scholarly journals Bioremediation by Cupriavidus metallidurans Strain MSR33 of Mercury-Polluted Agricultural Soil in a Rotary Drum Bioreactor and Its Effects on Nitrogen Cycle Microorganisms

2020 ◽  
Vol 8 (12) ◽  
pp. 1952
Author(s):  
Guillermo Bravo ◽  
Paulina Vega-Celedón ◽  
Juan Carlos Gentina ◽  
Michael Seeger
Keyword(s):  
Nitrogen Cycle ◽  
Agricultural Soil ◽  
Agricultural Soils ◽  
Mercury Pollution ◽  
Nitrifying Bacteria ◽  
Innovative Technology ◽  
Soil Bioremediation ◽  
Nitrogen Fixing ◽  
Cupriavidus Metallidurans ◽  
Rotary Drum

Nitrogen cycle microorganisms are essential in agricultural soils and may be affected by mercury pollution. The aims of this study are to evaluate the bioremediation of mercury-polluted agricultural soil using Cupriavidus metallidurans MSR33 in a rotary drum bioreactor (RDB) and to characterize the effects of mercury pollution and bioremediation on nitrogen cycle microorganisms. An agricultural soil was contaminated with mercury (II) (20–30 ppm) and subjected to bioremediation using strain MSR33 in a custom-made RDB. The effects of mercury and bioremediation on nitrogen cycle microorganisms were studied by qPCR. Bioremediation in the RDB removed 82% mercury. MSR33 cell concentrations, thioglycolate, and mercury concentrations influence mercury removal. Mercury pollution strongly decreased nitrogen-fixing and nitrifying bacterial communities in agricultural soils. Notably, after soil bioremediation process nitrogen-fixing and nitrifying bacteria significantly increased. Diverse mercury-tolerant strains were isolated from the bioremediated soil. The isolates Glutamicibacter sp. SB1a, Brevundimonas sp. SB3b, and Ochrobactrum sp. SB4b possessed the merG gene associated with the plasmid pTP6, suggesting the horizontal transfer of this plasmid to native gram-positive and gram-negative bacteria. Bioremediation by strain MSR33 in an RDB is an attractive and innovative technology for the clean-up of mercury-polluted agricultural soils and the recovery of nitrogen cycle microbial communities.

scholarly journals Ammonia-oxidizing archaea are integral to nitrogen cycling in a highly fertile agricultural soil

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Laibin Huang ◽  
Seemanti Chakrabarti ◽  
Jennifer Cooper ◽  
Ana Perez ◽  
Sophia M. John ◽  
...  
Keyword(s):  
Nitrogen Cycle ◽  
Agricultural Soil ◽  
Agricultural Soils ◽  
Ammonia Oxidizing Bacteria ◽  
Central Process ◽  
Soil Nitrification ◽  
Plant Nitrogen ◽  
Ammonia Oxidizing Archaea ◽  
Activity Measurements ◽  
Nitrite Oxidizing Bacteria

AbstractNitrification is a central process in the global nitrogen cycle, carried out by a complex network of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), complete ammonia-oxidizing (comammox) bacteria, and nitrite-oxidizing bacteria (NOB). Nitrification is responsible for significant nitrogen leaching and N2O emissions and thought to impede plant nitrogen use efficiency in agricultural systems. However, the actual contribution of each nitrifier group to net rates and N2O emissions remain poorly understood. We hypothesized that highly fertile agricultural soils with high organic matter mineralization rates could allow a detailed characterization of N cycling in these soils. Using a combination of molecular and activity measurements, we show that in a mixed AOA, AOB, and comammox community, AOA outnumbered low diversity assemblages of AOB and comammox 50- to 430-fold, and strongly dominated net nitrification activities with low N2O yields between 0.18 and 0.41 ng N2O–N per µg NOx–N in cropped, fallow, as well as native soil. Nitrification rates were not significantly different in plant-covered and fallow plots. Mass balance calculations indicated that plants relied heavily on nitrate, and not ammonium as primary nitrogen source in these soils. Together, these results imply AOA as integral part of the nitrogen cycle in a highly fertile agricultural soil.

