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1

Iron oxyhydroxide mineralization on microbial extracellular polysaccharides  

E-print Network

Iron oxyhydroxide mineralization on microbial extracellular polysaccharides Clara S. Chan a Iron biominerals can form in neutral pH microaerophilic environments where microbes both catalyze iron, and high-resolution transmission electron microscopy (HRTEM). We focused on iron microbial mat samples from

2

The role of iron oxyhydroxides in phosphorus chemistry of some East Texas forest soils  

E-print Network

and citrate- dithionite (CD) and acid ammonium-oxalate (AAO) extractable P, Al, Fe, and Mn within the mineral soil upper 100 cm were determined. Colorimetric determination of AAO- and CD-extractable P by the molybdenum blue ascorbic acid method, without.................................................................................................................1 COLORIMETRIC DETERMINATION OF SOIL PHOSPHATE IN ACID AMMONIUM-OXALATE AND CITRATE-DITHIONITE SOIL EXTRACTS WITHOUT PREDIGESTION STEP .................................................................................4 Overview...

Hass, Amir

2006-10-30

3

Magnetic birefringence of iron oxyhydroxide nanoparticles stabilised by sucrose  

Microsoft Academic Search

Magnetically induced optical birefringence is used to investigate pharmaceutically important iron–sucrose aqueous suspensions. XRD and TEM measurements of the system of oxyhydroxide particles stabilised by sucrose have shown that this system contains iron oxyhydroxide in the form of 2–5nm particles. The mineral form of the iron-core is suggested to be akaganeite. Anisotropy of the optical polarizability and magnetic susceptibility of

M. Koralewski; M. Pochylski; J. Gierszewski

2011-01-01

4

Biogenic iron oxyhydroxide formation at mid-ocean ridge hydrothermal vents: Juan de Fuca Ridge  

E-print Network

Biogenic iron oxyhydroxide formation at mid-ocean ridge hydrothermal vents: Juan de Fuca Ridge in mid-ocean ridge (MOR) hydrothermal end-member fluids at concentrations ranging from 0.007 to 25 mmol seafloor incubations of sulfide mineral assemblages at the Main Endeavor Segment of the Juan de Fuca Ridge

5

Role of sol with iron oxyhydroxide/sodium dodecyl sulfate composites on Fenton oxidation of sorbed phenanthrene in sand.  

PubMed

In situ Fenton oxidation has been recently used to oxidize sorbed organic contaminants in soil. The objective of present contribution was to study the role of sodium dodecyl sulfate (SDS) as anionic surfactant and sol with iron oxyhydroxide/SDS for Fenton oxidation of sorbed phenanthrene in sand. The most effective experimental condition for phenanthrene oxidation was the Fenton-like reaction system with 0.35% H2O2, 30 mM SDS, and 4 mM FeCl2. The Fenton-like reactions under these experimental conditions resulted in the production and sustenance of a stable sol with iron oxyhydroxide/SDS composites over 24 h. The formation of iron oxyhydroxide/SDS composites resulted in stabilization of H2O2, and then the Fenton-like reactions were sustained over 24 h. Furthermore, the sol of iron oxyhydroxide/SDS composites gave suitable sites to sustain oxidations of dissolved phenanthrene over a prolonged reaction span, which is required for in situ chemical oxidation. PMID:23666072

Park, Joo-Yang; Kim, Jung-Hwan

2013-09-15

6

Adsorption of selenium by amorphous iron oxyhydroxide and manganese dioxide  

USGS Publications Warehouse

This work compares and models the adsorption of selenium and other anions on a neutral to alkaline surface (amorphous iron oxyhydroxide) and an acidic surface (manganese dioxide). Selenium adsorption on these oxides is examined as a function of pH, particle concentration, oxidation state, and competing anion concentration in order to assess how these factors might influence the mobility of selenium in the environment. The data indicate that 1. 1) amorphous iron oxyhydroxide has a greater affinity for selenium than manganese dioxide, 2. 2) selenite [Se(IV)] adsorption increases with decreasing pH and increasing particle concentration and is stronger than selenate [Se(VI)] adsorption on both oxides, and 3. 3) selenate does not adsorb on manganese dioxide. The relative affinity of selenate and selenite for the oxides and the lack of adsorption of selenate on a strongly acidic surface suggests that selenate forms outer-sphere complexes while selenite forms inner-sphere complexes with the surfaces. The data also indicate that the competition sequence of other anions with respect to selenite adsorption at pH 7.0 is phosphate > silicate > molybdate > fluoride > sulfate on amorphous iron oxyhydroxide and molybdate ??? phosphate > silicate > fluoride > sulfate on manganese dioxide. The adsorption of phosphate, molybdate, and silicate on these oxides as a function of pH indicates that the competition sequences reflect the relative affinities of these anions for the surfaces. The Triple Layer surface complexation model is used to provide a quantitative description of these observations and to assess the importance of surface site heterogeneity on anion adsorption. The modeling results suggest that selenite forms binuclear, innersphere complexes with amorphous iron oxyhydroxide and monodentate, inner-sphere complexes with manganese dioxide and that selenate forms outer-sphere, monodentate complexes with amorphous iron oxyhydroxide. The heterogeneity of the oxide surface sites is reflected in decreasing equilibrium constants for selenite with increasing adsorption density and both experimental observations and modeling results suggest that manganese dioxide has fewer sites of higher energy for selenite adsorption than amorphous iron oxyhydroxide. Modeling and interpreting the adsorption of phosphate, molybdate, and silicate on the oxides are made difficult by the lack of constraint in choosing surface species and the fact that equally good fits can be obtained with different surface species. Finally, predictions of anion competition using the model results from single adsorbate systems are not very successful because the model does not account for surface site heterogeneity. Selenite adsorption data from a multi-adsorbate system could be fit if the equilibrium constant for selenite is decreased with increasing anion adsorption density. ?? 1990.

Balistrieri, L. S.; Chao, T. T.

1990-01-01

7

Effect of Transport and Aging Processes on Metal Speciation in Iron Oxyhydroxide Aggregates, Tar Creek Superfund Site, Oklahoma  

NASA Astrophysics Data System (ADS)

Following the cessation of mining activity in the late 20th century, Tar Creek Superfund Site was left highly contaminated by Pb, Zn, and Cd. Tar Creek, which flows through the site and into the Neosho River, has been studied extensively because of its potential to transport metals from the mining site to downstream communities. Previous research identified aggregated iron oxyhydroxide material, which forms when mine seepage mixes with Tar Creek surface water, as a major transport vector of metals. Frequent flooding in Tar Creek deposits aggregates on downstream floodplains, where wetting and drying processes alter the speciation of iron and other metals. This study seeks to better quantify those changes and to determine how transport and aging affects the human and ecological health risk. Sequential extractions of aggregate samples collected from the creek demonstrate that Fe is present in both amorphous (10-35% of Fe extracted) and more crystalline (8-23% of Fe extracted) phases. Substantial portions of heavy metals sorb to amorphous iron oxyhydroxide phases (accounting for 10-30% of Pb and Zn extracted) but are not associated with more crystalline iron oxide phases (representing only 1% or less of the Pb and Zn extracted). Samples have a high organic matter content (18-25% mass loss on ignition), but only Fe was significantly extracted by the oxidizing step targeting organic matter (1-2% of Pb and Zn extracted, but 10-26% of Fe extracted). The majority of metals were extracted by the soluble or residual steps. If metals and organic matter inhibit transformation of amorphous iron oxyhydroxide material to nano and crystalline iron oxides, then a steady-state volume of amorphous iron oxyhydroxide material with a high total sorption capacity may exist within Tar Creek, enhancing the metal flux accommodated by this transport mechanism. Once transported downstream and deposited on floodplains, however, it is hypothesized that repeated changes in soil matrix composition and thermodynamic conditions could facilitate a transformation to more crystalline iron phases and increase metal bioavailability. While preliminary data from in-creek aggregates show no clear trend in mineralogical composition with downstream transport, only the furthest downstream samples have 2-line ferrihydrite in amounts detectable by XRD.

Estes, E. R.; Schaider, L. A.; Shine, J. P.; Brabander, D. J.

2010-12-01

8

Associations between iron oxyhydroxide nanoparticle growth and metal adsorption/structural incorporation  

SciTech Connect

The interaction of metal ions and oxyanions with nanoscale mineral phases has not yet been extensively studied despite the increased recognition of their prevalence in natural systems as a significant component of geomedia. A combination of macroscopic uptake studies to investigate the adsorption behavior of As(V), Cu(II), Hg(II), and Zn(II) onto nanoparticulate goethite ({alpha}-FeOOH) as a function of aging time at elevated temperature (75 C) and synchrotron-based X-ray studies to track changes in both the sorption mode and the rate of nanoparticle growth reveal the effects that uptake has on particle growth. Metal(loid) species which sorb quickly to the iron oxyhydroxide particles (As(V), Cu(II)) appear to passivate the particle surface, impeding the growth of the nanoparticles with progressive aging; in contrast, species that sorb more slowly (Hg(II), Zn(II)) have considerably less impact on particle growth. Progressive changes in the speciation of these particular metals with time suggest shifts in the mode of metal uptake with time, possibly indicating structural incorporation of the metal(loid) into the nanoparticle; this is supported by the continued increase in uptake concomitant with particle growth, implying that metal species may transform from surface-sorbed species to more structurally incorporated forms. This type of incorporation would have implications for the long-term fate and mobility of metals in contaminated regions, and affect the strategy for potential remediation/modeling efforts.

Kim, C.S.; Lentini, C.J.; Waychunas, G.A.

2008-09-15

9

Biogenic iron oxyhydroxide formation at mid-ocean ridge hydrothermal vents: Juan de Fuca Ridge  

SciTech Connect

Here we examine Fe speciation within Fe-encrusted biofilms formed during 2-month seafloor incubations of sulfide mineral assemblages at the Main Endeavor Segment of the Juan de Fuca Ridge. The biofilms were distributed heterogeneously across the surface of the incubated sulfide and composed primarily of particles with a twisted stalk morphology resembling those produced by some aerobic Fe-oxidizing microorganisms. Our objectives were to determine the form of biofilm-associated Fe, and identify the sulfide minerals associated with microbial growth. We used micro-focused synchrotron-radiation X-ray fluorescence mapping (mu XRF), X-ray absorption spectroscopy (mu EXAFS), and X-ray diffraction (mu XRD) in conjunction with focused ion beam (FIB) sectioning, and highresolution transmission electron microscopy (HRTEM). The chemical and mineralogical composition of an Fe-encrusted biofilm was queried at different spatial scales, and the spatial relationship between primary sulfide and secondary oxyhydroxide minerals was resolved. The Fe-encrusted biofilms formed preferentially at pyrrhotite-rich (Fe1-xS, 0<_ x<_ 0.2) regions of the incubated chimney sulfide. At the nanometer spatial scale, particles within the biofilm exhibiting lattice fringing and diffraction patterns consistent with 2-line ferrihydrite were identified infrequently. At the micron spatial scale, Fe mu EXAFS spectroscopy and mu XRD measurements indicate that the dominant form of biofilm Fe is a short-range ordered Fe oxyhydroxide characterized by pervasive edge-sharing Fe-O6 octahedral linkages. Double corner-sharing Fe-O6 linkages, which are common to Fe oxyhydroxide mineral structures of 2-line ferrihydrite, 6-line ferrihydrite, and goethite, were not detected in the biogenic iron oxyhydroxide (BIO). The suspended development of the BIO mineral structure is consistent with Fe(III) hydrolysis and polymerization in the presence of high concentrations of Fe-complexing ligands. We hypothesize that microbiologically produced Fe-complexing ligands may play critical roles in both the delivery of Fe(II) to oxidases, and the limited Fe(III) oxyhydroxide crystallinity observed within the biofilm. Our research provides insight into the structure and formation of naturally occurring, microbiologically produced Fe oxyhydroxide minerals in the deep-sea. We describe the initiation of microbial seafloor weathering, and the morphological and mineralogical signals that result from that process. Our observations provide a starting point from which progressively older and more extensively weathered seafloor sulfide minerals may be examined, with the ultimate goal of improved interpretation of ancient microbial processes and associated biological signatures.

Toner, Brandy M.; Santelli, Cara M.; Marcus, Matthew A.; Wirth, Richard; Chan, Clara S.; McCollom, Thomas; Bach, Wolfgang; Edwards, Katrina J.

2008-05-22

10

Comparison study on transformation of iron oxyhydroxides: Based on theoretical and experimental data  

NASA Astrophysics Data System (ADS)

We have investigated the catalytic transformation of ferrihydrite, feroxyhyte, and lepidocrocite in the presence of Fe(II). In this paper, the transformation from akaganeite and goethite to hematite in the presence of trace Fe(II) was studied in detail. The result indicates that trace Fe(II) can accelerate the transformation of akaganeite and goethite. Compared with the transformation of other iron oxyhydroxides (e.g., ferrihydrite, feroxyhyte, lepidocrocite, and akaganeite), a complete transformation from goethite to hematite was not observed in the presence of Fe(II). On the basis of our earlier and present experimental results, the transformation of various iron oxyhydroxides was compared based on their thermodynamic stability, crystalline structure, transformation mechanism, and transformation time.

Lu, Bin; Guo, Hui; Li, Ping; Liu, Hui; Wei, Yu; Hou, Denglu

2011-08-01

11

Surface complexation effects on phosphate adsorption to ferric iron oxyhydroxides along pH and salinity gradients in estuaries and coastal aquifers  

NASA Astrophysics Data System (ADS)

Non-conservative behavior of dissolved inorganic phosphate (DIP) in estuaries is generally ascribed to desorption from iron and aluminum (hydr)oxides with increasing salinity. Here, we assess this hypothesis by simulating the reversible adsorption of phosphate onto a model oxide (goethite) along physico-chemical gradients representative of surface and subsurface estuaries. The simulations are carried out using a surface complexation model (SCM), which represents the main aqueous speciation and adsorption reactions of DIP, plus the ionic strength-dependent coulombic interactions in solution and at the mineral-solution interface. According to the model calculations, variations in pH and salinity alone are unlikely to explain the often reported production of DIP in surface estuaries. In particular, increased aqueous complexation of phosphate by Mg 2+ and Ca 2+ ions with increasing salinity is offset by the formation of ternary Mg-phosphate surface complexes and the drop in electrical potential at the mineral-water interface. However, when taking into account the downstream decrease in the abundance of sorption sites, the model correctly simulates the observed release of DIP in the Scheldt estuary. The sharp increase in pH accompanying the admixing of seawater to fresh groundwater should also cause desorption of phosphate from iron oxyhydroxides during seawater intrusion in coastal aquifers. As for surface estuaries, the model calculations indicate that significant DIP release additionally requires a reduction in the phosphate sorption site density. In anoxic aquifers, this can result from the supply of seawater sulfate and the subsequent reductive dissolution of iron oxyhydroxides coupled to microbial sulfate reduction.

Spiteri, Claudette; Cappellen, Philippe Van; Regnier, Pierre

2008-07-01

12

A new method for preparation of magnetite from iron oxyhydroxide or iron oxide and ferrous salt in aqueous solution  

NASA Astrophysics Data System (ADS)

In this study, a new method is proposed for the preparation of Fe 3O 4 from iron oxyhydroxides (goethite, akaganeite, lepidocrocite, feroxyhyte and ferrihydrite) or iron oxide (hematite) and ferrous salt in aqueous solution. The product is magnetite with various particle sizes. Products are characterized by X-ray powder diffraction, IR spectra and vibrating sample magnetometery.

Kahani, S. A.; Jafari, M.

2009-07-01

13

Mineralogy and inorganic chemistry of naturally occurring biogenic iron oxyhydroxides: Spectroscopic evidence of thermal maturation  

NASA Astrophysics Data System (ADS)

Microbial mats were sampled at four sites at the Lo'ihi Seamount and examined for changes in mineralogy and inorganic chemistry via synchrotron-sourced X-ray Absorption Spectroscopy (XAS). These mats are rich in iron oxyhydroxides with morphologies similar to those produced by iron oxidizing microorganisms related to Zetaproteobacteria such as Mariprofundus ferroxydans, which have been shown to be present and active in all of these mat ecosystems. The same particle morphologies are observed consistently at all four sites, which range in temperature (4 - 40°C) and hydrothermal activity (dead to very active). Fe L-edge XAS reveals no significant differences in Fe speciation between the morphologies. Mineralogy, however, as reflected in O 1s XAS measurements, appears to be a function of thermal maturation with the hottest site harboring more crystalline particles. Morphology does not factor into the changes in mineralogy. These measurements are confirmed by Fe 1s XAS spectroscopy. The C 1s XAS spectroscopy is highly variable and may be related to overall maturation (age) or undetermined factors. Elucidating the effect of thermal maturation on biogenic iron oxhydroxide particles is essential to understanding the environmental influences on their preservation in the rock record.

