In recent years concern has grown over the contribution of nitrogen (N) fertilizer use to nitrate (NO3−) water pollution and nitrous oxide (N2O), nitric oxide (NO), and ammonia (NH3) atmospheric pollution. Characterizing soil N effluxes is essential in developing a strategy to mitigate N leaching and emissions to the atmosphere. In this paper, a previously described and tested mechanistic N cycle model (TOUGHREACT-N) was successfully tested against additional observations of soil pH and N2O emissions after fertilization and irrigation, and before plant emergence. We used TOUGHREACT-N to explain the significantly different N gas emissions and nitrate leaching rates resulting from the different N fertilizer types, application methods, and soil properties. The N2O emissions from NH4-N fertilizer were higher than from urea and NO3−-N fertilizers in coarse-textured soils. This difference increased with decreases in fertilization application rate and increases in soil buffering capacity. In contrast to methods used to estimate global terrestrial gas emissions, we found strongly non-linear N2O emissions as a function of fertilizer application rate and soil calcite content. Speciation of predicted gas N flux into N2O and N2 depended on pH, fertilizer form, and soil properties. Our results highlighted the need to derive emission and leaching factors that account for fertilizer type, application method, and soil properties.

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.

This publication evaluates the role of nitrogen and phosphorus fertilizers in water pollution and summarizes the research on the complex relations between nutrient inputs and outputs. Precise control of fertilizer use depends on gaining a better understanding through research of the behavior of applied nitrogen and phosphorus in soils. The chemical and biological processes of immobilization, mineralization, and denitrification require further intensive study. Our ultimate goal should be the development of mathematical models that depict the integrated behavior of all components of the nitrogen cycle significant to agriculture and the associated environment.

The importance to preserve soil and water have is increasingly recognized. Agricultural practices and ecological trends both affect and are affected by soil physical properties. The more frequency of natural disasters, as landslides and thunderstorms addresses the importance to integrate soil characteristics in predictive models. Soil physics research has grown considerably specially in the use of innovative sensors, soil databases, and modeling techniques have been introduced into soil water relationship and environmental monitoring. Those advances are thoroughly dispersed in articles and conference proceedings In this volume, the authors will bring together the effectiveness of many new field and lab sensors and examine the current state-of-the-art in modeling and data analysis. It also includes innovative approaches and case studies in tropical soils. Future directions in soil physics research are given by key researchers in this discipline.

This book aims to identify, present and discuss key driving forces and pressures on ecosystem services. Ecosystem services are the contributions that ecosystems provide to human well-being. The scope of this atlas is on identifying solutions and lessons to be applied across science, policy and practice. The atlas will address different components of ecosystem services, assess risks and vulnerabilities, and outline governance and management opportunities. The atlas will therefore attract a wide audience, both from policy and practice and from different scientific disciplines. The emphasis will be on ecosystems in Europe, as the available data on service provision is best developed for this region and recognizes the strengths of the contributing authors. Ecosystems of regions outside Europe will be covered where possible.