Nitrogen Cycle Bacteria in Agricultural Soils

2021 ◽  
pp. 335-356
Author(s):  
Guillermo Bravo ◽  
Paulina Vega-Celedón ◽  
Constanza Macaya ◽  
Ingrid-Nicole Vasconez ◽  
Michael Seeger
Keyword(s):  
Nitrogen Cycle ◽  
Agricultural Soils

scholarly journals Possibilities of the Use of Aerial Photographs in the Protection of Agricultural Soil Fund

Geografie ◽  
1990 ◽  
Vol 95 (2) ◽  
pp. 87-95
Author(s):  
Zdeněk Lipský
Keyword(s):  
Agricultural Soil ◽  
Agricultural Soils ◽  
Water Erosion ◽  
Negative Influence ◽  
Aerial Photographs ◽  
Black And White ◽  
Soil Wetting

The author considers two main processes showing a negative influence on the quality and use of agricultural soils, namely water erosion and wetting. The paper treats of general advantages of aerial photographs. Practical examples are presented of direct and indirect interpretation of erosion phenomena and soil wetting by means of black-and-white, multispectral and infrared aerial photographs. In the conclusion, the main spheres of the problem of the soil fund protection are dealt with. Most of these problems could be solved by the application of aerial photographs.

scholarly journals Long-Term Exposure of Agricultural Soil to Veterinary Antibiotics Changes the Population Structure of Symbiotic Nitrogen-Fixing Rhizobacteria Occupying Nodules of Soybeans (Glycine max)

2018 ◽  
Vol 84 (9) ◽  
Author(s):  
Cécile Revellin ◽  
Alain Hartmann ◽  
Sébastien Solanas ◽  
Edward Topp
Keyword(s):  
Agricultural Soil ◽  
23S Rrna ◽  
Rrna Gene ◽  
Nodule Occupancy ◽  
Nitrogen Fixing ◽  
Swine Production ◽  
Soybean Roots ◽  
The Impact ◽  
Field Plots

ABSTRACTAntibiotics are entrained in agricultural soil through the application of manures from medicated animals. In the present study, a series of small field plots was established in 1999 that receive annual spring applications of a mixture of tylosin, sulfamethazine, and chlortetracycline at concentrations ranging from 0.1 to 10 mg · kg−1soil. These antibiotics are commonly used in commercial swine production. The field plots were cropped continuously for soybeans, and in 2012, after 14 annual antibiotic applications, the nodules from soybean roots were sampled and the occupying bradyrhizobia were characterized. Nodules and isolates were serotyped, and isolates were distinguished using 16S rRNA gene and 16S to 23S rRNA gene intergenic spacer region sequencing, multilocus sequence typing, and RSα fingerprinting. Treatment with the antibiotic mixture skewed the population of bradyrhizobia dominating the nodule occupancy, with a significantly larger proportion ofBradyrhizobium liaoningenseorganisms even at the lowest dose of 0.1 mg · kg−1soil. Likewise, all doses of antibiotics altered the distribution of RSα fingerprint types. Bradyrhizobia were phenotypically evaluated for their sensitivity to the antibiotics, and there was no association betweenin situtreatment and a decreased sensitivity to the drugs. Overall, long-term exposure to the antibiotic mixture altered the composition of bradyrhizobial populations occupying nitrogen-fixing nodules, apparently through an indirect effect not associated with the sensitivity to the drugs. Further work evaluating agronomic impacts is warranted.IMPORTANCEAntibiotics are entrained in agricultural soil through the application of animal or human waste or by irrigation with reused wastewater. Soybeans obtain nitrogen through symbiotic nitrogen fixation. Here, we evaluated the impact of 14 annual exposures to antibiotics commonly used in swine production on the distribution of bradyrhizobia occupying nitrogen-fixing nodules on soybean roots in a long-term field experiment. By means of various sequencing and genomic fingerprinting techniques, the repeated exposure to a mixture of tylosin, sulfamethazine, and chlortetracycline each at a nominal soil concentration of 0.1 mg · kg−1soil was found to modify the diversity and identity of bradyrhizobia occupying the nodules. Nodule occupancy was not associated with the level of sensitivity to the antibiotics, indicating that the observed effects were not due to the direct toxicity of the antibiotics on bradyrhizobia. Altogether, these results indicate the potential for long-term impacts of antibiotics on this agronomically important symbiosis.

