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Avaliação comparativa, via calorimetria, da atividade microbiana de um latossolo vermelho, cultivado por cana-de-açúcar, citros e de mata natural; Comparative evaluation of microbial activity of red latosol cultivated with sugarcane, citrus and natural forest using calorimetry

Amanda Carolina Covizzi Bertelli
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 16/02/2011 PT
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Este estudo investiga a influência de práticas agrícolas na atividade microbiana de solos, utilizando-se a calorimetria. Foram estudados solos sobre três diferentes condições de manejo. Os solos foram retirados da região de Pirassununga, Estado de São Paulo e são de condições: solo de mata natural, cultivado com citros e cultivado com cana-de-açúcar. As coordenadas: mata natural (21°56´33,54"S; 47°19´51,85"O), citros (21°56´25,14"S; 47°19´53,31"O) e cana-de-açúcar (21°56´35,25"S; 47°;9´54,64"O). O estudo calorimétrico corresponde ao registro da energia dissipada em função do tempo, utilizando-se glicose como substrato. As amostras de foram também caracterizadas por diversas análises químicas (teor de carbono, pH e acidez total), e biológica (contagem de microorganismos), além das técnicas térmicas como TGA e DSC. Os resultados de calorimetria evidenciam diferenças entre os diferentes manejos em relação a parâmetros como: eficiência de assimilação da matéria orgânica (hH), constante de crescimento microbiano (k), e a quantidade biomassa viva formada (DX). O valor de "peak time" obedeceu a ordem citros

Avaliação da atividade microbiana em solo com o herbicida ametrina e adição de biofertilizante = : Evaluation of microbial activity in soil with the herbicide ametryn and addition of biofertilizer; Evaluation of microbial activity in soil with the herbicide ametryn and addition of biofertilizer

Ana Paula Justiniano Régo
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 26/02/2013 PT
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A ametrina é um herbicida utilizado em culturas de cana-de-açúcar no período de pré e pós emergência das plantas daninhas. É um composto persistente no meio ambiente, podendo lixiviar para água subterrânea e escoar para águas superficiais, provocando impacto na comunidade aquática. No presente trabalho avaliou-se a atividade microbiana em solo com histórico de aplicação da ametrina em cultivo de cana de açúcar, acrescidos de concentrações de solução de ametrina e biofertilizante comercial Microgeo. Coletaram-se três amostras de solo em área de cultivo de cana de açúcar, sendo o primeiro solo caracterizado como argiloso, o segundo arenoso, o terceiro arenoso, mas esterilizado em estufa a 106ºC. As concentrações utilizadas da ametrina nos experimentos foram de 8 e 12 ?g/mL e, as de biofertilizante foram 1, 5 e 10%. Para avaliar a atividade microbiana do solo utilizou-se o método respirométrico de Bartha que quantifica a geração de CO2 em mg/L e após o processo de biodegradação o método enzimático de hidrólise de FDA para avaliar a estimativa da atividade microbiana. Quantificou-se a população de bactérias heterotróficas e fungos expressos em UFC/g de solo antes e após o experimento de respirometria. Realizou-se teste de toxicidade com o organismo-teste Daphnia similis exposta ao herbicida ametrina nas concentrações 0...

Estudo calorimétrico comparativo do efeito da aplicação de herbicidas na atividade microbiana em diferentes solos; Calorimetric study of the comparative effect of herbicides on the microbial activity in different soils

