Number Of Soil Microorganisms Research Articles

Bioremediation of Oil-Contaminated Soils of South Kazakhstan

In a weakly or moderately polluted with oil (0.3-1.0%) the total number of soil microorganisms, including hydrocarbon-oxidizing, you can improve cultural practices (tillage, irrigation, fertilization) without making out of hydrocarbon-oxidizing microorganisms (HOM). In the arid zone is more expedient to begin bioremediation of oil-contaminated areas of work for the fall, to use autumn and spring soil moisture for mineralization activity of microorganisms.

INFLUENCE OF SEWAGE SLUDGE ON THE CHOSEN SOIL PROPERTIES AND MICROBIOLOGICAL PARAMETERS OF URBAN GRASS MIXTURES RHIZOSPHERE

The aim of this study was to analyse the influence of municipal sewage sludge on selected microbiological parameters in the rhizosphere of lawn grass mixtures. Four experiments on the lawns along the main roads of Bialystok were founded. The factors in the experiment were three doses of sewage sludge (0 – control; 7.5 and 15 kg·m-2) and two grass mixtures (Eko and Roadside). The studied parameters were monitored twice during 2011 vegetation season by determining the total number of soil microorganisms, the total number of Gram-negative bacteria, the number of bacteria of Pseudomonas fluorescens species, the number of amylolytic and proteolytic bacteria. Sewage sludge amended to soil resulted in a change of physical-chemical properties of soil. The sewage sludge application to soil influenced significantly the number of proteolytic and Gram-negative bacteria.

Isolation and identification of phytate-degrading rhizobacteria with activity of improving growth of poplar and Masson pine

A number of soil microorganisms can convert insoluble forms of phosphorus (P) to an accessible form to increase plant yields. Phytate is such a large kind of insoluble organic phosphorus that plants cannot absorb directly in soil, so the objectives of this study were to isolate, screen phytate-degrading rhizobacteria (PDRB), and to select potential microbial inocula that could increase the P uptake by plants. In this study, a total of 24 soil samples were collected from natural habitats of eight poplar and pine planting areas from the eastern to southern China. 17 PDRB strains were preliminarily screened from the rhizosphere soil of poplars and pines by the visible decolorization in the phytate selective medium. The highest ratio of the total diameter (colony + halo zone) to the colony diameter of the isolates was JZ-GX1, 3.85. Afterward, 17 PDRB strains were further determined for their abilities to degrade sodium phytate based on the amount of liberated inorganic P in liquid phytate specific medium. The results showed that the phytase ability of the three highest PDRB strains: JZ-GX1, JZ-DZ1 and JZ-ZJ1 were up to 2.58, 2.36 and 2.24 U/mL, respectively, much better than most of the bacteria reported in previous studies. In the soil-plant experiment, compared to CK, the best three strains of PDRB all could significantly promote growth of poplar and Masson pine under container growing. The three efficient PDRB strains were identified as follow: JZ-GX1, Rahnella aquatilis, both JZ-DZ1 and JZ-ZJ1 being autofluorescent, Pseudomonas fluorescens, by 16S rDNA gene sequencing technology, Biolog Identification System and biological characterization. The present study suggests that the three screened PDRB strains would have great potential application as biological fertilizers in the future.

Soil response to chemicals used in a field experiment

Abstract The effect of chemicals (Reglone 200 SL and Elastiq 550 EC) on soil microorganisms and their enzymatic activity was estimated. The study was conducted in a field experiment which was set up in the split-block design and comprised three treatments. Soil samples were taken six times, twice in each year of study. The results showed that the application of chemicals generally had no negative effect on the number of soil microorganisms. The application of Reglone 200 SL caused an increase of proteolytic and ureolytic activity and affected the activity of dehydrogenases, acid and alkaline phosphatases in the soil. The soil subjected of Elastiq 550 EC was characterized by lower activity of dehydrogenases, protease, urease and alkaline phosphatase.

