The turn of the millennium from the twentieth to the twenty-first century provides an occasion to review our understanding of a biological process, biological nitrogen fixation, that is of prime importance for the continued survival of mankind. This process has provided a basis for maintaining soil fertility since the beginning of organised agriculture, yet its very existence was confirmed only just over a century ago. In the intervening years, an enormous intellectual effort has dispersed much of the mystery surrounding biological nitrogen fixation. Biological fixation is widely exploited in agriculture, as are nitrogen fertilisers prepared for the last hundred years under extreme conditions of temperature and pressure. However, despite all our efforts, the fundamental nature of the reactions involved at the heart of the biological process remain unknown. This book aims to describe what we have learned in the last one hundred years or so about biological nitrogen fixation, about what its chemistry appears to be, and how it is applied in agriculture. This ambitious objective has not been attempted recently. It is aimed at students and those who wish to enter these very challenging areas of research, and who need to learn the state of the art at the turn of the millennium.The authors are all acknowledged world experts in their fields. They have prepared concise, well referenced and authoritative accounts of their subjects. This book provides a unique summary of the current state of knowledge that will be indispensable to all students and researchers, actual and potential, interested in biological nitrogen fixation.

This book provides an introductory-level survey of biological nitrogen fixation, covering the role of the process in the global nitrogen cycle as well as its biochemistry, physiology, genetics, ecology, general biology and prospects for its future exploitation.

Nitrogen fixation research is presented as a rapidly developing, synergistic area of modern science, using the methods of, and accumulating data from, many fundamental branches of biology and chemistry. These include catalytic mechanisms, protein structure and function, molecular organization of genes and the regulation of their activities, biochemistry of plants and microorganisms, the signalling and surface interactions between organisms, microbial taxonomy and evolution, formal and population genetics, and ecology. The relationships between biological nitrogen fixation research and different branches of applied biology are addressed and analyzed, such as: the monitoring of genetically engineered microorganisms, selection of plant-associated microbes, plant breeding, increasing the protein content of crops, providing ecologically safe food production, and diminishing the chemical pollution of the environment. Immediate impacts and long-term prospects for nitrogen fixation research are presented: both fundamentals and applications.

In the tradition of Jared Diamond's Guns, Germs, and Steel, this gives the very early history of how human ingenuity overcame the risk of famine through productive agriculture. Starting with a layman's guide to the chemistry of nitrogen fixation, the book goes on to show how humans emerged from nomadic lifestyles and began developing towns and settlements. When they for the first time began planting the same fields year after year, they noticed quickly the need to ensure soil fertility. But how? The method they came up with is still in use to this day.

Nitrogen availability is one of the most critical factors that limits plant productivity. The largest reservoir of nitrogen is the atmosphere, but this gaseous molecular nitrogen only becomes available to plants through the biological nitrogen fixation process, which only prokaryotic cells have developed. The discovery that microbes were providing fixed nitrogen to legumes and the isolation of the first nitrogen-fixing bacteria occured at the end the 19th Century, in Louis Pasteur's time. We are now building on more than 100 years of research in this field and looking towards the 21st Century. The International Nitrogen Fixation Congress series Started more than 20 years ago. The format of this Congress is designed to gather scientists from very diverse origins, backgrounds, interests and scientific approaches and is a forum where fundamental knowledge is discussed alongside applied research. This confluence of perspectives is, we believe, extremely beneficial in raising new ideas, questions and concepts.

This self-contained volume covers fundamental and applied aspects of nitrogen-fixation research. The book describes milestones in the discovery of the associative and endophytic nitrogen-fixing bacteria found involved with cereal crops, forage grasses, and sugar cane. It provides a comprehensive overview of their phylogeny, physiology, and genetics as well as of the biology of their association with their host plants, including tools for in situ localization and population-dynamics analysis. Also included are chapters describing the functions required for a bacterium to be competent and competitive in the rhizosphere, and analysis of associations of cyanobacteria with fungi, diatoms, bryophytes, cycads, Azolla, and Gunnera.