Introduction of Soil Microbiology

Alexander, Martin

doi:10.1097/00010694-196201000-00034

Cited by 287 publications

(371 citation statements)

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“…Este isolamento teria levado à seleção de microrganismos menos eficientes na assimilação e utilização do carbono (Alexander, 1977;Sakamoto & Oba, 1994).…”

Section: Resultsunclassified

Carbono orgânico e biomassa microbiana do solo em plantios de Acacia mangium no Cerrado de Roraima

et al. 2010

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RESUMOO objetivo do estudo foi avaliar os efeitos de plantios de Acacia mangium, localizados no cerrado em Roraima, sobre o carbono orgânico e biomassa microbiana do solo. Foram realizadas amostragens de solo nas profundidades de 0-20 cm e 20-40 cm em dois plantios de A. mangium com cerca de cinco anos de idade, e em duas áreas de Cerrado nativo consideradas referência. Um dos plantios de A. mangium (localizado na Fazenda Cigolina) correspondeu a um plantio homogêneo (espaçamento de 3,6 m entre linhas e 2,0 m entre plantas) enquanto que o outro (localizado no Campo Experimental Água Boa -CEAB) correspondeu a um plantio em faixas com duas linhas de plantio (espaçamento de 6 m entre linhas, 2,5 m entre plantas e cerca de 30 m entre faixas). As amostras de solo foram analisadas quanto ao carbono orgânico, carbono da biomassa microbiana, respiração basal do solo e quociente metabólico, além de atributos químicos de fertilidade. Foi verificado que os plantios de A. mangium não proporcionaram aumentos significativos do carbono orgânico do solo em comparação às áreas de referência. Entretanto, na média geral, esses plantios proporcionaram aumento do carbono da biomassa microbiana do solo e redução do quociente metabólico, indicando a possibilidade de acúmulo de carbono orgânico no solo em longo prazo. Também foi observado que, em comparação ao plantio da fazenda Cigolina e às áreas de referência, o carbono microbiano do solo foi maior e acompanhado de menor quociente metabólico no plantio de A. mangium no CEAB, mostrando que a estrutura de plantio exerceu influência sobre a biomassa microbiana do solo. PALAVRAS-CHAVE:Respiração basal do solo, quociente metabólico, Amazônia, plantios florestais, qualidade do solo. Soil organic carbon and soil microbial biomass in Acacia mangium plantation in the Savanna of Roraima ABSTRACTThe aim of this study was to evaluate the effects of Acacia mangium plantation in the Roraima's Savanna, on soil organic carbon and soil microbial biomass. Soil samplings were collected on the depths of 0-20 cm and 20-40 cm in two Acacia mangium plantation sites, about five years old, and in two sites of native savanna as reference. One of the A. mangium sites (located at Fazenda Cigolina) was composed by a homogeneous plantation (3.6 m between row and 2.0 m between trees) and, the other one (located at Campo Experimental Agua Boa Experimental -CEAB) was composed by a plantation on which the planting distances had strips of two rows 6 meters apart, 2.5 meters between trees and 30 meters between strips). Soil samples were analyzed regarding soil organic carbon, microbial biomass carbon, soil basal respiration and metabolic quotient, besides soil fertility attributes. Results showed that A. mangium plantations did not provide significant increases of organic carbon on the soil comparing with sites used as reference. However, generally, A. mangium plantation increased soil microbial biomass carbon and reduced metabolic quotient, indicating a possibility of soil organic carbon accumulation in long-term. It...

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“…Este isolamento teria levado à seleção de microrganismos menos eficientes na assimilação e utilização do carbono (Alexander, 1977;Sakamoto & Oba, 1994).…”

Section: Resultsunclassified

Carbono orgânico e biomassa microbiana do solo em plantios de Acacia mangium no Cerrado de Roraima

et al. 2010

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“…This is surprising as streptomycetes, generally accounting for an abundant percentage of the soil microflora, are particularly effective colonizers of plant root Systems and are able to endure unfavorable growth conditions by forming spores (Alexander 1977). While the bénéficiai effect of some strains of PGPR on particular crops is certain, the mechanisms em-5 ployed by PGPR are unclear (Glick 1995 Merriman et al (1974) reported the use of a Streptomyces griseus (Krainsky) Waksman and Henrici isolate as a seed treatment of barley, oat, wheat and carrot, in order to increase their growth.…”