EFFECT OF FERTIGATION ON SOIL MICROBIOLOGICAL ACTIVITY AND PRODUCTIVITY OF APPLE ORCHARD

A field experiment was conducted at Fruit Research Institute Cacak (Serbia) to evaluate the influence of fertigation on development of soil microorganisms and production of apple ‘Gloster’, ‘Hapke Delicious’ and ‘Morens Jonagored’. The experiment involved three variants of treatment: high water-soluble mineral fertilizer NPK 16:8:32, high water-soluble mineral fertilizer NPK 12:0:43; microbiological fertilizer (inoculum on associative nitrogen-fixing bacteria, Klebsiella species). Unfertilized soil served as the control. Fertilizers were incorporated with Venturi Injector three times over the growing season. The effect of the applied fertigation measures on soil biological parameters was monitored by determining the number of soil microorganisms by indirect dilution methods of growing on adequate culture media. Of all the variants examined, the most stimulatory effect on development of soil microorganisms was expressed in fertigation treatment that involved microbiological fertilizer in all the examined cultivars. The results of the investigation suggest that incorporation of microorganisms contributes to more productive, nutrient-efficient and environmentally safe orchard management system.

Remediating abilities of different plant species grown in diesel-fuel-contaminated leached chernozem

The phytotoxicity and the possibility of phytoremediation of leached chernozem polluted with diesel fuel (1%) were studied by using eight plant species belonging to the Poaceae and Fabaceae genera. The diesel-fuel concentration in planted unfertilized and ammonium nitrate-supplemented soil was reduced 32–55% and 75–94%, respectively. The effect of phytoremediation was more distinct in unfertilized than in fertilized soil. Using correlation matrix analysis of the relationships between plant resistances to diesel fuel contamination, the number of soil microorganisms (including pollutant degraders) in planted soil, soil enzymatic and respiration activities, and pollutant removal, we found common regularities of phytoremediation of diesel fuel-contaminated leached chernozem for the tested plant species. In unfertilized soil, accumulation of plant biomass was a key point of pollutant removal. This occurred because plants were able to maintain the needed number and activity of hydrocarbon degraders in their root zones. In fertilized soil, the plant–pollutant–microbial interactions tended to intensify the metabolic activity of the soil biota, leading to a dramatic reduction in the hydrocarbon concentration in leached chernozem. At the same time, the relationships between plants and hydrocarbon-degrading microorganisms were not weakened by fertilization. Maize (Zea mays L.), sorghum (Sorghum bicolor L. Moench), and rye (Secale cereale L.) are recommended for use in the phytoremediation of diesel-fuel-contaminated leached chernozem.

Distributive Characteristics of Soil Microorganisms at Wetland on Mongolian Plateau in Inner Mongolia (E1483)

This research is to study the distributive characteristics of soil microorganisms at river wetland on Mongolian Plateau in Inner Mongolia. The results showed that the quantities distribution of various floras of soil microorganisms in different plots (such as bump-top and in-between-bumps in enclosed and grazing regions, low floodplain and high floodplain) at wetland of the Xilin River are the same, which is bacteria＞actinomycetes＞fungi.In enclosed region, the amounts of bacteria are higher than that of other regions. Since is under natural restoration process in enclosed region, there is no significant difference between bump-top and in-between-bumps. At bump-top, it is seasonally flooded, and at in-between-bumps, there is always ponded water to cause high water content. Since high water content is not in favor to the survival of actinomycetes, the number of actinomycetes at bump-top is higher than that at in-between-bumps. Though there is low requirement of water for fungi, the number of fungi at bump-top is higher than that at in-between-bumps. In grazing region, there are more soil microorganisms at bump-top due to shorter flooded time and better air ventilation. At bump-top, organic matter is much richer, due to resupplied from animal manure, withered grass and falling leaves, which is in favor to the reproduction of actinomycetes and fungi. Since there are mostly hydrophilic plants and less biodiversity at in-between-bumps, the number of soil microorganisms is smaller. In floodplain region, the amount of bacteria at low floodplain is higher than that at high floodplain, due to higher water content, which is in favor to the reproduction of bacteria. Actinomycetes are basophilic bacteria. The amount of actinomycetes at low floodplain is higher than that at high floodplain, since high water content has led low floodplain to alkali soil. The amount of fungi at high floodplain is higher due to more suitable environment for survival and reproduction.

