Developments in Plant and Soil Sciences – serie
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179 produkter
179 produkter
Del 34 - Developments in Plant and Soil Sciences
Applications of Continuous and Steady-State Methods to Root Biology
Inbunden, Engelska, 1989
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This book provides an excellent illustration of the interrelationship between progress in scientific methodology and conceptual advances, and its publica tion should contribute to further advances. It is well known that major advances in understanding often follow the development of new methods. The development of the acetylene reduction assay for nitrogenase activity provides a good example of this interrelationship between theory and methods. Theoretical knowledge led to a search for substrates for nitro genase that could be assayed for more easily than ammonium, the normal product of the enzyme. The discovery of the reduction of acetylene to ethylene by nitrogenase provided the ideal answer to the problem by provid ing a rapid, specific, nondestructive, and inexpensive assay for nitrogenase activity. This assay is now used by almost every laboratory doing research on nitrogen fixation. However, further use and development of the acetylene reduction assay has shown that it can underestimate nitrogenase activity and can even give incorrect relative values under some circumstances. The major problem is that exposure of legume nodules to acetylene can cause a large increase in the resistance to oxygen diffusion into the nodule. This reduced supply of oxygen decreases the rate of nitrogenase activity within a few minutes.
Del 37 - Developments in Plant and Soil Sciences
Legumes in Farming Systems
Inbunden, Engelska, 1989
2 152 kr
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Proceedings of a Workshop, organized by the Directorate-General for Agriculture (DG VI) of the Commission of the European Communities, and held in Boignville (France) on May 25-27, 1988
Del 40 - Developments in Plant and Soil Sciences
Effects of Crop Rotation on Potato Production in the Temperate Zones
Proceedings of the International Conference on Effects of Crop Rotation on Potato Production in the Temperate Zones, held August 14–19, 1988, Wageningen, The Netherlands
Inbunden, Engelska, 1989
1 616 kr
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This volume contains the Proceedings of the International Conference on Effects of Crop Rotation on Potato Production in the Temperate Zones. This conference was held in the International Agricultural Centre at Wageningen, The Netherlands, August 14 - 19, 1988, under the auspices of the European Association for Potato Research (EAPR), the Potato Association of America (PAA) and the Dutch National Council for Agricultural Research (NRLO). The length of rotations affect the performance of potato crops and yields are often reduced if rotations are too short. The kinds of crops within a rotation will also affect potato performance, especially those grown in the previous season. It was a major aim of the conference to bring together specialists of various disciplines to examine these determinants of potato yield. The Organizing Committee is glad that all relevant aspects of the theme are highlighted in these proceedings. The contents of the contributions are primarily left to the responsibility of the authors. J. Vos C.D. van Loon G.J. Bollen ORGANIZATION OF THE CONFERENCE The European Association for Potato Research (EAPR) and the Potato Association of America (PAA) nominated representatives in the Conference Committee. PAA was represented by prof. dr E.E. Ewing (Ithaca, USA) and by dr R.E. Thornton (Pullman, USA); EAPR was represented by prof. dr J.C. Holmes (Edinburgh, UK), ir C.D. van Loon (Lelystad, NL), and dr ir J. Vos (chairman; Wageningen, NL).
Inbunden, Engelska, 1990
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The genetic work that has been carried out with volume, and especially in Section V 'Germplasm crop plants indicates that many nutritional charac- resources and creation of genotypes for specific teristics are independently inherited and could be environmental including low input systems', is selected for a breeding program. evident. This can be considered as genuine progress This volume presents the proceedings of the in the direction of an effective use of nutrients by 'Third International Symposium on Genetic plants. Aspects of Plant Mineral Nutrition' held in We look forward to more advances in our un- Braunschweig 1988, and demonstrates the wide derstanding of the mechanisms involved in the acceptance that cultivars respond differently to nutrient efficiency of crop plants and in the nutritional and stress factors. An improved re- development and improvement of screening sponse of cultivars to nutrients and stress con- techniques at the Fourth Symposium to be held in ditions is accessible via screening, selection and Australia in 1991. breeding of the available plant genetic resources and will help to reduce the inputs and to protect the N. EI Bassam environment. M.Dambroth The contribution of the plant breeders in this B.c. Loughman XI N. El Bassam et al. (Eds.), Genetic aspects a/plant mineral nutrition, 1-7. PLSO PN 122 (c) 1990 Kluwer Academic Publishers.
