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ABSTRACT: Cadmium (Cd) pollution can alter soil flora and fauna, as well as the microbial community associated with the main biogeochemical
cycles of a soil. The present study was conducted to investigate the effect of two different concentrations of Cd pollutant,
6.5mg kg−1 (low level) and 12.5mg kg−1 (high level) on microbial community activity, abundance, and structure in a semiarid soil after a 60-day incubation period
at laboratory level. Available Cd, water soluble carbon (WSC), microbial biomass carbon (Cmic), adenosine triphosphate (ATP) content, and real-time polymerase chain reaction were used to measure the influence of Cd
on the abundance and activity of the microbial community. Bacteria and fungi community structure and diversity based on denaturing
gradient gel electrophoresis (DGGE) analysis were also analyzed. The percentage of Cd extracted by diethylenetriamine pentaacetic
acid increased with the higher total concentration of Cd added to the soil, being 16.9% at low level and 77.9% at the high
level. WSC, Cmic, and ATP content decreased significantly as soil Cd concentration increased (WSC 29% and 34%, Cmic 27% and 35%, and ATP 32% and 47%, at low and high levels, respectively). While fungal diversity already decreased with low
levels of Cd concentration, and was even more negatively affected by the higher pollution levels, bacterial (acidobacteria,
α-proteobacteria, and β proteobacteria) diversity only showed a decline with the higher Cd concentration. The fungi-to-bacteria
ratio showed by the different treatments could imply that fungi abundance is less influenced by increased Cd pollution, although
fungi diversity as revealed by DGGE analysis diminished as soil Cd concentration increased.
Water Air and Soil Pollution 04/2012; 203(1):229-242. · 1.63 Impact Factor
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ABSTRACT: The Adenosine triphosphate (ATP) content, dehydrogenase, phosphatase, urease, and β-glucosidase activity decreased after manure
amendment plus solarization (biosolarization), but they recovered after cropping, reaching levels higher than or similar to
those before the biosolarization. However, these biochemical parameters decreased and did not recover with time in the methyl
bromide (MeBr) treatment. Potential negative soil effects were assayed by measuring, ecotoxicity (Vibrio fisheri luminescence), germination index, electrical conductivity, and heavy metals content. Biosolarization did not negatively affect
these parameters, while MeBr application irreversibly decreased the germination index and ecotoxicity. Higher-quality pepper
production (extra and first class) were observed with biosolarization but not with MeBr, but no differences were found for
pepper yield. Biosolarization gave a Meloidogyne incognita (M. incognita) incidence similar to that of MeBr application.
Biology and Fertility of Soils 04/2012; 45(1):37-44. · 2.32 Impact Factor
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ABSTRACT: BACKGROUND: The use of isolates of the genus Trichoderma to control Fusarium wilt in melon plants is one of the most recent and effective alternatives to chemical treatments. In this work we have studied the immobilization of the isolate Trichoderma harzianum T-78 on different carriers as an efficient method to control vascular Fusarium wilt of melon in nurseries. Different formulations were developed: liquids (spore suspension, guar gum and carboxymethylcellulose) and solids (bentonite, vermiculite and wheat bran).RESULTS: The introduction of F. oxysporum resulted in a significant decrease in seedling fresh weight. The treatments which gave a lesser reduction in weight and showing a greater biocontrol effect were the liquid conidial suspension and the solid treatments with bentonite and superficial vermiculite. Microbiological analyses revealed that the conidial suspension and all the solid treatments, except wheat bran, significantly decreased F. oxysporum populations. Of all the treatments assayed, bentonite produced the greatest decline in the F. oxysporum population.CONCLUSIONS: The most effective treatments against Fusarium wilt on melon plants were the solid treatments bentonite and superficial vermiculite. These two treatments gave the greatest plant weight, the lowest percentage of infected plants and the greatest T. harzianum population throughout the assay. Copyright © 2009 Society of Chemical Industry
Journal of the Science of Food and Agriculture 02/2009; 89(5):827 - 833. · 1.44 Impact Factor
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ABSTRACT: The effect of continuous monospecie cropping on the microbial activity of arable semiarid soils was studied. Soil cultivation reduced organic carbon and humic substance contents. The total carbohydrate content was little influenced by the type of monospecie whereas the water-soluble carbohydrate and soluble carbon content were affected. The soils with unirrigated crops showed the lowest values of microbial biomass carbon and basal respiration. The high qCO2 values suggest a certain instability of the arable soils. In general, monospecie cropping in semiarid areas had a negative effect on enzymatic activities particularly in soils where unirrigated crops were grown. The soils dedicated to monospecie cropping showed lower values of microbiological and biochemical properties than native soils.
Communications in Soil Science and Plant Analysis 08/2006; 32(3&4)(537–552 (2001)):537-552. · 0.51 Impact Factor
