Measurement of bacterial and fungal contributions to respiration of selected agricultural and forest soils

1975 ◽  
Vol 21 (3) ◽  
pp. 314-322 ◽  
Author(s):  
J. P. E. Anderson ◽  
K. H. Domsch
Keyword(s):  
Forest Soils ◽  
Agricultural Soils ◽  
Selective Inhibitors ◽  
Average Ratio ◽  
Incubation Periods ◽  
Pure Cultures ◽  
Inhibitor Selectivity ◽  
Fungal Populations ◽  
Litter Sample

A technique using selective inhibitors was used to estimate the relative contributions of bacterial and fungal populations to the respiration of six soils and one litter sample. The ratios of bacterial to fungal respiration in the four agricultural soils, given in percentage of the total microbial activity, ranged from 10/90 to 35/65, with the average ratio being about 30/70. In the forest soils, the ratios were 20/80 and 30/70, and in a beech litter sample, the ratio was 40/60. The fungi clearly dominated in all samples. The ratios were not found to be pH related. The difficulties which had previously limited the use of selective inhibitors for in situ soil ecological investigations, such as insufficient inhibitor specificity, inhibitor inactivation or degradation, and errors of measurement caused by elimination of competitor populations, were either resolved or methodologically avoided in the experiments. Inhibitor selectivity was demonstrated using both mixed and pure cultures of microorganisms from each soil. Through the use of experiments with short incubation periods (6–8 h), problems with population shifts and inhibitor degradation were eliminated.

Annual denitrification rates in agricultural and forest soils: a review

Soil Research ◽  
1999 ◽  
Vol 37 (6) ◽  
pp. 1073 ◽  
Author(s):  
L. Barton ◽  
C. D. A. McLay ◽  
L. A. Schipper ◽  
C. T. Smith
Keyword(s):  
Forest Soils ◽  
Large Range ◽  
Agricultural Soils ◽  
Site Management ◽  
Pilot Studies ◽  
The Past ◽  
Sampling Protocols ◽  
Soil Site ◽  
Soil Process

Denitrification is an important soil process for assessing nitrogen cycling and controlling nitrogen pollution in the environment. Numerous studies of denitrification rates in soils have been reported over the last decade, many with sampling protocols that are more reliable than in the past. In this paper, we review denitrification rates for agricultural and forest soils that have been reported in the literature, discuss factors that appear to be important in controlling the amount of denitrification that occurs in these soils, and summarise modelling approaches that have been used to predict annual denitrification rates. Most studies of in situ denitrification in upland soils have been conducted in agricultural grassland and forest ecosystems, with a paucity of studies reported from other ecosystems. A large range of annual, in situ, denitrification rates have been reported (0–239 kg N/ha.year), with the highest rates typically occurring in irrigated, nitrogen-fertilised soils. However, most annual denitrification rates reported in the literature appear to be fairly low, with over half of the rates in forest soils being <1 kg N/ha.year (mean of 1.9 kg N/ha.year). Rates of denitrification in agricultural soils tend to be higher than in forest soils, with 85% of rates reported being >1 kg N/ha.year, and a mean rate of 13 kg N/ha.year. Numerous soil, site, and management factors have been reported to affect the denitrification process in situ. The literature indicates that the highest rates of denitrification can be expected in nitrogen-fertilised soils, or where site management increases soil nitrate availability. Where nitrate is non-limiting, denitrification rates appear to be highest in irrigated loam soils. The review suggests that it is difficult to predict denitrification rates based on our current understanding, and that pilot studies should still be conducted if soil nitrogen balances are required.

scholarly journals Retention of the Antibiotic Cefuroxime onto Agricultural and Forest Soils

2021 ◽  
Vol 11 (10) ◽  
pp. 4663
Author(s):  
Raquel Cela-Dablanca ◽  
Carolina Nebot ◽  
Lucia Rodríguez López ◽  
David Ferández-Calviño ◽  
Manuel Arias-Estévez ◽  
...  
Keyword(s):  
Forest Soils ◽  
Linear Models ◽  
Agricultural Soils ◽  
Organic Matter Content ◽  
Matter Content ◽  
Batch Type ◽  
Exchangeable Ca ◽  
Influence Of Ph ◽  
Best Fit ◽  
Soil Colloids

