Sustainable Food Production and Environmental Preservation by Nitrogen-Fixing Symbionts in Southeast Asia

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For sustainable food production and environmental preservation in Southeast Asia, we surveyed/researched fields there, focusing on symbiotic systems of leguminous plants, their rhizobia, and mycorrhiza. We also conducted yearly project meetings, (Philippines/2001, Malaysia/2002, Vietnam/2003, and Indonesia/2004) with specialists from eight Japanese universities including Osaka U., Tohoku U., U. of Tokyo, Hiroshima U., Kagosima U., Kagawa U., Osaka Prefecture U., and Niigata U., and leading scientists from Thailand, Malaysia, Indonesia, the Philippines, and Vietnam ;. At each meeting, we presented our field and laboratory research data in seminars opened to scientists/students in Southeast Asian countries, with 35 to 70 persons in attendance.Our major findings for this 4 year project include :a)Acid-and salt-tolerant rhizobia isolated in Thailand, the Philippines, and Indonesian soils can be utilized for bean production in the acidic soils of Southeast Asia ; soybeans, peanuts, and snap … More beans. Inoculation of nitrogen-fixing rhizobia increased bean yield significantly. Now, inoculated rhizobia are sold at low cost and/or supplied free to farmers in the above countries.b)Microorganisms stimulating plant growth were isolated in Malaysia, the Philippines, and Vietnam soils. These microorganisms, including phosphate-solubilizing bacteria, nitrogen-fixing microorganisms, cyanobacteria, and Azospririllum, increased crop yields, fruit production, and the protein content in seeds.c)In Thailand, more than 10% deforestation occurred in the past 10 years ; a serious problem for other Southeast Asian countries too. For reforestation, nitrogen-fixing rhizobia and mycorrhiza were isolated in the rhizosphere. These isolates stimulated growth in leguminous/non-leguminous trees in nutrient poor soil, and are now being used at the nursery stage for forests in Indonesia and Thailand.d)A Japanese group isolated diazotrophic endophytes from gramineous plants and investigated their colonization and nitrogen fixation. These bacteria made significant contributions to the supply of nitrogen sources, allowing for rice production without chemical fertilizers. Less