Accumulation of As and Pb in Vegetables Grown in Agricultural Soils Contaminated by Historical Mining in Zacatecas, Mexico

2021 ◽  
Author(s):  
Silvia Salas Muñoz ◽  
Elvia Valdez Valdez ◽  
Jorge Armando Mauricio Castillo ◽  
Fátima Berenice Salazar Badillo ◽  
Héctor René Vega Carrillo ◽  
...  
Keyword(s):  
Agricultural Soil ◽  
Agricultural Soils ◽  
Arsenic Concentration ◽  
Pollution Index ◽  
Lead Content ◽  
National Standard ◽  
Mining Activities ◽  
Human Beings ◽  
Historical Mining ◽  
Edible Parts

Abstract Historical mining activities are a source of environmental pollution that affects the food chain and the health of human beings. The aim of this study was assessment the accumulation of arsenic and lead in vegetables grown in agricultural soils contaminated by old mining in Zacatecas, Mexico. The concentration of arsenic and lead in agricultural soil and edible parts of carrot, garlic, and pepper was analyzed by atomic absorption spectrometry. The soil-vegetable bioconcentration factor and pollution load index were determined. The pH values of the farmland were alkaline. The concentration of arsenic in agricultural soil exceeds the permissible limit for arsenic of Mexican standards and international representing health risks. The lead content in most soil samples they were low. The arsenic and lead content in edible parts of species vegetable exceeded the national standard from various countries and the values established by the Codex Alimentarius (FAO-WHO). The highest arsenic concentration was found both in Capsicum annum and Allium sativum. The highest concentration of Pb was in pepper fruits. Among vegetable the high BCF value was for arsenic, ranging from 2.33 to 0.64, and the average for all vegetable samples was 1.01. The pollution index indicates that arsenic is the dominant pollutant accumulated in soil and vegetables grown in agricultural soils. According to the findings, the state and national agricultural and health authorities should not recommend the cultivation of vegetables in agricultural soil located in this area of historical mining activities. Likewise, preventive measures must be taken on the consumption of contaminated vegetables and certifying their safety.

The response to inoculation of the three chromosome races of Trifolium ambiguum sown with and without a companion grass. II. The effect of the method of inoculation on the clover and grass

1966 ◽  
Vol 66 (3) ◽  
pp. 321-325
Author(s):  
D. Gareth Jones ◽  
Alice M. Evans
Keyword(s):  
Nitrogen Cycle ◽  
Skim Milk ◽  
Nitrogen Fixing ◽  
Nodule Bacteria ◽  
Trifolium Ambiguum ◽  
Chromosome Races ◽  
Early Establishment

The inoculation of legumes is often carried out using skim-milk as the carrier for the nodule bacteria. Increased germination due to inoculation has often been reported but in this investigation the effects of the skim-milk and the bacteria have been separated. The results indicate that the early establishment of T. ambiguum was stimulated by the skim milk rather than the nodule bacteria. The mechanism of this effect is thought to be due to extra N present in the milk and possibly to an enhanced nitrogen-cycle in the inoculated soil and evidence is produced of increases in certain freeliving nitrogen fixing and nitrifying microorganisms.

Spatial Distribution and Evaluation of Cadmium in Agricultural Soils Based on GIS: A Case Study of Chaoyang City in China

2012 ◽  
Vol 518-523 ◽  
pp. 2806-2811
Author(s):  
Wen Juan Jia ◽  
Ying Yan ◽  
Ying Su ◽  
Ming Da Liu
Keyword(s):  
Spatial Distribution ◽  
Agricultural Soil ◽  
Agricultural Soils ◽  
Geoaccumulation Index ◽  
Pollution Index ◽  
Average Concentration ◽  
Soil Samples ◽  
Soil Environment ◽  
Index Method

To identify the concentration and spatial distribution of cadmium (Cd) in agricultural soils, 207 soil samples were collected from Chaoyang and analyzed based on pollution index methods and GIS. The concentration of Cd in the soils of Chaoyang ranged from 0.030 to 0.687 mg/kg, with an average concentration of 0.246 mg/kg. The evaluated results of Cd in agricultural soils of Chaoyang shows that the pollution excess rate is 2.90%, the total agricultural soil environment of Cd was still clean, but some areas were accumulated by Cd. The differences between two evaluated methods indicate that evaluated criteria had a direct impact on the evaluation results, compared to integrated pollution index, the Geoaccumulation index method was more accurate and objective.

Sign in / Sign up

Export Citation Format

Share Document