Gabriel Jeronymo Curti
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 05/12/2014 PT
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Sabe-se que na agricultura a qualidade de um solo é dependente do tipo de manejo. No presente trabalho foi aplicada a microcalorimetria isotérmica para se investigar a influência do herbicida atrazina na atividade microbiana de um solo envelhecido de mata nativa, mantido a aproximadamente 4 °C, durante três anos. Além da utilização da microcalorimetria isotérmica, foram realizadas as análises de DSC e TG com a finalidade de se avaliar a quantidade de matéria orgânica presente no solo estudado, cujo valor quantificado foi de (3,5 ± 0,2)% g/g. Também foi realizado o cálculo da humidade do solo e as análises elementares [CHN e EDS (Energy Dispersive X-Ray Detector) acoplado ao MEV (Microscópio Eletrônico de Varredura)]. As amostras de solo utilizadas na análise microcalorimétrica foram previamente incubadas com acetonitrila e com soluções de atrazina em acetonitrila nas concentrações de 1000 e 2000 ppm, durante aproximadamente 48 horas. Em seguida, foi descoberto com o emprego da microcalorimetria isotérmica que a acetonitrila ainda permanecia no solo após o período de incubação, além do fato de que o efeito da atrazina sobre os microrganismos do solo não era detectável, uma vez que os valores para o calor gerado durante a incubação com aquele solvente e com as soluções de atrazina em acetonitrila nas concentrações de 1000 e 2000 ppm...

Soil biochemistry and microbial activity in vineyards under conventional and organic management at Northeast Brazil

Freitas,Nicácio de Oliveira; Yano-Melo,Adriana Mayumi; Silva,Fábio Sérgio Barbosa da; Melo,Natoniel Franklin de; Maia,Leonor Costa
Fonte: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz" Publicador: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2011 EN
Relevância na Pesquisa
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The São Francisco Submedium Valley is located at the Brazilian semiarid region and is an important center for irrigated fruit growing. This region is responsible for 97% of the national exportation of table grapes, including seedless grapes. Based on the fact that organic fertilization can improve soil quality, we compared the effects of conventional and organic soil management on microbial activity and mycorrhization of seedless grape crops. We measured glomerospores number, most probable number (MPN) of propagules, richness of arbuscular mycorrhizal fungi (AMF) species, AMF root colonization, EE-BRSP production, carbon microbial biomass (C-MB), microbial respiration, fluorescein diacetate hydrolytic activity (FDA) and metabolic coefficient (qCO2). The organic management led to an increase in all variables with the exception of EE-BRSP and qCO2. Mycorrhizal colonization increased from 4.7% in conventional crops to 15.9% in organic crops. Spore number ranged from 4.1 to 12.4 per 50 g-1 soil in both management systems. The most probable number of AMF propagules increased from 79 cm-3 soil in the conventional system to 110 cm-3 soil in the organic system. Microbial carbon, CO2 emission, and FDA activity were increased by 100 to 200% in the organic crop. Thirteen species of AMF were identified...

Influence of Deep Ocean Sewage Outfalls on the Microbial Activity of the Surrounding Sediment

Novitsky, James A.; Karl, David M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1985 EN
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The microbial activity near two deep ocean sewage outfalls off the coast of the island of Oahu, Hawaii, was characterized. Water samples and sediment samples to a depth of 4.5 cm were analyzed from an area of approximately 4.5 × 104 m2 surrounding the outfalls. Although the effluent water at both sites exhibited heterotrophic activity that was 2 orders of magnitude greater than water from a control site, ambient water samples taken within 1 m of the discharge ports exhibited activity only twice that of the control water. The heterotrophic activity of the outfall sediment was only elevated above that of the control site for surface samples collected within 10 m of the outfall. Likewise, the rates of microbial nucleic acid synthesis and carbon production in the sediment were only elevated immediately adjacent to the outfalls. Total microbial biomass, as determined by the ATP content of the sediment, varied spatially but was generally elevated at the outfall sites. The specific growth rates calculated for the sediment microbial populations, however, were not greater at the outfall sites. At one site the rocks surrounding the diffuser pipe were covered with copious amounts of slime that appeared to be composed entirely of microbial cells and filaments. This microbial mat was extremely active with respect to heterotrophic activity and biomass production. Overall...