Section: Actinomycetes As Pgprmentioning

confidence: 99%

“…In fact, about 60% of the new insecticides and herbicides reported in the past 5 yr originate from Streptomyces (Tanaka and Omura 1993). It is also estimated that as many as three-quarters of ail streptomycete species are capable of antibiotic production (Alexander 1977). Actinomycetes produce a variety of antibiotics with diverse chemical structures such as polyketides, b-lactams and peptides in addition to a variety of other secondary metabolites that hâve antifungal, anti-tumor and immunosuppressive activities (Behal 2000).…”

Section: Introductionmentioning

confidence: 99%

Actinomycetes, promising tools to control plant diseases and to promote plant growth

Doumbou¹,

Salove²,

Crawford³

et al. 2005

phyto

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Les actinomycètes représentent une grande proportion de la biomasse microbienne du sol et ont la capacité de produire une large variété d’antibiotiques et d’enzymes extracellulaires. Plusieurs souches d’actinomycètes s’avèrent capables de protéger les plantes contre des maladies. Cette revue se penche sur le potentiel des actinomycètes comme (a) source de composés agronomiques, (b) agents stimulant la croissance des plantes et (c) agents de lutte biologique. La revue donne aussi des exemples de lutte biologique contre les agents phytopathogènes bactériens et fongiques par l’utilisation d’espèces d’actinomycetes déjà disponibles sur le marché ou qui le seront probablement au cours des prochaines années.Actinomycetes represent a high proportion of the soil microbial biomass and have the capacity to produce a wide variety of antibiotics and of extracellular enzymes. Several strains of actinomycetes have been found to protect plants against plant diseases. This review focuses on the potential of actinomycetes as (a) source of agroactive compounds, (b) plant growth promoting organisms, and (c) biocontrol tools of plant diseases. This review also addresses examples of biological control of fungal and bacterial plant pathogens by actinomycetes species which have already reached the market or are likely to be exploited commercially within the next few years

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“…Fogel & Cromack (1977) found that lignin content appears to be a more important determinant of breakdown rates than nitrogen, and suggested that interaction between phenolic, lignin-like and nitrogen-containing compounds may be important in determining interspecific differences in leaf breakdown rates. Melillo, Aber & Muratore (1982) also suggested that if large amounts of exogenous nitrogen are available to microbes involved in decomposition, lignin content may become a more important determinant of decomposition, since lignin has been shown to slow decomposition by interfering with the degradation of cellulose and other carbohydrates (Alexander, 1977).…”

Section: Discussionmentioning

confidence: 99%

Microbial activity associated with seston in headwater streams: effects of nitrogen, phosphorus and temperature

1987

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SUMMARY. 1. The influences of temperature and dissolved nitrates and phosphates on microbial activity associated with suspended fine particulate organic matter (seston) were evaluated in four headwater streams in the southern Appalachian Mountains.2. 4. Microorganisms attached to refractory particulate organic matter do not appear to be limited by nitrogen or phosphorus even in streams with ambient nutrient concentrations as low as 0.06 mg NO 3 1" 1 and <0.03 mg P0 4 1-'. 5. Our results indicate that variations in water temperature resulting from diurnal and seasonal temperature fluctuations, forest clear-cutting, and catchment elevation and aspect can have marked effects upon microbial activity and production, while short-term alterations in nutrient regime appear to have no significant effect on microbial activity associated with seston.

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Introduction of Soil Microbiology

Cited by 287 publications

References 0 publications

Carbono orgânico e biomassa microbiana do solo em plantios de Acacia mangium no Cerrado de Roraima

Carbono orgânico e biomassa microbiana do solo em plantios de Acacia mangium no Cerrado de Roraima

Actinomycetes, promising tools to control plant diseases and to promote plant growth

Microbial activity associated with seston in headwater streams: effects of nitrogen, phosphorus and temperature

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