the last eight years. In discussing the way ahead and a future agenda, a number of major research challenges, as well as policy questions are outlined.

This textbook contains the material for a course in the major principles of modelling crop growth processes. There is much more to crop growth than what is discussed in this textbook, but it provides a sound basis for further work and study in this field. Chapter by chapter the book leads the reader to different modelled aspects of crop growth, and at the end, the reader will have a good understanding of the Wageningen simulation model SUCROS for the potential production situation. By then, it will be much easier to find one's way through descriptions and listings of other models. Throughout the text, the study of the different topics is facilitated by exercises that support the course in a hands-on computer practical exercise. A very simple crop growth model, almost entirely based on radiation interception, is given first. This skeleton model is then expanded by submodels for respiration, carbon assimilation, plant development, and a more detailed model for radiation interception and reflection. Modelling of transpiration and the leaf energy balance is given by way of introduction. There are many listings of the submodels, written in the simulation language FST (FORTRAN Simulation Translator), as well as of SUCROS itself, together with plentiful comments. Some supporting theory is provided in the form of Appendices. The book is meant for students and scientists who would like to acquire a working knowledge of the technique of crop growth modelling.

New directions in plant systems research are presented and discussed in this book. The book offers new insights in physiology and genetics of crop adaptation for wheat and maize, along with innovative approaches in architectural and physiology-based modelling of crop functioning. An outlook and dialogue on future directions in plant system research challenges readers with contrasting opinions on the way forward.

Systems approaches for agricultural development are needed to determine rational strategies for the role of agriculture in national development. Mathematical models and computer simulation provide objective tools for applying science to determine and evaluate options for resource management at field, farm and regional scales. However, these tools would not be fully utilizable without incorporating social and economic dimensions into their application. The second international symposium, Systems Approaches for Agricultural Development, held in Los Banos, 6-8 December 1995, fostered this link between the bio-physical sciences and the social sciences in the choice of keynote papers and oral presentations, a selection of which is included in this book. The book's contents further reflect how systems approaches have definitely moved beyond the research mode into the application mode. The large number and high quality of interdisciplinary research projects reported from different parts of the globe, to determine land use options that will meet multiple goals and yet sustain natural resource bases, is a key indicator of this coming of age'. At the farm level, where trade-off decisions between processes and products (commodities) feature strongly, much progress is also evident in the development of systems-based tools for decision making. This book will be of particular interest to all agricultural scientists and planners, as well as students interested in multidisciplinary and holistic approaches for agricultural development."

Systems approaches for agricultural development are needed to determine rational strategies for the role of agriculture in national development. Mathematical models and computer simulation provide objective tools for applying science to determine and evaluate options for resource management at field, farm and regional scales. However, these tools would not be fully utilizable without incorporating social and economic dimensions into their application. The second international symposium, Systems Approaches for Agricultural Development (SAAD), held in Los Banos, 6-8 December 1995, fostered this link between the biophysical sciences and the social sciences in the selection of keynote papers and oral presentations, a selection of which are included in these books. The contents further reflect how systems approaches have definitely moved beyond the research mode into the application mode. The large number and high quality of interdisciplinary research projects reported from different parts of the globe, to determine land use options that will meet multiple goals and yet sustain natural resource bases, is a key indicator of this coming of age'. At the farm level, where trade-off decisions between processes and products (commodities) feature strongly, much progress is also evident in the development of systems-based tools for decision making. At the field level optimization of resource use and minimizing environmental effects has become of major concern for which systems approaches are indispensable. The books, of which Volume I deals with regional and farm studies level and Volume II with field level studies, will be of particular interest to all agricultural scientists and planners, as well as students interested in multidisciplinary and holistic approaches to agricultural development."

Facing new challenges with respect to sustainable agriculture and rural development strategies for low-income countries, related to global environmental change and globalization of markets, an interdisciplinary Wageningen University and Research Centre group set out to draw lessons from the DLO-IC projects of the last eight years. In discussing the way ahead and a future agenda, a number of major research challenges, as well as policy questions are outlined.

This textbook contains the material for a course in the major principles of modelling crop growth processes. There is much more to crop growth than what is discussed in this textbook, but it provides a sound basis for further work and study in this field. Chapter by chapter the book leads the reader to different modelled aspects of crop growth, and at the end, the reader will have a good understanding of the Wageningen simulation model SUCROS for the potential production situation. By then, it will be much easier to find one's way through descriptions and listings of other models. Throughout the text, the study of the different topics is facilitated by exercises that support the course in a hands-on computer practical exercise. A very simple crop growth model, almost entirely based on radiation interception, is given first. This skeleton model is then expanded by submodels for respiration, carbon assimilation, plant development, and a more detailed model for radiation interception and reflection. Modelling of transpiration and the leaf energy balance is given by way of introduction. There are many listings of the submodels, written in the simulation language FST (FORTRAN Simulation Translator), as well as of SUCROS itself, together with plentiful comments. Some supporting theory is provided in the form of Appendices. The book is meant for students and scientists who would like to acquire a working knowledge of the technique of crop growth modelling.