Microbial Activity in Organic Soils as Affected by Soil Depth and Crop †

Tate, Robert L.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1979 EN
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The microbial activity of Pahokee muck, a lithic medisaprist, and the effect of various environmental factors, such as position in the profile and type of plant cover, were examined. Catabolic activity for [7-14C]salicylic acid, [1,4-14C]succinate, and [1,2-14C]acetate remained reasonably constant in surface (0 to 10 cm) soil samples from a fallow (bare) field from late in the wet season (May to September) through January. Late in January, the microbial activity toward all three compounds decreased approximately 50%. The microbial activity of the soil decreased with increasing depth of soil. Salicylate catabolism was the most sensitive to increasing moisture deep in the soil profile. At the end of the wet season, a 90% decrease in activity between the surface and the 60- to 70-cm depth occurred. Catabolism of acetate and succinate decreased approximately 75% in the same samples. Little effect of crop was observed. Variation in the microbial activity, as measured by the catabolism of labeled acetate, salicylate, or succinate, was not significant between a sugarcane (Saccharum officinarum L.) field and a fallow field. The activity with acetate was insignificantly different in a St. Augustine grass [Stenotaphrum secundatum (Walt) Kuntz] field...

Microbial activity and dissolved organic matter dynamics in the soils are affected by salinity and sodicity

Mavi, M.; Marschner, P.; Chittleborough, D.; Cox, J.
Fonte: CSIRO; DVD Publicador: CSIRO; DVD
Tipo: Conference paper
Publicado em //2010 EN
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A laboratory incubation experiment was conducted to assess changes in microbial activity, dissolved organic matter (DOM) and nutrients dynamics in response to salinity and sodicity. We hypothesised that salinity would decrease microbial activity due to osmotic stress, whereas sodicity would increase microbial activity as a result of increased organic matter solubility. A non-saline non-sodic soil was repeatedly leached using a combination of 1M NaCl and 1M CaCl2 solutions to reach EC1:5 0.4, 1.2, 2.5 and 4.0 dS/m combined with SAR < 3, 10 and 20. Two percent finely ground wheat straw residue was added as an amendment. The results indicate that cumulative respiration on day 64 was more strongly affected by EC than SAR. Cumulative respiration was highest at low EC1:5 (0.4) and high SAR (20) and lowest at high EC1:5 (4.0) and high SAR (20). Increasing salinity adversely affected the microbial activity in the soil, whereas increased the microbial activity in response to sodicity was only observed at EC1:5 (0.4).; M. S. Mavi, P. Marschner, D. J. Chittleborough and J. W. Cox

Soil microbial activity and community structure as affected by osmotic and matric potential.

Chowdhury, Nasrin
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2011
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Salinization of soils is a serious land degradation problem, causing poor plant growth and low microbial activity due to osmotic stress, ion toxicity and imbalanced element uptake. In arid, semi arid or seasonally arid (Mediterranean) regions, low or fluctuating matric potential causes further stress to soil microorganisms in saline soil by decreasing the osmotic potential as salts in the soil solution become more concentrated, as well as by reducing diffusion and thus substrate availability. Soil properties such as soil texture, water retention characteristics and organic matter content also influence soil microbial activity and community structure and the effect of salinity and matric potential on soil microorganisms. While the effects of low matric and low osmotic potential on soil microorganisms have been studied separately, little is known about their interaction. The objective of this thesis was to determine the interaction between soil matric and osmotic potential on soil microbial activity and community structure. Most experiments described in this thesis were carried out with two non-saline soils (sand and sandy loam) differing in nutrient status, microbial biomass and community composition. Osmotic stress was induced by application of different rates of NaCl. In all experiments...