Antibiotics in wastewater, sewage sludge, manures, and slurries constitute a risk for the environment when spread on soils. This work studies the adsorption and desorption of the antibiotic cefuroxime (CFX) in 23 agricultural and forest soils, using batch-type experiments. Our results show that the adsorption values were between 40.75 and 99.57% in the agricultural soils, while the range was lower (from 74.57 to 93.46%) in forest soils. Among the Freundlich, Langmuir, and Linear models, the Freundlich equation shows the best fit for the adsorption results. In addition, agricultural soils with higher pH are the ones that present the highest adsorption. Further confirmation of the influence of pH on adsorption is given by the fact that Freundlich’s KF parameter and the Linear model Kd parameter shows a positive correlation with pH and with the exchangeable Ca and Mg values, which are known to affect the charges of the soil colloids and the formation of cationic bridges between adsorbents and adsorbate. In addition, Freundlich’s n parameter shows a positive and significant correlation with the organic matter content, related to the high adsorption taking place on forest soils despite their pH < 5. Regarding desorption, in most cases, it is lower than 1%, which indicates that CFX is adsorbed in a rather irreversible way onto these soils. Overall, these results can be considered relevant regarding their potential impact on environmental quality and public health.

A method for linking in situ activities of hydrolytic enzymes to associated organisms in forest soils

2007 ◽  
Vol 39 (9) ◽  
pp. 2414-2419 ◽  
Author(s):  
Shufu Dong ◽  
Denise Brooks ◽  
Melanie D. Jones ◽  
Susan J. Grayston
Keyword(s):  
Forest Soils ◽  
Hydrolytic Enzymes

scholarly journals Soil organic carbon in northern Spain (Galicia, Asturias, Cantabria and País Vasco)

2015 ◽  
Vol 5 ◽  
Author(s):  
Elías Luis Calvo ◽  
Francisco Casás Sabarís ◽  
Juan Manuel Galiñanes Costa ◽  
Natividad Matilla Mosquera ◽  
Felipe Macías Vázquez ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Forest Soils ◽  
Agricultural Soils ◽  
Calcareous Soils ◽  
Mean Annual Precipitation ◽  
Moisture Regime ◽  
Organic Carbon Content ◽  
Northern Spain ◽  
Pais Vasco

The soil organic carbon content was analyzed in more than 7 000 soil samples under different land uses, climates and lithologies from northern Spain (Galicia, Asturias, Cantábria y País Vasco). GIS maps (1:50 000) were made of the % SOC and SOC stocks. The % SOC varies according to land use (higher in forest and scrub soils and lower in agricultural soils) and climate, and there is a highly significant correlation between SOC content and mean annual precipitation. There are significant differences between the soils of Galicia/Western Asturias (GA<sub>w</sub>) and those of the rest of the study area (Central and Eastern Asturias, Cantabria and País Vasco) (A<sub>ce</sub>CV), although these are neighbouring regions. In forest and/or scrub soils with a <em>udic</em> soil moisture regime, in GA<sub>w</sub>, the SOC is usually &gt; 7% and the average stocks 260 t ha<sup> -1</sup> (0-30 cm), and &gt;340 t ha<sup>-1</sup> (0-50 cm) in soils with thick organic matter rich horizons (&gt; 40 cm); these values greatly exceed the average contents observed in forest soils from temperate zones. Under similar conditions of vegetation and climate in soils of A<sub>ce</sub>CV the SOC average is 3% and the mean stocks 90-100 t ha<sup>-1</sup> (0-30 cm). The <em>andic</em> character of acid forest soils in GA<sub>w</sub> and the formation of C-Al,Fe complexes are pointed out as the SOC stabilization mechanism, in contrast to the neutral and calcareous soils that predominate in A<sub>ce</sub>CV, where the main species of OC are easily biodegradable.

