First published in 1927 as the second edition of a 1914 original, this book examines the effect of various inorganic substances on the growth of plants. Brenchley performs experiments to prove that certain compounds then in use in artificial fertilisers, including arsenic compounds, sometimes had a deleterious effect on the plants to which they were applied in various settings. This book will be of value to anyone with an interest in the history of botany and of agriculture.

Due to the rapid increase in world population and improving living standards, the global agriculture sector is confronting with challenges for the sustainability of agricultural production and of the environment. Intensive high-yield agriculture is typically dependent on addition of fertilizers (synthetic chemicals, animal manure, etc.). However, non-point nutrient losses from agricultural fields due to fertilization could adversely impact the environment. Increased knowledge on plant nutrient chemistry is required for improving utilization efficiency and minimizing loses from both inorganic and organic nutrient sources. For this purpose, the book is composed of 19 chapters that highlight recent research activities in applied nutrient chemistry geared toward sustainable agriculture and environment. Topics of interest include, but are not limited, to speciation, quantification, and interactions of various plant nutrients and relevant contributories in manure, soil, and plants. This book outlooks emerging researchable issues on alternative utilization and environmental monitoring of manure and other agricultural by products that may stimulate new research ideas and direction in the relevant fields.

The dramatic worldwide increase in agricultural and industrial productivity has created severe environmental problems. Soil and groundwater reservoirs have been polluted with pesticides, xenobiotics and agro-chemicals. The global consensus to reduce inputs of chemical pesticides and agrochemical fertilizers, which are perceived at being hazardous by some consumers, has provided opportunities for the development of novel, benign sustainable crop management strategies. The future of agricultural depends upon our ability to enhance the productivity without damage to their long-term production potential. One of the strategies is the application of effective microbial products beneficial for both farmers and ecosystems. This kind of approach can ensure both ecological and economic sustainability. Soil microbial populations are immersed in framework of interactions, which are known to affect plant fitness and soil quality. For betterment of life of human being, improved quality and variety of products are formed due to versatile action of different group of microorganisms, Microbes are able to degrade solid waste material into compost which is a mixture of decayed organic matter, manure etc. Incomplete microbial degradation of organic waste where the microbial process varies aerobic to anaerobic form is stated as compost, if added to soil improves plant growth and development. The biological activities and microbial metabolism in the soil contribute to alter its mixture and fertility. Incorporation of organic remain in the form of compost is known to influence favourably the physio-chemical and biological properties of soil. The beneficial activities bestowed upon plants by compost utilization are multifaceted, hence most promising alternatives for achieving sustainable agricultural production. An increased awareness on compost has led to their use in agricultural concern. Contents in the present book will comprised various chapters on the role of beneficial bacteria in the composting process. The application is depicted to achieve the attainable productivity besides, in disease management and suppressiveness of organisms of phytopathogenic in nature. Significance of the compost elicits certain responses e.g. soil reclamation, soil fertility, soil health and disease management exhibit due to quality compost amendment in soil. It serves as low cost prospective option for sustainable crop production and protection.

Soil and Fertilizers: Managing the Environmental Footprint presents strategies to improve soil health by reducing the rate of fertilizer input while maintaining high agronomic yields. It is estimated that fertilizer use supported nearly half of global births in 2008. In a context of potential food insecurity exacerbated by population growth and climate change, the importance of fertilizers in sustaining the agronomic production is clear. However, excessive use of chemical fertilizers poses serious risks both to the environment and to human health. Highlighting a tenfold increase in global fertilizer consumption between 2002 and 2016, the book explains the effects on the quality of soil, water, air and biota from overuse of chemical fertilizers. Written by an interdisciplinary author team, this book presents methods for enhancing the efficiency of fertilizer use and outlines agricultural practices that can reduce the environmental footprint. Features: Includes a thorough literature review on the agronomic and environmental impact of fertilizer, from degradation of ecosystems to the eutrophication of drinking water Devotes specific chapters to enhancing the use efficiency and effectiveness of the fertilizers through improved formulations, time and mode of application, and the use of precision farming technology Reveals geographic variation in fertilizer consumption volume by presenting case studies for specific countries and regions, including India and Africa Discusses the pros and cons of organic vs. chemical fertilizers, innovative technologies including nuclear energy, and the U.N.'s Sustainable Development Goals Part of the Advances in Soil Sciences series, this solutions-focused volume will appeal to soil scientists, environmental scientists and agricultural engineers.