Haddad, A.; Fakra, S.; Orcutt, B. N.; Toner, B.; Edwards, K. J.

2011-12-01

14

Chemistry and electrochemistry of nanostructured iron oxyhydroxides as lithium intercalation compounds for energy storage  

NASA Astrophysics Data System (ADS)

The structural characterization and electrochemical performance of three nanosized iron oxyhydroxides (?-FeOOH, ?-FeOOH and ?-FeOOH) are reported in this work. The interest of having small particle sizes is to be able to circumvent the low intrinsic ionic conductivity of these materials through the increase of the active volume proportion of the operating grain, during the insertion process. Low temperature synthesis routes, in aqueous media, were thus used to obtain such crystallites with nanometer dimensions. The theoretical specific capacity of these materials is as high as 300 mA h g-1 which is actually very interesting for lithium batteries applications. However, the electrochemical behaviour greatly depends on the structure of the compounds. A phase transformation was, for example, evidenced in the case of ?-FeOOH first lithiation whereas the best performance were obtained with ?-FeOOH, which develops a stable capacity of 180 mA h g-1, after 10 cycles, at C/10.

Benoit, C.; Bourbon, C.; Berthet, P.; Franger, S.

2006-05-01

15

Novel iron oxyhydroxide lepidocrocite nanosheet as ultrahigh power density anode material for asymmetric supercapacitors.  

PubMed

A simple one-step electroplating route is proposed for the synthesis of novel iron oxyhydroxide lepidocrocite (?-FeOOH) nanosheet anodes with distinct layered channels, and the microstructural influence on the pseudocapacitive performance of the obtained ?-FeOOH nanosheets is investigated via in situ X-ray absorption spectroscopy (XAS) and electrochemical measurement. The in situ XAS results regarding charge storage mechanisms of electrodeposited ?-FeOOH nanosheets show that a Li(+) can reversibly insert/desert into/from the 2D channels between the [FeO6 ] octahedral subunits depending on the applied potential. This process charge compensates the Fe(2+) /Fe(3+) redox transition upon charging-discharging and thus contributes to an ideal pseudocapacitive behavior of the ?-FeOOH electrode. Electrochemical results indicate that the ?-FeOOH nanosheet shows the outstanding pseudocapacitive performance, which achieves the extraordinary power density of 9000 W kg(-1) with good rate performance. Most importantly, the asymmetric supercapacitors with excellent electrochemical performance are further realized by using 2D MnO2 and ?-FeOOH nanosheets as cathode and anode materials, respectively. The obtained device can be cycled reversibly at a maximum cell voltage of 1.85 V in a mild aqueous electrolyte, further delivering a maximum power density of 16 000 W kg(-1) at an energy density of 37.4 Wh kg(-1). PMID:24850774

Chen, Ying-Chu; Lin, Yan-Gu; Hsu, Yu-Kuei; Yen, Shi-Chern; Chen, Kuei-Hsien; Chen, Li-Chyong

2014-09-24

16

Cyanide uptake from wastewater by modified natrolite zeolite-iron oxyhydroxide system: application of isotherm and kinetic models.  

PubMed

A method for the removal of cyanides from wastewater is described. The method involves the adsorption of cyanides by a modified natural zeolite (natrolite) using batch technique. A new iron oxyhydroxide-natrolite system was used in this study. A combination of XRD, XRF and FTIR spectroscopies, as well as TG/DSC thermal analyses was used for characterization of zeolitic materials. Effects of parameters such as pH, amount of adsorbent and contact time on the cyanide removing yield are studied. It was observed that the yield increases by increasing dosage of adsorbent and contact time at a fixed pH 7.5. A yield of 82% was achieved at optimum conditions for removing cyanide from industrial wastewaters. The experimental data obtained for optimum conditions were selected for modeling the adsorption behavior of the materials using six isotherm equations (Freundlich, Langmuir, Langmuir-Freundlich, Dubinin-Radushkevich, Redlich-Peterson and Toth). The obtained modeling results indicated that, although the three-parameter models, taking into account the surface heterogeneity, provided the closest approach to the measurement data, the parameters estimates could be highly biased. The kinetic studies proved that the second-order kinetic was the applicable model. PMID:19144469

Noroozifar, Meissam; Khorasani-Motlagh, Mozhgan; Fard, Parisa Ahmadzadeh

2009-07-30

17

Development of a reactive force field for iron-oxyhydroxide systems.  

PubMed

We adopt a classical force field methodology, ReaxFF, which is able to reproduce chemical reactions, and train its parameters for the thermodynamics of iron oxides as well as energetics of a few iron redox reactions. Two parametrizations are developed, and their results are compared with quantum calculations or experimental measurements. In addition to training, two test cases are considered: the lattice parameters of a selected set of iron minerals, and the molecular dynamics simulation of a model for alpha-FeOOH (goethite)-water interaction. Reliability and limitations of the developed force fields in predicting structure and energetics are discussed. PMID:20455552

Aryanpour, Masoud; van Duin, Adri C T; Kubicki, James D

2010-06-01

18

Size-dependent behavior of nanocrystalline titania and iron oxyhydroxide biominerals  

NASA Astrophysics Data System (ADS)

Biomineralization and chemical weathering products are predominantly nanocrystalline. Such phases comprise the majority of reactive surface area in soils and sediments. Microbial oxidation of dissolved iron leads to precipitation of nanocrystalline Fe-oxyhydroxides. Initial ~ 2nm diameter ferrihydrite-like particles nucleate on microbial polymers and form submicron-diameter spherical aggregates via floculation in solution. We have used titania (TiO2) as a model system to explore relationships between size and structure, phase stability, crystal growth mechanisms, phase transformation kinetics, and surface properties. Initial amorphous titania sol-gel products restructure to form 2-4 nm particles that, upon heating, grow to ~ 5 nm, then transform to anatase. Molecular dynamics simulations suggest conversion from four and five coordinated Ti4+ in < 3 nm particles to octahedrally coordinated Ti4+ in larger particles. Four and five coordinated Ti sites are supported by prior synchrotron-based studies on nanotitania. Furthermore, calculated XRD patterns for energy-minimized 2 nm particle structures coincide well with experimental patterns. Particle growth primarily occurs via solid state oriented attachment. Small misorientations between adjacent particles introduce new structural components, as well as dislocations and extended defects that can serve as nucleation sites for subsequent phase transformations. 2-3 nm ferrihydrites transform to ~ 3-6 nm randomly oriented feroxyhyte and goethite (FeOOH) crystals. FeOOH nanocrystals aggregate via oriented attachment to form tens of nanometer diameter imperfect single crystals. The sequence of crystallization steps and similarities in crystal growth and defect formation mechanisms in the titania and iron systems suggest oriented attachment is an important pathways for structural change and crystal growth in many natural and synthetic nanophase materials.

Banfield, Jillian F.

2000-03-01

19

Neptunium and Plutonium Sorption to Snake River Plain, Idaho Soil  

SciTech Connect

The behavior of Np and Pu on soil collected from the subsurface disposal area at the Idaho National Engineering and Environmental Laboratory was investigated by performing short-duration, sorption experiments to measure sorption isotherms. Neptunium sorption can be described with a Freundlich isotherm; however, Pu sorption can only be described in this fashion as a conservative estimate of minimum sorption. Geochemical modeling predictions suggest that initial sorption of Np is controlled predominantly by surface complexation on clay minerals, while Pu is controlled by a competition between complexation with iron oxyhydroxides and the precipitation of hydrolysis products. Longer-term sorption is governed by the transformation of these species to oxide minerals. Solution ionic strength and carbonate alkalinity did not significantly affect Np or Pu soil sorption.

Mincher, Bruce Jay; Fox, Robert Vincent; Cooper, David Craig; Groenewold, Gary Steven

2003-07-01

20

KINETICS OF SOIL NITROGEN MINERALIZATION FROM UNDISTURBED AND DISTURBED SOIL  

Microsoft Academic Search

Knowledge of soil nitrogen (N) mineralization processes is essential for modeling soil processes in agriculture. Many authors have found discrepancies in N mineralization between disturbed and undisturbed samples. Nevertheless, most simulation models use a first-order kinetic model (exponential model) for all the layers under study, devised from studies using disturbed and superficial samples. The goal of the present study was

Ariel Ringuelet; Omar Antonio Bachmeier

2002-01-01

21

Time-resolved Study of Early-stage Formation of Iron Oxyhydroxide Nanoparticles in Simulated Acid Mine Drainage (AMD) Solutions  

NASA Astrophysics Data System (ADS)

Early stage development of ferric iron oxyhydroxide (FeOOH) nanoparticles from bicarbonate-neutralized Fe2(SO4)3 solutions was investigated using time-resolved UV-Vis spectroscopy and quick extended X-ray absorption fine structure (Q-EXAFS) spectroscopy. Two neutralization ratio ( h =[HCO3-]/[Fe3+]) of 1 and 2 were used. The neutralized systems changed visually from transparent solutions after the base addition to blurry and then opaque suspensions at extended reaction time. For the h=1 solution, its absorbance measured at 600 nm (due to scattering because of no absorption bands at this wavelength) increased quickly within initial 10 min, slightly between 10 - 26 min, and explosively afterwards. These three stages have been previously ascribed to hydrolysis and initial condensation, condensation, and aggregation processes, respectively. For the h=2 solution, only the two later evolution stages were recorded. UV-Vis spectra of the h=1 solution show that three absorption bands, likely resulting from Fe3+-sulfate species, gradually disappeared with the increase of reaction time and were not visible at about 10 min. Meanwhile, an electron pair transition (EPT) band centered at 485 nm emerged and gradually grew in its amplitude, indicating particles of a FeOOH phase being formed. For h=2, the three bands were not observed, but the EPT band at 485 nm was pronounced in the first collected spectrum and also grew with time, indicating that FeOOH particles were already formed from the very beginning. In addition, in both of the h=1 and 2 solutions the bands around 370 - 400 nm shifted to higher wavelength, suggesting that FeOOH particle size increased with time. Time-resolved Q-EXAFS spectra were collected every 2 s and were averaged over 15 consecutive scans, resulting in a time resolution of 30 s. For the h=1 solution, the EXAFS radial structural functions (RSF) initially had no or very weak peaks at positions corresponding to edge- and corner-sharing Fe shells. After 10 min of reaction time, the two Fe shells became obvious. This corroborates with the UV-Vis analysis that Fe-sulfate clusters were present at the beginning and FeOOH particles emerged later. For the h=2 solution, RSF shows high amplitudes of the two Fe shells in the first EXAFS spectrum. The amplitudes significantly grew with time, consistent with increasing Fe coordination numbers obtained by EXAFS shell-by-shell fitting. The EXAFS fitting also shows that the second Fe-Fe distance decreased from 3.41 to 3.36 Ĺ with time while the first Fe-Fe distance was almost constant at 3.03 Ĺ. X-ray diffraction identified the final precipitates as schwertmannite, a FeOOH phase containing structural sulfate.

Zhu, M.; Legg, B.; Zhang, H.; Waychunas, G. A.; Banfield, J. F.

2011-12-01

22

Nitrogen mineralization in a tussock tundra soil  

SciTech Connect

The effects of substrate quality, temperature, and moisture on nitrogen mineralization from a tussock tundra soil were examined with laboratory soil incubations utilizing both air-dried samples and field-moist intact cores. The potentially mineralizable nitrogen (PMN) was highly correlated to both total soil nitrogen (positively) and the carbon/nitrogen ratio (negatively). All soil horizons exhibited a net nitrogen mineralization even at a high carbon/nitrogen ratio of 92. It was concluded that field-moist intact soil cores provide a more reliable estimate than the air-dried samples of both PMN and the mineralization rate under standard laboratory conditions. There was no significant effect of moisture tension (0.0 to 0.4 bars) on net nitrogen mineralization. The average Q/sub 10/ (temperature effect) for net nitrogen mineralization was 2.5. Based on this study and others, it was concluded that temperature through its effect on nitrogen mineralization plays an important role in controlling plant productivity in these naturally nitrogen-deficient tundra ecosystems.

Marion, G.M.; Miller, P.C.

1982-01-01

23

Interactions of Soil Minerals with Organic Components and Microorganisms  

Microsoft Academic Search

Minerals, organic matter and microorganisms of the pedosphere are the key factors necessary for soil formation (pedogenesis) and other soil processes (1). The mineral composition of soil is a major part of the ecology of microorganisms. Interaction of soil minerals with microorganisms affects the metabolic transformation of natural and xenobiotic organic compounds and the fate of metals and other inorganic

BOLLAG Jean-Marc; LEYVAL Corinne

24

Original article Soil nitrogen mineralization in adjacent stands of larch,  

E-print Network

Original article Soil nitrogen mineralization in adjacent stands of larch, pine and oak in central January 1996; accepted 23 May 1996) Summary - To examine the effects of tree species on soil nitrogen (N) mineralization we monitored rates of soil nitrogen mineralization and nitrification using the buried bag

Paris-Sud XI, Université de

25

Poliovirus Adsorption by 34 Minerals and Soils  

PubMed Central

The adsorption of radiolabeled infectious poliovirus type 2 by 34 well-defined soils and mineral substrates was analyzed in a synthetic freshwater medium containing 1 mM CaCl2 and 1.25 mM NaHCO3 at pH 7. In a model system, adsorption of poliovirus by Ottawa sand was rapid and reached equilibrium within 1 h at 4°C. Near saturation, the adsorption could be described by the Langmuir equation; the apparent surface saturation was 2.5 × 106 plaque-forming units of poliovirus per mg of Ottawa sand. At low surface coverage, adsorption was described by the Freundlich equation. The soils and minerals used ranged from acidic to basic and from high in organic content to organic free. The available negative surface charge on each substrate was measured by the adsorption of a cationic polyelectrolyte, polydiallyldimethylammonium chloride. Most of the substrates adsorbed more than 95% of the virus. In general, soils, in comparison with minerals, were weak adsorbents. Among the soils, muck and Genesee silt loam were the poorest adsorbents; among the minerals, montmorillonite, glauconite, and bituminous shale were the least effective. The most effective adsorbents were magnetite sand and hematite, which are predominantly oxides of iron. Correlation coefficients for substrate properties and virus adsorption revealed that the elemental composition of the adsorbents had little effect on poliovirus uptake. Substrate surface area and pH, by themselves, were not significantly correlated with poliovirus uptake. A strong negative correlation was found between poliovirus adsorption and both the contents of organic matter and the available negative surface charge on the substrates as determined by their capacities for adsorbing the cationic polyelectrolyte, polydiallyldimethylammonium chloride. PMID:6274259

Moore, Rebecca S.; Taylor, Dene H.; Sturman, Lawrence S.; Reddy, Michael M.; Fuhs, G. Wolfgang

1981-01-01

26

Clay mineral type effect on bacterial enteropathogen survival in soil.  

PubMed

Enteropathogens released into the environment can represent a serious risk to public health. Soil clay content has long been known to have an important effect on enteropathogen survival in soil, generally enhancing survival. However, clay mineral composition in soils varies, and different clay minerals have specific physiochemical properties that would be expected to impact differentially on survival. This work investigated the effect of clay materials, with a predominance of a particular mineral type (montmorillonite, kaolinite, or illite), on the survival in soil microcosms over 96 days of Listeria monocytogenes, Salmonella Dublin, and Escherichia coli O157. Clay mineral addition was found to alter a number of physicochemical parameters in soil, including cation exchange capacity and surface area, and this was specific to the mineral type. Clay mineral addition enhanced enteropathogen survival in soil. The type of clay mineral was found to differentially affect enteropathogen survival and the effect was enteropathogen-specific. PMID:24035982

Brennan, Fiona P; Moynihan, Emma; Griffiths, Bryan S; Hillier, Stephen; Owen, Jason; Pendlowski, Helen; Avery, Lisa M

2014-01-15

27

Soil Tillage Influences on Soil Mineral Nitrogen and Nitrate Leaching in  

E-print Network

Soil Tillage Influences on Soil Mineral Nitrogen and Nitrate Leaching in Swedish Arable Soils �sa and Nitrate Leaching in Swedish Arable Soils. Abstract Leaching of nitrogen (N) is an unwanted effect

28

Reverse micelle synthesis of nanoscale metal containing catalysts. [Nickel metal (with a nickel oxide surface layer) and iron oxyhydroxide nanoscale powders  

SciTech Connect

The need for morphological control during the synthesis of catalyst precursor powders is generally accepted to be important. In the liquefaction of coal, for example, iron-bearing catalyst precursor particles containing individual crystallites with diameters in the 1-100 nanometer range are believed to achieve good dispersion through out the coal-solvent slurry during liquefaction 2 runs and to undergo chemical transformations to catalytically active iron sulfide phases. The production of the nanoscale powders described here employs the confining spherical microdomains comprising the aqueous phase of a modified reverse micelle (MRM) microemulsion system as nanoscale reaction vessels in which polymerization, electrochemical reduction and precipitation of solvated salts can occur. The goal is to take advantage of the confining nature of micelles to kinetically hinder transformation processes which readily occur in bulk aqueous solution in order to control the morphology and phase of the resulting powder. We have prepared a variety of metal, alloy, and metal- and mixed metal-oxide nanoscale powders from appropriate MRM systems. Examples of nanoscale powders produced include Co, Mo-Co, Ni[sub 3]Fe, Ni, and various oxides and oxyhydroxides of iron. Here, we discuss the preparation and characterization of nickel metal (with a nickel oxide surface layer) and iron oxyhydroxide MRM nanoscale powders. We have used extended x-ray absorption fine structure (EXAFS) spectroscopy to study the chemical polymerization process in situ, x-ray diffraction (XRD), scanning and transmission electron microcroscopies (SEM and TEM), elemental analysis and structural modelling to characterize the nanoscale powders produced. The catalytic activity of these powders is currently being studied.