Effective carbon sequestration in Italian agricultural soils by in situ polymerization of soil organic matter under biomimetic photocatalysis

2018 ◽  
Vol 29 (3) ◽  
pp. 485-494 ◽  
Author(s):  
Alessandro Piccolo ◽  
Riccardo Spaccini ◽  
Vincenza Cozzolino ◽  
Assunta Nuzzo ◽  
Marios Drosos ◽  
...  
Keyword(s):  
Organic Matter ◽  
Carbon Sequestration ◽  
Soil Organic Matter ◽  
In Situ Polymerization ◽  
Agricultural Soils

Annihilation Behaviors of Athermal ω-Phase Crystals Due to Electron Irradiation

2000 ◽  
Vol 6 (4) ◽  
pp. 362-367 ◽  
Author(s):  
Hajime Matsumoto ◽  
Eiichi Sukedai ◽  
Hatsujiro Hashimoto
Keyword(s):  
Electron Beam ◽  
Electron Irradiation ◽  
Beam Current ◽  
Dark Field ◽  
Electron Beam Current ◽  
Ω Phase ◽  
Observation Methods ◽  
Incubation Periods ◽  
Beam Currents

AbstractAnnihilation behaviors of athermal ω-phase crystals formed by cooling at 131 K for 10.8 ks under four different electron irradiation conditions of acceleration voltages of 200 kV and 160 kV, and beam currents of approximately 20 pA/cm2 and 5 pA/cm2 were investigated using in situ dark field and HREM observation methods at 131 K. The effect of acceleration voltages on the lifetimes is recognized, i.e., in the case of approximately equal electron beam current, lifetimes at 200 kV become shorter than those at 160 kV. Also, lifetimes depend on the electron beam current at 200 kV, i.e., the higher the beam currents, the shorter the lifetimes become. However, no distinct dependence can be seen at 160 kV. Since annihilations of athermal ω-phase crystals begin after the electron irradiation for a certain period in each condition, which depends on acceleration voltages and beam currents, it is suggested that the annihilation behaviors have incubation periods.

In situ gross nitrogen transformations differ between temperate deciduous and coniferous forest soils

2011 ◽  
Vol 108 (1-3) ◽  
pp. 259-277 ◽  
Author(s):  
Jeroen Staelens ◽  
Tobias Rütting ◽  
Dries Huygens ◽  
An De Schrijver ◽  
Christoph Müller ◽  
...  
Keyword(s):  
Forest Soils ◽  
Coniferous Forest ◽  
Nitrogen Transformations ◽  
Temperate Deciduous

scholarly journals In Situ Phylogenetic Structure and Diversity of Wild Bradyrhizobium Communities

2009 ◽  
Vol 75 (14) ◽  
pp. 4727-4735 ◽  
Author(s):  
J. L. Sachs ◽  
S. W. Kembel ◽  
A. H. Lau ◽  
E. L. Simms
Keyword(s):  
Host Species ◽  
Root Surface ◽  
Small Subset ◽  
Root Tips ◽  
Phylogenetic Structure ◽  
Pure Cultures ◽  
Nodulation Status ◽  
Host Infection ◽  
Root Surfaces

ABSTRACTBacteria often infect their hosts from environmental sources, but little is known about how environmental and host-infecting populations are related. Here, phylogenetic clustering and diversity were investigated in a natural community of rhizobial bacteria from the genusBradyrhizobium. These bacteria live in the soil and also form beneficial root nodule symbioses with legumes, including those in the genusLotus. Two hundred eighty pure cultures ofBradyrhizobiumbacteria were isolated and genotyped from wild hosts, includingLotus angustissimus,Lotus heermannii,Lotus micranthus, andLotus strigosus. Bacteria were cultured directly from symbiotic nodules and from two microenvironments on the soil-root interface: root tips and mature (old) root surfaces. Bayesian phylogenies ofBradyrhizobiumisolates were reconstructed using the internal transcribed spacer (ITS), and the structure of phylogenetic relatedness among bacteria was examined by host species and microenvironment. Inoculation assays were performed to confirm the nodulation status of a subset of isolates. Most recovered rhizobial genotypes were unique and found only in root surface communities, where little bacterial population genetic structure was detected among hosts. Conversely, most nodule isolates could be classified into several related, hyper-abundant genotypes that were phylogenetically clustered within host species. This pattern suggests that host infection provides ample rewards to symbiotic bacteria but that host specificity can strongly structure only a small subset of the rhizobial community.