Inbunden, Engelska, 1991
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Many agricultural crops worldwide, especially in semi-arid climates, suffer from iron deficiencies. Among plants sensitive to iron deficiency are apples, avocado, bananas, barley, beans, citrus, cotton, grapes, peanuts, pecans, potatoes, sorghum, soybeans, and numerous ornamental plants. Deficiencies are usually recognized by chlorotic, in new leaves and are typically found among sensitive crops grown in calcareous or yellowed, interveinal areas soils which cover over 30% of the earth's land surface. Iron deficiency may lead, in extreme cases, to complete crop failure. In intensive agriculture on calcareous soils, iron often becomes a major limiting nutrient for optimal crop production, thus, correction of iron deficiency is required. Various chemicals and practices are available. They are, however, costly and do not always result in a complete remedy of the deficiency. Crucial questions relative to the cost-benefit equation such as the recovery rate of plants and the long-term fertilizing effect have not yet been resolved. The complexity of iron nutrition problems requires an understanding of the chemistry of iron oxides in soils, of the chemistry of both natural and synthetic chelates, of rhizosphere microbiology and biochemistry, and of the physiological involvement of the plant in iron uptake and transport.
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Soil acidity is a major limitation to crop production in many parts of the world. Plant growth inhibition results from a combination of factors, including aluminum, manganese, and hydrogen ion toxicities and deficiencies of essential elements, particularly calcium, magnesium, phosphorus, and molybdenum. Agricultural management practices and acid precipitation have increased acid inputs into the ecosystem and heightened concern about soil acidity problems. While application of lime has proved to be effective in ameliorating surface soil acidity in many areas, significant soil acidity problems still exist. Scientists from Alberta, Canada, recognized the need to provide a forum for researchers from different disciplines to exchange information and ideas on solving problems of plant growth in acid soils. As a result of their efforts, the First International Symposium on Plant-Soil Interactions at Low pH was held at Grande Prairie, Alberta, Canada, in July 1987. In many acid soil areas, liming materials are not readily available, the cost may be prohibitive, or subsoil acidity cannot be corrected by surface application of lime. New management approaches involving both the plant and the soil are needed in these situations. Progress has been made in the selection and breeding of acid-tolerant plants. However, continued progress will be limited by our lack of understanding of the physiological and biochemical basis of differential acidity tolerance among plants.
Inbunden, Engelska, 1991
865 kr
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Inbunden, Engelska, 1992
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Until recently the interest of plant physiologists in the structure and function of the root, as compared with the above-ground organs, was rather limited. In contrast to the data obtained from agricultural research, where the root is understood as an organ of water and nutrient uptake, recent studies on root systems have evolved as a consequence of an increase in our general knowledge of the transport of substances across biological cell membranes. This has led to increased interest in studies of ion uptake and transport from a novel viewpoint. Parallel to this, the complexity of the histological structure of the root has necessitated a study of this structure in relation to processes which take place in the root. The evaluation of such complex relationships is, in this book, concentrated on recent findings concerning the anatomical structure of the root in relation to its functional manifestations. Based on the principles of structure and function, the metabolic processes in the root, as well as the uptake and transport of water and ions are dealt with. The emphasis throughout is on the structural features. Finally, a short chapter has been included about the root under conditions of environmental stress.
Inbunden, Engelska, 1991
1 616 kr
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Tropical Africa escaped from the glaciers that covered the temperate parts of the world during the Ice Age. The legacy is that most of the parent materials of the soils of tropical Africa are old, highly weathered and devoid of bases and phosphate-bearing minerals. Traditional farming systems which were relatively stable and sustainable relied on long fallow periods after one to two years of cropping to maintain the productive capacity of the soils. In recent times and especially in densely populated areas, a sizeable class of 'landless' farmers have begun to cultivate marginal lands or to invade the 'forest reserves' thereby exacerbating the problems of land and environ mental degradation. of soil fertility that will facilitate the production of adequate quantities of the principle Maintaining a level staples has become a major challenge to agricultural scientists in tropical Africa. To increase the nutrient supplying power of soils requires the inputs of fertilizers. These can be organic or inorganic. The efficiency with which these externally supplied inputs can increase agricultural production and reduce soil and environmental deterioration is dependent on the ability of scientists to determine the right types and quantities of the products to apply to each soil, crop and cropping system as well as the ability of farmers to acquire requisite farm manage ment skills.