Darab, J.G.; Fulton, J.L.; Linehan, J.C.

1993-03-01

29

Mineralization of metsulfuron-methyl in Chinese paddy soils.  

PubMed

A laboratory study was conducted to investigate the mineralization of metsulfuron-methyl (MSM) in paddy soils in response to soil moisture, temperature and soil properties. The results indicated that MSM mineralization was relatively limited in the paddy soils when soil temperature was low. Only 2.2-6.0% of the applied (14)C mineralized after 84d of incubation at 15 degrees C. The mineralization of MSM was enhanced by increasing soil moisture and soil temperature. Soil moisture would have different impact on the response of MSM mineralization to variation in soil temperature. An increase of 10 degrees C accelerated the average rate of MSM mineralization by 2.3 times at 50% water-holding capacity (WHC) and 1.9 times at 40% WHC. Regression analysis showed that soil pH, organic carbon contents, microbial biomass carbon contents, and silt/clay fractions were the dominant factors affecting MSM mineralization, with pH as the most important factor. The relatively slow mineralization rate of MSM suggested long persistence of this herbicide in soil, thus increasing its potential ecological risk, especially when applied in alkaline soils and in cold areas. PMID:19906402

Wang, Haizhen; Xu, Jianming; Yates, Scott R; Zhang, Jiabao; Gan, Jay; Ma, Jincai; Wu, Jianjun; Xuan, Richeng

2010-01-01

30

Ectomycorrhizal fungi in mineral soil * AND N. ROSENSTOCK  

E-print Network

conditions, soil-fauna and spore dispersal. Soil conditions affect species diversity of ectomycorrhizal fungi deposition (Lilleskov et al., 2002). Altering nitrogen conditions in soil affects the outcome of speciesEctomycorrhizal fungi in mineral soil A. ROSLING 1, * AND N. ROSENSTOCK 2 1 Department of Forest

Bruns, Tom

31

Biogeophysical factors inuencing soil respiration and mineral nitrogen content in an old eld soil  

E-print Network

Biogeophysical factors in¯uencing soil respiration and mineral nitrogen content in an old ®eld soil of Soil Ecology and Microbiology, Department of Natural Resources Science, 210B Woodward Hall, 9 East evolution and mineral N content of an old ®eld soil to test two alternative habitat hypotheses

Neher, Deborah A.

32

Relationship between carbon and nitrogen mineralization in a subtropical soil  

NASA Astrophysics Data System (ADS)

In most soils, more than 90% nitrogen is bonded with carbon in organic forms. This indicates that carbon mineralization should be closely coupled with nitrogen mineralization, showing a positive correlation between carbon and nitrogen mineralization. To test this hypothesis above, we conducted an incubation using a subtropical soil for 10 days at 15 °C and 25 °C. 13C-labeled glucose and 15N-labeled ammonium or nitrate was used to separate CO2 and mineral N released from mineralization of soil organic matter and added glucose or inorganic nitrogen. Phospholipid fatty acid (PLFA) and four exoenzymes (i.e. ?-1,4- Glucosaminidase, chitinase, acid phosphatase, ?-1,4-N- acetyl glucosamine glycosidase) were also analyzed to detect change in microbial activities during the incubation. Our results showed that CO2 release decreased with increasing nitrogen mineralization rates. Temperature did not change this relationship between carbon and nitrogen mineralization. Although some changes in PLFA and the four exoenzymes were observed, these changes did not contribute to changes in carbon and nitrogen mineralization. These findings indicates that carbon and nitrogen mineralization in soil are more complicated than as previously expected. Future investigation should focus on why carbon and nitrogen mineralization are coupled in a negative correlation not in a positive correlation in many soils for a better understanding of carbon and nitrogen transformation during their mineralization.

Li, Qianru; Sun, Yue; Zhang, Xinyu; Xu, Xingliang; Kuzyakov, Yakov

2014-05-01

33

Coexisting Bacterial Populations Responsible for Multiphasic Mineralization Kinetics in Soil  

PubMed Central

Experiments were conducted to study populations of indigenous microorganisms capable of mineralizing 2,4-dinitrophenol (DNP) in two soils. Previous kinetic analyses indicated the presence of two coexisting populations of DNP-mineralizing microorganisms in a forest soil (soil 1). Studies in which eucaryotic and procaryotic inhibitors were added to this soil indicated that both populations were bacterial. Most-probable-number counts with media containing different concentrations of DNP indicated that more bacteria could mineralize low concentrations of DNP than could metabolize high concentrations of it. Enrichments with varying concentrations of DNP and various combinations of inhibitors consistently resulted in the isolation of the same two species of bacteria from soil 1. This soil contained a large number and variety of fungi, but no fungi capable of mineralizing DNP were isolated. The two bacterial isolates were identified as a Janthinobacterium sp. and a Rhodococcus sp. The Janthinobacterium sp. had a low ?max and a low Km for DNP mineralization, whereas the Rhodococcus sp. had much higher values for both parameters. These differences between the two species of bacteria were similar to differences seen when soil was incubated with different concentrations of DNP. Values for ?max from soil incubations were similar to ?max values obtained in pure culture studies. In contrast, Ks and Km values showed greater variation between soil and pure culture studies. The results of this study help to confirm predictions that two physiologically distinct bacterial populations are responsible for the multiphasic mineralization kinetics observed in the soil studied. PMID:16348277

Schmidt, S. K.; Gier, M. J.

1990-01-01

34

Effect of soil metal contamination on glyphosate mineralization: role of zinc in the mineralization rates of two copper-spiked mineral soils.  

PubMed

A systematic investigation into lowered degradation rates of glyphosate in metal-contaminated soils was performed by measuring mineralization of [(14)C]glyphosate to (14)CO(2) in two mineral soils that had been spiked with Cu and/or Zn at various loadings. Cumulative (14)CO(2) release was estimated to be approximately 6% or less of the amount of [(14)C]glyphosate originally added in both soils over an 80-d incubation. For all but the highest Cu treatments (400 mg kg(-1)) in the coarse-textured Arkport soil, mineralization began without a lag phase and declined over time. No inhibition of mineralization was observed for Zn up to 400 mg kg(-1) in either soil, suggesting differential sensitivity of glyphosate mineralization to the types of metal and soil. Interestingly, Zn appeared to alleviate high-Cu inhibition of mineralization in the Arkport soil. The protective role of Zn against Cu toxicity was also observed in the pure culture study with Pseudomonas aeruginosa, suggesting that increased mineralization rates in high Cu soil with Zn additions might have been due to alleviation of cellular toxicity by Zn rather than a mineralization specific mechanism. Extensive use of glyphosate combined with its reduced degradation in Cu-contaminated, coarse-textured soils may increase glyphosate persistence in soil and consequently facilitate Cu and glyphosate mobilization in the soil environment. PMID:21298705

Kim, Bojeong; Kim, Young Sik; Kim, Bo Min; Hay, Anthony G; McBride, Murray B

2011-03-01

35

Fractionation of Fe isotopes by soil microbes and organic acids  

USGS Publications Warehouse

Small natural variations in Fe isotopes have been attributed to biological cycling. However, without understanding the mechanism of fractionation, it is impossible to interpret such variations. Here we show that the ?56Fe of Fe dissolved from a silicate soil mineral by siderophore-producing bacteria is as much as 0.8% lighter than bulk Fe in the mineral. A smaller isotopic shift is observed for Fe released abiotically by two chelates, and the magnitude of the shift increases with affinity of the ligand for Fe, consistent with a kinetic isotope effect during hydrolysis of Fe at the mineral surface. Fe dissolved abiotically without chelates shows no isotopic shift. The ?56Fe of the exchange fraction on soil grains is also lighter by ~0.6%-1% than Fe from both hornblende and iron oxyhydroxides. The kinetic isotope effect is therefore preserved in open systems such as soils. when recorded in the rock record, Fe isotopic fractionation could document Fe transport by organic molecules or by microbes where such entities were present in the geologic past.

Brantley, Susan L.; Liermann, Laura; Bullen, Thomas D.

2001-01-01

36

Carbon Sequestration by Smectite Clay Minerals in Soils  

Microsoft Academic Search

Molecular simulations can be used to explore fundamental interactions that govern the formation of organo-mineral complexes in soils, complexes that in turn control the size and turnover of soil carbon pools. A suitable model organic molecule, featuring properties and behavior typical of the recalcitrant portion of soil carbon in humic substances, is needed for these simulations. The latest iteration of

Garrison Sposito; Rebecca Sutton

2006-01-01

37

nt adsorptionby soil minerals,in Elenletils in Soil-Plant -Aninal  

E-print Network

-matterreactions involving [. Giordano, and W. L. Lindsay Soil ScienceSociety of America t of Fertilizers, Commonweahh0cesse.s nt adsorptionby soil minerals,in Elenletils in Soil-Plant - Aninal rrk. USA. .. ( l96l). Molybdenumreactions ium and titanium, Soil Sci. Soc. i on the exhaustion of sewage e chemistry of lead in soil: solid

Short, Daniel

38

Effect of Mineral and Organic Soil Constituents on Microbial Mineralization of Organic Compounds in a Natural Soil  

PubMed Central

This research addressed the effect of mineral and organic soil constituents on the fate of organic compounds in soils. Specifically, it sought to determine how the associations between organic chemicals and different soil constituents affect their subsequent biodegradation in soil. Four 14C-labeled surfactants were aseptically adsorbed to montmorillonite, kaolinite, illite, sand, and humic acids. These complexes were mixed with a woodlot soil, and 14CO2 production was measured over time. The mineralization data were fitted to various production models by nonlinear regression, and a mixed (3/2)-order model was found to most accurately describe the mineralization patterns. Different mineralization patterns were observed as a function of the chemical and soil constituents. Surfactants that had been preadsorbed to sand or kaolinite usually showed similar mineralization kinetics to the control treatments, in which the surfactants were added to the soil as an aqueous solution. Surfactants that had been bound to illite or montmorillonite were typically degraded to lesser extents than the other forms, while surfactant-humic acid complexes were degraded more slowly than the other forms. The desorption coefficients (Kd) of the soil constituent-bound surfactants were negatively correlated with the initial rates of degradation (k1) and estimates of 14CO2 yield (Po) as well as actual total yields of 14CO2. However, there was no relationship between Kd and second-stage zero-order rates of mineralization (ko). Microbial community characteristics (biomass and activity) were not correlated with any of the mineralization kinetic parameters. Overall, this study showed that environmental form had a profound effect on the ultimate fate of biodegradable chemicals in soil. This form is defined by the physicochemical characteristics of the chemical, the composition and mineralogy of the soil, and the mode of entry of the chemical into the soil environment. PMID:16349465

Knaebel, David B.; Federle, Thomas W.; McAvoy, Drew C.; Vestal, J. Robie

1994-01-01

39

Calculation of nitrogen mineralization in soil food webs  

Microsoft Academic Search

In agricultural practices in which the use of inorganic fertilizer is being reduced in favour of the use of organic manure, the availability of nitrogen (N) in soil for plant growth depends increasingly on N mineralization. In simulation models, N mineralization is frequently described in relation to the decomposition of organic matter, making a distinction in the quality of the

P. C. Ruiter; J. A. Veen; J. C. Moore; L. Brussaard; H. W. Hunt

1993-01-01

40

Mineral Hosts for Uranium in Oak Ridge Soils  

Microsoft Academic Search

Successful prediction of the environmental fate of toxic metals requires an understanding of mineral-metal- microbe interactions. Many aspects of metal sequestration and\\/or remediation involve adsorption by or incorporation in redox active mineral hosts in soils and aquifers. Two fundamental goals of environmental mineralogy, therefore, are characterization of these hosts and illumination of the mineralogical mechanisms active in metal reduction, sorption

J. E. Stubbs; D. C. Elbert; D. R. Veblen

2006-01-01

41

The potential impact of soil ingestion on human mineral nutrition  

Microsoft Academic Search

Geophagia, the intentional and repeated ingestion of soil material, is a complex eating behaviour with incomprehensible aetiology. It is generally assumed that geophagia may help supplement mineral nutrients and thus should not be dissuaded, particularly in subsistence communities. This is largely based on the assumption that a large proportion of mineral nutrients in geophagic materials is potentially available for absorption

P. S. Hooda; C. J. K. Henry; T. A. Seyoum; L. D. M. Armstrong; M. B. Fowler

2004-01-01

42

Relevance of mineral-organic associations in cryoturbated permafrost soils  

NASA Astrophysics Data System (ADS)

Enhanced microbial decomposition of deep buried organic matter (OM) increase the release of CO2and CH4from high latitude ecosystems, thus being an uncertain but potentially crucial positive feedback to global warming. The role of soil minerals as stabilization agents of OM against microbial attack gain in importance as soon abiotic soil conditions will change in permafrost soils. We investigated changes in storage and turnover of soil organic carbon (OC) and total nitrogen (TN) associated with minerals in 27 cryoturbated permafrost soils from the west to the east Siberian Arctic. Furthermore, we studied the mineral composition and the potential of OM to interact with soil minerals via different binding mechanisms. Mineral-associated organic matter (MOM) was separated from particulate plant debris by density fractionation in sodium polytungstate (density cut-off 1.6 g cm-3). Their apparent 14C ages were determined by accelerator mass spectrometry and potential mineralization rates were analyzed in a 180 days incubation experiments at 5 and 15° C. The mineral composition was analyzed by X-ray diffraction and selective extractions. Desorption experiments (stepwise extraction with KCl and NaH2PO4) using the permafrost soils as well as reference soils from temperate regions (three Stagnolsols from Germany) were performed to study OM sorbed to mineral surfaces or complexed with polyvalent metal ions. The proportion of OC associated with minerals (MOC) ranged from 5.1 to 14.9 kg m-2 (average: 11.0 kg m-2), corresponding to ~55% from the total soil OC storage (average: 20.2 ± 8.0 kg m-2) in the first meter of the Cryosols. In contrast to temperate soils, where maximum MOC concentrations are present in topsoils, cambic, or spodic horizons, cryoturbation in permafrost soils leads to high MOC concentrations within the whole solum. Cryoturbated OM-rich pockets in the subsoil store 18% (2.0 ± 1.3 kg m-2) of the MOC while another 34% (3.8 ± 3.5 kg m-2) was located in the uppermost permafrost. In topsoil horizons, mineralization rates showed a similar pattern for MOM and the bulk soil controls. In contrast, even higher MOM respiration rates then the bulk control were found in the cryoturbated OM-rich pockets and permafrost horizons. These findings deviate from temperate soil environments where MOM is considered to contribute to a 'stabilized pool' with mean residence times from hundreds to thousands of years. Statistical analysis indicated that mineral-organic interactions primarily occurred with poorly crystalline Fe and Al phases and Fe/Al-OM complexes. However, the minor desorption of organic polyelectrolytes by NaH2PO4 in permafrost soils indicated that significantly lower amounts of OC were bound by ligand exchange to Fe and Al minerals or the edges of clay minerals in permafrost soils compared to the temperate reference soils. Therefore, stabilization of OM by mineral surfaces or polyvalent metal ions appears to be of minor relevance in arctic environments compared to temperate soils.

Gentsch, Norman; Mikutta, Robert; Bárta, Ji?í; ?apek, Petr; Gittel, Antje; Richter, Andreas; Šantr??ková, Hanna; Schnecker, Jörg; Shibistova, Olga; Urich, Tim; Wild, Birgit; Guggenberger, Georg

2014-05-01

43

Soil Interfaces in a Changing World International Symposium of Interactions of Soil Minerals with  

E-print Network

Sciences, University of Delaware, Newark, Delaware, USA, and Institute of Soil Science, UniversitySoil Interfaces in a Changing World 6th ISMOM International Symposium of Interactions of Soil Minerals with Organic Components and Microorganisms 3rd InterCongress of Commission 2.5 IUSS Soil chemical

Sparks, Donald L.

