The mission of the International Fertilizer Development Center is to increase food production through the improvement of fertilizers and fertilizer practices for the developing countries with special emphasis on tropical and subtropical agriculture. The principal aim is to ensure that fertilizer technology is not a limiting factor to food production in those regions. Although the full extent to which deficiency of micronutrients hampers food production is yet un known, there is ample evidence that problem areas exist and more will be identified as crop production is intensified and marginal lands are exploited. Therefore, it seems fully appropriate at this time that IFDC, as an international organization, take a leadership role in developing micronutrient fertilizer technology appropriate for the tropics and subtropics. The gravity of micronutrient deficiency as a limiting factor to crop pro duction varies from crop to crop and from soil to soil. The effects may range from slight yield reductions to complete crop failure. While the economic impact of omitting micronutrients in seriously affected areas (e.g., Zn in Brazilian Cerrado) is convincing, it is difficult to estimate the yearly loss in crop production due to unsuspected micronutrient deficiency. Active soil and crop testing programs in regions with advanced agricultural systems are aimed at recognizing micronutrients as a limiting plant nutrient in time to allow corrective measures and prevent yield loss. Successful micronutrient monitoring systems are generally limited to developed economies or to developing economies producing export cash crops."

This Fertilizer Manual was prepared by the International Fertilizer Development Center (IFDC) as a joint project with the United Nations Industrial Development Organi zation (UNIDO). It is designed to replace the UN Fertilizer Manual published in 1967 and intended to be a reference source on fertilizer production technology and economics and fertilizer industry planning for developing countries. The aim of the new manual is to describe in clear, simple language all major fertilizer processes, their requirements, advan tages and disadvantages and to show illustrative examples of economic evaluations. The manual is organized in five parts. Part I deals with the history of fertilizers, world outlook, the role of fertilizers in agriculture, and raw materials and includes a glossary of fertilizer-related terms. Part II covers the production and transportation of ammonia and all important nitrogen fertilizers-liquids and solids. Part III deals with the characteristics of phosphate rock, production of sulfuric and phosphoric acid, and all important phosphate fertilizers, including nitrophosphates and ammonium phosphates. Part IV deals with potash fertilizers-ore mining and refining and chemical manufac ture; compound fertilizers; secondary and micronutrients; controlled-release fertilizers; and physical properties of fertilizers. Part V includes chapters on planning a fertilizer industry, pollution control, the economics of production of major fertilizer products anJ intermediates, and problems facing the world fertilizer industry."

Proceedings of an International Symposium

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.

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.

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.

Organic farming is a system approach utilizing the natural cycles and biological interactions for crop production and protection. It aims at harmonizing with nature and a method of production without destroying the environment. Vermitechnology is one of the important components of organic farming. The earthworm (verm) is now known to be a good biological element for the recovery of vermifertilizer and vermin- protein for use in agro-ecosystems, aquaculture, poultry etc. Earthworm culture, popularly called vermiculture is being widely practicised in a big commercialized manner. Therefore, it is high time to enter into the vermitechnology as a part of the biotechnology programme. In India, some companies have adopted vermiculture, but by and large the general awareness remains limited, despite the fact that several non-governmental organizations and governmental institutions are trying hard to popularize vermitechnology. This book is an attempt to help those desirous of starting a vermicutlure and vermicompost industry. Based on this rationale, the Vermiculture Research Station in Aligarh, India embarked on an extensive programme of transferring vermitechnology to the farmers back in 2000 under the Lab to Land programme. The farmers were given specialized training through field demonstrations in vermitechnology, organizing special courses and setting-up their own field units in rural areas. It is heartening to note that female farmers have also come forward in this new venture and are now producing quality vermicompost to supplement their income.

This book describes many important principles of fertilizer management and the environmental pollution problems due to the indiscriminate soil fertilization rate. The long-term impacts of organic or mineral fertilizer use have implications on soil fertility, crop yields, water quality, climatic change, greenhouse gas emissions, etc. Twelve chapters provide the state of the art of some important topics on subsistence agriculture, modern agronomy, and technological improvements which have sharply increased yields from cultivation, with a special emphasis on the sustainable management and environmental impact of commercial and nontraditional fertilizers. Without a doubt, this book is a valuable contribution to the agricultural sciences and it would not have been possible without the invaluable contributions, immeasurable acknowledgements, and recognized expertise from the authors.

Nitrate and nitrite are two ions largely diffused in the environment because they take part in the nitrogen cycle. Moreover, a great part of atmospheric nitrogen may be oxidized to nitrite and nitrate by microorganisms in plants, soil or water. The more stable form of oxidized nitrogen is nitrate ion, but, through microbial activity, it can be reduced to nitrite ion which is more chemically reactive. Nitrate and its salts are widely used, especially as inorganic fertilizers, and for many other purposes such as oxidizing agents, explosives, in the chemical industry and as food preservatives. This book discusses the agricultural uses, management practices and environmental effects of nitrogen fertilizers.