Salinity affects the response of soil microbial activity and biomass to addition of carbon and nitrogen

Mavi, M.; Marschner, P.
Fonte: CSIRO Publishing Publicador: CSIRO Publishing
Tipo: Artigo de Revista Científica
Publicado em //2013 EN
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Addition of carbon (C) and nitrogen (N) to soil can enhance microbial tolerance to salinity, but it is not known if salinity changes the response of microbial activity and biomass to addition of C and N, or how nutrient addition affects microbial tolerance to salinity. We prepared salinity treatments of non-saline soil [electrical conductivity (EC1 :5) 0.1 dSm–1] without salt addition or adjusted to four salinity levels (2.5, 5.0, 7.5, 10 dSm–1) using a combination of CaCl2 and NaCl. The soils were amended with 2.5 mgC g–1 as glucose or as mature wheat straw (C/N ratio 47 : 1), with NH4Cl added to glucose to achieve a C/N ratio similar to that of wheat straw, or with NH4Cl added to glucose or wheat straw to achieve a C/N ratio of 20. Soil respiration was measured over 30 days. Microbial biomass C and N (MBC, MBN), dissolved organic C (DOC), and total dissolved N (TDN) were measured on day 30. Cumulative respiration and MBC concentration decreased with increasing EC, less so with glucose than with wheat straw. The MBC concentration was more sensitive to EC than was cumulative respiration, irrespective of C source. Addition of N to glucose and wheat straw to bring the C/N ratio to 20 significantly decreased cumulative respiration and MBC concentration at a given EC. This study showed that in the short term...

Microbial activity and biomass in saline soils as affected by carbon availability.

Elmajdoub, Bannur Mohamed Ahmed
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2014
Relevância na Pesquisa
678.4173%
Soil salinity is a serious land degradation problem which reduces plant growth and microbial activity due to (1) low osmotic potential which causes plant water stress, and (2) ion toxicity and ion imbalances (nutrient deficiencies) as result of high salt concentrations in the soil solution. Therefore, salinity affects organic matter turnover by influencing the amount of organic matter input in the soil and decomposition rate. Microbial activity and biomass in saline soils have been extensively studied, but a little is known about the effect of organic carbon (OC) addition on adaptation of soil microbes to salinity. The objective of this thesis was to determine the effect of OC availability on adaptation of soil microbial activity and biomass to salinity. In most experiments described in this thesis, one non-saline and four saline soils from the field with similar texture (sandy clay loam) and electrical conductivities in a 1:5 soil: water extract (EC₁﹕₅) of 0.1, 1.1, 3.1 and 5.2 dS m⁻¹ or electrical conductivity of the saturation extract (ECₑ) of 1, 11, 24 and 43 dS m⁻¹ were used. In other experiments a non-saline loamy sand was amended with NaCl to achieve a range of EC levels. The optimum water content for respiration was determined by incubating the soils amended with glucose at different water contents and measuring the respiration for 10 days at 25ºC. Glucose...

Response of microbial activity and biomass to changes in soil salinity and water content.

Yan, Nan
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2014
Relevância na Pesquisa
677.80484%
Salinization is a serious land degradation problem because osmotic stress and toxic ions cause poor plant growth and low soil microbial activity. The effect of salinity on soil microbes has been studied previously, but usually at constant salinity. However, in the field salinity may vary over time. Another factor influencing the effect of salinity on soil microbes is the soil water content. The osmotic potential, which is a measure of the salt concentration in the soil solution, increases as soils dry. The aim of the experiments described in this thesis was to assess how soil microbial activity and microbial biomass respond to changes in soil salinity and soil water content. One non-saline and four saline soils from Monarto, South Australia (35° 05´ S and 139° 06´ E) were used in the experiments. Soils were air-dried after collection. In some experiments, salinity was induced by adding certain amount of NaCl (dissolved in RO water), or decreased by leaching. Preliminary experiments were carried out to quantify the salts or water needed to reach the desired salinity. Pea (Pisum sativum L.) straw (C/N=26) was used as available substrate in most experiments except for experiments in Chapter four, where glucose was used. Soil CO₂ release (respiration as measure of microbial activity) was measured daily throughout each experimental period...