The Distributive Characteristics of Soil Microorganisms at Dry Lake Wetland on Semiarid Grassland

This research investigated the distributive characteristics of soil microorganisms at dry lake wetland on semiarid grassland. Four plots, typical steppe (DT), lake side (HB), lake bed (HD), and lake center (HX), were selected from Huitengxile located in semiarid grassland to conducted this investigation. The results showed that the number of aerobic bacteria at DT is 1.07 times that at HB, 1.14 times that at HX, and 1.45 times that at HD. The number of fungi at DT is 3.81 times that at HD, 10.65 times that at HB, and 25.75 times that at HX. There is significant difference between HX, HB and the other two plots (p<0.05). Also, there is significant difference between HD and DT. The number of Spore-forming bacteria at DT is 1.65 times that at HD, 2.15 times that at HB, and 6.35 times that at HX. There is significant difference between HD, HB and the other two plots, as well. The number of actinomycetes at HB is highest which is 2.12 times that at HD, 2.27 times that at DT, and 3.43 times that at HX. Moreover, there is a distinct feature of transverse distribution for soil microorganisms communities at dry lake wetland on semiarid grassland. Excluding actinomycetes, the number of soil microorganisms at dry lake wetland were both lower than that at typical steppe. There is a significant correlation between the total amount of soil microorganisms and microbial biomass C at dry lake wetland. These results can be used as the theoretical foundation for the restoration of degraded lake wetland, and the exploitation and utilization of wetland microbial resources.

Polynuclear aromatic hydrocarbons (PAHs) mediate cadmium toxicity to an emergent wetland species

Growth and pollutant removal by emergent wetland plants may be influenced by interactions among mixed pollutants in constructed wetlands. A glasshouse experiment was conducted to investigate interactive effects of cadmium (Cd) × polynuclear aromatic hydrocarbons (PAHs) × plant treatments on growth of Juncus subsecundus, Cd and PAH removal from soil and the total number of microorganisms in soil. Growth and biomass of J. subsecundus were significantly influenced by interaction of Cd and PAHs, significantly decreasing with either Cd or PAH additions, but with the effect of Cd on plant growth being stronger than that of PAHs. The mixture of low Cd and low PAH lessened Cd toxicity to plants, resulting in improved plant growth and increased Cd accumulation in plant tissues, thus enhancing Cd removal by plants. The dissipation of PAHs in soils was significantly influenced by interactions of Cd, PAH and plant presence or absence. The total number of microorganisms in soils was significantly increased by the PAH additions. The interactive effect of Cd and PAHs on plant growth may be linked to the changes in the abundance of microorganisms in the rhizosphere, probably via a positive effect of PAH metabolites and/or phytohormones produced by microorganisms on plant growth.

Overcoming of soil contamination with pesticides in forest nurseries using the activity of microorganisms

The use of pesticides during cultivation of pine seedlings in forest nurseries results in the formation two phenotypes of teratomorph seedlings - conditionally normal and abnormal. Growing forest cultures from teratomorph seedlings leads to their low survival rate. It is known that pesticides and their metabolic products can remain in soil for many years. It is therefore impossible to rely only on natural degradation of pesticides in soil. A promising way of removing pesticides from soil is their microbiological decomposition. This method is preferable because there is a meliorative organic substance not far from forest nurseries - i.e. forest litter rich in microorganisms. The purpose of these experiments was to examine the influence of forest litter applied on pesticide decomposition in soil and morphology of pine seedlings. The rates of forest litter that were most effective in decomposition of pesticides and the activity of microbial communities in litter, depending on forest stand structure, were determined. Estimation of that action was based on the morphology of seedlings (rate of pine seedlings with normal, conditionally normal and abnormal phenotypes), intensity of CO2 emission from soil and catalase activity, which correlates with the number of soil microorganisms. The results of these experiments showed the most effective activity of forest litter at the application rate of 20 kg/m2. The number of seedlings with normal phenotype rose from 32% up to 40%. Besides, it was noted that saprophytes were most effective in pine forest litter, which is characterized by a more acid reaction of soil solution, while most others were rich in fungi. The highest number of normal phenotype seedlings, intensity of CO2 emission and activity of soil catalase were correlated with the microbiological activity of the applied pine forest litter.

