Agricultural intensification, soil biodiversity and ecosystem function in the tropics: the role of nitrogen-fixing bacteria

Kahindi, Jhp; Woomer, Paul L.; George, Thomas; Moreira, Fátima Maria de Souza; Karanja, Nancy

doi:10.1016/s0929-1393(96)00151-5

Cited by 95 publications

(51 citation statements)

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“…Additionally, the second most common OTU detected in this study (OTU 2 in Table S1) was previously found to be the fourth most frequent OTU 95 in a global survey of nifH sequences (the three OTUs that were observed more frequently were primarily from marine environments) (30). These results confirm the ubiquity of genera such as Azospirillum and Bradyrhizobium, not only as symbiotic N-fixing bacteria, but also potentially as free-living soil diazotrophs (31,32).…”

Section: Discussionsupporting

confidence: 85%

Nitrogen Fertilization Has a Stronger Effect on Soil Nitrogen-Fixing Bacterial Communities than Elevated Atmospheric CO ₂

Berthrong

Yeager

Gallegos-Graves

et al. 2014

Appl Environ Microbiol

132

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c Biological nitrogen fixation is the primary supply of N to most ecosystems, yet there is considerable uncertainty about how Nfixing bacteria will respond to global change factors such as increasing atmospheric CO 2 and N deposition. Using the nifH gene as a molecular marker, we studied how the community structure of N-fixing soil bacteria from temperate pine, aspen, and sweet gum stands and a brackish tidal marsh responded to multiyear elevated CO 2 conditions. We also examined how N availability, specifically, N fertilization, interacted with elevated CO 2 to affect these communities in the temperate pine forest. Based on data from Sanger sequencing and quantitative PCR, the soil nifH composition in the three forest systems was dominated by species in the Geobacteraceae and, to a lesser extent, Alphaproteobacteria. The N-fixing-bacterial-community structure was subtly altered after 10 or more years of elevated atmospheric CO 2 , and the observed shifts differed in each biome. In the pine forest, N fertilization had a stronger effect on nifH community structure than elevated CO 2 and suppressed the diversity and abundance of N-fixing bacteria under elevated atmospheric CO 2 conditions. These results indicate that N-fixing bacteria have complex, interacting responses that will be important for understanding ecosystem productivity in a changing climate. N itrogen is the most common nutrient limiting productivity in terrestrial ecosystems and enters ecosystems predominantly through bacterial fixation. However, we lack a clear understanding of how N-fixing bacteria respond to climate change drivers or how conserved those responses might be across biomes in a geographic region. Nonagricultural biomes in the eastern United States that experience elevated atmospheric CO 2 and increasing N deposition include hardwood forests to the north, pine forests to the south, and brackish marsh areas along the eastern seaboard. Rising atmospheric CO 2 concentrations and shifting patterns of N deposition can interact and affect N fixation processes in soil (1). To determine if populations of N-fixing bacteria in soils of different biomes showed similarities in composition and in responses to elevated CO 2 , we conducted a systematic survey of soil N-fixing bacterial communities across four biomes in the eastern United States, utilizing long-term, free-air CO 2 enrichment (FACE) experiments (2). One of these field experiments combined elevated CO 2 and N fertilization treatments, allowing us to determine their interactive effects on the N-fixing community in a pine forest in the southeastern United States.Progressive N limitation theory proposes that ecosystems become more N limited with rising CO 2 , which suggests that the continued sequestration of CO 2 in terrestrial biomass will require greater N fixation inputs (3, 4). The increased ecosystem demand for N under elevated CO 2 has been documented after several years of whole-forest CO 2 enrichment (5, 6). N-fixing bacteria, which span many taxonomic groups with high levels of ...

