Gaseous Loss Of Nitrogen From Plant Soil Systems

A growing interest has been shown recently in the dymanics of nitrogen in agricultural and natural ecosystems. This has been caused by increasing demands for food and fibre by a rapidly expanding world population, and by a growing concern that increased land clearing, cultivation and use of both fertilizer and biologically fixed nitrogen can have detrimental effects on the environment. These include effects on water quality, eutrophication of surface waters and changes in atmospheric composition all caused by increased cycling of nitrogenous compounds. The input and availability of nitrogen frequently affects the productivity of farming systems more than any other single management factor, but often the nitrogen is used inefficiently. Much of the fertilizer nitrogen applied to the soil is not utilised by the crop: it is lost either in solution form, by leaching of nitrate, or in gaseous forms as ammonia, nitrous oxide, nitric oxide or dinitrogen. The leached nitrate can contaminate rivers and ground waters, while the emitted ammonia can contaminate surface waters or combine with atmospheric sulfur dioxide to form aerosols which affect visibility, health and climate. There is also concern that increased evolution of nitrous oxide will deplete the protective ozone layer of the stratosphere. The possibility of a link between the intensity of agricultural use of nitrogen, nitrous oxide emissions and amounts of stratospheric ozone has focussed attention on these interactions.

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

Many trace gases are exchanged between the atmosphere and the biosphere. Although much research has been published on the photosynthetic exchanges of carbon dioxide, oxygen, and water vapor, this book focuses on the importance of biogenic trace gases on atmosphere chemistry and ecosystem stability. Included are methane and its effect on the radiative properties of the atmosphere, hydrocarbons (isoprene and monoterpenes), and their role in the production of ozone and carbon monoxide. Also covered are sulfur and nitrogen gases, both of which can lead to ecosystem acidification. The biochemistry and physiology of production of these and other gases are investigated. Plant physiologists, ecologists, and atmospheric chemists and modelers will benefit from this book.

Climate Change, Human Systems and Policy is a component of Encyclopedia of Natural Resources Policy and Management in the global Encyclopedia of Life Support Systems (EOLSS), which is an integrated compendium of twenty one Encyclopedias. The Theme on Climate Change, Human Systems and Policy presented in three volumes, deals with the interaction between climate and human systems for policy development. These volumes discuss History, Status, and Prediction of Global Climate Change; Potential Large-scale Effects of Global Warming; Public Perceptions Toward Global Climate Change; Effects of Potential Sea-Level Rises; Economics of Potential Climate Change; Response Strategies for Stabilization of Atmospheric Composition; Policy Framework and Systems Management of Global Climate Change. These three volumes are aimed at the following five major target audiences: University and College students Educators, Professional practitioners, Research personnel and Policy analysts, managers, and decision makers and NGOs.

The study of soils today has taken on increased importance because a rapidly expanding population is placing demands on the soil never before experienced. This has led to an increase in land degradation. Land degradation is one of the most severe problems facing mankind. Volume 11 of Advances in Soil Science was devoted entirely to this critical area of soil science. From the beginning of agriculture until about 1950, increased food production came almost entirely from expanding the cropland base. Since 1950, however, the yield per unit of land area for major crops has increased dramatically. Much of the increase in yields was because of increased inputs of energy. Between 1950 and 1985, the farm tractor fleet quadrupled, world irrigated area tripled, and use of fertilizer increased ninefold. Between 1950 and 1985, the total energy used in world agriculture increased 6. 9 times. Until recently, sustainability was seldom, if ever, mentioned in agricultural literature. Now, it is one of the most widely used terms. The high costs ofirriga tion development, escalating energy costs during the 1970s, public concern over potential negative impacts of fertilizer and pesticides on water supplies, soil ero sion, soil compaction and salinity problems, and other concerns have caused many people to question whether many of the present agriculture systems can be sustained. As a result, soil science is beginning to focus more on sustaining the resource base.