Effect of multipurpose compost on economically valuable celery traits and soil microbiocenosis

The complex effect of multipurpose compost (MPC) on the system soil-associative microflora-plant, increasing the numbers of soil microorganisms, their enzymatic activity, and NPK content and promoting an increase of celery yield by 1.5–2 times, is revealed. In this case, the content of nitrates in organs is within the limits of the maximum allow concentration.

Soil microbial activity measured by microcalorimetry in response to long-term fertilization regimes and available phosphorous on heat evolution

Microcalorimetric technique was used to investigate the effects of balanced versus nutrient-deficiency fertilization on soil microbial activity in a long-term (19-year) fertilizer experiment. The number of microorganisms in soils was measured by viable cell count, and the power-time curves were recorded for soil samples supplemented with glucose and ammonium sulphate, also with or without sodium dihydrogen phosphate for P-deficiency fertilization. Both the bacterial and the fungal populations were significantly higher ( P < 0.05) under balanced fertilization than under nutrient-deficiency fertilization. The microbial activity presented by heat dissipation per cell unit indicated that microorganisms under balanced fertilizer treatments had more efficient metabolism, while decreased microbial activity under nutrient-deficiency treatments was firstly due to soil available P, followed by N and K ( P < 0.05). In addition, microbial growth in soils under P-deficiency fertilization was stimulated by adding available P, while the lower growth rate, less peak heat, and longer peak time all indicated the low activity of soil microorganisms. We emphasize the importance of balanced fertilization, as well as the role of available P, in maintaining and promoting soil microbial activity.

Features of soil enzyme activities and the number of microorganisms in plantations and their relationships with soil nutrients in the Qinling Mountains, China

We studied the distribution of soil nutrients, the number of soil microorganisms, soil enzyme activities, and their relationships in pure and mixed plantations. Soil enzyme activities, the number of soil microorganisms, and soil nutrients were measured in plantations of Chinese pine (Pinustabulaeformis), larch (Larix kaempferi), sharp tooth oak (Quercus aliena var. acuteserrata), Manchurian catalpa (Catalpa fargesii), and mixed plantations in the Qinling Mountains, China. Compared with pure plantations, the conifer-broad-leaved broadleaf mixed plantations increased total N, available N, total P, available K, and organic matter in the forest soil; promoted the activities of invertase and urease by 16.7% and 53.8%; and increased the total amount of soil microorganisms by 95.9% and the number of bacteria by 104.5% (p<0.05). The correlations between soil enzymes, number of microorganisms, and soil nutrients were significant (p<0.05), and the correlations between the number of soil bacteria and basic nutrient prosperities (total N, available N, available K, and organic matter (OM)) were significant or highly significant. The correlations between the number of soil actinomycetes, and soil total N, available N, OM, and pH were also significant or highly significant. A suitable mixture of planted conifers and broad-leaved species improves the quality and amount of soil nutrients, increases the number of soil microorganisms and changes their redistribution. The change of soil enzymes and the number of soil microorganisms are indications of the change tendency of soil nutrients.

Effects of alternate partial root-zone irrigation on soil microorganism and maize growth

Partial root-zone irrigation creates a dynamic heterogeneous distribution of soil moisture that may affect the numbers and activities of soil microorganisms. In this study, three irrigation methods, i.e. conventional irrigation (CI), alternate partial root-zone irrigation (APRI, alternate watering on both sides of the pot) and fixed partial root-zone irrigation (FPRI, fixed watering on one side of the pot), and three watering levels, i.e. well-watered, mild and severe water deficit, were applied on pot-grown maize. Numbers of soil microorganisms, plant height, stalk diameter, leaf area and biomass accumulation were monitored over the treatment period. A quadratic parabola relationship between the number of soil microorganisms and soil water content was found, indicating the number of soil microorganisms reached a peak at the mild soil water deficit condition, possibly due to better soil aeration. The peak number of soil microorganism was obtained when soil water content was 66, 79 and 75% of field capacity for CI, FPRI and APRI, respectively. Soil microorganisms were evenly distributed in both sides of APRI and their total numbers were always higher than those under other two irrigation methods for the same soil water content. The count of soil microorganisms in the dry root zone of FPRI was reduced by a lack of water. Maximum biomass accumulation was obtained under well watered condition but severe water deficit led to a 50% reduction in the CI treatment. Such reduction was much smaller under APRI and therefore the highest water use efficiency was obtained. Our results suggest that APRI maintained the best aeration and moisture condition in the soil and enhanced the activities of soil microorganisms, which might also have benefited the plant growth.

