Cold storage and laboratory incubation of intact soil cores do not reflect in-situ nitrogen cycling rates of tropical forest soils

2008 ◽  
Vol 40 (9) ◽  
pp. 2480-2483 ◽  
Author(s):  
Julia Arnold ◽  
Marife D. Corre ◽  
Edzo Veldkamp
Keyword(s):  
Tropical Forest ◽  
Nitrogen Cycling ◽  
Cold Storage ◽  
Forest Soils ◽  
Soil Cores ◽  
Laboratory Incubation ◽  
Intact Soil Cores ◽  
Intact Soil

Seasonal and site-specific variations in nitrogen fixation in a high arctic area, Ny-Ålesund, Spitsbergen

1997 ◽  
Vol 43 (8) ◽  
pp. 759-769 ◽  
Author(s):  
Turid Liengen ◽  
Rolf Arnt Olsen
Keyword(s):  
Nitrogen Fixation ◽  
C:N Ratio ◽  
High Arctic ◽  
Rapid Decline ◽  
Soil Cores ◽  
Nostoc Commune ◽  
In Situ Conditions ◽  
Intact Soil Cores ◽  
Intact Soil

Nitrogen fixation was measured in different habitats in the area of Ny-Ålesund, Spitsbergen, using the acetylene reduction method on intact soil cores and Nostoc commune growing in macroscopic sheet communities. The samples were incubated both under constant conditions (19 °C and 200 μE∙m−2∙s−1) and under in situ conditions. Cyanobacteria were considered to be the major nitrogen-fixing organisms. The nitrogen fixation rates showed a seasonal variation during the growing season of 1994, with low activities just after the snow melt, increasing until the middle of August and showing a rapid decline after the snow fell on August 29. The soil temperature at the time of sampling showed a positive, linear correlation with the nitrogen fixation activities measured on intact soil cores, whereas the nitrogen fixation activities measured in situ of N. commune showed a positive, linear dependence on the moisture content in the sheets and the incubation temperatures inside the incubation vessels during the experiments. The optimal temperature of the nitrogen fixation activity was about 20 °C, both for N. commune and a Puccinellia salt marsh. The highest nitrogen fixation rate measured in situ was at a patterned ground, which had the highest pH, the highest concentrations of extractable calcium and magnesium, and the highest C:N ratio measured.Key words: nitrogen fixation, cyanobacteria, Nostoc commune, high arctic.

Responses of Soil Microbes to Hydrological Perturbations in Tropical Forest Soils

2021 ◽  
Author(s):  
Stephany S Chacon ◽  
Aizah Khurram ◽  
Markus Bill ◽  
Hans Bechtel ◽  
Jana Voriskova ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Forest Soils ◽  
Climate Change Impacts ◽  
Cell Extracts ◽  
Microbial Response ◽  
Intact Soil Cores ◽  
Throughfall Exclusion ◽  
The Tropics ◽  
Meso Scale ◽  
Precipitation Cycles

<p>Model projections predict that climate change impacts on the tropics will include an increased frequency of drought and precipitation cycles. Such environmental fluctuations at the soil pore-scale play an important role in shaping microbial adaptive capacity, and trait composition of a community, which feeds back on to the breakdown and formation of soil organic matter (SOM). Understanding the factors controlling the carbon balance of humid tropical forest soils remains a social imperative. Microbial feedback to SOM pools is critical. Herein, we examine the microbial response to drought perturbations across  3 different, but complementary scales. At the largest scale, we explored the impacts of drought across a 1 m precipitation gradient spanning four sites from the Caribbean coast to the interior of Panama. At each site 4, throughfall exclusion plots (10 x 10 m) were established to reduce precipitation by 50 %. In addition, 4 corresponding control plots were also constructed. At the meso-scale, we incubated intact soil cores from one of these sites (P12) under 3 different hydrological treatments (control, drought, rewetting-drying cycles) for over a 5-month period. For the field and meso-scale experiments, we evaluated changes imparted by hydrological perturbations using multi-omic approaches, and physico-chemical measurements.   In order to identify the traits involved in response to drought at the field and meso-scale, we isolated a range of bacteria to subject to stress at the scale of the single-cell and simple communities.  Cell extracts were subjected to osmotic or matric stress and the short-term physiological responses determined using non-destructive synchrotron radiation-based Fourier Transform-Infrared spectromicroscopy. Through this approach, we identified changes in metabolic allocation within different cells, in particular to the secondary metabolome of the different bacteria. Our contribution will discuss the outcomes of these multi-scale experiments.  Specifically focusing on how shifts in the microbial community and physiological changes may influence tropical soil carbon stability under future scenarios of altered drought and precipitation cycles.</p>

scholarly journals Denitrification Rate and Its Potential to Predict Biogenic N2O Field Emissions in a Mediterranean Maize-Cropped Soil in Southern Italy

Land ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 97 ◽  
Author(s):  
Annachiara Forte ◽  
Angelo Fierro
Keyword(s):  
Pore Space ◽  
Denitrification Rate ◽  
Linear Functions ◽  
N2o Emissions ◽  
Soil Cores ◽  
High Soil ◽  
N2o Fluxes ◽  
Intact Soil Cores ◽  
Intact Soil ◽  
Soil Nitrates