Estudo calorimetrico da atividade microbiana de solo canavieiro, manejado sob diferentes condições; Calorimetric study of the soil microbial activity from sugarcane plant region, tilled under different conditions

Gabriel Jeronymo Curti
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 31/07/2009 PT
Relevância na Pesquisa
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Esse estudo investiga a influência de práticas agrícolas na atividade microbiana de solos, utilizando-se a calorimetria. Quatro amostras de solo foram coletadas no município de Pradópolis, São Paulo, Brasil (21°19'8'' S 48°7'16' ' W), onde se praticavam dois diferentes tipos de manejo: solo sujeito à queima periódica, e solos não sujeitos à queima, em que, 2, 4, e 7 cortes consecutivos da cultura de cana foram observados. Nesses solos também houve contínuo incremento de cobertura vegetal. O estudo calorimétrico corresponde ao registro da energia dissipada em função do tempo, utilizando-se glicose como substrato. As amostras foram também caracterizadas por diversas análises químicas (teor de carbono total e acidez), físicas (porosidade, densidade, argila dispersa), biológica (número de microorganismos), e por técnicas de análise térmica como TGA, e DSC. Os resultados de calorimetria evidenciam diferenças entre os diferentes manejos em relação a parâmetros como: eficiência de assimilação da matéria orgânica (hH), constante de crescimento microbiano (k), e a quantidade biomassa viva formada (DX). O solo associado a práticas de queimada apresentou uma baixa eficiência percentual de assimilação de matéria orgânica (hH = 53 %)...

Microbial activity in non-agricultural degraded soils exposed to semiarid climate

Bastida, F.; Moreno, J. L.; Hernández Fernández Muñoz, María Teresa; García Izquierdo, Carlos
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 579917 bytes; image/jpeg
ENG
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The degree of degradation of soils can be measured by reference to a variety of chemical, physical, biochemical and biological properties, the last two being particularly sensitive to the changes that take place. Among these parameters, those related with the soil carbon content, such as total organic carbon and microbial biomass carbon, are of the greatest interest although others are also important indicators of microbial activity, including ATP and phosphatase activity. This study looks at the microbial activity of various soils in SE Spain which present different degrees of plant cover. The results demonstrate that vegetation is of fundamental importance for the development of microbial populations and their activity since soils with a substantial vegetal cover showed higher values for the above parameters than those with a reduced cover, which are more degraded. A seasonal study of the soil properties showed that the time of year exercises an important influence on the parameters that are indicative of microbial activity.; The project “Indicators and threshold for desertification, soil quality, and remediation” (INDEX GOCE-CT-2003-505450) is funded by the EU and the “Programa Nacional de Formación de Profesorado Universitario” is funded by the Spanish Ministry of Science and Technology.; Peer reviewed

The long-term effects of the management of a forest soil on its carbon content, microbial biomass and activity under a semi-arid climate

Bastida, F.; Moreno, J. L.; Hernández Fernández Muñoz, María Teresa; García Izquierdo, Carlos
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 190855 bytes; application/pdf
ENG
Relevância na Pesquisa
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10 pages, 2 figures, 5 tables.; Terracing of soil is a reforestation practice well established in South-eastern Spain (semi-arid climate), because it increases plant growth by means of run-off reduction. This is a crucial factor because in this zone the climatic conditions (especially the scarce rainfall) impede plant development. In this work, the influence in the long-term (13 years) of two types of physical management (terracing and strip planting) in the reforestation of a mountainside with Pinus halepensis Millar, together with the addition of an organic amendment (produced from municipal refuse), was evaluated by means of different biochemical and microbiological parameters, including those related to the size and general activity of microbial populations, such as microbial biomass C (MBC), basal respiration, ATP, dehydrogenase activity and hydrolase activities. Also, the study of labile C fractions (water-soluble C, WSC) provided information regarding the metabolic potential of the soil microorganisms. Three-way ANOVA showed that organic amendment significantly increased general microbial activity and carbon fractions. Strips produced, in the long-term, only a slightly positive effect on the microbial activity. The results indicate that terracing...