For centuries, bird guano has played a pivotal role in the agricultural and economic development of Latin America, East Asia and Oceania. As their populations ballooned during the Industrial Revolution, North American and European powers came to depend on this unique resource as well, helping them meet their ever-increasing farming needs. This book explores how the production and commodification of guano has shaped the modern Pacific Basin and the world's relationship to the region. Marrying traditional methods of historical analysis with a broad interdisciplinary approach, Gregory T. Cushman casts this once little-known commodity as an engine of Western industrialization, offering new insight into uniquely modern developments such as environmental consciousness and conservation movements; the ascendance of science, technology and expertise; international relations; and world war.

This book elucidates the importance of long-term experiments in revealing evidence of soil fertility decline in Africa. An evaluation of experiences from on-going long-term experiments is given in broad detail. The first chapter explains the paradigm shift in soil fertility management then provides justification for long-term experiments before illuminating experiences from long-term experiments in East, West and Southern Africa. The second, sixth, eighth and ninth chapters give an in-depth account of crop management practices and soil fertility interventions in long-term trials within specific agro-ecological zones in West Africa. The rest of the chapters (chapter three, four, five and seven) address crop management, tillage practices and, organic and inorganic fertilizer applications in the context of long-term experiments in specific agro-ecological zones in East Africa.

The last two decades have seen rapid advances in the technology used to produce pot plants. Glasshouses designed and orientated to give maximum light transmission, fully automatic heating and ventilating systems, carbon dioxide enrichment of the atmosphere, controlled photoperiods using automatic blackouts and incandescent lamps which enable plants such as chrysanthemum to be flowered at any time of the year, mist propagation techniques, chemical growth regulators which control the height of plants, automatic watering and feeding systems, etc.: these are only some of the developments which have transformed pot plant culture. There have also been many changes in the composts and systems used to grow the plants. Mineral soils, which formed the basis of the John Innes Composts, are now either too expensive or too difficult to obtain in suitable quality and sufficient quantity. Consequently the grower has been forced to seek other materials such as peat, perlite, vermiculite, plastic foam, shredded bark, etc. New types of fertilisers, new methods of heat sterilisation and new chemical sterilising agents are also being used.

By the year 2050, the world's population is expected to reach nine billion. To feed and sustain this projected population, world food production must increase by at least 50 percent on much of the same land that we farm today. To meet this staggering challenge, scientists must develop the technology required to achieve an "evergreen" revolution--one that increases crop productivity without degrading natural resources. With 30 percent new material, the updated and revised third edition of Growth and Mineral Nutrition of Field Crops covers all aspects of crop growth and mineral nutrition that contribute to sustainable, high-yield agriculture. Bringing together international scientific knowledge of crop production and the impacts of agriculture on the environment, this book: * Includes two new chapters on remediation of heavy-metal contaminated soils and cover crops * Covers theoretical and practical aspects of mineral nutrition of field crops * Provides recommendations for judicious use of fertilizers, which will reduce cost of crop production and enhance high crop yields without risking environmental pollution * Provides growth patterns for annual crops and forages * Includes a handful of color pictures of nutrient deficiencies for easy diagnostic purposes To make the book as practical as possible, each chapter is supported by experimental results and extensive references. A large number of figures and tables are also included to save readers time when researching. The overall emphasis of this reference is on the soil's ability to sustain high crop yields and a healthy human population.

Put Theory into Practice

Scarcity of natural resources, higher costs, higher demand, and concerns about environmental pollution ? under these circumstances, improving food supply worldwide with adequate quantity and quality is fundamental. Based on the author's more than forty years of experience, The Use of Nutrients in Crop Plants builds a bridge between theoretical aspects of mineral nutrition and practical applicability of basic principles of fertilization and use efficiency of essential plant nutrients.

Provides Authoritative and Practical Information

The book explores how to maximize essential nutrients uptake and use efficiency by food crops and how to improve productivity without degrading the environment. It covers nutrients and their cycle in soil-plant systems, functions, and deficiency symptoms. The author includes management strategies that can lead to a reduction in the cost of crop production and environmental degradation. He emphasizes field conditions, crop production, and soil chemistry. Comprehensive coverage of essential nutrients and experimental results are accompanied by tables and figures of updated experimental data that make practical information easily accessible.

A Valuable Tool for Improving Crop Yield

Agricultural science is very dynamic in nature and fertilizer practices change with time due to the release of new cultivars and changing production practices in sustainable crop production systems. The Use of Nutrients in Crop Plants provides in-depth scientific information that is applicable through many methods of crop production. It is a valuable tool for improving crop yields at lower cost and less stress on the environment.