The denitrification rate in C2H2-amended intact soil cores and soil N2O fluxes in closed static chambers were monitored in a Mediterranean irrigated maize-cropped field. The measurements were carried out during: (i) a standard fertilization management (SFM) activity and (ii) a manipulation experimental (ME) test on the effects of increased and reduced application rates of urea at the late fertilization. In the course of the SFM, the irrigations following early and late nitrogen fertilization led to pulses of denitrification rates (up to 1300 μg N2O-N m−2 h−1) and N2O fluxes (up to 320 μg N2O-N m−2 h−1), thanks to the combined action of high soil temperatures and not limiting nitrates and water filled pore space (WFPS). During the ME, high soil nitrates were noted in all the treatments in the first one month after the late fertilization, which promoted marked N-losses by microbial denitrification (from 500 to 1800 μg N2O-N m−2 h−1) every time the soil WFPS was not limiting. At similar maize yield responses to fertilizer treatments, this result suggested no competition for N between plant roots and soil microbial community and indicated a probable surplus of nitrogen fertilizer input at the investigated farm. Correlation and regression analyses (CRA) on the whole set of data showed significant relations between both the denitrification rates and the N2O fluxes with three soil physical-chemical parameters: nitrate concentration, WFPS and temperature. Specifically, the response functions of denitrification rate to soil nitrates, WFPS and temperature could be satisfactorily modelled according to simple Michaelis-Menten kinetic, exponential and linear functions, respectively. Furthermore, the CRA demonstrated a significant exponential relationship between N2O fluxes and denitrification and simple empirical functions to predict N2O emissions from the denitrification rate appeared more fitting (higher concordance correlation coefficient) than the predictive empirical algorithm based on soil nitrates, WFPS and temperature. In this regard, the empirically established relationships between the denitrification rate on intact soil cores under field conditions and the soil variables provided local-specific threshold values and coefficients which may effectively work to calibrate and adapt existing N2O process-based simulation models to the local pedo-climatic conditions.

Effects of Starch Encapsulation on Clomazone and Atrazine Movement in Soil and Clomazone Volatilization

Weed Science ◽  
1995 ◽  
Vol 43 (3) ◽  
pp. 445-453 ◽  
Author(s):  
Todd L. Mervosh ◽  
Edward W. Stoller ◽  
F. William Simmons ◽  
Timothy R. Ellsworth ◽  
Gerald K. Sims
Keyword(s):  
Unsaturated Flow ◽  
Soil Surface ◽  
Silty Clay ◽  
Silt Loam ◽  
Starch Granules ◽  
Soil Cores ◽  
Silty Clay Loam ◽  
Intact Soil Cores ◽  
Water Tension ◽  
Intact Soil

The effects of formulation on clomazone volatilization and transport through soil were studied. After 22 days of leaching under unsaturated flow in 49-cm long intact soil cores, greater clomazone movement was observed in Plainfield sand than in Cisne silt loam or Drummer silty clay loam soils. Soil clomazone concentrations resulting in injury to oats occurred throughout Plainfield soil cores but were restricted to the upper 14 cm of Cisne and Drummer soils. In addition, clomazone was detected in the leachate from Plainfield soil only. In a similar study with Plainfield sand cores, clomazone was less mobile than atrazine; encapsulation of the herbicides in starch granules did not affect clomazone movement but greatly decreased atrazine movement from the soil surface. Similarly, starch encapsulation did not affect bioavailability of clomazone but did reduce bioavailability of atrazine. In a laboratory study with continual air flow, volatilization of clomazone applied to the soil surface was reduced by encapsulation in starch and starch/clay granules. Clomazone volatilization was not affected by soil water content within a range of 33 to 1500 kPa water tension. Following soil saturation with water, clomazone volatilization from both liquid and granular formulations increased. Granule size appeared to have a greater impact than granule composition on clomazone volatilization.

scholarly journals Leaching of Cryptosporidium parvum Oocysts, Escherichia coli, and a Salmonella enterica Serovar Typhimurium Bacteriophage through Intact Soil Cores following Surface Application and Injection of Slurry

2011 ◽  
Vol 77 (22) ◽  
pp. 8129-8138 ◽  
Author(s):  
Anita Forslund ◽  
Bo Markussen ◽  
Lise Toenner-Klank ◽  
Tina B. Bech ◽  
Ole Stig Jacobsen ◽  
...  
Keyword(s):  
Cryptosporidium Parvum ◽  
Pore Volume ◽  
Relative Concentration ◽  
Weather Conditions ◽  
Soil Cores ◽  
Content Type ◽  
E Coli ◽  
Serovar Typhimurium ◽  
Intact Soil Cores ◽  
Intact Soil

ABSTRACTIncreasing amounts of livestock manure are being applied to agricultural soil, but it is unknown to what extent this may be associated with contamination of aquatic recipients and groundwater if microorganisms are transported through the soil under natural weather conditions. The objective of this study was therefore to evaluate how injection and surface application of pig slurry on intact sandy clay loam soil cores influenced the leaching ofSalmonella entericaserovar Typhimurium bacteriophage 28B,Escherichia coli, andCryptosporidium parvumoocysts. All three microbial tracers were detected in the leachate on day 1, and the highest relative concentration was detected on the fourth day (0.1 pore volume). Although the concentration of the phage 28B declined over time, the phage was still found in leachate at day 148.C. parvumoocysts and chloride had an additional rise in the relative concentration at a 0.5 pore volume, corresponding to the exchange of the total pore volume. The leaching ofE. coliwas delayed compared with that of the added microbial tracers, indicating a stronger attachment to slurry particles, butE. colicould be detected up to 3 months. Significantly enhanced leaching of phage 28B and oocysts by the injection method was seen, whereas leaching of the indigenousE. coliwas not affected by the application method. Preferential flow was the primary transport vehicle, and the diameter of the fractures in the intact soil cores facilitated transport of all sizes of microbial tracers under natural weather conditions.

Sign in / Sign up

Export Citation Format

Share Document