44

Mineralization of biochars in soils of contrasting mineral composition from Australia  

NASA Astrophysics Data System (ADS)

Biochar application to soils is considered an attractive management strategy because of its agronomic benefits and mitigation of greenhouse gas emissions in some soils. However, the stability of biochars in soils with varying mineral composition has not been comprehensively evaluated. In this study, we measured the stability of two wood biochars (450 and 550°C; Eucalyptus saligna; ?13C ~-36‰) at three incubation temperatures (20, 40 and 60°C). The biochars (2% w/w) were incubated in the laboratory at 70% WHC with four soils (Inceptisol, Vertisol, Oxisol, Entisol) of contrasting soil properties including mineralogical composition. The results show that between 0.3 and 7% of added biochar C was mineralised during 12-month period. The lowest mineralization was observed in the Vertisol amended with the 550°C biochar incubated at 20°C, while the highest value occurred in the same soil amended with the 450°C biochar incubated at 60°C. The mineralization rate of biochar-C increased with increasing incubation temperature, and the mineralisation rate of 450°C biochar was consistently higher than the 550°C biochar in all soils. Biochar C stability was also influenced by soil types particularly at higher temperatures (40 and 60°C). The biochar application in the Inceptisol caused a positive priming of soil-C at all incubation temperatures; whereas in the other soils with higher clay content, biochar suppressed the mineralisation of soil-C over time.

Fang, Y. Y.; Singh, B.; Singh, B. P.; Krull, E.

2012-04-01

45

Mineralization of nitrogen by protozoan activity in soil  

Microsoft Academic Search

In general, more than 95% of the nitrogen in soils is present in organic forms. This nitrogen is not directly available to plants unless microbial decomposition takes place with the release of mineral nitrogen. In modern agriculture, nitrogen is often applied to arable soils as a fertilizer to support high levels of crop production. Nitrogen is one of the essential

P. J. Kuikman

1990-01-01

46

Analysis of manure and soil nitrogen mineralization during incubation  

Microsoft Academic Search

Understanding the N-cycling processes that ensue after manuring soil is essential in order to estimate the value of manure as an N fertilizer. A laboratory incubation of manured soil was carried out in order to study N mineralization, gas fluxes, denitrification, and microbial N immobilization after manure application. Four different manures were enclosed in mesh bags to allow for the

Francisco J. Calderón; Gregory W. McCarty; James B. Reeves

2005-01-01

47

Acid Rain's Dirty Business: Stealing Minerals from Soil  

Microsoft Academic Search

This article describes the hidden environmental effects of acid rain - leaching of base mineral ions from the soil, often changing soil chemistry dramatically. The primary information comes from Ecosystem studies at Hubbard Brook of Likens and Buso. The article also discusses both other opinions and possible solutions.

Jocelyn Kaiser

1996-01-01

48

Kinetics of methane oxidation in selected mineral soils  

NASA Astrophysics Data System (ADS)

The kinetic parameters of methane oxidation in three mineral soils were measured under laboratory conditions. Incubationswere preceded by a 24-day preincubationwith 10%vol. of methane. All soils showed potential to the consumption of added methane. None of the soils, however, consumed atmospheric CH4. Methane oxidation followed the Michaelis-Menten kinetics, with relatively low values of parameters for Eutric Cambisol, while high values for Haplic Podzol, and especially for Mollic Gleysol which showed the highest methanotrophic activity and much lower affinity to methane. The high values of parameters for methane oxidation are typical for organic soils and mineral soils from landfill cover. The possibility of the involvement of nitrifying microorganisms, which inhabit the ammonia-fertilized agricultural soils should be verified.

Walkiewicz, A.; Bulak, P.; Brzezińska, M.; W?odarczyk, T.; Polakowski, C.

2012-10-01

49

The effect of soil moisture on mineral nitrogen, soil electrical conductivity, and pH  

Microsoft Academic Search

Inorganic nitrogen in the soil is the source of N for non-legume plants. Rapid methods for monitoring changes in inorganic N concentrations would be helpful for N nutrient management. The effect of varying soil moisture content on soil mineral nitrogen, electrical conductivity (EC), and pH were studied in a laboratory experiment. Soil NO3-N increased as soil water-filled pore space (WFPS)

Rui Zhang; Brian J. Wienhold

2002-01-01

50

[Response of mineralization of dissolved organic carbon to soil moisture in paddy and upland soils in hilly red soil region].  

PubMed

Typical paddy and upland soils were collected from a hilly subtropical red-soil region. 14C-labeled dissolved organic carbon (14C-DOC) was extracted from the paddy and upland soils incorporated with 14C-labeled straw after a 30-day (d) incubation period under simulated field conditions. A 100-d incubation experiment (25 degrees C) with the addition of 14C-DOC to paddy and upland soils was conducted to monitor the dynamics of 14C-DOC mineralization under different soil moisture conditions [45%, 60%, 75%, 90%, and 105% of the field water holding capacity (WHC)]. The results showed that after 100 days, 28.7%-61.4% of the labeled DOC in the two types of soils was mineralized to CO2. The mineralization rates of DOC in the paddy soils were significantly higher than in the upland soils under all soil moisture conditions, owing to the less complex composition of DOC in the paddy soils. The aerobic condition was beneficial for DOC mineralization in both soils, and the anaerobic condition was beneficial for DOC accumulation. The biodegradability and the proportion of the labile fraction of the added DOC increased with the increase of soil moisture (45% -90% WHC). Within 100 days, the labile DOC fraction accounted for 80.5%-91.1% (paddy soil) and 66.3%-72.4% (upland soil) of the cumulative mineralization of DOC, implying that the biodegradation rate of DOC was controlled by the percentage of labile DOC fraction. PMID:24984493

Chen, Xiang-Bi; Wang, Ai-Hua; Hu, Le-Ning; Huang, Yuan; Li, Yang; He, Xun-Yang; Su, Yi-Rong

2014-03-01

51

[Occurrence relationship between iron minerals and clay minerals in net-like red soils: evidence from X-ray diffraction].  

PubMed

The high purity of clay minerals is a key factor to reconstruct the palaeoclimate in clay mineralogy, however, the existence of iron minerals (such as goethite and hematite) and organics lead to the intergrowth of clay minerals and other minerals, producing other mineral impurities in enriched clay minerals. Although the removal of organics in soil sediments has been fully investigated, the occurrence state of iron minerals remains controversial, hindering the preparation of high-purity clay minerals. Therefore, the occurrence relationship of iron minerals and clay minerals in Jiujiang net-like red soils of the middle to lower reaches of the Yangtze River was investigated using the sequential separation method, which provided some implications for the removal of iron minerals in soil sediments. The results indicated that goethite and hematite were mostly absorbed on the surface of hydroxy-interlayered smectite and illite in the form of films, and the rest were absorbed by kaolinite. PMID:23841442

Yin, Ke; Hong, Han-Lie; Han, Weni; Ma, Yu-Bo; Li, Rong-Biao

2013-04-01

52

Pedogenic Magnetic Minerals in Soils: Some Tests of Current Models  

NASA Astrophysics Data System (ADS)

The magnetic enhancement of soils is increasingly used as a proxy for continental climate, since it is related to the formation of pedogenic iron minerals under warm, humid conditions. Ultrafine magnetite is believed to be the major responsible of the magnetic enhancement, however, very little is known on the detailed formation mechanism, ant its relation to the soil iron cycle. Furthermore, the 'textbook' case of the Chinese Loess Plateau is not well replicated around the World: Loessic soils from the Midwestern US are systematically less enhanced than their Chinese counterpart under similar climatic conditions, and many loessic soils in Argentina are not enhanced at all. In trying to find a rationale behind these differences, I will address three main questions that need to be answered in a bottom-up approach to the problem. The first question is whether susceptibility is indeed controlled by fine magnetite, excluding any significant role of other minerals such as ferrihydrite, goethite, and hematite. This is a rock magnetic problem addressing the interpretation of magnetic measurements: is susceptibility an adequate proxy for the concentration of magnetic minerals in soils? Answering this question allows us to think directly in terms of abundance specific magnetic minerals, which is fundamental for any subsequent interpretation. The second question is directed to understanding the role of magnetic minerals in the soil iron cycle and how they are formed. This brings us to a discussion of the transfer function linking magnetic enhancement with climate. Is indeed rainfall the only parameter controlling pedogenesis? Why is rainfall apparently related with the logarithm of susceptibility in enhanced soils? Can we test current pedogenetic models against this empirical transfer function? The third question points to the role of parent material and later dust inputs. Midwestern US and Argentinian loesses are different from Chinese loess. Is this a reason for the differences observed in the magnetic enhancement of the respective soils? Enough material is now available to test current models and hypotheses with respect to the first two questions.

Egli, R.

2008-12-01

53

Availability of Potash in Some Soil-Forming Minerals  

E-print Network

, Technical Assistant M. P. HOLLEMAN. JR., Assistant Chief Clerk VETERINARY SCIENCE *M. FRANCIS, D. V. M., Chief H. SCHMIDT, D. V. S., Veterinarian J. J. REID, D. V. M., Veterinarian CHEMISTRY G. S FRAP~ Ph D Chief. State Chemisf S. E.' ASBU& M. s... was carried out in three separate series. In the first series, the amounts of potash added to the soil in the form of the soil minerals are comparatively small, equal to .25 gram of potash to 5000 grams soil or 500 parts per million of soil. In the second...

Fraps, G. S. (George Stronach)

1921-01-01

54

The effect of soil horizon and mineral type on the distribution of siderophores in soil  

NASA Astrophysics Data System (ADS)

Iron is a key component of the chemical architecture of the biosphere. Due to the low bioavailability of iron in the environment, microorganisms have developed specific uptake strategies like production of siderophores. Siderophores are operationally defined as low-molecular-mass biogenic Fe(III)-binding compounds, that can increase the bioavailability of iron by promoting the dissolution of iron-bearing minerals. In the present study, we investigated the composition of dissolved and adsorbed siderophores of the hydroxamate family in the soil horizons of podzol and the effect of specific mineral types on siderophores. Three polished mineral specimens of 3 cm × 4 cm × 3 mm (apatite, biotite and oligioclase) were inserted in the soil horizons (O (organic), E (eluvial) and B (upper illuvial)). After two years, soil samples were collected from both the bulk soil of the whole profile and from the soil attached to the mineral surfaces. The concentration of ten different fungal tri-hydroxamates within ferrichromes, fusigen and coprogens families, and five bacterial hydroxamates within the ferrioxamine family were detected. All hydroxamate types were determined in both soil water (dissolved) and soil methanol (adsorbed) extracts along the whole soil profile by high-performance liquid chromatography coupled to electrospray ionization mass spectrometry (HPLC-ESI-MS); hence, the study is the most extensive of its kind. We found that coprogens and fusigen were present in much higher concentrations in bulk soil than were ferrioxamines and ferrichromes. On the other hand, the presence of the polished mineral completely altered the distribution of siderophores. In addition, each mineral had a unique interaction with the dissolved and adsorbed hydroxamates in the different soil horizons. Thus siderophore composition in the soil environment is controlled by the chemical, physical and biological characteristics of each soil horizon and also by the available mineral types.

Ahmed, Engy; Holmström, Sara J. M.

2014-04-01

55

Soil texture and nitrogen mineralization potential across a riparian toposequence in a semi-arid savanna  

Microsoft Academic Search

Soil texture is an important influence on nutrient cycling in upland soils, with documented relationships between mineral particle size distribution and organic matter retention, nitrogen (N) mineralization, microbial biomass and other soil properties. However, little is known of the role of mineral particle size in riparian soils, where fluvial sorting creates strong spatial contrasts in the size distribution of sediments

J. Scott Bechtold; Robert J. Naiman

2006-01-01

56

Characterizing regional soil mineral composition using spectroscopyand geostatistics  

USGS Publications Warehouse

This work aims at improving the mapping of major mineral variability at regional scale using scale-dependent spatial variability observed in remote sensing data. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data and statistical methods were combined with laboratory-based mineral characterization of field samples to create maps of the distributions of clay, mica and carbonate minerals and their abundances. The Material Identification and Characterization Algorithm (MICA) was used to identify the spectrally-dominant minerals in field samples; these results were combined with ASTER data using multinomial logistic regression to map mineral distributions. X-ray diffraction (XRD)was used to quantify mineral composition in field samples. XRD results were combined with ASTER data using multiple linear regression to map mineral abundances. We testedwhether smoothing of the ASTER data to match the scale of variability of the target sample would improve model correlations. Smoothing was donewith Fixed Rank Kriging (FRK) to represent the mediumand long-range spatial variability in the ASTER data. Stronger correlations resulted using the smoothed data compared to results obtained with the original data. Highest model accuracies came from using both medium and long-range scaled ASTER data as input to the statistical models. High correlation coefficients were obtained for the abundances of calcite and mica (R2 = 0.71 and 0.70, respectively). Moderately-high correlation coefficients were found for smectite and kaolinite (R2 = 0.57 and 0.45, respectively). Maps of mineral distributions, obtained by relating ASTER data to MICA analysis of field samples, were found to characterize major soil mineral variability (overall accuracies for mica, smectite and kaolinite were 76%, 89% and 86% respectively). The results of this study suggest that the distributions of minerals and their abundances derived using FRK-smoothed ASTER data more closely match the spatial variability of soil and environmental properties at regional scale.

Mulder, V.L.; de Bruin, S.; Weyermann, J.; Kokaly, Raymond F.; Schaepman, M.E.

2013-01-01

57

[Analysis of XRD spectral characteristics of soil clay mineral in two typical cultivated soils].  

PubMed

The present paper took black soil and chernozem, the typical cultivated soil in major grain producing area of Northeast, as the study object, and determinated the soil particle composition characteristics of two cultivated soils under the same climate and location. Then XRD was used to study the composition and difference of clay mineral in two kinds of soil and the evolutionary mechanism was explored. The results showed that the two kinds of soil particles were composed mainly of the sand, followed by clay and silt. When the particle accumulation rate reached 50%, the central particle size was in the 15-130 microm interval. Except for black soil profile of Shengli Xiang, the content of clay showed converse sequence to the central particle in two soils. Clay accumulated under upper layer (18.82%) in black soil profile while under caliche layer (17.41%) in chernozem profile. Clay content was the least in parent material horizon except in black profile of Quanyanling. Analysis of clay XRD atlas showed that the difference lied in not only the strength of diffraction peak, but also in the mineral composition. The main contents of black soil and chernozem were both 2 : 1 clay, the composition of black soil was smectite/illite mixed layer-illite-vermiculite and that of chernozem was S/I mixture-illite-montmorillonite, and both of them contained little kaolinite, chlorite, quartz and other primary mineral. This paper used XRD to determine the characteristics of clay minerals comprehensively, and analyzed two kinds of typical cultivated soil comparatively, and it was a new perspective of soil minerals study. PMID:25269317

Zhang, Zhi-Dan; Luo, Xiang-Li; Jiang, Hai-Chao; Li, Qiao; Shen, Cong-Ying; Liu, Hang; Zhou, Ya-Juan; Zhao, Lan-Po; Wang, Ji-Hong

2014-07-01

58

Spectroscopy and reactivity of mineral analogs of the Martian soil  

NASA Technical Reports Server (NTRS)

To answer the question of why life occurred on Earth but not on Mars requires a study of the geochemical and physical aspects of the Martian soil. Some of the best Mars analog mineral models of the soil have been prepared and justified according to known constraints of chemical composition, reflectance spectroscopy, and chemical reactivity. Detailed laboratory reflectance spectra in the ultraviolet, visible, and near infrared (.30 to 2.5 microns) and the infrared (2.5 to 25 microns) regions have been obtained for the pure candidate minerals and some analog mixtures and compared to Mars reflectance spectra. Modeling of the reflectance spectra from optical constraints determined for the analog minerals has begun and will be interpreted in terms of the effects of particle size variation, component mixing, and soil packing upon remotely sensed reflectance spectra. This has implications not only for Mars, but for other planets and planetoids. The ratio of Fe(II)/Fe(III) in the Martian soil analog materials on spectral reflectance in the visible range has begun, and the results will be evaluated according to conformity with the visible Mars reflectance spectrum. Some initial LR and GEX data have been collected for the mineral samples and their mixtures, which can be compared with the Viking data and interpreted in terms of the redox (Fe(II)/Fe(III) environment.

Banin, A.; Orenberg, J.; Roush, T.