Rhizosphere biology is approaching a century of investigations wherein growth-promoting rhizomicroorganisms (PGPR) have attracted special attention for their ability to enhance productivity, profitability and sustainability at a time when food security and rural livelihood are a key priority. Bio-inputs - either directly in the form of microbes or their by-products - are gaining tremendous momentum and harnessing the potential of agriculturally important microorganisms could help in providing low-cost and environmentally safe technologies to farmers.One approach to such biologically-based strategies is the use of naturally occurring products such as PGPR. Advances in PGPR Research explores recent developments and global issues in biopesticide research, presented via extended case studies and up-to-date coverage of: * Low input biofertilizers and biofungicides used for sustainable agriculture. * Molecular techniques to enhance efficacy of microbial inputs. * Intellectual property issues in PGPR research. Written by an international team of experts, this book considers new concepts and global issues in biopesticide research and evaluates the implications for sustainable productivity. It is an invaluable resource for researchers in applied agricultural biotechnology, microbiology and soil science, and also for industry personnel in these areas.

The present investigation was carried out in the period 1977-1981 at the Department of Soil Science and Plant Nutrition of the Agricultural University Wageningen, Netherlands. This university supplied the major financial sup port through a research grant, with additional financial support rendered by the Dutch Nitrogen Fertilizer Industry and Unilever Research, Netherlands. This support is gratefully acknowledged. In the present form this report is the author's doctoral dissertation submitted to the Faculty of the Agricul tural University. The author hereby wishes to thank prof. dr. ir. A. van Diest for his criti cal reading and correction of the English text, and drjr. J. H. G. Slangen for his valuable advices during the investigations and in the course of the preparation of this report. The au thor also acknowledges the valuable support received from several Agricultural Research Institutes and University Depart ments which made facilities and manpower available to conduct the ex periments and to transform the results obtained into the present report. Contents Preface / v Abstract / 1 List of ab breviations / 2 Introduction / 3 2 Literature / 6 2. 1 Nitrogen transformations in soil / 7 2. 2 Nitrate uptake / 7 Nitrate reduction in plants / 7 2. 3 2. 4 Nitrate contents in plants / 8 2. 5 Cultural measures / 9 2. 5. 1 Nitrogen dressing / 9 2. 5. 1. 1 Nitrogen amount / 9 2. 5 . 1."

The dependence of present farming on artificial input of "chemical fertilizers" has caused numerous ecological tribulations associated with global warming and soil contamination. Moreover, there is an essential requirement for realistic agricultural practices on a comprehensive level. Accordingly, biofertilizers including microbes have been recommended as feasible environmentally sound solutions for agricultural practices which not only are natural, and cost-effective but also preserve soil environs and important biota of agricultural land. In addition, it enhances the nutrient quantity of soils organically. Microbial biofertilizers promote plant growth by escalating proficient absorption of nutrients for the plants and by providing an excellent disease-fighting mechanism.Agriculture, the backbone of human sustenance, has been put under tremendous pressure by the ever-increasing human population. Although various modern agro-techniques boosted agricultural production, the excessive use of synthetic fertilizers, pesticides and herbicides have proven extremely detrimental to agriculture as well as to the environment in which it is carried out. Besides this some faulty agricultural practices like monoculture and defective irrigation, further complicate the scenario by eliminating biodiversity, increasing the efflux of nutrients into the water bodies, the formation of algal blooms, eutrophication, damaging the water quality and lowering fish stocks. Biofertilizers are the organic compounds applied to crops for their sustainable growth and the sustainability of the environment as the microbiota associated with biofertilizers interact with the soil, roots and seeds to enhance soil fertility. Application of biofertilizers results in the increased mineral and water uptake, root development, vegetative growth and nitrogen fixation besides liberating growth-promoting substances and minerals that help the maintenance of soil fertility. They further act as antagonists and play a pivotal role in neutralising soil-borne plant pathogens and thus, help in the bio-control of diseases. Application of biofertilizers instead of synthetic fertilizers could be a promising technique to raise agricultural productivity without degrading environmental quality. The present book focuses on the latest research approaches and updates from the microbiota and their applications in the agriculture industry. We believe this book addresses various challenges and shed lights on the possible future of the sustainable agricultural system.