Comparative characterization of microbial communities in kurgans, paleosols buried under them, and background surface soils in the steppe zone of the Lower Volga region

A comparative analysis of the state of microbial communities in kurgans, paleosols buried under them, and background surface soils in the dry steppe zone of the Lower Volga region has been performed. It is shown that the population density of microorganisms of various trophic groups in the kurgans is an order of magnitude lower than that in the A1 horizon of the corresponding buried paleosols and background surface soils within the areas of chestnut, light chestnut, and solonetzic soils. The respiration activity of the microbial communities in the upper layer of the kurgans is comparable with that in the A1 horizons of the background surface soils; it decreases in the deeper layers of the kurgans. In the A1 horizon of the buried paleosols, the respiration activity is approximately the same as in the deep layers of the kurgans. In the buried paleosols, the spatial variability in the numbers of soil microorganisms is approximately the same or somewhat higher than that in the background surface soils. The spatial variability in the respiration activity of the buried paleosols is two to four times higher than that in the background surface soils.

The impact of composts prepared from different organic waste on the total number of soil microorganisms

The impact of composts prepared from different organic waste on the total number of soil microorganisms In a two-factor pot experiment impact of two doses of six types of composts prepared from the municipal sewage sludge with an addition of canteen waste, wheat straw and cocoa husk on the total number of bacteria, actinomycetes and fungi in the soil were exmined. The light soil used in the experiment was taken from the Ap level of an arable field. On all the objects with composts there was mineral NPK fertilization applied, the control object was fertilized with the NPK only. The test plant was grass Festulolium which was harvested three times and after the third cut the samples of the soil were taken for microbiological analyses. The conducted research shows that the number of microorganisms in soil was dependent on the dose and the type of the compost. The second dose of the compost, in comparison with the control object, in most composts considerably increased the number of bacteria and the first dose increased the number of actinomycetes. However, the number of fungi, in most cases, with both doses of composts, was lower than in the soil from the control object. The highest number of bacteria was noticed on the object with the co-most prepared from 35% sewage sludge + 35% canteen waste + 30% straw and actinomycetes on the object with the compost prepared from 35% sewage sludge + 35% canteen waste + 30% cocoa husk. The development of the soil fungi was restrained in the highest degree by the first dose of the compost prepared from 35% sewage sludge + 35% canteen waste + 15% straw + 15% cocoa husk and by the second dose of the compost prepared from 70% sewage sludge + 30% straw.

Influence of agricultural practices on soil microbial activity measured by microcalorimetry

To investigate the influence of different agricultural practices and vegetations on soil microbial activity and diversity, soil samples from different habitats were studied with their microbial activities measured by the microcalorimetric technique. Seven soil samples were collected in Wuhan, China from different locations with primary and regeneration forest, nursery and crop land, and uncultivated land. The number of microorganisms in soils was measured by viable count, and some physicochemical parameters were determined. Power–time curves were recorded for soil samples supplemented with glucose and ammonium sulphate, and the total heat changes of the microbial growth reaction, Q total (Jg −1) and the microbial growth rate constant, k (min −1) were calculated from the curves. All power–time curves presented typical changes of microbial activity. The curves of soil samples could be divided into two groups differing in agricultural practices and vegetations. The same grouping could also be reached according to the values of peak time ( t max). The most soil samples showed a higher correlation between the values of k and the counted bacterial numbers. The Q total correlated well with vegetation abundance and probably with microbial diversity. In conclusion, microbial activity of the soil samples determined by microcalorimetry reflected differences in soil vegetation and agricultural management.