1991-01-01

59

Mycobacterium Diversity and Pyrene Mineralization in Petroleum-Contaminated Soils  

PubMed Central

Degradative strains of fast-growing Mycobacterium spp. are commonly isolated from polycyclic aromatic hydrocarbon (PAH)-contaminated soils. Little is known, however, about the ecology and diversity of indigenous populations of these fast-growing mycobacteria in contaminated environments. In the present study 16S rRNA genes were PCR amplified using Mycobacterium-specific primers and separated by temperature gradient gel electrophoresis (TGGE), and prominent bands were sequenced to compare the indigenous Mycobacterium community structures in four pairs of soil samples taken from heavily contaminated and less contaminated areas at four different sites. Overall, TGGE profiles obtained from heavily contaminated soils were less diverse than those from less contaminated soils. This decrease in diversity may be due to toxicity, since significantly fewer Mycobacterium phylotypes were detected in soils determined to be toxic by the Microtox assay than in nontoxic soils. Sequencing and phylogenetic analysis of prominent TGGE bands indicated that novel strains dominated the soil Mycobacterium community. Mineralization studies using [14C]pyrene added to four petroleum-contaminated soils, with and without the addition of the known pyrene degrader Mycobacterium sp. strain RJGII-135, indicated that inoculation increased the level of degradation in three of the four soils. Mineralization results obtained from a sterilized soil inoculated with strain RJGII-135 suggested that competition with indigenous microorganisms may be a significant factor affecting biodegradation of PAHs. Pyrene-amended soils, with and without inoculation with strain RJGII-135, experienced both increases and decreases in the population sizes of the inoculated strain and indigenous Mycobacterium populations during incubation. PMID:11319104

Cheung, Pui-Yi; Kinkle, Brian K.

2001-01-01

60

NATURAL ATTENUATION OF COPPER IN SOILS AND SOIL MINERALS - II  

EPA Science Inventory

The bioabailability and toxicity of Cu in soils is controlled by a number of soil properties and processes. Some of these such as pH, adsorption/desorption and competition with beneficial cations have been extensively studied. However, the effects of natural attenuation (or aging...

61

NATURAL ATTENUATION OF COPPER IN SOILS AND SOIL MINERALS - I  

EPA Science Inventory

The bioavailability and toxicity of Cu in soils is controlled by a number of soil properties and processes. Some of these such as pH, adsorption/desorption and competition with beneficial cations have been extensively studied. However, the effects of natural attenuation (or aging...

62

Anaerobic N mineralization in paddy soils in relation to inundation management, physicochemical soil fractions, mineralogy and soil properties  

NASA Astrophysics Data System (ADS)

Anaerobic N mineralization measured from (saturated) repacked soil cores from 25 paddy fields in Bangladesh and was previously found to negatively related to soil N content on a relative basis. This suggests that other factors like soil organic matter (SOM) quality or abiotic factors instead control the anaerobic N mineralization process. We therefore assessed different physical and chemical fractions of SOM, management factors and various soil properties as predictors for the net anaerobic N mineralization. 1° First, we assessed routinely analyzed soil parameters (soil N and soil organic carbon, texture, pH, oxalate- and pyrophosphate-extractable Fe, Al, and Mn, fixed-NH4 content). We found no significant influences of neither soil mineralogy nor the annual length of inundation on soil N mineralization. The anaerobic N mineralization correlated positively with Na-pyrophosphate-extractable Fe and negatively with pH (both at P<0.01). At this stage it is, however, not known if these relations between net evolution of NH4 and pH and Fe content are causal or indirect. 2° Second, the 25 samples collected from farmers' fields were physically fractionated into particulate OM and silt and clay associated OM. The silt and clay sized OM was further chemically fractionated by oxidation with 6%NaOCl to isolate an oxidation-resistant OM fraction, followed by extraction of mineral bound OM with 10%HF thereby isolating the HF-resistant OM. None of the physicochemical SOM fractions were found useful predictors anaerobic N mineralization. The linkage between these chemical soil N fractions and N supplying processes actually occurring in the soil thus appears to be weak. Regardless, we hypothesize that variation in strength of N-mineral and N-OM linkages is likely to explain variation in bio-availability of organic N and proneness to mineralization. Yet, in order to separate kinetically different soil N fractions we then postulated that an alternative approach would be required, which instead isolates soil N fractions on the basis of bonding strength. In this respect bonding strength should be seen as opposite of proneness to dissolution of released N into water, the habitat of soil microorganisms mediating soil N mineralization. We hypothesize that soil N extracted by water at increasing temperatures would reflect such N fractions with increasing bonding strength, in turn equivalent to decreasing bio-availability. Although water has frequently been used to extract labile SOM, its use has mostly been limited to 100°C. 3° Third we developed sub critical water extraction (SCWE) at 100°C, 150°C and 200°C to isolate SOM fractions from the set of 25 paddy soil samples. In all cases, SCWE organic carbon (SCWE-OC) and N (SCWE-N) increased exponentially with the increase of temperature. SCWE preferentially extracted N over OC with increasing temperature. The efficiency of SCWE and the selectivity towards N were both lower in soils with increasingly reactive clay mineralogy. No correlations were found between the SCWE fractions and anaerobic N mineralization rate. In conclusion, SOM quantity and SOM quality, here represented by C and N distribution over physicochemical fractions, don't seem to dominantly determine anaerobic N mineralization in primarily young floodplain paddy soils. Other factors with exceeding control (pH and pyrophosphate extractable Fe) appear to exist. Possibly, the specific young genesis stage of most of the soils included (termed 'floodplain' soils) results in a limited availability of readily reducible Fe. Being an important alternative electron acceptor under submerged conditions, the availability of Fe, which is also controlled by pH, may be a bottleneck in the anaerobic N mineralization process. This needs to be further investigated by controlled incubation experiments with detailed follow-up of pH, redox potential, Fe in solution and mineral N.

Sleutel, Steven; Kader, Mohammed Abdul; Ara Begum, Shamim; De Neve, Stefaan

2013-04-01

63

Layer of organic pine forest soil on top of chlorophenol-contaminated mineral soil enhances contaminant degradation.  

PubMed

Chlorophenols, like many other synthetic compounds, are persistent problem in industrial areas. These compounds are easily degraded in certain natural environments where the top soil is organic. Some studies suggest that mineral soil contaminated with organic compounds is rapidly remediated if it is mixed with organic soil. We hypothesized that organic soil with a high degradation capacity even on top of the contaminated mineral soil enhances degradation of recalcitrant chlorophenols in the mineral soil below. We first compared chlorophenol degradation in different soils by spiking pristine and pentachlorophenol-contaminated soils with 2,4,6-trichlorophenol in 10-L buckets. In other experiments, we covered contaminated mineral soil with organic pine forest soil. We also monitored in situ degradation on an old sawmill site where mineral soil was either left intact or covered with organic pine forest soil. 2,4,6-Trichlorophenol was rapidly degraded in organic pine forest soil, but the degradation was slower in other soils. If a thin layer of the pine forest humus was added on top of mineral sawmill soil, the original chlorophenol concentrations (high, ca. 70 ?g g(-1), or moderate, ca. 20 ?g g(-1)) in sawmill soil decreased by >40 % in 24 days. No degradation was noticed if the mineral soil was kept bare or if the covering humus soil layer was sterilized beforehand. Our results suggest that covering mineral soil with an organic soil layer is an efficient way to remediate recalcitrant chlorophenol contamination in mineral soils. The results of the field experiment are promising. PMID:22752813

Sinkkonen, Aki; Kauppi, Sari; Simpanen, Suvi; Rantalainen, Anna-Lea; Strömmer, Rauni; Romantschuk, Martin

2013-03-01

64

Elemental composition of biomineralized amorphous mineral granules isolated from ants: correlation with ingested mineral particles from the soil.  

PubMed

Amorphous mineral granules are formed by concentric mineral layers containing polyphosphate, pyrophosphate and/or orthophosphate and several metallic cations such as Mg(2+), Ca(2+), K(+), Mn(2+), Fe(3+), Cu(2+), and Zn(2+). In this work, we analyzed amorphous mineral granules isolated from the ant species Camponotus abdominalis, Camponotus sp., Acromyrmex subterraneus and Pachycondyla marginata by energy-dispersive X-ray analysis. The elemental composition of the granules was compared to that of mineral particles, probably soil particles, to access the influence of the environment and of specific characteristics of each ant species in the elemental composition of the amorphous mineral granules. Both the granules and mineral particles presented Mg, Ca, Fe, and Zn in the four species. Additionally, Al tended to be present in both (or none) of the two types of material in a given ant species, suggesting that the aluminum found in the amorphous mineral granules could be derived from ingested soil particles. On the other hand, Sr was found in the amorphous mineral granules of some of the studied ant species, but not in the mineral particles. The fact that 3/4 of the elements found in the granules were found also in the mineral particles suggests that the mineral composition of the soil plays a fundamental role in the accumulation of some elements in the amorphous mineral granules of ants. These results suggest a major role of soil particles as a source of micronutrients for the four ant species. PMID:22750041

Carneiro, Fabricia G; Keim, Carolina N; Acosta-Avalos, Daniel; Farina, Marcos

2013-01-01

65

Stability of Soil Carbon Fractions - Aggregation Versus Mineral Association  

NASA Astrophysics Data System (ADS)

Models that seek to describe the dynamics of soil organic C typically distinguish between two or more C fractions according to differences of biochemical and microbial degradation. The rates are a consequence of recalcitrance, accessibility and interactions. Soil aggregation is an important mechanism controlling the accessibility of substrates by microbes and enzymes and thus the dynamics of minerals bound C are interacting with soil aggregate dynamics. In this study we focused on C fractions isolated by particle size fractionation. The main objective of our study was to differentiate between C stabilization of soil fractions due to accessibility/aggregation or to association with minerals. For a detailed understanding of these processes and the sources of respired soil CO2 we combined the measurement of heterotrophic respiration, CO2-13C analyses and radiocarbon dating of the respired CO2 in a long-term laboratory mineralization experiment. For the experiment we took soil material from the A horizon of an Albic Luvisol under Norway spruce forest (Picea abies) in southern Germany. The air dried bulk soil (< 2000 µm) was subjected to ultrasonication (1st step 60 J ml-1; 2nd step 440 J ml-1) and separated according to particle size in three fractions: > 63 µm to 2000 µm - sand, > 6.3 µm to 63 µm - silt and silt/clay fraction < 6.3 µm - clay. Solid-state 13C-CPMAS NMR spectroscopy was used to analyze the composition of bulk soil and fractions. The incubation of the three fractions and the bulk soil was done for 250 days in triplicate at 20 degree Celsius and 70% of maximal water holding capacity. A relative enrichment of alkyl C and an increase of the alkyl / O/N-alkyl C ratios in the order of sand < silt < clay were observed by 13C-NMR. On a long term the sand fraction and the bulk soil showed a sustained C bioavailability. For the silt and clay fraction similar respiration rates and a low C bioavailability were detected. The recombined fractions (by calculation) showed 35% higher amounts of respired CO2-C than the bulk soil. This difference accounts for the absence of restricted accessibility due to soil aggregation. Because of the high amounts of mineral bound C the main source of CO2-C (70%) in the recombined fraction is the clay fraction. Nevertheless the recalcitrance of mineral bound C is restricting the positive effects of aggregate disruption on the C turnover. The small fast decomposing C pool of the sand fraction is of minor importance to the total soil respiration balance. CO2-13C signatures showed higher values of the silt and clay fractions in contrast to the sand fraction, indicating a lower bioavailability of 13C-depleted carbon sources in the small fractions. The analyses of CO2-14C showed a shift to the utilization of older C sources with time.

Mueller, C. W.; Koegel-Knabner, I.

2007-12-01

66

Soil Nitrogen Mineralization Potential for Improved Fertilizer Recommendations and Decreased Nitrate Contamination of Groundwater  

E-print Network

to determine optimum conditions for estimating soil microbial biomass (SMB) from previously dried soils and to identify a quick, reliable biochemical predictor of soil N mineralization potential. Initial evaluations were conducted on a Weswood silty clay loam...

Franzluebbers, Alan; Haney, Richard; Hons, Frank

67

Characterization of zinc adsorption sites in two mineral soils  

Microsoft Academic Search

The adsorption of Zn, as compared with Mg, on two mineral soils, which differed in their major cation-exchange materials and with and without Ca-saturation, was measured in the presence of free CaCl2.The adsorption of Zn as well as Mg occurred on cation-exchange sites. The Zn adsorption data conformed to a two-term Langmuir equation. The presence of two kinds of adsorption

Koji Wada; Aly Abd-Elfattah

1978-01-01

68

Microprobe analyses of glasses and minerals from Luna-16 soil  

NASA Technical Reports Server (NTRS)

Electron microprobe analyses are presented for nine elements in 250 glasses and 434 pyroxenes, eight elements in 113 olivines, and six elements in 354 feldspars, 35 spinels, and 159 ilmenites. All grains are from the 125-425 micron fraction of horizon A and horizon D soil from the Luna 16 sample. A norm is presented for each glass analysis and the structural formula is calculated for each mineral analysis.

Brown, R. W.; Harmon, R. S.; Jakes, P.; Reid, A. M.; Ridley, W. I.; Warner, J. L.

1971-01-01

69

Sorption of tebuconazole onto selected soil minerals and humic acids.  

PubMed

The aim of the present study was to investigate tebuconazole sorption on common soil minerals (birnessite, ferrihydrite, goethite, calcite and illite) and humic acids (representing soil organic matter). Tebuconazole was used (i) in the commercial form Horizon 250 EW and (ii) as an analytical grade pure chemical. In the experiment with the commercially available tebuconazole, a significant pH-dependent sorption onto the oxides was observed (decreasing sorption with increasing pH). The highest sorption was found for ferrihydrite due to its high specific surface area, followed by humic acids, birnessite, goethite and illite. No detectable sorption was found for calcite. The sorption of analytical grade tebuconazole on all selected minerals was significantly lower compared to the commercial product. The sorption was the highest for humic acids, followed by ferrihydrite and illite and almost negligible for goethite and birnessite without any pH dependence. Again, no sorption was observed for calcite. The differences in sorption of the commercially available and analytical grade tebuconazole can be attributed to the additives (e.g., solvents) present in the commercial product. This work proved the importance of soil mineralogy and composition of the commercially available pesticides on the behavior of tebuconazole in soils. PMID:22428895

Cadková, Eva; Komárek, Michael; Kaliszová, Regina; Koudelková, V?ra; Dvo?ák, Ji?í; Van?k, Aleš

2012-01-01

70

Temperature sensitivity of microbial respiration, nitrogen mineralization, and potential soil enzyme activities in organic alpine soils  

Microsoft Academic Search

Investigations focusing on the temperature sensitivity of microbial activity and nutrient turnover in soils improve our understanding of potential effects of global warming. This study investigates the temperature sensitivity of C mineralization, N mineralization, and potential enzyme activities involved in the C and N cycle (tyrosine amino-peptidase, leucine amino-peptidase, ß-glucosidase, ß-xylosidase, N-acetyl-ß-glucosaminidase). Four different study sites in the Austrian alpine

Oliver Koch; Dagmar Tscherko; Ellen Kandeler

2007-01-01

71

Distinct temperature sensitivity of soil carbon decomposition in forest organic layer and mineral soil  

NASA Astrophysics Data System (ADS)

The roles of substrate availability and quality in determining temperature sensitivity (Q10) of soil carbon (C) decomposition are still unclear, which limits our ability to predict how soil C storage and cycling would respond to climate change. Here we determined Q10 in surface organic layer and subsurface mineral soil along an elevation gradient in a temperate forest ecosystem. Q10 was calculated by comparing the times required to respire a given amount of soil C at 15 and 25°C in a 350-day incubation. Results indicated that Q10 of the organic layer was 0.22-0.71 (absolute difference) higher than Q10 of the mineral soil. Q10 in both the organic layer (2.5-3.4) and the mineral soil (2.1-2.8) increased with decreasing substrate quality during the incubation. This enhancement of Q10 over incubation time in both layers suggested that Q10 of more labile C was lower than that of more recalcitrant C, consistent with the Arrhenius kinetics. No clear trend of Q10 was found along the elevation gradient. Because the soil organic C pool of the organic layer in temperate forests is large, its higher temperature sensitivity highlights its importance in C cycling under global warming.