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Section: Discussionsupporting

confidence: 85%

Nitrogen Fertilization Has a Stronger Effect on Soil Nitrogen-Fixing Bacterial Communities than Elevated Atmospheric CO ₂

Berthrong

Yeager

Gallegos-Graves

et al. 2014

Appl Environ Microbiol

132

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“…In Barbalha, however, nodulation was expressively reduced possibly due to wide adaptation of native rhizobia population to semiarid environment (E3 x T1), contributing to inhibition of occupation of the nodulation sites by SEMIA 6144 and ESA 123. Based on reports available in literature, nodulation in several legume-rhizobia systems are negatively influenced by high temperature and low soil moisture (Kahindi et al, 1997;Kulkarni et al, 2000), whose characteristics are often found in Brazilian Semiarid. However, some native isolates may overcome the unfavorable conditions and improve its nodulation capacity contributing to plant establishment and production (Hungria and Vargas, 2000;Marinho et al, 2014).…”

Section: Resultsmentioning

confidence: 99%

Agronomic efficiency of Bradyrhizobium in peanut under different environments in Brazilian Northeast

Sizenando¹,

Ramos²,

Fernandes‐Júnior³

et al. 2016

Afr. J. Agric. Res.

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Several legumes have natural ability to associate with nitrogen-fixing bacteria known as rhizobia. The efficiency of this association depends on the plant and bacterial genotype and the edaphoclimatic conditions. Peanut is a tropical legume able to associate with a wide range of rhizobia and the selection of efficient bacteria is important to increase the nitrogen fixation in this crop. In order to investigate the agronomic efficiency of two Bradyrhizobium strains, two peanut genotypes were used in field trails carried out in three environments located at Brazilian Northeast. The genotypes (BR1 and L7 Bege) were submitted to rhizobial inoculation (SEMIA 6144 or ESA 123, both Bradyrhizobium strains), and chemical nitrogen fertilization in randomized block design experiments. The following traits were analyzed: flowering (F), main axis height (MAH), number of nodules/plant (NN), number of pods/plant (NP) and weight of pods (WP). Differential responses were found in all to treatments to NN, NP and WP, in the three environments studied. Overall, ESA 123 showed good agronomic performance inducing higher pod production. The results support the evaluation of the Bradyrhizobium in further experiments aiming at its recommendation to commercial inoculants in Brazilian Northeast region.

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“…Research on tropical soil biota has primarily focused on macrofauna, including demonstration of the importance of earthworms and termites in regulating nutrient cycling in humid soils [5,9,17,26], with less focus on microorganisms with the exception of several key microbially mediated processes such as nitrogen fixation [21,27]. Analysis of changes in microbial communities in tropical soils has hitherto been limited to a few land use types using traditional methods to detect changes in microbial biomass and soil respiration [4,31,37,41].…”

Section: Introductionmentioning

confidence: 99%

Soil Microbial Community Response to Land Use Change in an Agricultural Landscape of Western Kenya

et al. 2005

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Agricultural intensification, soil biodiversity and ecosystem function in the tropics: the role of nitrogen-fixing bacteria

Cited by 95 publications

References 100 publications

Nitrogen Fertilization Has a Stronger Effect on Soil Nitrogen-Fixing Bacterial Communities than Elevated Atmospheric CO ₂

Nitrogen Fertilization Has a Stronger Effect on Soil Nitrogen-Fixing Bacterial Communities than Elevated Atmospheric CO ₂

Agronomic efficiency of Bradyrhizobium in peanut under different environments in Brazilian Northeast

Soil Microbial Community Response to Land Use Change in an Agricultural Landscape of Western Kenya

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Agricultural intensification, soil biodiversity and ecosystem function in the tropics: the role of nitrogen-fixing bacteria

Cited by 95 publications

References 100 publications

Nitrogen Fertilization Has a Stronger Effect on Soil Nitrogen-Fixing Bacterial Communities than Elevated Atmospheric CO 2

Nitrogen Fertilization Has a Stronger Effect on Soil Nitrogen-Fixing Bacterial Communities than Elevated Atmospheric CO 2

Agronomic efficiency of Bradyrhizobium in peanut under different environments in Brazilian Northeast

Soil Microbial Community Response to Land Use Change in an Agricultural Landscape of Western Kenya

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Product

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Nitrogen Fertilization Has a Stronger Effect on Soil Nitrogen-Fixing Bacterial Communities than Elevated Atmospheric CO ₂

Nitrogen Fertilization Has a Stronger Effect on Soil Nitrogen-Fixing Bacterial Communities than Elevated Atmospheric CO ₂