Inbunden, Engelska, 1991
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1 616 kr
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Chemical fertilizers have had a significant impact on food production in the recent past and are today an indispensible part of modern agriculture. On the other hand, the oil crisis of the 1970s and the current Middle East problems are constant reminders of the vulnerability of the fossil fuel dependent agriculture. There are vast areas of the developing world where N fertilizers are neither available nor affordable and, in most of these countries, balance of payment problems have resulted in the removal of N fertilizer subsidies. The external costs of environmental degradation and human health far exceed economic concerns. Input efficiency of N fertilizer is one of the lowest and, in turn, contributes substantially to environmental pollution. Nitrate in ground and surface waters and the threat of the stability of the ozone layer from gaseous oxides of notrogen are major health and environmental concerns. The removal of large quantities of crop produce from the land also depletes soil of its native N reserves. Another concern is the decline in crop yields under continuous use of N fertilizers.These economic, environmental and production considerations dictate that biological alternatives which can augment and in some cases replace N fertilizers must be exploited. Long-term sustainability of agricultural systems must rely on the use and effective management of internal resources. The process of biological nitrogen fixation offers an economically attractive and ecologically sound means of reducing external nitrogen input and improving the quality of and quantity of internal resources. In this book, sustainability issues that dictate an increased use of biological nitrogen fixation and the constraints on its optimal use in agriculture are outlined.
Inbunden, Engelska, 1993
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The adaptation of desirable agricultural plants to infertile and problem soils is an increasingly important strategy for improving food supplies in many parts of the world. The plant breeding approach complements, and in some cases may replace agronomic practices such as the use of fertilizers and soil amendments to provide solutions which are economically and environmentally sustainable. The Symposium at which the papers in this volume were presented drew together workers in plant breeding, plant nutrition, physiology, biochemistry and molecular biology to discuss research on gene systems which affect the mineral nutrition of plants. Papers describe successes in plant breeding for problem soils as well as advances in understanding of mechanisms at the whole plant and cellular levels. Papers in the "molecular" area point the way to the contribution which the new biology will make to this field in the future. The reviews and research papers are grouped under five topics: better plants for acid soils; salinity tolerance; efficiency of uptake and use of macronutrients; efficiency for iron and micronutrients; and tolerance of heavy metals and boron.
Del 51 - Developments in Plant and Soil Sciences
Isotopic Studies of Azolla and Nitrogen Fertilization of Rice
Report of an FAO/IAEA/SIDA Co-ordinated Research Programme on Isotopic Studies of Nitrogen Fixation and Nitrogen Cycling by Blue-Green Algae and Azolla
Inbunden, Engelska, 1993
1 616 kr
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Nitrogen is the most limiting element for crop production. Traditionally, expensive commercial fertilizers are used to correct soil nitrogen deficiencies. Indeed, 50% of the increase in rice yields after World War II can be attributed to increased fertilizer nitrogen use. Although an increased rate of fertilizer nitrogen application has been advocated to meet the growing demand for food, it is unrealistic to advise the farmers to apply fertilizers they could hardly afford, and whose prices are likely to escalate in the years ahead. In addition, when they are not applied judiciously there are problems of environmental pollution as plants are capable of taking up only a relatively small portion of the applied nitrogen, a substantial amount being lost through various chemical and biological processes. The exploitation of cheaper alternatives or supplements to fertilizers have therefore gained much interest in recent years.Our increased interest in biological nitrogen fixation as a supplement or alternative to nitrogen fertilizers led to the convening of a consultants' meeting on "The Role of Isotopes in Studies on Nitrogen Fixation and Nitrogen Cycling by Blue-Green Algae and the Azolla-Anabaena azollae Association", in Vienna from 11-15 October 1982. The consultants' group recommended that the joint FAO/IAEA Divison of Nuclear Techniques in Food and Agriculture embark on a co-ordinated research programme in this field and that the initial emphasis should be placed on Azolla-Anabaena symbiosis. As a result, such a programme was initiated in 1984, which was concluded in 1989. The results and conclusions reported here are those that were generated during the five years of its operation.
Inbunden, Engelska, 1993
1 187 kr
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The common bean Phaseolus vulgaris L. is the most important pulse crop in Latin America, as well as in large parts of Asia and Africa. It is particularly important due to its ability, in symbiosis with Rhizobium bacteria, to fix atmospheric nitrogen and due to its high nutrient value. Incorporating contributions from plant breeders, microbiologists, plant physiologists and soil scientists, this volume reports the results of an FAO/IAEA Coordinated Research Programme (1985-1991), whose main objective was to enhance yield and biological nitrogen fixation in the common bean by reducing its reliance on soil and fertilizer nitrogen. The volume should be useful for scientists working on biological nitrogen fixation and legume production.
