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Microbiology of Tropical Soils and Plant Productivity

Microbiology of Tropical Soils and Plant Productivity PDF Author: Y.R. Dommergues
Publisher: Springer Science & Business Media
ISBN: 9789024726240
Category : Nature
Languages : en
Pages : 346

Book Description
It is an established fact that we must continually increase and improve agricultural production if we are to meet even the minimum requirements of a growing popu lation for food, shelter, and fuel. In recent years, the introduction of new plant varieties and the extensive use of fertilizers have effectively increased crop yields, but intensifying agricultural methods has often led to depleting soil fertility. Two examples of the harmful consequences of intensive farming practices are the loss of up to 2.5 cm of topsoil every 15 years in the United States through erosion and the alarming rise in environmental pollution through widespread use of pesticides. Countless other processes affecting the activity of soil micro flora and the inter actions between microorganisms and plants may pose an equal danger to soil equilibrium, but their potential hazards are often overlooked because of an insufficient understanding of soil microbiology on the part of scientists. In the first published study of its kind, the authors of this book have attempted to address major aspects of the microbial activity of soil in the tropics. Tropical conditions serve as an ideal context for a discussion of soil microbiology, since biological processes in the soil are particularly active in tropical environments in comparison to other settings and in relation to physical and chemical processes.

Microbiology of Tropical Soils and Plant Productivity

Microbiology of Tropical Soils and Plant Productivity PDF Author: Y.R. Dommergues
Publisher: Springer Science & Business Media
ISBN: 9789024726240
Category : Nature
Languages : en
Pages : 346

Book Description
It is an established fact that we must continually increase and improve agricultural production if we are to meet even the minimum requirements of a growing popu lation for food, shelter, and fuel. In recent years, the introduction of new plant varieties and the extensive use of fertilizers have effectively increased crop yields, but intensifying agricultural methods has often led to depleting soil fertility. Two examples of the harmful consequences of intensive farming practices are the loss of up to 2.5 cm of topsoil every 15 years in the United States through erosion and the alarming rise in environmental pollution through widespread use of pesticides. Countless other processes affecting the activity of soil micro flora and the inter actions between microorganisms and plants may pose an equal danger to soil equilibrium, but their potential hazards are often overlooked because of an insufficient understanding of soil microbiology on the part of scientists. In the first published study of its kind, the authors of this book have attempted to address major aspects of the microbial activity of soil in the tropics. Tropical conditions serve as an ideal context for a discussion of soil microbiology, since biological processes in the soil are particularly active in tropical environments in comparison to other settings and in relation to physical and chemical processes.

Azolla Utilization

Azolla Utilization PDF Author:
Publisher: Int. Rice Res. Inst.
ISBN: 9711041790
Category : Technology & Engineering
Languages : en
Pages : 305

Book Description


Studies on the Utilization of Azolla-anabaena Symbiosis by Flooded Rice

Studies on the Utilization of Azolla-anabaena Symbiosis by Flooded Rice PDF Author: Chanan Singh Johal
Publisher:
ISBN:
Category : Anabaena azollae
Languages : en
Pages : 178

Book Description


Biological Nitrogen Fixation for Sustainable Agriculture

Biological Nitrogen Fixation for Sustainable Agriculture PDF Author: J.K. Ladha
Publisher: Springer Science & Business Media
ISBN: 9401709106
Category : Nature
Languages : en
Pages : 212

Book Description
Chemical fertilizers have had a significant impact on food production in the recent past, and are today an indispensable part of modern agriculture. On the other hand, the oil crisis of the 1970s and the current Middle East problems are constant reminders of the vulnerability of our fossil fuel dependent agriculture. There are vast areas of the developing world where N fertilizers are neither available nor affordable and, in most of these countries, balance of payment problems have resulted in the removal of N fertilizer subsidies. The external costs of environmental degradation and human health far exceed economic concerns. Input efficiency of N fertilizer is one of the lowest and, in turn, contributes substantially to environmental pollution. Nitrate in ground and surface waters and the threat to the stability of the ozone layer from gaseous oxides of nitrogen are major health and environmental concerns. The removal of large quantities of crop produce from the land also depletes soil of its native N reserves. Another concern is the decline in crop yields under continuous use of N fertilizers. These economic, environmental and production considerations dictate that biological alternatives which can augment, and in some cases replace, N fertilizers must be exploited. Long-term sustainability of agricultural systems must rely on the use and effective management of internal resources. The process of biological nitrogen fixation offers and economically attractive and ecologically sound means of reducing external nitrogen input and improving the quality and quantity of internal resources. In this book, we outline sustainability issues that dictate an increased use of biological nitrogen fixation and the constraints on its optimal use in agriculture.