Xu, Wenhua; Li, Wei; Jiang, Ping; Wang, Hui; Bai, Edith

2014-10-01

72

Distinct temperature sensitivity of soil carbon decomposition in forest organic layer and mineral soil  

PubMed Central

The roles of substrate availability and quality in determining temperature sensitivity (Q10) of soil carbon (C) decomposition are still unclear, which limits our ability to predict how soil C storage and cycling would respond to climate change. Here we determined Q10 in surface organic layer and subsurface mineral soil along an elevation gradient in a temperate forest ecosystem. Q10 was calculated by comparing the times required to respire a given amount of soil C at 15 and 25°C in a 350-day incubation. Results indicated that Q10 of the organic layer was 0.22–0.71 (absolute difference) higher than Q10 of the mineral soil. Q10 in both the organic layer (2.5–3.4) and the mineral soil (2.1–2.8) increased with decreasing substrate quality during the incubation. This enhancement of Q10 over incubation time in both layers suggested that Q10 of more labile C was lower than that of more recalcitrant C, consistent with the Arrhenius kinetics. No clear trend of Q10 was found along the elevation gradient. Because the soil organic C pool of the organic layer in temperate forests is large, its higher temperature sensitivity highlights its importance in C cycling under global warming. PMID:25270905

Xu, Wenhua; Li, Wei; Jiang, Ping; Wang, Hui; Bai, Edith

2014-01-01

73

Distinct temperature sensitivity of soil carbon decomposition in forest organic layer and mineral soil.  

PubMed

The roles of substrate availability and quality in determining temperature sensitivity (Q10) of soil carbon (C) decomposition are still unclear, which limits our ability to predict how soil C storage and cycling would respond to climate change. Here we determined Q10 in surface organic layer and subsurface mineral soil along an elevation gradient in a temperate forest ecosystem. Q10 was calculated by comparing the times required to respire a given amount of soil C at 15 and 25°C in a 350-day incubation. Results indicated that Q10 of the organic layer was 0.22-0.71 (absolute difference) higher than Q10 of the mineral soil. Q10 in both the organic layer (2.5-3.4) and the mineral soil (2.1-2.8) increased with decreasing substrate quality during the incubation. This enhancement of Q10 over incubation time in both layers suggested that Q10 of more labile C was lower than that of more recalcitrant C, consistent with the Arrhenius kinetics. No clear trend of Q10 was found along the elevation gradient. Because the soil organic C pool of the organic layer in temperate forests is large, its higher temperature sensitivity highlights its importance in C cycling under global warming. PMID:25270905

Xu, Wenhua; Li, Wei; Jiang, Ping; Wang, Hui; Bai, Edith

2014-01-01

74

Mineral Dissolution and Precipitation due to Carbon Dioxide-Water-Rock Interactions: The Significance of Accessory Minerals in Carbonate Reservoirs (Invited)  

NASA Astrophysics Data System (ADS)

Accessory minerals in carbonate reservoirs, and in the caprocks that seal these reservoirs, can provide insight into multiphase fluid (CO2 + H2O)-rock interactions and the behavior of CO2 that resides in these water-rock systems. Our program integrates field data, hydrothermal experiments, and geochemical modeling to evaluate CO2-water-rock reactions and processes in a variety of carbonate reservoirs in the Rocky Mountain region of the US. These studies provide insights into a wide range of geologic environments, including natural CO2 reservoirs, geologic carbon sequestration, engineered geothermal systems, enhanced oil and gas recovery, and unconventional hydrocarbon resources. One suite of experiments evaluates the Madison Limestone on the Moxa Arch, Southwest Wyoming, a sulfur-rich natural CO2 reservoir. Mineral textures and geochemical features developed in the experiments suggest that carbonate minerals which constitute the natural reservoir will initially dissolve in response to emplacement of CO2. Euhedral, bladed anhydrite concomitantly precipitates in response to injected CO2. Analogous anhydrite is observed in drill core, suggesting that secondary anhydrite in the natural reservoir may be related to emplacement of CO2 into the Madison Limestone. Carbonate minerals ultimately re-precipitate, and anhydrite dissolves, as the rock buffers the acidity and reasserts geochemical control. Another suite of experiments emulates injection of CO2 for enhanced oil recovery in the Desert Creek Limestone (Paradox Formation), Paradox Basin, Southeast Utah. Euhedral iron oxyhydroxides (hematite) precipitate at pH 4.5 to 5 and low Eh (approximately -0.1 V) as a consequence of water-rock reaction. Injection of CO2 decreases pH to approximately 3.5 and increases Eh by approximately 0.1 V, yielding secondary mineralization of euhedral pyrite instead of iron oxyhydroxides. Carbonate minerals also dissolve and ultimately re-precipitate, as determined by experiments in the Madison Limestone, but pyrite will persist and iron oxyhydroxides will not recrystallize.

Kaszuba, J. P.; Marcon, V.; Chopping, C.

2013-12-01

75

Mineral exploration and soil analysis using in situ neutron activation  

USGS Publications Warehouse

A feasibility study has been made to operate by remote control an unshielded portable positive-ion accelerator type neutron source to induce activities in the ground or rock by "in situ" neutron irradiation. Selective activation techniques make it possible to detect some thirty or more elements by irradiating the ground for periods of a few minutes with either 3-MeV or 14-MeV neutrons. The depth of penetration of neutrons, the effect of water content of the soil on neutron moderation, gamma ray attenuation in the soil and other problems are considered. The analysis shows that, when exploring for most elements of economic interest, the reaction 2H(d,n)3He yielding ??? 3-MeV neutrons is most practical to produce a relatively uniform flux of neutrons of less than 1 keV to a depth of 19???-20???. Irradiation with high energy neutrons (??? 14 MeV) can also be used and may be better suited for certain problems. However, due to higher background and lower sensitivity for the heavy minerals, it is not a recommended neutron source for general exploration use. Preliminary experiments have been made which indicate that neutron activation in situ is feasible for a mineral exploration or qualititative soil analysis. ?? 1976.

Senftle, F.E.; Hoyte, A.F.

1966-01-01

76

Vertical profile measurements of soil air suggest immobilization of gaseous elemental mercury in mineral soil.  

PubMed

Evasion of gaseous elemental Hg (Hg(0)g) from soil surfaces is an important source of atmospheric Hg, but the volatility and solid-gas phase partitioning of Hg(0) within soils is poorly understood. We developed a novel system to continuously measure Hg(0)g concentrations in soil pores at multiple depths and locations, and present a total of 297 days of measurements spanning 14 months in two forests in the Sierra Nevada mountains, California, U.S. Temporal patterns showed consistent pore Hg(0)g concentrations below levels measured in the atmosphere (termed Hg(0)g immobilization), ranging from 66 to 94% below atmospheric concentrations throughout multiple seasons. The lowest pore Hg(0)g concentrations were observed in the deepest soil layers (40 cm), but significant immobilization was already present in the top 7 cm. In the absence of sinks or sources, pore Hg(0)g levels would be in equilibrium with atmospheric concentrations due to the porous nature of the soil matrix and gas diffusion. Therefore, we explain decreases in pore Hg(0)g in mineral soils below atmospheric concentrations--or below levels found in upper soils as observed in previous studies--with the presence of an Hg(0)g sink in mineral soils possibly related to Hg(0)g oxidation or other processes such as sorption or dissolution in soil water. Surface chamber measurements showing daytime Hg(0)g emissions and nighttime Hg(0)g deposition indicate that near-surface layers likely dominate net atmospheric Hg(0)g exchange resulting in typical diurnal cycles due to photochemcial reduction at the surface and possibly Hg(0)g evasion from litter layers. In contrast, mineral soils seem to be decoupled from this surface exchange, showing consistent Hg(0)g uptake and downward redistribution--although our calculations indicate these fluxes to be minor compared to other mass fluxes. A major implication is that once Hg is incorporated into mineral soils, it may be unlikely subjected to renewed Hg(0)g re-emission from undisturbed, background soils emphasizing the important role of soils in sequestering past and current Hg pollution loads. PMID:24428735

Obrist, Daniel; Pokharel, Ashok K; Moore, Christopher

2014-02-18

77

Infrared spectra of lunar soil analogs. [spectral reflectance of minerals  

NASA Technical Reports Server (NTRS)

The infrared spectra of analogs of lunar soils were investigated to further the development of methodology for interpretation of remotely measured infrared spectra of the lunar surface. The optical constants of dunite, bytownite, augite, ilmenite, and a mare glass analog were obtained. The infrared emittance spectra of powdered minerals were measured and compared with spectra calculated by the reflectance theory using a catalog of optical constants. The results indicate that the predictions of the theory closely simulate the experimental measurements if the optical constants are properly derived.

Aronson, J. R.

1977-01-01

78

Interaction of root exudates with the mineral soil constituents and their effect on mineral weathering  

NASA Astrophysics Data System (ADS)

Plants release significant amounts of high and low molecular weight organic compounds into the rhizosphere. Among these exudates organic acids (e.g. citric acid, malic acid, oxalic acid), phenolic compounds (e.g. flavonoids), amino acids and siderophores of microbial and/or plant origin strongly influence and modify the biogeochemical cycles of several elements, thus causing changes in their availability for plant nutrition. One class of these elements is composed by the trace elements; some of them are essential for plants even if in small concentrations and are considered micronutrients, such as Fe, Zn, Mn. Their solubility and bioavailability can be influenced, among other factors, by the presence in soil solution of low molecular weight root exudates acting as organic complexing agents that can contribute to the mineral weathering and therefore, to their mobilization in the soil solution. The mobilized elements, in function of the element and of its concentration, can be either important nutrients or toxic elements for plants. The objective of this study was to assess the influence of several root exudates (citric acid, malic acid, oxalic acid, genistein, quercetin and siderophores) on the mineralogy of two different soils (an agricultural calcareous soil and an acidic polluted soil) and to evaluate possible synergic or competitive behaviors. X-ray diffraction (XRD) coupled with Electron Probe Micro Analysis (EPMA) was used to identify the crystalline and amorphous phases which were subjected to mineral alteration when exposed to the action of root exudates. Solubilization of trace metals such as Cu, Zn, Ni, Cr, Pb, Cd as well as of major elements such as Si, Al, Fe and Mn was assessed by means of Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Soil microorganisms have proven to decrease mineral weathering by reducing the concentration of active root exudates in solution. Results obtained are an important cornerstone to better understand the biogeochemical processes acting in the rhizosphere which can play an important role in the availability of trace elements (either nutrient or toxic) for plant uptake. Research is supported by MIUR - FIRB "Futuro in ricerca", internal grant of Unibz (TN5031 & TN5046) and the Autonomous Province of Bolzano (Rhizotyr TN5218).

Mimmo, T.; Terzano, R.; Medici, L.; Lettino, A.; Fiore, S.; Tomasi, N.; Pinton, R.; Cesco, S.

2012-04-01

79

Nitrogen mineralization potentials of shrub-steppe soils with different disturbance histories  

Microsoft Academic Search

Disturbance of shrub-steppe soils and changes in the dominant plant cover may alter soil N-cycling processes. The mineralization of organic N to plant-available forms is an important component of the N cycle in shrub-steppe soils. Therefore, the soil N-mineralization potential (N{sub o}) was determined for two arid ecosystems, an undisturbed perennial shrub-steppe and an annual grassland, which was initially shrub-steppe

H. Jr. Bolton; R. E. Wildung; J. L. Smith

2009-01-01

80

A short-term mineral amendment impacts the mineral weathering bacterial communities in an acidic forest soil.  

PubMed

Mineral amendment (i.e. calcium, phosphorous, potassium and/or magnesium) is a management practice used in forestry to improve nutrient availability and recover soil fertility, especially in nutrient-poor forest ecosystems. However, whether this amendment can lead to modifications of the soil characteristics and an improvement in tree growth, and its impact on the soil bacterial communities, especially the mineral weathering bacterial communities, remains poorly documented. In this study, we investigated the short-term impact of a mineral amendment on the taxonomic and functional structure of the mineral weathering bacterial communities. To do this, a plantation of four-year old oak (Quercus petraea) trees amended with or without dolomite [CaMg(CO3)2] was established in the experimental forest site of Breuil-Chenue, which is characterized by an acidic soil and a low availability of calcium and magnesium. Three years after amendment, soil samples were used to isolate bacteria as well as to determine the soil characteristics and the metabolic potentials of these soil microbial communities. Based on a bioassay for quantifying the solubilisation of inorganic phosphorous, we demonstrate that the bacterial isolates coming from the non-amended bulk soil were significantly more efficient than those from the amended bulk soil. No difference was observed between the bacterial isolates coming from the amended and non-amended rhizospheres. Notably, the taxonomic analyses revealed a dominance of bacterial isolates belonging to the Burkholderia genus in both samples. Overall, our results suggest that the bioavailability of nutritive cations into soil impacts the distribution and the efficacy of mineral weathering bacterial communities coming from the soil but not those coming from the rhizosphere. PMID:23583355

Lepleux, C; Uroz, S; Collignon, C; Churin, J-L; Turpault, M-P; Frey-Klett, P

2013-09-01

81

Carbon and nitrogen mineralization dynamics in different soils of the tropics amended with legume residues and contrasting soil moisture contents  

Microsoft Academic Search

Seasonal drought in tropical agroecosystems may affect C and N mineralization of organic residues. To understand this effect,\\u000a C and N mineralization dynamics in three tropical soils (Af, An1, and An2) amended with haricot bean (HB; Phaseolus vulgaris L.) and pigeon pea (PP; Cajanus cajan L.) residues (each at 5 mg g?1 dry soil) at two contrasting soil moisture contents (pF2.5 and

Girma Abera; Endalkachew Wolde-meskel; Lars R. Bakken

82

Soil mineral nitrogen and nitrate leaching losses in soil tillage systems combined with a catch crop  

Microsoft Academic Search

Annual nitrogen leaching losses from arable land in south Sweden usually amount to 15–45kgha?1. The objective of this three-year study was to investigate the timing effect of mouldboard ploughing (early autumn, late autumn or spring) on soil mineral nitrogen content and nitrate leaching in a cropping system with spring-sown small grain crops (barley, oats and wheat). Late autumn ploughing was

Maria Stenberg; Helena Aronsson; Börje Lindén; Tomas Rydberg; Arne Gustafson

1999-01-01

83

Chemical and mineral composition of ectomycorrhizosphere soils of subalpine fir (Abies  

E-print Network

Chemical and mineral composition of ectomycorrhizosphere soils of subalpine fir (Abies lasiocarpa, Canada V2N 4Z9, e-mail: arocenaj@unbc.ca; and 2Department of Soil Science, University of British Columbia., Glowa, K. R., Massicotte, H. B. and Lavkulich, L. 1999. Chemical and mineral composition of ectomycorrhi

Massicotte, Hugues

84

SIMULTANEOUS INHIBITION OF CARBON AND NITROGEN MINERALIZATION IN A FOREST SOIL BY SIMULATED ACID PRECIPITATION  

EPA Science Inventory

Acid Precipitation may alter the rates of microbial processes in soil that are important for forest productivity. Acidification of soil can result in a depression of carbon mineralization. The present study was designed to determine whether the inhibition of carbon mineralization...

85

In situ investigation of dissolution of heavy metal containing mineral particles in an acidic forest soil  

Microsoft Academic Search

We report the application of an in situ method to obtain field dissolution rates of fine mineral particles in soils. Samples with different metal-containing mineral and slag particles (lead oxide, copper concentrate and copper slag) from the mining and smelting industry were buried in the topsoil of an acidic forest soil for up to 18 months. In addition we studied

Andreas Birkefeld; Rainer Schulin; Bernd Nowack

2006-01-01

86

Nitrogen mineralization and nitrification in upland and peatland forest soils in two Canadian Shield catchments  

Microsoft Academic Search

Net mineralization and nitrification in surface forest soils were measured in upland forest stands and valley peatlands using in situ soil incubations at two headwater catchments of Harp Lake, Ontario from July 1995 to October 1996. No difference in either net N mineralization or nitrification was observed between the two adjacent catchments despite differences in catchment N export. Annual rates

Kevin J. Devito; Cherie J. Westbrook; Sherry L. Schiff

1999-01-01

87

Effects of the duration of water saturation periods on organic carbon mineralization in a poorly-drained mineral soil  

NASA Astrophysics Data System (ADS)

In poorly-drained soils located in riparian areas, climate change is likely to affect the duration and frequency of water saturation periods and consequently rates of soil organic matter mineralization in these soils. Using laboratory incubations of an epistagnic Haplic Albeluvisol, the aim of this study was to quantify the effect the duration of water saturation periods on soil organic C (SOC) and N mineralization under saturated and non-saturated conditions. 120 undisturbed soils cores were incubated at 20°C during 64 days. Three treatments differing in the duration of the water saturation periods were considered. In the control treatment (T0), the soil water content was maintained at field capacity (71% WFPS) throughout the duration of the incubation. In treatment T1, the soil was saturated (100% WFPS) during 46 days, and desaturated and soil water content was maintained at field capacity until the end of incubation. In treatment T2, the soil was saturated (100% WFPS) during 19 days, and desaturated and soil water content was maintained at field capacity until the end of incubation. For each treatment, gas analyses (CO2) were performed at 10 dates on four replicates. SOC mineralization in T1 and T2 was low during the saturation phase (median value 2.7 and 1.5 mgC-CO2.kg-1.d-1 respectively) compared to that of the control treatment (median value 4.5 and 4.1 mgC-CO2.kg-1.d-1 respectively at 46th and 19th day) and that of the desaturated phase of T1 and T2 (median value 7.9 and 3.6 mgC-CO2.kg-1.d-1 respectively). In T1, CO2 concentration at the beginning of desaturation twice higher than that observed in the control treatment. The results also showed that whatever the duration of saturation periods SOC mineralization in T1 and T2 at desurated condition was similar to that of T0. However, the SOC mineralized on the whole 64 days of incubation was 45% less important for T1 and T2 than T0. This study showed that the duration of water saturation periods not affected organic carbon mineralization neither at saturated nor desaturated condition. In saturation condition carbon mineralization was provided by nitrate reduction respiration and desaturation beginning caused a flush of aerobic respiration. All these processes were not time depending but strongly linked to soil moisture and soil redox conditions.