Bioremediation of oil refinery sludge by landfarming in semiarid conditions: Influence on soil microbial activity

Marín, Antonio; Hernández Fernández Muñoz, María Teresa; García Izquierdo, Carlos
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 259768 bytes; application/pdf
ENG
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11 pages, 5 figures, 4 tables.; Bioremediation of a refinery sludge containing hydrocarbons in a semi-arid climate using landfarming techniques is described. The objective of this study was to assess the ability of this technique to reduce the total hydrocarbon content added to the soil with the refinery sludge in semiarid climate (low rain and high temperature). In addition, we have evaluted the effect of this techique on the microbial activity of the soil involved. For this, biological parameters (carbon fractions, microbial bilmass carbon, basal respiration and ATP) and biochemical parameters(different enzymatic activities) were determined. The results showed that 80% of the hydrocarbons were eiminated in eleven months, half of this reduction taking place during the first three months. The labile carbon fractions, MBC, basal respiration and ATP of the soils submitted to landfarming showed higher values than the control soil during the first months of the process, although these values fell down by the end of the experimental period as the hydrocarbons were degraded by mineralisation. All the enzymatic activities studied: oxydoreductases such as dehydrogenase activity, and hydrolases of C(β-glucosidase activity) and N Cycle (urease and protease) showed higher values in the soils amended with the refinery sludge than in the control. As in the case of the previous parameters...

Soil microbial activity after restoration of a semiarid soil by organic amendments

Ros Muñoz, Margarita Matilde; Hernández Fernández Muñoz, María Teresa; García Izquierdo, Carlos
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 259768 bytes; application/pdf
ENG
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7 pages, 4 figures, 2 tables.; Unsuitable agricultural practices together with adverse environmental conditions have led to degradation of soil in many Mediterranean areas. One method for recovering degraded soils in semiarid regions, is to add organic matter in order to improve soil characteristics, thereby enhancing biogeochemical nutrient cycles. In this study, the effect of adding the organic fraction of urban wastes (both fresh and composted) on different carbon fractions and on microbiological and biochemical parameters (microbial biomass C, basal respiration and different enzymatic activities) of a degraded soil of SE Spain has been assessed in a 2 year experiment. Three months after the addition of the organic material, spontaneous plant growth occurred and the plant cover lasted until the end of the experiment. Organic soil amendment initially increased the levels of soil organic matter, microbial biomass, basal respiration and some enzyme activities related to the C and N cycles These values decreased but always remained higher than those of the unamended soil. The results indicate that the addition of urban organic waste is beneficial for recovering degraded soils, the microbial activity of which clearly increases with amendment. The incorporation of compost seemed to have a greater positive effect on the soil characteristics studied than the incorporation of fresh organic matter.; Peer reviewed

Toxicity of cadmium to soil microbial activity: effect of sewage sludge addition to soil on the ecological dose

Moreno, J. L.; Hernández Fernández Muñoz, María Teresa; Pérez-Espinosa, A.; García Izquierdo, Carlos
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 259768 bytes; application/pdf
ENG
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10 pages, 4 figures, 4 tables.; Cadmium has a toxic effect on soil microbial activity which plays an important role in nutrient cycling and, therefore, in maintaining soil fertility. In addition, the mobility of this heavy metal in soil is affected by the addition of urban wastes such as sewage sludge. This study was conducted to determine the effect of sewage sludge amendment of a semiarid soil, previously polluted with Cd, on the toxic effect of this heavy metal on soil microbial biomass and its activity. Dehydrogenase activity, ATP content, microbial soil respiration and microbial biomass carbon were used as bioindicators of the toxic effect of Cd. The inhibition of microbial activity and biomass by different Cd concentrations ranging from 0 to 8000 mg Cd kg−1 soil was described by three mathematical models in order to calculate three ecological doses of Cd: ED50, ED10, and ED5. In general, higher ED values were calculated for the sewage sludge amended soil than for unamended soil. Thus the Cd toxicity to microbial activity of the sewage sludge amended soil can be considered lower than that of the unamended soil. Moreover, increased ED values with time after soil Cd contamination were observed.; Peer reviewed

