Legume Nitrogen Fixation In A Changing Environment

The world population will grow more rapidly during the few coming years. This must be accompanied by a parallel increase in the agricultural production to secure adequate food. Sustainability considerations mandate that alternatives to chemical nitrogen fertilizers must be urgently sought. Biological nitrogen (N2) fixation, a microbiological process which converts atmospheric N2 into a plant-usable form, offers this alternative. Among these renewable sources, N2-fixing legumes offer an economically attractive and ecologically sound means of reducing external inputs and improving internal resources. Environmental factors such as drought, elevated temperature, salinity, soil acidity and rising CO2 are known to dramatically affect the symbiotic process and thus play a part in determining the actual amount of nitrogen fixed by a given legume in the field. Understanding how nodule N2 fixation responds to the environment is crucial for improving legume production and maintaining sustainability in the context of global change. In this thoughtful and provocative new Brief, we provide critical information on how current and projected future changes in the environment will affect legume growth and their symbiotic N2 fixing capabilities. Each section reviews the main drivers of environmental change on the legume performance that include drought, elevated temperature, salinity and rising CO2, and soil acidity. Importantly we discuss the molecular approaches to the analysis of the stress response in legumes and the possible biotechnological strategies to overcome their detrimental effects.

This thoughtful and provocative book provides a concise, up-to-date presentation of how current and projected future phosphorus scarcity will affect legume growth and their symbiotic nitrogen-fixing capabilities. It is a timely examination of the physiological and molecular responses of nodules to phosphorous deficiency in attempt to identify common principles. Students and researchers in the many disciplines related to crop productivity will find this title an exciting contribution in the area of plant stress physiology. The knowledge in this volume can also aid plant breeders, particularly through new methods of genetic engineering, in developing unique and adaptive cultivars with higher symbiotic efficiency. The awareness of the rapidly rising world population must translate into a parallel increase in agricultural production in order to sustain the growing population both now and in the future. Hence, the demand for food crops to produce proteins and vegetable oil for human consumption is going to increase considerably during the coming years. The essential role of legumes in agriculture is well-recognized, given the abundant levels of proteins and oils found in plants along with their enormous contribution to the sustainability of agricultural systems and human health. The capacity of legumes to fix nitrogen (N2) in partnership with rhizobia provides an input-saving and resource-conserving alternative, thereby reducing the need for chemical fertilizers while enhancing overall crop productivity. The use of N2-fixing legumes to produce plant proteins results in a substantial decrease in the consumption of fossil fuels and therefore also in the agricultural effects to global warming. However, a major constraint to legume production is low soil phosphorus (P) availability, considering that an overwhelming majority of the world’s soils are classified as P-deficient. Low-P availability is especially problematic for legumes, since legume nodules responsible for N2 fixation have a high P requirement. Therefore, this book explains how nodule N2 fixation responds to low P availability, which is crucial for improving legume production and maintaining agricultural sustainability in the context of the global P crisis.

Genetical aspects and taxonomy; Quality of legume inoculants; Field experiments on nitrogen fixation by nodulated legumes; Legume nitrogen fixation and the environment; Nitrogen fixing symbioses in non-leguminous plants.

This book covers all aspect of legume production management technologies, plant ecological response, nutrients management, biological nitrogen fixation, molecular approaches, potential cultivars, biodiversity management under climate change. Also covered are various aspects of legume management under climate change such as, production management technology, ecology & adaptation, diseases, and international trade; physiology and crops response to nutrients, drought, salinity, and water use efficiency; Biodiversity management, molecular approaches and biological Nitrogen fixation; climate change and strategies. This book presents the most comprehensive and up to date review of research on different cool season grain legume crops, nutrients management, biotic and abiotic stresses management, agronomical approaches for drought management, salinity, drought, weed management and water use efficiency, impact on international trade around the world.

Biological nitrogen fixation has essential role in N cycle in global ecosystem. Several types of nitrogen fixing bacteria are recognized: the free-living bacteria in soil or water; symbiotic bacteria making root nodules in legumes or non-legumes; associative nitrogen fixing bacteria that resides outside the plant roots and provides fixed nitrogen to the plants; endophytic nitrogen fixing bacteria living in the roots, stems and leaves of plants. In this book there are 11 chapters related to biological nitrogen fixation, regulation of legume-rhizobium symbiosis, and agriculture and ecology of biological nitrogen fixation, including new models for autoregulation of nodulation in legumes, endophytic nitrogen fixation in sugarcane or forest trees, etc. Hopefully, this book will contribute to biological, ecological, and agricultural sciences.

Sustainability has a major part to play in the global challenge of continued development of regions, countries, and continents all around the World and biological nitrogen fixation has a key role in this process. This volume begins with chapters specifically addressing crops of major global importance, such as soybeans, rice, and sugar cane. It continues with a second important focus, agroforestry, and describes the use and promise of both legume trees with their rhizobial symbionts and other nitrogen-fixing trees with their actinorhizal colonization. An over-arching theme of all chapters is the interaction of the plants and trees with microbes and this theme allows other aspects of soil microbiology, such as interactions with arbuscular mycorrhizal fungi and the impact of soil-stress factors on biological nitrogen fixation, to be addressed. Furthermore, a link to basic science occurs through the inclusion of chapters describing the biogeochemically important nitrogen cycle and its key relationships among nitrogen fixation, nitrification, and denitrification. The volume then provides an up-to-date view of the production of microbial inocula, especially those for legume crops.

This book presents the science, application, and politics of the use of nitrogen-fixing crop plants across the globe in various environments. Nitrogen fixation can help provide a growing population with a nutritious, environmentally friendly, sustainable food supply. From new "omics" approaches to the role of nitrogen fixation in mitigating greenhouse gas emissions, from farming strategies in nonindustrialized nations to nitrogen fixation in the global economy, scientists will find the key issues and expanding research areas, and how they contribute to the next wave of advancements related to agriculture and the environment

Atmospheric N2. Non-Biological forms of N2 fixation. Biological forms of N2 fixation. N2 fixation in natural ecosystems. N2 fixation in forestry and recultivation.Fixation in agriculture. N2 fixation the leguminosae. The Microsymbiont. Nodulation. Different forms of nodules. Metabolism of N2 fixation. Influence of the environment. Assessment techniques for N2 fixation. Direct methods. Indirect methods. Supernodulating legumes. General characteristcs. symbiotic performance and the effect of nitrate. Carbon and nitrogen metabolism. Means to improve N2 fixation. Current approaches. Potential for future benefits.