This book presents innovative research on soil nitrogen cycling and nitrate leaching with a view to improving soil management and fertiliser nitrogen use efficiency and reducing nitrogen leaching losses. In this regard, nitrogen-15 (15N)-labelled fertiliser was used as a biochemical and physical stable isotope tracer in laboratory and field experiments. The major outcome of the research was the development, validation and application of a new compound-specific amino acid 15N stable isotope probing method for assessing the assimilation of fertiliser nitrogen by soil microbial biomass. The novelty of the method lies in its tracing of incorporated nitrogen into newly biosynthesised microbial protein in time-course experiments using gas chromatography-combustion-isotope ratio mass spectrometry. The approach provides previously unattainable insights into the microbial processing of different nitrogen fertilisers in different soils. Further, it identifies the mechanistic link between molecular-scale processes and observations of field-scale fertiliser nitrogen immobilisation studies. The method and the results presented here will have far-reaching implications for the development of enhanced recommendations concerning farm-based soil management practices for increasing soil productivity and reducing nitrogen losses, which is essential to minimising environmental impacts.

Presenting the first continental-scale assessment of reactive nitrogen in the environment, this book sets the related environmental problems in context by providing a multidisciplinary introduction to the nitrogen cycle processes. Issues of upscaling from farm plot and city to national and continental scales are addressed in detail with emphasis on opportunities for better management at local to global levels. The five key societal threats posed by reactive nitrogen are assessed, providing a framework for joined-up management of the nitrogen cycle in Europe, including the first cost-benefit analysis for different reactive nitrogen forms and future scenarios. Incorporating comprehensive maps, a handy technical synopsis and a summary for policy makers, this landmark volume is an essential reference for academic researchers across a wide range of disciplines, as well as stakeholders and policy makers. It is also a valuable tool in communicating the key environmental issues and future challenges to the wider public.

Soil sampling for microbiological analysis; Statistical treatment of microbial data; Soil sterilization; Soil water potencial; Most probable number counts; Light microscopic methods for studying soil microorganisms; Viruses; Recovery and enumeration of viable bacteria; Coliform bacteria; Autotrophic nitrifying bacteria; Free-living dinitrogen-fixing bacteria; Legume nodule symbionts; Anaerobic bacteria and processes; Denitrifiers; Actiomycetes; Frankia and the actinorhizal symbiosis; Filamentous fungi; Vesicular-arbuscular mycorrhizal fungi; Isolation of microorganisms producting antibiotics; Microbiological procedures for biodegradation research; Algae and cyanobacteria; Marking soil bacteria with lacZY; Detection of specific DNA sequences in environmental sample via polymerase chaim reaction; Isolation and purification of bacterial DNA from soil; Microbial biomass; Soil enzymes; Carbon mineralization; Isotopic methods for the study of soil organic matter dynamics ; Practical considerations in the use of nitrogen tracers in agricultural and environmental research; Nitrogen availability; Nitrogen mineralization, immobilization, and nitrification; Dinitrogen fixation; Measuring denitrification in the field; Sulfur oxidation and reduction in soils; Iron and manganese oxidation and reduction.

Thoroughly updated and revised, this second edition of the bestselling Soil Sampling and Methods of Analysis presents several new chapters in the areas of biological and physical analysis and soil sampling. Reflecting the burgeoning interest in soil ecology, new contributions describe the growing number and assortment of new microbiological

Forward. A call for integrated soil fertility management in Africa. Introduction. ISFM and the African farmer. Part I. The principles of ISFM: ISFM as a strategic goal, Fertilizer management within ISFM, Agro-minerals in ISFM, Organic resource management, ISFM, soil biota and soil health. Part II. ISFM practices: ISFM products and fields practices, ISFM practice in drylands, ISFM practice in savannas and woodlands, ISFM practice in the humid forest zone, Conservation Agriculture. Part III. The process of implementing ISFM: soil fertility diagnosis, soil fertility management advice, Dissemination of ISFM technologies, Designing an ISFM adoption project, ISFM at farm and landscape scales. Part IV. The social dimensions of ISFM: The role of ISFM in gender empowerment, ISFM and household nutrition, Capacity building in ISFM, ISFM in the policy arena, Marketing support for ISFM, Advancing ISFM in Africa. Appendices: Mineral nutrient contents of some common organic resources.