Inbunden, Engelska, 1993
5 369 kr
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The Eighth International Colloquium for the Optimization of Plant Nutrition was held in Lisbon, Portugal, 1992, and was attended by 280 scientists from 34 countries. The programme allowed the participants ample opportunity for discussions, and exchange of results and ideas. The present volume includes 103 refereed contributions that clearly reflect the main themes of the Colloquium. The published papers are related to the following problem areas: plant analytical procedures and associated concepts; diagnosis of nutrient status of plants in relation to fertilizer application; physiological and biochemical effects of stress (nutrient deficiencies/toxicities, salinity/alkalinity); assessment of nutrient requirements by crops and improvement of nutrient use efficiency based on dynamic models; optimization of crop nutrition in integrated agriculture in terms of maximum productivity and profitability, technical feasibility, and reduction of environmental pollution. Since 1964, International Colloquia have been organized every four years under the aegis of what is now known as the International Association for the Optimization of Plant Nutrition (IAOPN).The aim of these meetings has been to assess the continuing and increasing role of plant nutrition in developments in horticulture, agriculture, and forestry. Major progress has been made in use of artificial growth media, diagnosis of plant nutrient requirements and disorders of crops, the ongoing quest to improve both yield and quality of crops through efficient use of fertilizers, and the introduction of methods and materials in crop nutrition that spare the environment.
6 332 kr
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"Plant Nutrition - From Genetic Engineering to Field Practice", the 12th International Colloquium on Plant Nutrition, is part of a series which began in 1954. Early meetings were mainly concerned with the practical problems of soil fertility, with soil assessment, fertilizer requirements and methods of analysis. As the colloquia have progressed, the emphasis has slowly changed. The practical problems are still important, but there is increasing emphasis on plant physiology, plant biochemistry, membrane biochemistry, and on the chemistry of genes which control the proteins in order to transfer nutrient ions to the inside of cells. The meetings therefore provide a useful opportunity for each half of the science of plant nutrition to interact with, and learn from the other half. This volume begins with five papers which review current knowledge in important fields: the rhizosphere, molecular biology, electron microscopy, location and function of elements, and modelling nutrient responses in the field. These themes are continued in groups of shorter papers which follow.In addition, there are sections on nutrient dynamics and partitioning, diagnostic techniques, plant survival strategies, mycorrhizas, and on nutrients such as P, N, S, K, Ca, Mg, and micronutrients. A large section is devoted specifically to boron - reflecting the considerable current interest in this element. In total there are 177 refeered papers providing both a broad overview and a detailed picture of the latest developments in pure and applied plant nutrition.
Inbunden, Engelska, 1994
2 366 kr
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The symposium on "Zinc in Soils and Plants" is the third in a series which began with "Copper in Soils and Plants" in Perth in 1981 and continued with "Manganese in Soils and Plants" in Adelaide in 1988. The symP9sium brings together a series of valuable accounts of many aspects of the reactions of zinc in soils, the uptake, transport and utilization of zinc in plants, the diagnosis and correction of zinc deficiency in plants and the role of zinc in animal and human nutrition. I am grateful for the financial support provided by Grains Research and Development Corporation, Rural Industries Research and Development Corporation, Wool Research and Development Corporation, Ansett Australia, and Qantas Australian. I am most appreciative of the willingness of many scientists to act as referees: G S P Ritchie, R J Gilkes, N C Uren, K Tiller, BLeach, H Greenway, N E Longnecker, J F Loneragan, Z Rengel, C A Atkins, J W Gartrell, P J Randall, D G Edwards, R J Hannam, R J Moir, J E Dreosti, N Suttle, C L White, H Marschner, N Wilhelm, M McBride. All provided valuable comments on the manuscripts. Finally, I thank Mrs M Davison who provided excellent secretarial assistance. A.D.Robson September 1993 Chapter 1.
Häftad, Engelska, 1994
2 152 kr
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This book is the most up-to-date and comprehensive review of our knowledge of the management of mycorrhizas in agriculture, horticulture and forestry. It contains twenty-four reviews written by leading international scientists from eight countries. The reviews consider the ecology, biology and taxonomy of arbuscular and ectomycorrhizal fungi, the information and functioning of mycorrhizas and opportunities for managing these symbioses. The book will be essential reading for scientists and advisors responsible for ensuring that the maximum benefit is obtained from mycorrhizal symbioses in agriculture, horticulture and forestry and in the reclamation of degraded lands.