Substrate uptake by Gordonia amarae in activated sludge foams by FISH-MAR

2006 ◽  
Vol 54 (1) ◽  
pp. 39-45 ◽  
Author(s):  
E.L. Carr ◽  
K.L. Eales ◽  
R.J. Seviour
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Carbon Sources ◽  
Mycolic Acid ◽  
Substrate Uptake ◽  
Wastewater Treatment Process ◽  
Pure Cultures ◽  
Gordonia Amarae

Gordonia amarae is a right-angled branching filament belonging to the mycolic acid-containing Actinobacteria which is commonly found in many foaming activated sludge wastewater treatment plants. Although studies on different substrates as sole carbon sources by pure cultures of G. amarae have been carried out, none have examined substrate uptake by this organism in situ. Uptake of several hydrophilic and hydrophobic substrates by G. amarae was evaluated in situ using a combination of fluorescence in situ hybridization and microautoradiography. G. amarae could assimilate a range of both hydrophilic and hydrophobic substrates. From the data, G. amarae appears to be physiologically active under aerobic, anaerobic and anoxic condition (NO2 and NO3) for some substrates. This might explain why attempts to control foaming caused by G. amarae using anoxic and anaerobic selectors have been unsuccessful. This study emphasizes that bacteria can behave differently in situ to pure cultures and that it is important to evaluate the in situ physiology of these bacteria if we are to better understand their role in the wastewater treatment process.

scholarly journals Comparison of Six Commercially Available Transport Media for Maintenance of Serpulina (Treponema) Hyodysenteriae

1992 ◽  
Vol 4 (3) ◽  
pp. 285-292 ◽  
Author(s):  
G. E. Duhamel ◽  
R. J. Bernard ◽  
M. R. Mathiesen ◽  
K. M. Eskridge
Keyword(s):  
Pure Culture ◽  
Selective Medium ◽  
Fecal Flora ◽  
Transport Medium ◽  
Selective Transport ◽  
Incubation Periods ◽  
Pure Cultures ◽  
Treponema Hyodysenteriae ◽  
Better Than ◽  
Anaerobic Media

Two anaerobic (A1 and A2), 1 selective (S1), and 3 conventional (C1, C2, and C3) transport media formulations were compared for their capacity to maintain the viability of Serpulina (Treponema) hyodysenteriae. Initial experiments compared the recovery of S. hyodysenteriae from pure cultures held in each transport medium for 0.5, 1, 2, 3, 5, and 7 days at −40 C, 4 C, 25 C, and 36 C. Subsequent experiments compared each transport medium for maintenance of S. hyodysenteriae in fecal specimens obtained from experimentally infected pigs after holding for up to 7 days at 25 C. In each experiment, the viability of S. hyodysenteriae in each transport medium incubated at each temperature and for each period was determined by inoculating the transport medium onto either trypticase soy agar with 5% sheep blood or selective BJ agar and incubating at 42 C anaerobically. Viability and fecal flora contamination were evaluated blindly after 2-, 4-, and 6-day incubation periods. At −40 C, recovery of viable S. hyodysenteriae from pure culture did not differ among the transport media from 0.5 to 7 days, and all of the transport media consistently maintained the viability of the spirochetes for 7 days. At 4 C, the anaerobic and selective transport media maintained the viability of pure cultures of S. hyodysenteriae significantly better than did the conventional transport media group at day 7 ( P = 0.019). At the same temperature, the anaerobic media maintained viability better than did the conventional media at 5 days ( P < 0.042). At 25 C, the anaerobic transport media were significantly better than the conventional transport media at maintaining the viability of pure cultures of the spirochetes at 2, 3, and 5 days ( P < 0.018) and were significantly better than the selective medium at 3 days (P = 0.012). At 36 C, the recovery of viable spirochetes was significantly better with the anaerobic transport media than with both the conventional media for days 2–7 ( P < 0.006) and the selective medium for days 3–7 ( P < 0.049). Fecal specimens held in transport media Al and C1, as a group, had significantly higher viability than those held in the other transport media formulations taken as a group at all incubation times, except 0.5 day ( P < 0.0046). Contamination of selective BJ medium by fecal flora was markedly higher after holding fecal specimens in conventional transport media than in anaerobic and selective transport media. In a dilution trial of a pure culture of spirochetes, transport media Al and A2 maintained the viability of 108 S. hyodysenteriae for 7 days; however, medium Al was 10–100-fold more effective than medium A2 when lower initial concentrations of spirochetes were sampled. In a dilution trial of a fecal specimen, medium Al maintained the viability of 101 spirochetes for 2.5 days compared with 103 with medium C1. Overall, media A1 and C1 were the most satisfactory transport media for recovery of viable S. hyodysenteriae from fecal specimens held at 25 C for up to 7 days.

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