Dissertation
Optimizing biological nitrogen fixation and evaluating Iraqi extension education
Washington State University
Doctor of Philosophy (PhD), Washington State University
08/2009
DOI:
https://doi.org/10.7273/000005984
Abstract
An alternative to synthetic nitrogen (N) fertilizer is the use of legumes with rhizobia bacterial symbionts that fix soil atmospheric N into plant-available forms. In this study we evaluated biological nitrogen fixation by strains of Rhizobium leguminosarum associated with breeding lines of peas (Pisum sativum L.) and lentils (Lens culinaris Medik.). We also isolated Mesorhizobium ciceri from Middle Eastern soils and compared interactions of Middle Eastern and commercial strains of M. ciceri with U.S. and Middle Eastern varieties of chickpeas (Cicer arietinum L.). In all trials, plant varieties had a greater effect in determining the proportion of plant N provided by fixation (PNF) than did rhizobial strains. Within each legume species, the greatest PNF was provided by Eston and Meritt lentils (80%), Shawnee and Bohatyr peas (91%), and Sierra chickpeas (87%). Our results suggest that crop breeding should be a fruitful avenue for increasing biological N fixation. Since science should utilize public outreach and serve society, extension education lectures were taught to Iraqis whose access to N fertilizers is limited. The recent war and instability have significantly impacted the country's agricultural production and knowledge support systems. To support revitalization of the Iraqi agricultural system, the USDA funded a consortium of five U.S. universities to provide training to agricultural extension personnel from Iraq. Surveys of the trainees guided training agendas and enhanced our understanding of extension, cropping systems, and information needs in Iraq. Both basic and advanced agricultural resources are lacking in Iraq, especially in plant protection, food and vegetable production, machinery use and repair, row crop production, and soil fertility. There is great demand for training, technology, basic farm equipment, seed, and fertilizers. In addition further training is needed in utilizing on-farm resources to efficiently produce crops while reversing the physical and chemical damage to Iraq's soil and other natural resources. Biological N fixation could provide significantly more N to cropping systems, both in developing countries where fertilizers are limited and developed countries where fertilizers are available but expensive. This work improves our understanding of both research and extension opportunities to increase use of biological N fixation.
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Details
- Title
- Optimizing biological nitrogen fixation and evaluating Iraqi extension education
- Creators
- Rita Abi-Ghanem
- Contributors
- Lynne A. Carpenter-Boggs (Chair)Jeffrey L Smith (Committee Member)Mark Mazzola (Committee Member)William Lee Pan (Committee Member)John P. Reganold (Committee Member) - Washington State University, Department of Crop and Soil Sciences
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Crop and Soil Sciences
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 109
- Identifiers
- 99901055031101842
- Language
- English
- Resource Type
- Dissertation