Tete, Emmanuel; Viaud, Valérie; Walter, Christian

2013-04-01

88

Indigenous and enhanced mineralization of pyrene, benzo[a]pyrene, and carbazole in soils.  

PubMed Central

We studied the mineralization of pyrene, carbazole, and benzo[a]pyrene in soils obtained from three abandoned coal gasification plants in southern Illinois. The soils had different histories of past exposure to hydrocarbon contamination and different amounts of total organic carbon, microbial biomass, and microbial activity. Mineralization was measured by using serum bottle radiorespirometry. The levels of indigenous mineralization of 14C-labeled compounds ranged from 10 to 48% for pyrene, from undetectable to 46% for carbazole, and from undetectable to 25% for benzo[a]pyrene following long-term (greater than 180-day) incubations. Pyrene and carbazole were degraded with short or no lag periods in all soils, but benzo[a]pyrene mineralization occurred after a 28-day lag period. Mineralization was not dependent on high levels of microbial biomass and activity in the soils. Bacterial cultures that were capable of degrading pyrene and carbazole were isolated by enrichment, grown in pure culture, and reintroduced into soils. Reintroduction of a pyrene-degrading bacterium enhanced mineralization to a level of 55% within 2 days, compared with a level of 1% for the indigenous population. The carbazole degrader enhanced mineralization to a level of 45% after 7 days in a soil that showed little indigenous carbazole mineralization. The pyrene and carbazole degraders which we isolated were identified as a Mycobacterium sp. and a Xanthamonas sp., respectively. Our results indicated that mineralization of aromatic hydrocarbons can be significantly enhanced by reintroducing isolated polycyclic aromatic hydrocarbon-degrading bacteria. PMID:1785924

Grosser, R J; Warshawsky, D; Vestal, J R

1991-01-01

89

Interactive priming of biochar and labile organic matter mineralization in a smectite-rich soil.  

PubMed

Biochar is considered as an attractive tool for long-term carbon (C) storage in soil. However, there is limited knowledge about the effect of labile organic matter (LOM) on biochar-C mineralization in soil or the vice versa. An incubation experiment (20 °C) was conducted for 120 days to quantify the interactive priming effects of biochar-C and LOM-C mineralization in a smectitic clayey soil. Sugar cane residue (source of LOM) at a rate of 0, 1, 2, and 4% (w/w) in combination with two wood biochars (450 and 550 °C) at a rate of 2% (w/w) were applied to the soil. The use of biochars (~ -36‰) and LOM (-12.7‰) or soil (-14.3‰) with isotopically distinct ?(13)C values allowed the quantification of C mineralized from biochar and LOM/soil. A small fraction (0.4-1.1%) of the applied biochar-C was mineralized, and the mineralization of biochar-C increased significantly with increasing application rates of LOM, especially during the early stages of incubation. Concurrently, biochar application reduced the mineralization of LOM-C, and the magnitude of this effect increased with increasing rate of LOM addition. Over time, the interactive priming of biochar-C and LOM-C mineralization was stabilized. Biochar application possesses a considerable merit for long-term soil C-sequestration, and it has a stabilizing effect on LOM in soil. PMID:21950729

Keith, Alexandra; Singh, Balwant; Singh, Bhupinder Pal

2011-11-15

90

Effects of mycorrhizal fungus isolates on mineral acquisition by Panicum virgatum in acidic soil  

Microsoft Academic Search

Plant ability to withstand acidic soil mineral deficiencies and toxicities can be enhanced by root-arbuscular mycorrhizal\\u000a fungus (AMF) symbioses. The AMF benefits to plants may be attributed to enhanced plant acquisition of mineral nutrients essential\\u000a to plant growth and restricted acquisition of toxic elements. Switchgrass (Panicum virgatum L.) was grown in pHCa (soil:10?mM CaCl2, 1?:?1) 4 and 5 soil (Typic

R. B. Clark; R. W. Zobel; S. K. Zeto

1999-01-01

91

Root Influence on Nitrogen Mineralization and Nitrification in Avena barbata Rhizosphere Soil  

Microsoft Academic Search

Micro-15N pool dilution was used to quantify rates of gross N mineralization, consumption, and nitrification in bulk soil and in soil within 2 mm of root sections of Avena barbata (slender wild oats), an annual grass common to California oak woodland-savannas. Rates of gross N mineralization in rhizosphere soil (9.2 mg N kg21d21) were about ten times higher than in

D. J. Herman; K. K. Johnson; C. H. Jaeger; E. Schwartz; M. K. Firestone

2006-01-01

92

[Mineralization of soil organic carbon and its relationship with soil enzyme activities in apple orchard in Weibei].  

PubMed

A total of 36 kinds of soil samples were collected from apple orchards under three kinds of management model, including clear tillage model, intercropping white clover model and intercropping small crown flower model, the mineralization of soil organic carbon and four kinds of soil enzymes activities were determined, and the relationship between the two parameters was also analyzed. The results showed that the soil organic carbon mineralization of all the three treatments was almost the same. The daily SOC mineralization rate first increased and then decreased, and finally tended to be stable. After 31 days incubation experiment, the maximum accumulative amount of SOC mineralization occurred in white clover treatment with 590 mg x kg(-1), followed by small crown flower treatment with 541 mg x kg(-1), and the minimum value was 367 mg x kg(-1) in the control treatment, and the accumulative amount of SOC mineralization decreased with increasing soil depth. Discovered by the first-order kinetics, the fitting parameter Cp value ranged from 0.252 to 2.74 g x kg(-1) and k value ranged from 0.019 to 0.051 d(-1), and the two grass treatments both showed significant difference in Cp value from the control treatment, and the soil invertase and cellulose activities showed obvious relationship with soil organic carbon mineralization. PMID:25244868

Jia, Man-Li; Guo, Hong; Li, Hui-Ke

2014-07-01

93

Mechanistic roles of soil humus and minerals in the sorption of nonionic organic compounds from aqueous and organic solutions  

USGS Publications Warehouse

Mechanistic roles of soil humus and soil minerals and their contributions to soil sorption of nonionic organic compounds from aqueous and organic solutions are illustrated. Parathion and lindane are used as model solutes on two soils that differ greatly in their humic and mineral contents. In aqueous systems, observed sorptive characteristics suggest that solute partitioning into the soil-humic phase is the primary mechanism of soil uptake. By contrast, data obtained from organic solutions on dehydrated soil partitioning into humic phase and adsorption by soil minerals is influenced by the soil-moisture content and by the solvent medium from which the solute is sorbed. ?? 1985.

Chiou, C. T.; Shoup, T. D.; Porter, P. E.

1985-01-01

94

[Compositional characteristics and roles of soil mineral substances in depressions between hills in karst region].  

PubMed

Based on the investigation and analysis of seven soil mineral substance variables, nine vegetation factors, four topographical factors, and ten soil physicochemical factors in the 200 m x 40 m dynamic monitoring plots in farmland, forest plantation, secondary forest, and primary forest in the depressions between hills in karst region, and by using traditional statistical analysis, principal component analysis (PCA), and canonical correlation analysis (CCA), this paper studied the compositional characteristics and roles of soil mineral substances as well as the coupling relationships between the mineral substances and the vegetation, topography, and other soil properties. In the depressions, soil mineral substances were mainly composed of SiO2, Al2O3, K2O, and Fe2O3, whose contents were obviously lower than the mean background values of the soils in the world and in the zonal red soils at the same latitudes. The soil CaO and MgO contents were at medium level, while the soil MnO content was very low. The composition of soil mineral substances and their variation degrees varied with the ecosystems, and the soil development degree also varied. There was a positive correlation between vegetation origin and soil origin, suggesting the potential risk of rock desertification. Due to the high landscape heterogeneity of the four ecosystems, PCA didn't show good effect in lowering dimension. In all of the four ecosystems, soil mineral substances were the main affecting factors, and had very close relationships with vegetation, topography, and other soil properties. Especially for SiO2, CaO, and MnO, they mainly affected the vegetation species diversity and the soil organic matter, total nitrogen, and total potassium. This study indicated that soil mineral substances were the one of the factors limiting the soil fertility and vegetation growth in the depressions between hills in karst region. To effectively use the soil mineral resources and rationally apply mineral nutrients would have significances in the restoration and reconstruction of karst degraded ecosystems. PMID:22720612

Han, Mei-Rong; Song, Tong-Qing; Peng, Wan-Xia; Huang, Guo-Qin; Du, Hu; Lu, Shi-Yang; Shi, Wei-Wei

2012-03-01

95

Endogeic earthworms shape bacterial functional communities and affect organic matter mineralization in a tropical soil  

Microsoft Academic Search

Priming effect (PE) is defined as a stimulation of the mineralization of soil organic matter (SOM) following a supply of fresh organic matter. This process can have important consequences on the fate of SOM and on the management of residues in agricultural soils, especially in tropical regions where soil fertility is essentially based on the management of organic matter. Earthworms

Laetitia Bernard; Lydie Chapuis-Lardy; Tantely Razafimbelo; Malalatiana Razafindrakoto; Anne-Laure Pablo; Elvire Legname; Julie Poulain; Thomas Brüls; Michael O'Donohue; Alain Brauman; Jean-Luc Chotte; Eric Blanchart

2012-01-01

96

Ultrasonically aided mineral processing technique for remediation of soil contaminated by heavy metals  

Microsoft Academic Search

In this study, power ultrasound was used as aiding method for the mineral processing technique, which have recently been developed for the remediation of soil contaminated by heavy metal containing bullets, their broken parts and alteration products. Power ultrasound was used to disperse the soil to remove metals and metal compounds from soil particle surfaces instead of attrition conditioning. The

Hanna Kyllönen; Pentti Pirkonen; Väinö Hintikka; Pekka Parvinen; Antti Grönroos; Hannu Sekki

2004-01-01

97

What shapes edaphic communities in mineral and ornithogenic soils of Cierva Point, Antarctic Peninsula?  

NASA Astrophysics Data System (ADS)

Three mineral soil and four ornithogenic soil sites were sampled during summer 2006 at Cierva Point (Antarctic Peninsula) to study their bacterial, microalgal and faunal communities in relation to abiotic and biotic features. Soil moisture, pH, conductivity, organic matter and nutrient contents were consistently lower and more homogeneous in mineral soils. Ornithogenic soils supported larger and more variable bacterial abundances than mineral ones. Algal communities from mineral soils were more diverse than those from ornithogenic soils, although chlorophyll- a concentrations were significantly higher in the latter. This parameter and bacterial abundance were correlated with nutrient and organic matter contents. The meiofauna obtained from mineral soils was homogeneous, with one nematode species dominating all samples. The fauna of ornithogenic soils varied widely in composition and abundance. Tardigrades and rotifers dominated the meiofauna at eutrophic O2, where they supported a large population of the predatory nematode Coomansus gerlachei. At site O3, high bacterial abundance was consistent with high densities of the bacterivorous nematodes Plectus spp. This study provides evidence that Antarctic soils are complex and diverse systems, and suggests that biotic interactions (e.g. competition and predation) may have a stronger and more direct influence on community variability in space and time than previously thought.

Mataloni, G.; Garraza, G. González; Bölter, M.; Convey, P.; Fermani, P.

2010-08-01

98

Factors Influencing 2,4-D Sorption and Mineralization in Soil  

Microsoft Academic Search

This study quantified 2,4-D [(2,4-dichlorophenoxy)acetic acid] sorption and mineralization rates in five soils as influenced by soil characteristics and nutrient contents. Results indicated that 2,4-D was weakly sorbed by soil, with Freundlich distribution coefficients ranging from 0.81 to 2.89 µg g mL . First-order mineralization rate constants varied from 0.03 to 0.26, corresponding to calculated mineralization half-lives of 3 and 22 days, respectively.

Paula Picton; Annemieke Farenhorst

2004-01-01

99

Changes in mineral soil biogeochemical cycling and environmental conditions following tree harvest in the Northeast  

NASA Astrophysics Data System (ADS)

In the northeastern United States, reductions in carbon dioxide emissions have been attempted by using local wood as a renewable alternative to oil. Although woody biomass products are readily available, recent findings suggest that forest disturbance may cause release of carbon from the deeper mineral soil. Worldwide, deep soils sequester more than half of soil carbon, making it critical in the global carbon cycle; however, most studies on the effect of harvesting have focused on the organic soil horizon. Our research aimed to uncover changes in biogeochemistry and environmental conditions in deeper, mineral soil after clear cutting forests. We quantified post-harvest mineral soil carbon pools through a regional study. We utilized stands of different ages to measure the recovery of soil carbon over time since harvest. Stands included in this study were cut approximately 5, 12, 25, 50, or 120 ybp, in order to identify changes in soil carbon over time since harvest. We sampled harvested stands in six research or protected forests across New York, New Hampshire, Massachusetts, and Vermont. Soil samples were collected to a depth of 60 cm below the surface of the mineral soil using a gas-powered augur and 9.5 cm diameter drill bit. Soil samples were analyzed at Dartmouth College. In order to understand specific changes in mineral soil carbon dynamics following harvest, measurements of carbon fluxes, such as soil respiration and DOC transport were conducted at five different-aged stands at Bartlett Experimental Forest, NH. While parameters that may influence carbon storage—such as pH, clay content, tree cover and elevation— did not vary across the different-aged stands in each forest, carbon pools did vary over time. We found changes in carbon pools in at least three experimental forests across the northeast. At Bartlett Experimental Forest, we found a gradual decline in mineral soil carbon storage from between 85-87 Mg ha-1 in 120 year old and primary forest stands to a minimum of 53 Mg ha-1 in the 75 year old stand. In our carbon flux measurements, we observed higher DOC concentrations in lysimeter samples collected at 30 cm at 12 years after harvest. We have also documented consistently higher soil temperatures across summer months at 50 cm below the mineral soil in the recently clear-cut site at Bartlett Experimental Forest. These changes in biogeochemical and environmental conditions suggest that forest clearing does affect mineral soil, and our findings may help identify a mechanism to explain the observed carbon loss from soils in clear-cut forests.

Vario, C.; Friedland, A.

2012-12-01

100

[Characteristics of soil organic carbon mineralization at different temperatures in paddy soils under long-term fertilization].  

PubMed

Dynamics of soil organic carbon mineralization affected by long-term fertilizations and temperature in relation to different soil carbon fractions were investigated in paddy soils. Soil samples were collected from the plough layer of 3 long-term national experimental sites in Xinhua, Ningxiang and Taojiang counties of Hunan Province. Mineralization of soil organic C was estimated by 33-day aerobic incubation at different temperatures of 10, 20 and 30 degrees C. The results showed that the rates of CO2 production were higher during the earlier phase (0-13 d) in all treatments, and then decreased according to a logarithm function. Higher incubation temperature strengthened C mineralization in the different treatments. The quantities of cumulative CO2 production in NPK with manure or straw treatments were greater than in inorganic fertilizers treatments. The Q10 values in the different soil treatments ranged from 1.01-1.53. There were significantly positive correlations between the Q10 values and soil total organic carbon (TOC), easy oxidation organic carbon (EOOC), humic acid carbon (C(HA)), fulvic acid carbon (CFA). The cumulative amount of mineralized C was significantly positively correlated with microbial biomass carbon (MBC) at 10 and 20 degrees C, but not significantly at 30 degrees C. Significant correlations were found between the cumulative amount of mineralized C and different soil carbon fractions and C(HA)/C(FA). The correlations of differ- ent soil carbon fractions with the ratio of cumulative mineralized C to TOC were negatively correlated at 10 degrees C, but not significantly at 20 and 30 degrees C. These results suggested that the application of NPK with manure or straw would be helpful to increase the sequestration of C in paddy soils and reduce its contribution of CO2 release in the atmosphere. PMID:25129934

Lin, Shan; Chen, Tao; Zhao, Jin-Song; Xiang, Rong-Biao; Hu, Rong-Gui; Zhang, Shui-Qing; Wang, Mi-Lan; Lu, Zhao-Qi

2014-05-01

101

Minerals  

MedlinePLUS

Minerals are important for your body to stay healthy. Your body uses minerals for many different jobs, including building bones, making ... regulating your heartbeat. There are two kinds of minerals: macrominerals and trace minerals. Macrominerals are minerals your ...

