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dc.contributor.authorKahindi, JHP
dc.contributor.authorWoomer, P
dc.contributor.authorGeorge, T
dc.contributor.authorMoreira, FM de Souza
dc.contributor.authorKaranja, NK
dc.contributor.authorGiller, KE
dc.date.accessioned2013-07-25T13:09:48Z
dc.date.available2013-07-25T13:09:48Z
dc.date.issued1997-08
dc.identifier.citationApplied Soil Ecology Volume 6, Issue 1, August 1997, Pages 55–76 Soil Biodiversity, Agricultural Intensification and Agroecosystem Functionen
dc.identifier.urihttp://www.sciencedirect.com/science/article/pii/S0929139396001515
dc.identifier.urihttp://erepository.uonbi.ac.ke:8080/xmlui/handle/123456789/51264
dc.description.abstractAmong the nitrogen (N2)-fixing bacteria, the rhizobia in symbiosis with legumes are generally the most important in agriculture, although Frankia, cyanobacteria and heterotrophic free-living N2 -fixers may fix significant amounts of nitrogen under specific conditions. The taxonomy of N2-fixing bacteria is undergoing substantial revisions due to the advent of molecular methods for phylogenetic analysis, and in certain cases this has proved useful in unravelling ecological relationships among confusing groups. Molecular methods are also proving useful in studies of biodiversity within populations of rhizobial species. Rhizobia are surprisingly competent free-living bacteria, although few fix nitrogen in the free-living state, and the major factors that determine their population sizes in the absence of legume hosts are environmental stresses (such as soil acidity factors), protozoal grazing and some factors associated with agricultural intensification such as increases in salinity or heavy metal pollution of the soil. Rhizobial populations generally increase in response to the presence of the host legume. Due to the high degree of host-specificity between legume hosts and rhizobial species, loss of a single rhizobial species can result in loss of N2-fixation by that legume, although many legumes can be nodulated by several species of rhizobia. However, as only a single, compatible rhizobial genotype or strain is necessary for establishment of effective N, -fixation (i.e. the basis of the rhizobial inoculant industry), it is questionable whether biodiversity within species is necessary to ensure function, although this may confer resilience in the face of further environmental stresses.en
dc.language.isoenen
dc.publisherUniversity of Nairobien
dc.subjectAzorhizobium; Bradyrhizobium; Cyanobacteria; Free-living nitrogen-fixing bacteria; Rhizobium; Legumes; Nitrogen fixationen
dc.titleAgricultural intensification, soil biodiversity and ecosystem function in the tropics: the role of nitrogen-fixing bacteriaen
dc.typeArticleen
local.publisherCollege of Agriculture and Veterinary Medicineen


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