Aimed mainly at a professional audience, this book is intended to provide a user-friendly handbook on biochar. It de-mystifies the scientific, engineering and managerial issues surrounding biochar and makes the whole topic more understandable and approachable to potential users. These include policy makers, landowners and farmers, landuse, agricultural and environmental consultants, industry and lobby groups and NGOs.

The chapters review state-of-the-art knowledge in a non-technical way of biochar production, soil science, agriculture, environmental impacts, economics, the law and regulation and climate change policy. They explain the facets of biochar through the use of explanatory boxes, info-graphics and concise summaries of key concepts and understanding. The authors also present research findings from the first coordinated European biochar field trial, representing the largest biochar field trial globally, including the effects of several biochars (made from typical European feedstocks) on soil properties, soil functioning and crop growth and the costs and benefits of producing and using biochar. They evaluate whether the claimed climate change benefits of biochar are really justified compared to other choices on how we use our limited resources. They provide hands-on practical information and knowledge on how to combine biochar with other soil amendments (such as manure and composts) and with agronomic good practice, how to ensure that it is safe and effective and how to select the most appropriate biochar for different agronomic circumstances.

The book then summarises the key information for those who need to be aware of biochar from a policy perspective at local, national, EU and international levels.

In his insightful new book, Holy Shit: Managing Manure to Save Mankind, contrary farmer Gene Logsdon provides the inside story of manure-our greatest, yet most misunderstood, natural resource. He begins by lamenting a modern society that not only throws away both animal and human manure-worth billions of dollars in fertilizer value-but that spends a staggering amount of money to do so. This wastefulness makes even less sense as the supply of mined or chemically synthesized fertilizers dwindles and their cost skyrockets. In fact, he argues, if we do not learn how to turn our manures into fertilizer to keep food production in line with increasing population, our civilization, like so many that went before it, will inevitably decline.

With his trademark humor, his years of experience writing about both farming and waste management, and his uncanny eye for the small but important details, Logsdon artfully describes how to manage farm manure, pet manure and human manure to make fertilizer and humus. He covers the field, so to speak, discussing topics like:

How to select the right pitchfork for the job and use it correctly

How to operate a small manure spreader

How to build a barn manure pack with farm animal manure

How to compost cat and dog waste

How to recycle toilet water for irrigation purposes, and

How to get rid ourselves of our irrational paranoia about feces and urine.

Gene Logsdon does not mince words. This fresh, fascinating and entertaining look at an earthy, but absolutely crucial subject, is a small gem and is destined to become a classic of our agricultural literature.

We are entering a new era in production agronomics. Agricultural scientists the world over call for the development of techniques that simultaneously increase soil carbon storage and reduce agriculture s energy use. In response, site-specific or precision agriculture has become the focus and direction for the three motivating forces that are changing agriculture today: the expanding capacity of personal computers, the molecular biology revolution, and the recent developments in information technology such as the increasing use of geographical information systems (GIS).

Using mathematics, technology, and creativity, GIS Applications in Agriculture, Volume Two: Nutrient Management for Energy Efficiency examines the development of nutrient management practices that help producers improve their profitability and energy efficiency. Throughout the book, chapters demonstrate how complex mathematical and spatial modeling approaches can provide the basis for much of our present and certainly our future management practices.

Highlighting recent successes and the nuts and bolts associated with implementing the proposed techniques, the book covers energy efficiency calculations, techniques for overcoming yield-limiting factors, soil information collection and analysis, and remote sensing for improving management decisions. It describes the development of an economically optimum site-specific corn plant population equation based on an experiment containing many field sites, the estimation of soil productivity and energy efficiency using online data sources, and the assessment and implementation of site-specific carbon and water management systems, analyzing energy efficiency of compost and manures.

Emphasizing the mathematics that will enable producers to make full use of the technological advances made during the 21st century, GIS Applications in Agriculture, Volume Two holds the key to the successful, sustainable, and efficient production of food to feed the ever increasing world population.

The importance of understanding the metabolism of agrochemicals in plants has never been greater. In a world where food safety and environmental concerns are increasing, knowledge of the metabolic processes within plants and the terminal residues of agrochemicals in food crops is invaluable. Written by experts in the agrochemical industry and academia, Metabolism of Agrochemicals in Plants is the first text to give systematic coverage of this important topic.
This text brings together the current status of the subject with chapters on regulatory considerations, comparative metabolism of plants and animals, and the different phases of metabolism. Including new and novel research in primary metabolism, herbicide metabolism and bound residues, this work is unique and thoroughly up to date. This is an essential text for chemists and biochemists working in the agrochemical and pharmaceutical industries and academia as well as analytical chemists, regulatory chemists and environmental scientists.
Metabolism of Agrochemicals in Plants is a volume in the Wiley Series in Agrochemicals and Plant Protection. This series brings together current scientific and regulatory knowledge and perspectives on all aspects of the use of chemicals and biotechnology in agriculture.

