Nutrient-balance assessments are valuable tools for delineating the consequences of farming on soil fertility. Various approaches and methods for different situations have been used in the past. This bulletin presents a state-of-the-art review of nutrient balance studies. It brings out the evolution of the approaches and methods, provides for comparisons among them, features the improvements made, and highlights remaining issues. This analysis will be useful in further development of the assessment methodologies as reliable tools for devising time-scale soil fertility management interventions.

Using data on three countries in sub-Saharan Africa, this report compares macro- and microlevel approaches to determine soil nutrient balances with an innovative mesolevel approach. It highlights the added value that a mesolevel approach can provide in terms of its usefulness to mesolevel stakeholders in articulating and targeting scale-specific soil fertility enhancing measures, and its validity as an entry point for policy-makers and private-sector intervention. Contains numerous color figures and tables.

This open access book highlights concepts discussed at two international conferences that brought together world-renowned scientists to advance the science of potassium (K) recommendations for crops. There was general agreement that the potassium recommendations currently in general use are oversimplified, outdated, and jeopardize soil, plant, and human health. Accordingly, this book puts forward a significantly expanded K cycle that more accurately depicts K inputs, losses and transformations in soils. This new cycle serves as both the conceptual basis for the scientific discussions in this book and a framework upon which to build future improvements. Previously used approaches are critically reviewed and assessed, not only for their relevance to future enhancements, but also for their use as metrics of sustainability. An initial effort is made to link K nutrition in crops and K nutrition in humans. The book offers an invaluable asset for graduate students, educators, industry scientists, data scientists, and advanced agronomists.

Integrated studies on the assessment and improvement of soil and water quality have to deal almost inevitably with issues of scale, since the spatial support of measurements, the model calculations and the presentation of results usually vary. This book contains the selected and edited proceedings of a workshop devoted to issues of scale entitled: `Soil and Water Quality at Different Scales', which was held in 1996 in Wageningen. It is intended for environmental researchers, scientists and MSc and PhD students. Part 1 covers current issues and methodologies with scale related soil and water quality research. Part 2 covers agroecological and hydrological case studies in which scale transforms form an important part of the research chain. Part 3 consists of papers focusing on methodologies and up and downscaling. Part 4 contains review papers based on modellers' and statisticians' considerations as well as the papers and posters presented during the workshop. Part 5 consists of short research notes.

Soil-The Basis of All Terrestrial LifeAncient civilizations and cultures-Mayan, Aztec, Mesopotamian, Indus, and Yangtze-were built on good soils, surviving only as long as soils had the capacity to support them. In the twenty-first century, productive soil is still the engine of economic development and essential to human well-being. The quality of

Nutrient imbalances have a substantial impact on the productivity and sustainability of agroecosystems worldwide. Fertilizer and manure use, atmospheric deposition, international transportation of produce, solute and gas emissions and soil erosion have all contributed to deficits and surpluses, which in some areas have reached alarming proportions. This book describes and explores the latest concepts of the causes of nutrient imbalances, including the importance of different spatial scales, and examines ways to quantify and manage nutrient stocks, the increasing amount of legislation and the urgent need for the development of integrated nutrient management technologies. Nutrient Disequilibria in Agroecosystemsalso includes case studies, from fish farms in eastern Asia to nutrient flow monitoring in Kenyan tea/maize farms, the dairy sector in New Zealand and ecological farming in Switzerland, the future for global-level research in soil fertility management and nutrient flow analysis. This title should enhance research and the adoption of (inter)national policies on soil fertility maintenance with its global, multi-scale, multi-disciplinary approach.