This volume provides a unique collection of contributions addressing both the ‘too much’ and ‘too little’ sides of the nitrogen story. Building on analyses started at the 6th International Nitrogen Conference, Kampala, the book explores the idea of ‘just enough nitrogen’: sufficient for sustainable food production, but not so much as to lead to unsustainable pollution and climate problems. The range of nitrogen threats examined, solutions evaluated and science-policy analyses presented here has provided the foundation to agree the ‘Kampala Statement-for-Action on Nitrogen in Africa and Globally,’ as reported in this volume. Humanity today faces unprecedented challenges: How to feed a growing population? How to reduce air pollution, water pollution and climate change? How to handle regional differences in an era of increasing globalization? These questions are at the heart of this edited volume which examines the multi-dimensional nature of the global nitrogen challenge. While humans have massively altered the nitrogen cycle, the consequences have become polarized. Some regions have too much nitrogen, associated with pollution and wasteful use of a valuable resource, while other regions have too little nitrogen, leading to constraints on food production and depletion of soil nutrient stocks. The volume provides a unique collection of contributions addressing both the ‘too much’ and ‘too little’ sides of the nitrogen story. Building on analyses started at the 6th International Nitrogen Conference, Kampala, the book explores the idea of ‘just enough nitrogen’: sufficient for sustainable food production, but not so much as to lead to unsustainable pollution and climate problems. The range of nitrogen threats examined, solutions evaluated and science-policy analyses presented here has provided the foundation to agree the ‘Kampala Statement-for-Action on Nitrogen in Africa and Globally,’ as reported in this volume. Together, the contributions in this book are now informing actions by the International Nitrogen Initiative (INI) in working with the United Nations Environment Programme and others to establish the International Nitrogen Management System (INMS). A key outcome has been to catalyse development of the first Resolution on Sustainable Nitrogen Management, as adopted by the fourth UN Environment Assembly (UNEA/EA.4/Res.14). The work is written for researchers and policy makers and all those interested in seeing how sustainable nitrogen management can contribute to meeting many of the UN Sustainable Development Goals.

This open access book discusses the current role of smallholders in connection with food security and poverty reduction in developing countries. It addresses the opportunities they enjoy, and the constraints they face, by analysing the availability, access to and utilization of production factors. Due to the relevance of smallholder farms, enhancing their production capacities and economic and social resilience could produce positive impacts on food security and nutrition at a number of levels. In addition to the role of small farmers as food suppliers, the book considers their role as consumers and their level of nutrition security. It investigates the link between agriculture and nutrition in order to better understand how agriculture affects human health and dietary patterns. Given the importance of smallholdings, strategies to increase their productivity are essential to improving food and nutrition security, as well as food diversity.

Agricultural Systems, Second Edition, is a comprehensive text for developing sustainable farming systems. It presents a synthetic overview of the emerging area of agroecology applications to transforming farming systems and supporting rural innovation, with particular emphasis on how research can be harnessed for sustainable agriculture. The inclusion of research theory and examples using the principles of cropping system design allows students to gain a unique understanding of the technical, biological, ecological, economic and sociological aspects of farming systems science for rural livelihoods. This book explores topics such as: re-inventing farming systems; principles and practice of agroecology; agricultural change and low-input technology; ecologically-based nutrient management; participatory breeding for developing improved and relevant crops; participatory livestock research for development; gender and agrarian inequality at the local scale; the nature of agricultural innovation; and outreach to support rural innovation. The extensive coverage of subjects is complemented with integrated references and a companion website, making this book essential reading for courses in international agricultural systems and management, sustainable agricultural management, and cropping systems. This book will be a valuable resource for students of agricultural science, environmental engineering, and rural planning; researchers and scientists in agricultural development agencies; and practitioners of agricultural development in government extension programs, development agencies, and NGOs. - Provides students with an enhanced understanding of how research can be harnessed for sustainable agriculture - Incorporates social, biological, chemical, and geographical aspects important to agroecology - Addresses social and development issues related to farming systems

“Top agricultural scientists from around the world have taken up the challenge of sustainable agriculture, with the specific focus on integrating agronomic, climatological, biophysical and socio-economic perspectives and processes. Every chapter (of the Handbook) contributes to addressing the growing food-security challenges facing the world.”Foreword by Jeffrey Sachs, Director of the Earth Institute at Columbia UniversityClimate effects on agriculture are of increasing concern in both the scientific and policy communities because of the growing population and the greater uncertainty in the weather during growing seasons. Changes in production are directly linked to variations in temperature and precipitation during the growing season and often to the offseason changes in weather because of soil water storage to replenish the soil profile. This is not an isolated problem but one of worldwide interest because each country has concerns about their food security.The Agricultural Model Intercomparison and Improvement Project (AgMIP) was developed to evaluate agricultural models and intercompare their ability to predict climate impacts. In sub-Saharan Africa and South Asia, South America and East Asia, AgMIP regional research teams (RRTs) are conducting integrated assessments to improve understanding of agricultural impacts of climate change (including biophysical and economic impacts) at national and regional scales. Other AgMIP initiatives include global gridded modeling, data and information technology (IT) tool development, simulation of crop pests and diseases, site-based crop-climate sensitivity studies, and aggregation and scaling.

In the 1980s and 1990s, green manure/cover crop (GMCC) systems became a popular agricultural technology in research and development efforts for smallholder tropical and subtropical farmers. However, few syntheses of these experiences have been conducted. This volume of case studies contributes to bridging this gap by reviewing field-level experiences with these systems. Twelve case studies are included. Eleven of them describe experiences from Latin America (4 cases), Africa (6 cases) and Asia (1 case) and the twelfth case reports on the development of a GMCC systems database. Two concluding chapters, `Learning from the Case Studies' and `Future Perspectives', build upon the cases. The systems described are diverse. Some systems have been spontaneously adopted by farmers, while others have been introduced to the farmers through diffusion efforts. Some of the cases reviewed describe small, localized efforts while others report on large-scale, well-known ones, such as the combination of GMCCs and conservation tillage in Santa Catarina, Brazil, the maize-Mucuna system in northern Honduras, and the improved fallow systems in Eastern Zambia. Most experiences include both development and research aspects and to the extent possible the cases integrate these two. Discussion of the strengths and shortcomings of the systems and efforts is frank, and the goal is to learn from these experiences to benefit future efforts. It is expected that both researchers and development practitioners and students of tropical farming systems and soil management will find this volume of case studies useful.