The Composting Handbook provides a single guide to the science, principles and best practices of composting for large-scale composting operations facing a variety of opportunities and challenges converting raw organic materials into a useful and marketable product. Composting is a well-established and increasingly important method to recycle and add value to organic by-products. Many, if not most, of the materials composting treats are discarded materials that would otherwise place a burden on communities, industries, farms and the environment. Composting converts these materials into a valuable material, compost, that regenerates soils improving soils for plant growth and environmental conservation. The Composting Handbook expands on previously available resources by incorporating new information, new subjects and new practices, drawing its content from current scientific principles, research, engineering and industry experience. In both depth and breadth, it covers the knowledge that a compost producer needs to succeed. Topics include the composting process, methods of composting, equipment, site requirements, environmental issues and impacts, business knowledge, safety, and the qualities, uses and markets for the compost products. The Composting Handbook is an invaluable reference for composting facility managers and operators, prospective managers and operators, regulators, policy makers, environmental advocates, educators, waste generators and managers and generally people interested in composting as a business or a solution. It is also appropriate as a textbook for college courses and a supplemental text for training courses about composting or organic waste management.

Human excreta is a valuable fertilizer for improving soil quality and crop productivity, with a potential to replace or complement the mineral fertilizers. The main challenges related to human excreta regarding agricultural applications are microbial contamination risks, loss of nutrients, and odor issues. Fertilization by lacto-fermented faeces supplemented by biochar has benefits such as improved soil bulk density, nitrate and potassium concentrations as well as the yield and yield components of corn, compared to untreated, simple stored faeces, urine, cattle manure, and unfertilized controls. Even though the mineral fertilizer produced corn with significantly higher height and leaf length, it did not add significantly higher yields than lacto-fermented faeces supplemented by biochar. A faeces treatment process by combined lacto-fermentation with thermophilic composting and biochar supplementation had better reduction of coliforms, Escherichia coli, Enterococcus faecalis and Clostridium perfringens, and higher germination of radish and growth of tomatoes than combined lacto-fermentation with vermicomposting. Urine lacto-fermentation contributed to a pH reduction below 4, a decrease in the ammonium concentration and odor strength, as well as an increase in the germination rates compared to untreated stored urine. The results of this study provide important information that can set the basis for scaling up a sustainable technology for the treatment of source separated human excreta while improving its potential for resource recovery.

The dramatic worldwide increase in agricultural and industrial productivity has created severe environmental problems. Soil and groundwater reservoirs have been polluted with pesticides, xenobiotics and agro-chemicals. The global consensus to reduce inputs of chemical pesticides and agrochemical fertilizers, which are perceived at being hazardous by some consumers, has provided opportunities for the development of novel, benign sustainable crop management strategies.

The future of agricultural depends upon our ability to enhance the productivity without damage to their long-term production potential. One of the strategies is the application of effective microbial products beneficial for both farmers and ecosystems. This kind of approach can ensure both ecological and economic sustainability. Soil microbial populations are immersed in framework of interactions, which are known to affect plant fitness and soil quality.

For betterment of life of human being, improved quality and variety of products are formed due to versatile action of different group of microorganisms, Microbes are able to degrade solid waste material into compost which is a mixture of decayed organic matter, manure etc. Incomplete microbial degradation of organic waste where the microbial process varies aerobic to anaerobic form is stated as compost, if added to soil improves plant growth and development. The biological activities and microbial metabolism in the soil contribute to alter its mixture and fertility. Incorporation of organic remain in the form of compost is known to influence favourably the physio-chemical and biological properties of soil. The beneficial activities bestowed upon plants by compost utilization are multifaceted, hence most promising alternatives for achieving sustainable agricultural production.

An increased awareness on compost has led to their use in agricultural concern. Contents in the present book will comprised various chapters on the role of beneficial bacteria in the composting process. The application is depicted to achieve the attainable productivity besides, in disease management and suppressiveness of organisms of phytopathogenic in nature. Significance of the compost elicits certain responses e.g. soil reclamation, soil fertility, soil health and disease management exhibit due to quality compost amendment in soil. It serves as low cost prospective option for sustainable crop production and protection.