Nitrogen is an important agricultural input that is critical for crop production. However, the introduction of large amounts of nitrogen into the environment has a number of undesirable impacts on water, terrestrial, and atmospheric resources. This book explores the use of nitrogen in U.S. agriculture and assesses changes in nutrient management by farmers that may improve nitrogen use efficiency. It also reviews a number of policy approaches for improving nitrogen management and identifies issues affecting their potential performance.

The innovative 3R "Recycle-Reuse-Reduce" AGROCARBON technology provides recycling of agricultural organic and mineral by-products provides carbon products for soil amendment and restoration of soil natural balance. This book explains how the input feed streams are plant and animal origin carboniferous by-products, such as refuse grain, sawdust, food grade animal bone meal, food processing and/or other agro by-products. The innovative technology is providing surface modified charcoals and minerals for plant availability and post processing the chars by integrated biotechnological means. The process is upgrading by-products to high added-value biological control, plant growth promotion and natural fertilisation combined products for environmentally friendly vegetable cultivation, with carbon sequestration potential. The 3R is a horizontally arranged and indirectly heated low temperature zero emission carbonisation system (operating under vacuum, up to 850 DegreesC+/-50 DegreesC material core temperature) and directly integrated novel agro biotechnological processing units of agrocarbon specific solid state fermentation and formulations. Performance: 1. Food crop mineral deficiency and disturbance stress mitigation in temperate climatic regions by restoration of soil natural balance. 2. Input feed streams: low value organic and/or inorganic by-products; such as refuse grain, sawdust and/or high Phosphorous content animal bone meal, and/or other by products; which can be valorisation transformed by added-value integrated thermal and biotechnological means. 3. The 3R biotechnology integrated industrialised biochar production technology is a modern zero emission solution, in which process all and any output products are recycled and reused, aiming prevention-protection-preservation approaches. 4. The output products are different types of soil biotechnology specific solid carrier composits and adapted microbiological fungus and/or bacteria strain consortiums. Depending on the soil and climate application scenario conditions, different types of soil and climate relevant 3R NPK products can be made. 5. The application objective of the products are the natural balance and functionality restorations of degraded temperate agriculture soils with controlled microbiological activity and precision farming nutrient supply. Further objectives are the promotion of humus building and mineral mobilisation towards plant availability, for sustainable, improved, economical and ecological food crop production in the fields of organic and low input low green house gas farmings, while carbon sequestration is also targeted. 6. The application targets combined effects, such as plant growth promotion, biological control against soil borne plant pathogens and natural NPK fertilisation, especially sequenced mobilised Phosphorus supply and improved nutrient use efficiency. 7. The application sectors are the organic farming and/or low input farming for environmentally friendly vegetable cultivation and other food crop productions. 8. STATUS: "product like" field demonstration plant has been developed, successfully tested, scale up optimisation and comprehensive industrialised engineering design made for 30,000 m3/year input feed stream as of modern US/EU industrial norms and standards. Patented original solution. Available for licensing and technology transfer.

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

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.

The world population will grow more rapidly during the few coming years. This must be accompanied by a parallel increase in the agricultural production to secure adequate food. Sustainability considerations mandate that alternatives to chemical nitrogen fertilizers must be urgently sought. Biological nitrogen (N2) fixation, a microbiological process which converts atmospheric N2 into a plant-usable form, offers this alternative. Among these renewable sources, N2-fixing legumes offer an economically attractive and ecologically sound means of reducing external inputs and improving internal resources. Environmental factors such as drought, elevated temperature, salinity, soil acidity and rising CO2 are known to dramatically affect the symbiotic process and thus play a part in determining the actual amount of nitrogen fixed by a given legume in the field. Understanding how nodule N2 fixation responds to the environment is crucial for improving legume production and maintaining sustainability in the context of global change. In this thoughtful and provocative new Brief, we provide critical information on how current and projected future changes in the environment will affect legume growth and their symbiotic N2 fixing capabilities. Each section reviews the main drivers of environmental change on the legume performance that include drought, elevated temperature, salinity and rising CO2, and soil acidity. Importantly we discuss the molecular approaches to the analysis of the stress response in legumes and the possible biotechnological strategies to overcome their detrimental effects.

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.

