Global agriculture is now at the crossroads. The Green Revolution of the last century is losing momentum. Rates of growth in food production are now declining, with land and water resources becoming scarcer, while world population continues to grow. We need to continue to identify and share the knowledge that will support successful and sustainable

Phytomass and Primary Production of the Various Vegetational Zones and of the Entire Biosphere The biosphere is that thin layer at the earth's surface in which living organisms exist and biological cycling takes place. It includes the upper horizons of the soil in which plants root, the atmosphere near the ground, (insofar as organisms penetrate this space), and all the surface waters. More than 99% of the earth's biomass is phytomass, to which we shall limit our discussion. Amounts of phytomass are distinctly related to vegeta tional zones. Because accurate determination of phytomass and primary production is difficult, only gross estimates have been available until recently. However, in 1970, Bazilevich et al. published (in Russian) more accurate calculations, based on the rapidly accumulating literature, for the various thermal zones and bioclimatic regions of the earth. These authors calculated mean phyto mass and mean annual primary production for the various regions as dry mass (in tons) per hectare. On the basis of measurements of the areas covered by the individual regions, excluding rivers, lakes, glaciers, and permanent snow, total phytomass and total annual primary production for the various regions were obtained (see table). The sum of these figures is the phytomass and annual production of the land surface of the earth. In addition, the table gives corresponding data for the waters of the earth. The values involved are potential i. e. , they are based on natural vegetation uninfluenced by man.

North American Agroforestry Explore the many benefits of alternative land-use systems with this incisive resource Humanity has become a victim of its own success. While we’ve managed to meet the needs—to one extent or another—of a large portion of the human population, we’ve often done so by ignoring the health of the natural environment we rely on to sustain our planet. And by deteriorating the quality of our air, water, and land, we’ve put into motion consequences we’ll be dealing with for generations. In the newly revised Third Edition of North American Agroforestry, an expert team of researchers delivers an authoritative and insightful exploration of an alternative land-use system that exploits the positive interactions between trees and crops when they are grown together and bridges the gap between production agriculture and natural resource management. This latest edition includes new material on urban food forests, as well as the air and soil quality benefits of agroforestry, agroforestry’s relevance in the Mexican context, and agroforestry training and education. The book also offers: A thorough introduction to the development of agroforestry as an integrated land use management strategy Comprehensive explorations of agroforestry nomenclature, concepts, and practices, as well as an agroecological foundation for temperate agroforestry Practical discussions of tree-crop interactions in temperate agroforestry, including in systems such as windbreak practices, silvopasture practices, and alley cropping practices In-depth examinations of vegetative environmental buffers for air and water quality benefits, agroforestry for wildlife habitat, agroforestry at the landscape level, and the impact of agroforestry on soil health Perfect for environmental scientists, natural resource professionals and ecologists, North American Agroforestry will also earn a place in the libraries of students and scholars of agricultural sciences interested in the potential benefits of agroforestry.

Learn to create and use simulation models—the most reliable and cost-effective tools for predicting real-world results! The Handbook of Processes and Modeling in the Soil-Plant System is the first book to present a holistic view of the processes within the soil-plant-atmosphere continuum. Unlike other publications, which tend to be more specialized, this book covers nearly all of the processes in the soil-plant system, including the fundamental processes of soil formation, degradation, and the dynamics of water and matter. It also illustrates how simulation modeling can be used to understand and forecast multiple interactions among various processes and predict their environmental impact. This unique volume assembles information that until now was scattered among journals, bulletins, reports, and symposia proceedings to present models that simulate almost all of the processes occurring in the soil-plant system and explores the results that these models are capable of producing. With chapters authored by experts with years of research and teaching experience, the Handbook of Processes and Modeling in the Soil-Plant System examines: physical, chemical, and biological soil processes the soil formation and weathering process and its modeling the impact of radioactive fallout on the soil-plant system soil degradation processes and ways to control them water and matter dynamics in the soil-plant system growth and development of crops at various levels of production the potentials and limitations of using simulation models Students, educators, and professionals alike will find the Handbook of Processes and Modeling in the Soil-Plant System an invaluable reference on the soil-plant-atmosphere system and an ideal tool to help develop an effective decision support system.

Soils and Landscape Restoration provides a multidisciplinary synthesis on the sustainable management and restoration of soils in various landscapes. The book presents applicable knowledge of above- and below-ground interactions and biome specific realizations along with in-depth investigations of particular soil degradation pathways. It focuses on severely degraded soils (e.g., eroded, salinized, mined) as well as the restoration of wetlands, grasslands and forests. The book addresses the need to bring together current perspectives on land degradation and restoration in soil science and restoration ecology to better incorporate soil-based information when restoration plans are formulated. - Incudes a chapter on climate change and novel ecosystems, thus collating the perspective of soil scientists and ecologists on this consequential and controversial topic - Connects science to international policy and practice - Includes summaries at the end of each chapter to elucidate principles and key points

Mineral Nitrogen in the Plant-Soil System provides integrated accounts of the transformations and fate of mineral nitrogen in the plant-soil system. This book emphasizes the understanding of various processes and the factors that affect these processes. It also focuses on the role of biological nitrogen fixation in nitrogen cycling in natural and agricultural systems. The book is divided into seven major chapters and each chapter is further subdivided into various subtopics. The first chapter introduces and outlines the origin, distribution, and cycling of nitrogen in natural and agricultural terrestrial ecosystems. Chapter 2 focuses on the processes of decomposition and mineralization-immobilization turnover. The processes of nitrification are discussed in detail in Chapter 3. The following four chapters discuss topics of retention and movement of nitrogen in soils; gaseous losses of nitrogen; uptake and assimilation of mineral nitrogen by plants; and lastly, the use of nitrogen in agronomic practice. The book will be invaluable to graduate students and researchers in the field of agriculture. This will also cater other parties interested, such as agronomists, soil scientists, plant physiologists, horticulturists, and foresters.

This innovative study presents concepts and problems in soil physics, and provides solutions using original computer programs. It provides a close examination of physical environments of soil, including an analysis of the movement of heat, water and gases. The authors employ the programminglanguage Python, which is now widely used for numerical problem solving in the sciences. In contrast to the majority of the literature on soil physics, this text focuses on solving, not deriving, differential equations for transport. Using numerical procedures to solve differential equations allowsthe solution of quite difficult problems with fairly simple mathematical tools. Numerical methods convert differential into algebraic equations, which can be solved using conventional methods of linear algebra. Each chapter introduces a soil physics concept, and proceeds to develop computer programsto solve the equations and illustrate the points made in the discussion.Problems at the end of each chapter help the reader practise using the concepts introduced. The text is suitable for advanced undergraduates, graduates and researchers of soil physics. It employs an open source philosophy where computer code is presented, explained and discussed, and provides thereader with a full understanding of the solutions. Once mastered, the code can be adapted and expanded for the user's own models, fostering further developments. The Python tools provide a simple syntax, Object Oriented Programming techniques, powerful mathematical and numerical tools, and a userfriendly environment.