Practical Application of Azolla for Rice Production

Practical Application of Azolla for Rice Production PDF Author: W.S. Silver
Publisher: Springer Science & Business Media
ISBN: 9400962010
Category : Science
Languages : en
Pages : 227

Book Description
The production of rice has increased considerably in recent years due to the release of improved varieties and the adoption of better fertilization practices. Nevertheless, the production and use of inorganic N fertilizer involves costly investments in terms of energy and transport, the need for complex manufacturing plants, as well as the potential for environmental pollution. The use of agricultural systems that include dinitrogen fixing organisms appears to be an economically sound cultural practice. In the particular case of rice, biological nitrogen fixation by Azolla, blue-green algae (BGA), and heterotrophic microorganisms has long been recognized, in southeast Asia, as a fertilizer for rice culture. The Azolla-Anabaena association has the unique property of being able to retain a significant amount of nitrogenase activity in the presence of combined nitrogen, making the system compatible with inorganic nitrogen fertilization. Researchers working with Azolla (N fixation) are dispersed in 2 countries of southeast Asia, Africa, Europe and Latin America, making it difficult to share ideas, concepts and research results on a more personal basis. Considering the potential positive impact of growing rice in association with Azolla, and the lack, to date, of an international gathering of scientists dedicated to Azolla research, the First International Workshop on "Practical Applications of Azolla for Rice Production" was organized by the University of Puerto Rico-Mayaguez Campus.

Isotopic Studies of Azolla and Nitrogen Fertilization of Rice

Isotopic Studies of Azolla and Nitrogen Fertilization of Rice PDF Author: K.S. Kumarasinghe
Publisher: Springer Science & Business Media
ISBN: 9401116814
Category : Technology & Engineering
Languages : en
Pages : 156

Book Description
Nitrogen is the most limiting element for crop production. Traditionally, expensive commercial fertilizers are used to correct soil nitrogen deficiencies. Indeed, 50% of the increase in rice yields after World War II can be attributed to increased fertilizer nitrogen use. Although an increased rate of fertilizer nitrogen application has been advocated to meet the growing demand for food, it is unrealistic to advise the farmers to apply fertilizers they could hardly afford, and whose prices are likely to escalate in the years ahead. In addition, when they are not applied judiciously there are problems of environmental pollution as plants are capable of taking up only a relatively small portion of the applied nitrogen, a substantial amount being lost through various chemical and biological processes. The exploitation of cheaper alternatives or supplements to fertilizers have therefore gained much interest in recent years. Our increased interest in biological nitrogen fixation as a supplement or alternative to nitrogen fertilizers led to the convening of a consultants' meeting on `The Role of Isotopes in Studies on Nitrogen Fixation and Nitrogen Cycling by Blue-Green Algae and the Azolla-Anabaena azollae Association', in Vienna from 11--15 October 1982. The consultants' group recommended that the Joint FAI/IAEA Division of Nuclear Techniques in Food and Agriculture embark on a coordinated research programme in this field and that initial emphasis should be placed on Azolla-Anabaena symbiosis. As a result, such a programme was initiated in 1984, which was concluded in 1989. The results and conclusions reported here are those that were generated during the five years of its operation.

 PDF Author:
Publisher: IICA
ISBN:
Category :
Languages : en
Pages : 130

Book Description


Effect of Azolla on Irrigated Rice in Brazil

Effect of Azolla on Irrigated Rice in Brazil PDF Author: Karl Georg Gutbrod
Publisher:
ISBN:
Category : Azolla as fertilizer
Languages : en
Pages : 192

Book Description
Azolla green manure effect on paddy rice was compared to N fertilization with urea in 4 cultivation systems at two sites in Brazil, during the seasons 1983/84 and 1984/85. Fertilizer nitrogen equivalence was calculated by plotting parameter values obtained in Azolla treatments on the response regressions to N fertilization.

Azolla As A Green Manure

Azolla As A Green Manure PDF Author: Thomas A Lumpkin
Publisher: Westview Press
ISBN:
Category : Nature
Languages : en
Pages : 256

Book Description
History. Botany and ecology. Physiology. Nursery culture and multiplication. Field Cultivation. Pests and pest control. Use in labor-intensive farming systems. Potential mechanization of azzola cultivation in rice fields. Other uses. Potential for the future.

Organic Matter and Rice

Organic Matter and Rice PDF Author:
Publisher: Int. Rice Res. Inst.
ISBN: 9711041049
Category : Agricultural wastes
Languages : en
Pages : 642

Book Description