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 describes the results of the research of the project entitled Phosphorus Renewable Raw Materials: A Resource Base for the New Generation of Fertilizers' attributed to the National Center for Research and Development of Poland. This book is divided into three chapters that are assigned to different stages of the project undertaken by different R&D institutions. The concept and possible options of valorization of waste biomass, such as bones, fish bones, and ashes originated from the incineration of sludge from a waste-water treatment plant from the tertiary stage of biological treatment as resources of phosphorus were described by the team from Wroclaw University of Science and Technology. As a method of by-products valorization, the solubilization process was proposed. Two strategies were proposed: Ex-situ and in-situ. The in-situ manner resulted with suspension fertilizer with a low concentration of P2O5 while ex-situ gave the possibility to obtain two solid formulations with the high content of P2O5. All of them could be used in agriculture and horticulture as granular fertilizers or as substrates. The different content of P2O5, as well as other nutrients in obtained formulations, were described as an effect of utilization of different raw materials as well as various additional substances such as binders necessary for the stability of final formulations. What is more, the efficiency of obtained formulations was strongly related to the kind of microorganism used as an 'activator' of unavailable phosphorus, which was discussed in details. The technology of production for biofertilizers in pilot-scale was described by the Institute of New Chemical Synthesis in Pulawy with the following issues underlined: Design of installation to produce fertilizers based on renewable raw materials; plant construction and production of the product; and preliminary economic analysis. The University of Warmia and Mazury in Olsztyn described the utilitarian properties of new fertilizer formulations that were evaluated in field tests with special attention to granular and suspension biofertilizer. In that chapter, the major results of the agronomic evaluation of new suspension and granular phosphorus biofertilizers from secondary raw materials (sewage sludge ash, animal bones, and animal blood) were presented. Biofertilizers contained Bacillus megaterium or Acidithiobacillus ferrooxidans bacteria. New bioproducts were tested in field experiments in reference to traditional commercial phosphorus fertilizers (superphosphate, phosphorite, etc.). The research confirmed that phosphorus biofertilizers from renewable raw materials were similar to commercial fertilizers in terms of their crop-enhancing efficiency and did not reduce yield quality and quantity.

In this book, the biosorption process used to produce biological components of fertilisers was examined. For this purpose, the waste biomass obtained from the supercritical fluid extraction of oils from multiple berries seeds was used. It was shown that post-extraction residues of black currant, raspberrys and strawberry seeds constitute a valuable material for agricultural purposes. Detailed characteristics of these materials were presented. Moreover, it was shown that berries seeds are characterised by good biosorption properties. It was possible to increase the content of microelements essential for plants by applying the biosorption process. The utilitarian properties of enriched materials were tested in field experiments. Bioavailability of microelements from enriched post-extraction residues of the berries seeds to plants was assessed and the biofortification of edible parts of plants with micronutrients from the new products was achieved.

This volume provides a current look at how development of intensive live stock production, particularly hogs, has affected human health with respect to zoonotic diseases primarily transmitted by food but also by water, air and oc cupational activity. While information presented focuses on the development of increasing livestock production in Canada, examples are given and compar isons are made with other countries (Denmark, Taiwan, the Netherlands and the United States) where the levels of livestock production are much more intense and where the industry is more mature. Canada is also searching for solutions to enable handling the growing volume of its livestock waste properly. Lessons learned from the experience of those who have gone before are invaluable and are drawn together in this volume to serve as useful guidance for others in plot ting the courses of action possible to avoid serious environmental setbacks and negative human health effects through foodborne illness. A significant portion of the text is devoted to a discussion of enteric illness in humans caused by zoonotic pathogens. The second chapter deals with sur vival of pathogens (which cause foodborne illness) in manure environments. An evaluation of the human health hazard likely to occur from the use of ma nure as fertilizer is important because of the recent trend toward an increase in foodborne illness from the consumption of minimally processed fruits and vegetables that may have been fertilized with animal-derived organic materials."

The Boron '97 meeting was a great success in summarising all recent developments in basic and applied research on boron's function, especially in plants. New techniques have since been developed and new insight has been gained into the role of boron in plant and animal metabolism. Nevertheless, there were still lots of open questions. The aim of the present workshop held in Bonn as a satellite meeting to the International Plant Nutrition Colloquium was thus to gather all actual information which has been gained since the Boron '97 meeting and to compile knowledge, both from animal and plant sciences. Furthermore, applied aspects had to be addressed too, as there is an increasing awareness of boron deficiencies even in crops such as wheat, which have formerly not been considered as responsive to boron application. Genetic differences in boron demand and efficiency within one species are a further important topic which has gained importance since the 1997 meeting. More in-depth knowledge on the mechanisms of boron efficiency are required as an increased efficiency will be one major possibility to maintain and improve crop yields for resource-poor farmers. Nevertheless, it has also clearly been shown that an adequate supply of boron is needed to obtain high yields of crops with a high quality, and that a sustainable agriculture has to provide an adequate boron supply to compensate for inevitable losses through leaching (especially in the humid tropics and temperate regions) and for the boron removal by the crop.