Organic amendment and mycorrhizal inoculation as a practice in afforestation of soils with Pinus halepensis Miller: effect on their microbial activity

García Izquierdo, Carlos; Hernández Fernández Muñoz, María Teresa; Roldán Garrigos, Antonio; Albaladejo Montoro, Juan; Castillo Sánchez, Victor Manuel
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 259768 bytes; application/pdf
ENG
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9 pages, 6 tables.; Soil amendment with organic materials prior to afforestation as well as the use of mycorrhizal inoculation, are advisable practices in afforestation of semiarid areas. In this work, the effect of both organic amendment and mycorrhizal treatment on the microbial activity of a soil afforested with Aleppo pine (Pinus halepensis Miller) was studied. Labile carbon fractions (water soluble carbon and water soluble carbohydrates), microbiological parameters (microbial biomass carbon, basal respiration and metabolic quotient), and enzyme activities such as oxydoreductases (deshydrogenase and catalase activities) and hydrolases (urease, protease and phosphatase) were determined. All these parameters were found positively influenced by organic amendment and mycorrhizal treatment of plant roots by inoculation of fungi or forest soil addition. The best result was obtained when mycorrhizal inoculation with fungi was supplemented by organic amendment.; This work was funded by the CICYT (Comision Interministerial de Ciencia y Tecnologia), Project AGF-95-0097.; Peer reviewed

Effects of atrazine on microbial activity in semiarid soil

Moreno, J. L.; Aliaga, Asunción; Navarro, Simón; Hernández Fernández Muñoz, María Teresa; García Izquierdo, Carlos
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 515158 bytes; application/pdf
ENG
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8 pages, 6 tables, 5 figures.; The effect of an atrazine formulation on microbial biomass, microbial respiration, ATP content and dehydrogenase and urease activity in a semiarid soil and the influence of time on the response of soil microbial activity to the herbicide treatment were assessed. The atrazine formulation was added to soil as aqueous solutions of different concentrations of active ingredient to obtain a range of concentrations in the soil from 0.2 to 1000 mg kg−1. Microcosms of soil with the different herbicide concentrations and untreated control soil were incubated for 6 h, 16 and 45 days. In general, an increase in the measured microbiological and biochemical parameters with atrazine concentration in soil was observed. The increase in microbial activity with atrazine pollution was noticeable after lengthy incubation.; Peer reviewed

Soil biochemistry and microbial activity in vineyards under conventional and organic management at Northeast Brazil; Atividade bioquímica e microbiológica do solo em videiras sob manejo orgânico e convencional no Nordeste do Brasil

Freitas, Nicácio de Oliveira; Yano-Melo, Adriana Mayumi; Silva, Fábio Sérgio Barbosa da; Melo, Natoniel Franklin de; Maia, Leonor Costa
Fonte: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz Publicador: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/04/2011 ENG
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The São Francisco Submedium Valley is located at the Brazilian semiarid region and is an important center for irrigated fruit growing. This region is responsible for 97% of the national exportation of table grapes, including seedless grapes. Based on the fact that organic fertilization can improve soil quality, we compared the effects of conventional and organic soil management on microbial activity and mycorrhization of seedless grape crops. We measured glomerospores number, most probable number (MPN) of propagules, richness of arbuscular mycorrhizal fungi (AMF) species, AMF root colonization, EE-BRSP production, carbon microbial biomass (C-MB), microbial respiration, fluorescein diacetate hydrolytic activity (FDA) and metabolic coefficient (qCO2). The organic management led to an increase in all variables with the exception of EE-BRSP and qCO2. Mycorrhizal colonization increased from 4.7% in conventional crops to 15.9% in organic crops. Spore number ranged from 4.1 to 12.4 per 50 g-1 soil in both management systems. The most probable number of AMF propagules increased from 79 cm-3 soil in the conventional system to 110 cm-3 soil in the organic system. Microbial carbon, CO2 emission, and FDA activity were increased by 100 to 200% in the organic crop. Thirteen species of AMF were identified...