Agrochemicals Detection, Treatment and Remediation focuses on the latest research surrounding the detection and remediation of a new generation of agrochemical contaminants. The book defines the occurrence, sources, types and effects of agrochemicals, including herbicides, insecticides, fungicides and soil fumigants in the environment. The book covers both advanced physical and chemical methods for the abatement of these emerging contaminants in environmental media. Environmental Engineers and Researchers will find this to be a valuable reference on advanced processes for resource recovery, including nanotechnology for the recovery of phosphate from fertilizer industry wastewater.

This book provides a comprehensive overview of grassland nitrogen incorporating information from crop science, soils and fertilizers, ruminant consumption and environmental aspects. The published information is reviewed on the various transformations of nitrogen in temperate grassland systems. These include those taking place in soils. The effects of soil, weather and management practices are discussed and considerable emphasis is placed on soil-plant-animal interactions. A second aim of the book is to describe the factors that influence the response of grassland to the application of fertilizer nitrogen, and how the optimum rate of application may be determined. In addition, nitrogen balances are described for different grassland systems, showing how the annual inputs and outputs vary greatly depending on sward type and management. The book is of interest to a wide readership, especially those engaged in research, teaching and advisory work, and students taking courses in agricultural and environmental sciences.

Water, energy, and food are basic requirements for life, and this book presents solutions for obtaining these from sewage wastewater treatment plants. It describes the optimal recovery of value-added products from municipal sewage plants in developing countries, and explains how the plants' operations can become both economical and sustainable. Further, it shows how the clean effluent that is obtained is then suitable for agricultural use in the production of bio-fertilizers, and graywater for irrigation, and how the recovered biogas could be used for energy and heating needs. Practical case studies from three separate sewage plants are presented to illustrate the processes involved.

Rapid urbanization has created a major challenge with regard to waste management and environmental protection. However, the problem can be ameliorated by turning organic waste into compost for use as an agricultural fertilizer in peri-urban areas. This is especially significant in less developed countries, where food security is also a key issue. This book addresses these subjects and is based on papers presented at a workshop held in Ghana by the International Board for Soil Research and Management (IBSRAM, now part of the International Water Management Institute) and FAO. Special reference is given to Sub-Saharan Africa, with acknowledgement to experiences from other parts of the world. Contributing authors are from several European, as well as African, countries

Phosphorus is essential to all life. A critical component of fertilizers, Phosphorus currently has no known substitute in agriculture. Without it, crops cannot grow. With too much of it, waterways are polluted. Across the globe, social, political, and economic pressures are influencing the biogeochemical cycle of phosphorus. A better understanding of this non-renewable resource and its impacts on the environment is critical to conserving our global supply and increasing agricultural productivity. Most of the phosphorus-focused discussion within the academic community is highly fragmented. Phosphorus, Food, and Our Future will bring together the necessary multi-disciplinary perspectives to build a cohesive knowledge base of phosphorus sustainability. The book is a direct continuation of processes associated with the first international conference on sustainable phosphorus held in the United States, the Frontiers in Life Sciences: Sustainable Phosphorus Summit, though it is not a book of conference proceedings; rather, the book is part of an integrated, coordinated process that builds on the momentum of the Summit. The first chapter will introduce the biological and chemical necessity of phosphorus. The subsequent ten chapters will explore different facets of phosphorus sustainability and the role of policy on future global phosphorus supplies. The final chapter will synthesize all of the emerging views contained in the book, drawing out the leading dilemmas and opportunities for phosphorus sustainability.

Nitrogen constitutes about 79 percent of the earth's atmosphere, yet, in an agricultural plant production system, it is still common for soils to be deficient of the nitrogen needed for maximum plant growth. But nitrogen fertilizers that are essential for the economically driven production of food and fiber are recognized as polluters of natural waters, and it has become increasingly apparent that manufactured and naturally occurring nitrogen resources must be better managed. This book addresses the problem by describing how the various factors such as types of soils and crops, irrigation methods, climate, and the nitrogen cycle itself affect levels of nitrogen in plant production systems. The book also provides a practical guide to the many advantages and disadvantages of using different fertilizers across such factors as environment, type of plant, and method of farming. This book will be part of the solution to nitrogen management and agricultural problems and will be of interest to workers in local, state, and federal agricultural extension services, consulting firms, environmental regulators, and students and researchers in soil chemistry. This book is intended for workers in