Inbunden, Engelska, 1994
865 kr
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During the past three decades there has been a large amount of research on biological nitrogen fixation, in part stimulated by increasing world prices of nitrogen-containing fertilizers and environmental concerns. In the last several years, research on plant-microbe interactions, and symbiotic and asymbiotic nitrogen fixation has become truly interdisciplinary in nature, stimulated to some degree by the use of modern genetic techniques. These methodologies have allowed us to make detailed analyses of plant and bacterial genes involved in symbiotic processes and to follow the growth and persistence of the root-nodule bacteria and free-living nitrogen-fixing bacteria in soils. Through the efforts of a large number of researchers we now have a better understanding of the ecology of rhizobia, environmental parameters affecting the infection and nodulation process, the nature of specificity, the biochemistry of host plants and microsymbionts, and chemical signalling between symbiotic partners. This volume gives a summary of current research efforts and knowledge in the field of biological nitrogen fixation.Since the research field is diverse in nature, this book presents a collection of papers in the major research areas of physiology and metabolism, genetics, evolution, taxonomy, ecology, and international programmes.
Del 58 - Developments in Plant and Soil Sciences
Structure and Function of Roots
Proceedings of the Fourth International Symposium on Structure and Function of Roots, June 20–26, 1993, Stará Lesná, Slovakia
Inbunden, Engelska, 1995
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These papers summarize the present status of knowledge related to the structure and function of primary root tissues and their cells, as presented at the Fourth International Symposium on the Structure and Functions of Roots. The organizers assembled leading scientists from all over the world. All five subject areas that were presented at the symposium are covered in the book.
Inbunden, Engelska, 1995
3 224 kr
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The current status of the work being conducted throughout the world in the field of iron deficiency in plants is reviewed in this book, which consists of research papers and invited lectures on specific topics related to iron deficiency. The book includes chapters reviewing the molecular and biochemical mechanisms elicited by iron deficiency in plants, algae and bacteria. Papers and reviews providing new information on the Strategy I-type and the Strategy II-type responses in higher plants are also included. Other chapters deal with new research directed towards finding possible means of controlling iron deficiency in crops of economic interest, including early diagnosis, fertilization, fertirrigation and plant breeding. Several papers involve the study of lime-induced iron chlorosis under semi-arid crop conditions in Mediterranean environments.
1 079 kr
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As atmospheric CO2 increases there will almost certainly be alterations in soil carbon fluxes. It is likely that such alterations will be accompanied by changes in the partitioning of carbon between organic structures and to soil processes. These changes have the potential for further altering the structure and function of terrestrial ecosystems. While there has been increasing recognition of the importance of soil-mediated responses to global climate change, the nature and magnitude of these responses are not well understood. In an effort to expand our assessment of the significance of belowground responses to rising atmospheric CO2, a workshop has been organized that resulted in the peer-reviewed contributions that are contained in this volume.
865 kr
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"Plant Production on the Threshold of a New Century" describes and compares problems and frontier developments in the different sectors of plant production, integrating developments in basic plant sciences, crop science and socio-economic science, leading to sustainable plant production. Hence the book formulates goals and constraints in policy, economy, production, environment and land use; indicates how these goals and constraints may be translated into farming styles and cropping systems; and describes how the fundamental plant sciences can contribute to the implementation of such farming styles and cropping systems.
Inbunden, Engelska, 1995
3 224 kr
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From the research results and discussions presented in this text, theories are formulated of the various interrelationships of the nutritional aspects which allow the implementation of specific management strategies to improve stability and productivity of forest ecosystems. In particular, the effects of environmental changes as related to the impacts of air pollution, global change and land use on nutrient uptake and cycling processes in forest ecosystems are dealt with in detail. The book is divided into six main issues and each topic contains reviews as well as selected results of recent studies.
Inbunden, Engelska, 1995
1 616 kr
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The sustainability of both natural and managed ecosystems is strongly influenced by soil biological processes. A major question in soil biology and ecosystem ecology is the extent to which these processes are affected by the function and structure of the soil's biotic community. This book presents the discussions of a group of soil biologists and ecosystem ecologists in which they synthesize available information, present innovative methodologies, and develop cross-taxa and cross-habitat collaborations to advance the understanding of soil biodiversity. The volume addresses the extent and regulation of soil biodiversity and describes initial approaches to the linking of soil biodiversity and ecosystem function. It is intended for researchers and students in a wide range of environmental scientific disciplines.