The influence of topography on the spatial distribution of fertility indices in an ameliorated agrolandscape in the area of terminal moraines

The effect of geomorphic conditions on the morphological, chemical, and physical properties; the biochemical activity; and the distribution of soil microorganisms in the plow horizon of ameliorated swampy podzolic soils has been studied along the catena on a gentle slope of the northeastern aspect of a moraine hill. The indices of soil fertility gradually improve from the top of the hill to the adjacent hollow. In this direction, the soil acidity becomes weaker under the impact of liming, the soil texture becomes somewhat heavier, and the contents of humus and the major nutrients increase in parallel with the increase in the number of soil microorganisms and their enzymatic activity.

Effects of Plant Species on CH4 and N2O Fluxes from a Volcanic Grassland Soil in Nasu, Japan

To investigate the effects of plant species in grassland on methane (CH4) and nitrous oxide (N2O) fluxes from soil, fluxes from an orchardgrass (Dactylis glomerata L.) grassland, white clover (Trifolium repens L.) grassland and orchardgrass/white clover mixed grassland were measured weekly from April 2001 to March 2002 using a vented closed chamber method. Related environmental parameters (soil inorganic N content, soil pH (H2O) value, soil moisture content, soil temperature, grass yield, and the number of soil microorganisms) were also regularly monitored. On an annual basis, CH4 consumption in the soil of the orchardgrass grassland, white clover grassland and orchardgrass/white clover mixed grassland was 1.8, 2.4, and 1.8 kg C ha−1 year−1, respectively. The soil bulk density of the white clover grassland was lower than that of the other grasslands. Fluxes of CH4 were positively correlated with the soil moisture content. White clover increased the CH4 consumption by improving soil aeration. Nitrogen supply to the soil by white clover did not decrease the CH4 consumption in the soil of our grasslands. On the other hand, annual N2O emissions from the orchardgrass grassland, white clover grassland, and orchardgrass/white clover mixed grassland were 0.39, 1.59, and 0.67 kg N ha−1 year−1, respectively. Fluxes of N2O were correlated with the NO3 − content in soil and soil temperature. White clover increased the N2O emissions by increasing the inorganic N content derived from degrading white clover in soil in summer.

Reduction of potato scab and verticillium wilt with ammonium lignosulfonate soil amendment in four Ontario potato fields

Single applications of ammonium lignosulfonate (ALS, ca. 6 t solids/ha) were made at four commercial potato fields in Ontario (sites K, V, W, and G in 1998, 1999, 2000, and 2000, respectively). Potato tubers were planted 2-4 weeks after ALS incorporation. The effects on potato scab, verticillium wilt, tuber yield, soil chemistry, and soil microbiology were determined in the year of application, and for a second crop at sites K (1999), V (2000), and G (2001). Potato scab severity was significantly reduced (50-80%) by ALS treatment in the year of application at all sites. Significantly less scab was present for the second crop at sites K and G. The incidence of Verticillium dahliae infected plants was also significantly decreased (40-50%) by ALS treatment at all sites in the year of application and for the second crop at site K. Ammonium lignosulfonate significantly increased total tuber yield by 2.5 times at site G in 2000. There was no effect on tuber yield at the other sites. However, marketable yield (tubers with <5% surface scab) was significantly increased three- to seven-fold over the control plots at all sites in the year of application. Although marketable yield was consistently higher in subsequent crops at all sites, it was only statistically significant at site G. Soil pH was immediately reduced following application of ALS by 0.4-0.6 units at all sites except site W, where it had no effect. Soil pH returned to control levels by the second season at all sites except site G, which remained one log unit lower than the control treatment. Numbers of soil microorganisms increased two- to eight-fold at all sites within weeks of ALS application. Fungal numbers increased the most and remained elevated for two seasons at site K compared with control plots. The results of this study clearly demonstrate that use of ALS as a soil amendment can significantly reduce the severity of potato scab and verticillium wilt in potato crops.