Mineral Nitrogen In The Plant-Soil System

PrefaceChapter 1 Origin, Distribution, and Cycling of Nitrogen in Terrestrial Ecosystems I. Introduction II. The Nitrogen Cycle A. Geobiological Distribution of Nitrogen B. Cycling Processes III. Additions of Nitrogen to Ecosystems A. Wet and Dry Deposition B. Biological Nitrogen Fixation C. Industrial Nitrogen Fixation IV. Losses of Nitrogen from Ecosystems A. Gaseous Losses B. Leaching Losses C. Soil Erosion V. Transfers of Nitrogen within Ecosystems A. Uptake of Nitrogen by Plants B. Input of Detritus C. Decomposition of Litter D. Nitrification VI. Nitrogen Content of Soils A. Soil-Forming Factors B. Plant Succession and Nitrogen Accumulation C. Ecosystem Disturbance and Recovery VII. Conclusions ReferencesChapter 2 The Decomposition Process: Mineralization, Immobilization, Humus Formation, and Degradation I. Introduction II. Processes of Decomposition A. Breakdown of Organic Residues B. Phases of Nitrogen Release and Accumulation C. Role of Decomposer Organisms D. Degradation of the Microbial Biomass III. Humus Formation, Composition, and Degradation A. Origin and Formation B. Structure C. Chemical Forms of Soil Organic Nitrogen D. Degradation E. Biochemistry of Nitrogen Mineralization IV. Factors Affecting Decomposition A. Substrate Quality B. Moisture C. Temperature D. Soil pH E. Inorganic Nutrients F. Additions of Organic Residues G. Pesticides H. Growing Plants I. Cultivation J. Clay Content K. Physical Inaccessibility V. Conclusions ReferencesChapter 3 Nitrification I. Introduction II. Processes of Nitrification A. Chemoautotrophic Nitrification B. Heterotrophic Nitrification C. Methylotrophic Nitrification D. Chemical Nitrification III. Factors Regulating Nitrification A. Substrates and Products B. Soil pH C. Aeration and Moisture D. Temperature E. Allelopathic Substances F. Limiting Supply of Ammonium under Vegetation G. Nutrient Deficiencies H. Trace Element Toxicities I. Pesticides J. Specific Inhibitors IV. Role of Nitrification in Ecosystems A. Significance of Nitrification B. Nitrification in Natural Ecosystems C. Nitrification in Agricultural Ecosystems V. Conclusions ReferencesChapter 4 Retention and Movement of Nitrogen in Soils I. Introduction II. Adsorption and Fixation Processes A. Adsorption of Ammonium B. Fixation of Ammonium by Clays C. Adsorption of Ammonia D. Fixation of Ammonia by Soil Organic Matter E. Adsorption of Nitrate III. Erosion and Surface Runoff A. Processes of Loss B. Factors Affecting Losses IV. Leaching Losses of Nitrate A. Description of Solute Movement B. Prediction of Nitrate Leaching C. Estimation of Leaching Losses D. Factors Affecting Leaching Losses V. Significance of Runoff and Leaching Losses A. Consequence of Losses B. Methods to Control Losses VI. Conclusions ReferencesChapter 5 Gaseous Losses of Nitrogen I. Introduction II. Ammonia Volatilization A. Processes B. Factors Affecting Volatilization III. Biological Generation of Gaseous Nitrogenous Products A. Processes B. Factors Affecting Biological Gaseous Losses IV. Chemodenitrification A. Nitrite Accumulation B. Mechanisms V. Extent, Significance, and Fate of Losses A. Ammonia Volatilization B. Denitrification and Nitrification C. Chemodenitrification VI. Conclusions References Chapter 6 Uptake and Assimilation of Mineral Nitrogen by Plants I. Introduction II. Processes of Uptake A. Ammonium Uptake B. Nitrate Uptake C. Factors Influencing Uptake D. Foliar Absorption III. Processes of Assimilation A. Reduction of Nitrate to Nitrite B. Reduction of Nitrite to Ammonium C. Urea Hydrolysis D. Ammonia Assimilation E. Detoxification of Ammonia F. Reassimilation of Ammonia G. Sites of Nitrogen Assimilation H. Regulation of Nitrogen Assimilation IV. Transportation of Nitrogenous Substances A. Xylem Transport B. Phloem Transport C. Circulation, Storage, and Remobilization of Nitrogen V. Ecological and Physiological Aspects of Nitrogen Nutrition A. Preference for Ammonium or Nitrate B. Reasons for Preferences C. Responses to a Limiting Supply of Nitrogen D. Responses to an Oversupply of Nitrogen VI. Conclusions References Chapter 7 Nitrogen and Agronomic Practice I. Introduction II. Nitrogen in Plant Production A. Nitrogen Uptake and Content of Plants B. Nature of Plant Responses to Applied Nitrogen C. Effect of Applied Nitrogen on Crop Quality III. Factors Affecting Crop Responses to Nitrogen A. Form, Time, and Method of Nitrogen Application B. Nitrogen-Supplying Capacity of Soils C. Available Soil Water D. Tillage Method E. Genetic Effects on Crop Residues F. Leguminous Crops G. Disease and Pest Incidence IV. Assessment of Soil Nitrogen Availability A. Residual Mineral Nitrogen B. Potentially Mineralizable Nitrogen C. Modeling Approaches D. Fertilizer Nitrogen Recommendations V. Nitrogen Supply for Crops A. Nitrogenous Fertilizers B. Role of Symbiotic Dinitrogen Fixation VI. Conclusions ReferencesIndex