3 802 kr
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The understanding of plant-soil interactions in acid soils is important for improved food production in many parts of the world. The context of the book touches on basic and applied aspects of the physics, chemistry and biology of acid soils and their effect on growth of plants. It contains a large section on management of acid soils for plant (food) production and on socioeconomic aspects of management of acid soils. This is important because a large portion of the world's acid soils occurs in less developed countries. Plant-Soil Interactions at Low pH: Principles and Management contains a substantial number of papers, including nine invited reviews, presented at the Third International Symposium of Plant-Soil Interactions at Low pH. The major themes include chemistry and physics of acid soils, microbial and faunal activity in acid soils, mechanisms of acid tolerance of plants, selection and breeding of acid-tolerant plants, diagnosis and correction of acid soil infertility, socioeconomic aspects of acid soil management and management systems for agriculture, horticulture and forestry on acid soils.
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The subsistence agriculture of the pre-chemical era efficiently sustained the nitrogen status of soils by maintaining a balance between N loss and N gain from biological nitrogen fixation (BNF): the microbial conversion of atmospheric N to a form usable by plants. This was possible with less intensive cropping, adaptation of rational crop rotations and intercropping schemes, and the use of legumes as green manure. Modern agriculture concentrates on maximum output, however, overlooking input efficiency; it is not sustainable. Intensive monocropping, with no or inadequate crop rotations or green manuring, together with the excessive use of chemical N fertilizers, results in an imbalance between N gain and N loss. The losses are often larger than the gains, and soil N status declines. The challenge is to sustain soil N fertility in many different tropical and temperate farming systems operating at high productivity levels. This requires judicious integration of BNF components, maintaining a good balance between N losses and gains.In this book, papers on BNF in crop forage and tree legumes are augmented with discussions of integrated farming systems involving BNF, soil and N management, and recycling of legume residues. BNF by non-legumes are discussed, and attempts to transform cereals into nodulating plants are critically reviewed. Advances in the development of novel methodologies to understand symbiotic relations and to assess N2 fixation in the field are described, and means are presented to enhance BNF through plant and soil management or breeding and selection. Problems encountered in exploiting BNF under field conditions are examined, as are promising approaches to improving BNF exploitation.
Inbunden, Engelska, 1996
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Food production remains the highest agricultural priority, subject to the constraint that it be done in harmony with nature, or at least with minimum environmental pollution. The amount of fertilizer applied can be controlled using modern application techniques, including soil and crop management, guaranteeing higher economic profit and lower environmental cost. It is in such a context that the present study addresses the efficient and rational use of mineral and organic fertilizers while preserving environmental quality. The book discusses the impact on surface and groundwaters, soils and crops, and experience of nitrate leaching, denitrification, ammonia volatilization, heavy metal pollution, agricultural and urban waste management, and international and national legislation.
Inbunden, Engelska, 1996
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The West African Sahel is the transition zone between the Saharadesert in the north of Africa and the more humid Sudanian zones in the south. Although diverse in many ways, the Sahelian countries have the common problem of a fragile agricultural sector. This predicament is mainly caused by low inherent soil fertility, limited and unpredictable rainfall, frequent droughts, and wind erosion that accelerates soil degradation and desertification, compounded by To assure food production in the future, means rapidly growing populations. of declining soil fertility and increasing must be found to offset the trends soil degradation through wind erosion. This is a challenge for agricultural research. Since 1985, the Special Research Program 308 'Adapted Farming in West Africa' at the UniversityofHohenheimin collaboration with the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) in Niger, has pursued the developmentof agricultural innovations for smallholder farmers in one of the most ecologically fragile regions of the world. The prevention of soil degradation, the restoration and maintenance of soil fertility, and the increase of land and labor productivity are key objectives of this multidisci plinary research program. From the beginning, a major focus of research has been wind erosion.
Inbunden, Engelska, 1996
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This volume contains the proceedings of the 8th Nitrogen Workshop which was held at the University of Ghent, Belgium, from 5 to 8 September 1994. Although nitrogen dynamics in different ecosystems have been studied for several decades, new orientations and other emphases have recently emerged. Previously, nitrogen was considered as an essential element mostly in terms of productivity, but now, more emphasis is attached to environmental consequences. The contributions to this volume tackle recent developments within the fields of nitrogen advice systems, plant response to fertilization, immobilization and mobilization, nitrification, denitrification, leaching, ammonia volatilization and biological nitrogen fixation. A large number of papers is devoted to the formation of gaseous nitrogen compounds, while mineralization-immobilization is another topic of important interest. The book also contains the reports of discussion groups on different aspects of the nitrogen cycle.