102

Isolation and identification of phytate-degrading bacteria and their contribution to phytate mineralization in soil.  

PubMed

To better understand the phosphorus (P) cycling in an agricultural soil environment, amounts of total, organic and inorganic P in 10 agricultural soil samples were analyzed. Since a large proportion (57.8%) of the total P in the soils was in organic form, a method was developed to evaluate the mineralization rate of organic P in the soil by adding phytate to the soil and analyzing the change in water-soluble P (WSP) content after incubating it for 3 days. Moreover, the relationship between the phytate mineralization activity and bacterial biomass in 60 agricultural soils was also investigated, where the phytate mineralization activity ranged from 0 to 61.7% (average: 18.8%), and the R˛ value between phytate mineralization activity and indigenous bacterial biomass was 0.11 only. Phytate-degrading bacteria were isolated from the soil environment, and identified as Pseudomonas rhodesiae JT29, JT32, JT33, JT34, JT35, Pseudomonas sp. JT30, and Flavobacterium johnsoniae JT31. When P. rhodesiae JT29 and F. johnsoniae JT31 were inoculated into the agricultural soils, the phytate mineralization activities were increased up to 16 and 27 times, respectively. It was concluded that promotion of effective phytate-degrading bacterial strains could improve the sustainable P management in the agricultural soils. PMID:24201147

Horii, Sachie; Matsuno, Toshihide; Tagomori, Junta; Mukai, Masaki; Adhikari, Dinesh; Kubo, Motoki

2013-01-01

103

Effects of flooding and warming on soil organic matter mineralization in Avicennia germinans mangrove forests and Juncus roemerianus salt  

E-print Network

) mineralization respond to soil water, temperature, and ecosystem type (Avicennia germinans mangrove forest vs and N respond to temper- ature (23 vs. 27 C), soil hydroperiod (inundated 4 vs. 20 h/d), and soilEffects of flooding and warming on soil organic matter mineralization in Avicennia germinans

Lajeunesse, Marc J.

104

Magnetic beneficiation of highland and hi-Ti mare soils - Rock, mineral, and glassy components  

NASA Technical Reports Server (NTRS)

The exploitation of lunar soil can provide valuable raw materials for in situ resource utilization at a lunar base. A study of magnetic characterization was undertaken of three mare and two highland soils obtained from NASA. Beneficiation of mare and highland soils by sizing and magnetic separation can effectively concentrate the important components of the soils (e.g., ilmenite, native Fe, plagioclase, and aggluminates). As a soil matures and the impact melts consume additional minerals and rocks, the modal percentage of the minerals will decrease. The 'normative' percentage will become much greater than the modal percentage. Therefore, greater efficiency of separation can be realized with the proper selection of maturity of the soil, as well as by secondary grinding to further liberate specific minerals from lithic fragments (e.g., ilmenite and plagioclase).

Taylor, Lawrence A.; Oder, Robin R.

1990-01-01

105

Effects of fungicides mancozeb and dinocap on carbon and nitrogen mineralization in soils.  

PubMed

In our study, effects of fungicides mancozeb and dinocap on C and N mineralization were measured in arable and grassland soil. The soils were treated with these fungicides at the application and 10 times lower doses and then incubated at 20 degrees C for 2 weeks. Carbon mineralization (basal and substrate-induced respiration) and nitrogen mineralization (potential ammonification and nitrification) were evaluated 1 and 14 days after the treatment. After 14 days, ammonification was decreased to 48% and 83% at dinocap application dose in arable and grassland soil, respectively. Application dose of mancozeb caused significant decrease of nitrification to 11.2% and 5.6% in arable and grassland soil, respectively. Basal respiration and substrate-induced growth were rather stimulated by fungicides, especially at lower application doses. To conclude, potential risk may exist to soil microorganisms and their activities in soils treated routinely by mancozeb or dinocap. PMID:18755509

Cernohlávková, Jitka; Jarkovský, Jirí; Hofman, Jakub

2009-01-01

106

Paenibacillus selenii sp. nov., isolated from selenium mineral soil.  

PubMed

Strain W126(T), a Gram-reaction-positive, spore-forming, rod-shaped, facultatively anaerobic bacterium, motile by means of peritrichous flagella, was isolated from selenium mineral soil in Hubei province of China. 16S rRNA gene sequence analysis demonstrated that this isolate belonged to the genus Paenibacillus, with 97.9?% sequence similarity to Paenibacillus anaericanus MH21(T), while compared with the other species of the genus Paenibacillus, the 16S rRNA gene sequence similarities were less than 96.0%. DNA-DNA hybridization between strain W126(T) and Paenibacillus anaericanus DSM 15890(T) was 24%. The major isoprenoid menaquinone was menaquinone-7. Anteiso-C(15?:?0) was the major fatty acid. The DNA G+C content was 42.3 mol%. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, three unknown aminophospholipids and an unknown lipid. Strain W126(T) contained A1?-meso-diaminopimelic acid in the cell-wall peptidoglycan. The phenotypic, chemotaxonomic and genotypic data indicate that strain W126(T) represents a novel species of the genus Paenibacillus, for which the name Paenibacillus selenii sp. nov. is proposed. The type strain is W126(T) (?=?KCTC 33420(T)?=?CCTCC AB 2014003(T)). PMID:24827707

Xiang, Wanwan; Wang, Gejiao; Wang, Yuantao; Yao, Rong; Zhang, Fujun; Wang, Rui; Wang, Dan; Zheng, Shixue

2014-08-01

107

Temperature Sensitivity of Soil Organic Carbon Mineralization along an Elevation Gradient in the Wuyi Mountains, China  

PubMed Central

Soil organic carbon (SOC) actively participates in the global carbon (C) cycle. Despite much research, however, our understanding of the temperature sensitivity of soil organic carbon (SOC) mineralization is still very limited. To investigate the responses of SOC mineralization to temperature, we sampled surface soils (0–10 cm) from evergreen broad-leaf forest (EBF), coniferous forest (CF), sub-alpine dwarf forest (SDF), and alpine meadow (AM) along an elevational gradient in the Wuyi Mountains, China. The soil samples were incubated at 5, 15, 25, and 35°C with constant soil moisture for 360 days. The temperature sensitivity of SOC mineralization (Q10) was calculated by comparing the time needed to mineralize the same amount of C at any two adjacent incubation temperatures. Results showed that the rates of SOC mineralization and the cumulative SOC mineralized during the entire incubation significantly increased with increasing incubation temperatures across the four sites. With the increasing extent of SOC being mineralized (increasing incubation time), the Q10 values increased. Moreover, we found that both the elevational gradient and incubation temperature intervals significantly impacted Q10 values. Q10 values of the labile and recalcitrant organic C linearly increased with elevation. For the 5–15, 15–25, and 25–35°C intervals, surprisingly, the overall Q10 values for the labile C did not decrease as the recalcitrant C did. Generally, our results suggest that subtropical forest soils may release more carbon than expected in a warmer climate. PMID:23342038

Xu, Xia; Ruan, Honghua; Wang, Jiashe

2013-01-01

108

Soil carbon and nitrogen mineralization as affected by atrazine and glyphosate  

Microsoft Academic Search

Atrazine alone and atrazine plus glyphosate were added to soil to determine their effect on soil microbial activity as measured by C and N mineralization (Cmin, Nmin) and soil extractable atrazine without the use of radiolabelled isotopes. Atrazine alone was added to soils as a formulated product (Aatrex 4L) at a field rate of 22 (94 mg kg-1), 42 (188

R. L. Haney; S. A. Senseman; L. J. Krutz; F. M. Hons

2002-01-01

109

Spatial arrangement of organic compounds on a model mineral surface: implications for soil organic matter stabilization.  

PubMed

The complexity of the mineral-organic carbon interface may influence the extent of stabilization of organic carbon compounds in soils, which is important for global climate futures. The nanoscale structure of a model interface was examined here by depositing films of organic carbon compounds of contrasting chemical character, hydrophilic glucose and amphiphilic stearic acid, onto a soil mineral analogue (Al2O3). Neutron reflectometry, a technique which provides depth-sensitive insight into the organization of the thin films, indicates that glucose molecules reside in a layer between Al2O3 and stearic acid, a result that was verified by water contact angle measurements. Molecular dynamics simulations reveal the thermodynamic driving force behind glucose partitioning on the mineral interface: The entropic penalty of confining the less mobile glucose on the mineral surface is lower than for stearic acid. The fundamental information obtained here helps rationalize how complex arrangements of organic carbon on soil mineral surfaces may arise. PMID:24328330

Petridis, Loukas; Ambaye, Haile; Jagadamma, Sindhu; Kilbey, S Michael; Lokitz, Bradley S; Lauter, Valeria; Mayes, Melanie A

2014-01-01

110

DYNAMICS OF MINERAL STRUCTURES AND THE FATE OF METALS IN SOILS AND SEDIMENTS  

EPA Science Inventory

Significant progress has been made in elucidating sorption reactions that control the partitioning of metals from solution to mineral surfaces in contaminated soil/sediment systems. Surface complexation models have been developed to quantify the forward reaction with reasonable ...

111

Microbial biomass and C mineralization in agricultural soils as affected by atrazine addition  

Microsoft Academic Search

This study examines the effects of atrazine on both microbial biomass C and C mineralization dynamics in two contrasting agricultural\\u000a soils (organic C, texture, and atrazine application history) located at Galicia (NW Spain). Atrazine was added to soils, a\\u000a Humic Cambisol (H) and a Gleyic Cambisol (G), at a recommended agronomic dose and C mineralization (CO2 evolved), and microbial biomass

J. Mahía; A. Cabaneiro; T. Carballas; M. Díaz-Ravińa

2008-01-01

112

Field measurement of net nitrogen mineralization of manured soil cropped to maize  

Microsoft Academic Search

We evaluated the in situ net nitrogen (N) mineralization in a soil cropped to maize and fertilized for 11 years with cattle\\u000a slurry or farmyard manure, both common on livestock farms of the Po River valley in Northern Italy. The net N mineralization\\u000a of the tilled soil layer was measured in six consecutive incubation periods after manure application, for a total

Stefano Monaco; Dario Sacco; Teresa Borda; Carlo Grignani

2010-01-01

113

Soil respiration, nitrogen mineralization and uptake in barley following cultivation of grazed grasslands  

Microsoft Academic Search

Soil tillage was studied as a strategy to synchronize N mineralization with plant demand following ploughing of two types\\u000a of grazed pastures [ryegrass\\/white clover (Lolium perenne\\/Trifolium repens) and pure ryegrass]. The swards were either rotovated and ploughed or ploughed only. Soil respiration, as determined by a\\u000a dynamic chamber method, was related to net N mineralization and to plant N uptake

J. Eriksen; L. S. Jensen

2001-01-01

114

Kinetics of di-(2-ethylhexyl)phthalate mineralization in sludge-amended soil  

Microsoft Academic Search

Sewage sludge is frequently used as a soil fertilizer although it may contain elevated concentrations of priority pollutants including di-(2-ethylhexyl)phthalate (DEHP). In the present study, the kinetics of microbial [[sup 14]C]DEHP mineralization was studied in laboratory microcosms with sewage sludge and agricultural soil. A biphasic model with two independent kinetic expressions was used to fit the mineralization data. The initial

Peter Lindequist Madsen; Jesper Bandsholm Thyme; Kaj Henriksen; P. Moeldrup; Peter Roslev

1999-01-01

115

Colorado potato beetle response to soil amendments: A case in support of the mineral balance hypothesis?  

Microsoft Academic Search

The mineral balance hypothesis [Phelan, L.P., Norris, K.H., Mason, J.F., 1996. Soil management history and host preference by Ostrinia nubilalis: evidence for plant mineral balance mediating insect–plant interactions. Environ. Entomol. 25, 1329–1336] suggests that the organic matter and microbial activity associated with organically managed soils afford a buffering capability to maintain nutrient balance in plants. An optimal nutrient balance, in

Andrei Alyokhin; Gregory Porter; Eleanor Groden; Francis Drummond

2005-01-01

116

Isolation and characterization of an isoproturon mineralizing Sphingomonas sp. strain SH from a French agricultural soil  

Microsoft Academic Search

The phenylurea herbicide isoproturon, 3-(4-isopropylphenyl)-1,1-dimethylurea (IPU), was found to be rapidly mineralized in\\u000a an agricultural soil in France that had been periodically exposed to IPU. Enrichment cultures from samples of this soil isolated\\u000a a bacterial strain able to mineralize IPU. 16S rRNA sequence analysis showed that this strain belonged to the phylogeny of\\u000a the genus Sphingomonas (96% similarity with Sphingomonas

Sabir Hussain; Marion Devers-Lamrani; Najoi El Azhari; Fabrice Martin-Laurent

2011-01-01

117

Stabilization of Soil Organic Matter: Association with Minerals or Chemical Recalcitrance?  

Microsoft Academic Search

Soil organic matter (OM) can be stabilized against decomposition by association with minerals, by its inherent recalcitrance\\u000a and by occlusion in aggregates. However, the relative contribution of these factors to OM stabilization is yet unknown. We\\u000a analyzed pool size and isotopic composition (14C, 13C) of mineral-protected and recalcitrant OM in 12 subsurface horizons from 10 acidic forest soils. The results

Robert Mikutta; Markus Kleber; Margaret S. Torn; Reinhold Jahn

2006-01-01

118

Clay mineralogy of weathering rinds and possible implications concerning the sources of clay minerals in soils.  

USGS Publications Warehouse

Weathering rinds on volcanic clasts in Quaternary deposits in the western US contain only very fine-grained and poorly crystalline clay minerals. Rinds were sampled from soils containing well-developed argillic B horizons in deposits approx 105 yr old or more. The clay-size fraction of the rinds is dominated by allophane and iron hydroxy-oxides, whereas the B horizons contain abundant well-crystallized clay minerals. The contrast between the clay mineralogy of the weathering rinds, in which weathering is isolated from other soil processes, and that of the associated soil matrices suggests a need to reassess assumptions concerning the rates at which clay minerals form and the sources of clay minerals in argillic B horizons. It seems that crystalline clay minerals form more slowly in weathering rinds than is generally assumed for soil environments and that the weathering of primary minerals may not be the dominant source of crystalline clay minerals in Middle to Late Pleistocene soil.-A.P.

Colman, S. M.

1982-01-01

119

Ofloxacin sorption in soils after long-term tillage: The contribution of organic and mineral compositions.  

PubMed

Intensive human activities in agricultural areas resulted in significant alteration of soil properties, which consequently change their interactions with various contaminants. This process needs to be incorporated in contaminant behavior prediction and their risk assessment. However, the relevant study is missing. This work was designed to examine the change of soil properties and ofloxacin (OFL) sorption after tillage. Soil samples were collected in Yuanyang, Mengzi, and Dianchi areas with different agricultural activities. Although the mineral compositions of soils from Yuanyang and Dianchi differed greatly, these compositions are similar after tillage, especially for paddy soils. Soil pH decreased generally after OFL sorption, suggesting that ion exchange of OFL with protons in soil organic matter (SOM) was important for OFL sorption. However, a positive relationship between SOM and OFL sorption was not observed. On the contrary, increased SOM decreased OFL sorption when soils from the same geological location were compared. Generally speaking, tillage activities or dense vegetations greatly decreased OFL sorption. The higher OFL sorption in B horizon than A horizon suggested limited leaching of OFL through soil columns. The summed sorption calculated based on the sorption of individual soil components and their percentages in soils was higher than the intact soil. This phenomenon may be understood from the interactions between soil components, such as the coating of SOM on mineral particles. This study emphasizes that soil should be treat as a dynamic environmental matrix when assessing antibiotic behaviors and risks, especially in the area with intense human activities. PMID:25173763

Zhou, Dandan; Chen, Bingfa; Wu, Min; Liang, Ni; Zhang, Di; Li, Hao; Pan, Bo

2014-11-01

120

Soil Mineral–Organic Matter--Microorganism Interactions: Fundamentals and Impacts  

Microsoft Academic Search

Minerals, organic matter, and microorganisms are integral parts of the pedosphere and related environments. These three components are not separate entities but rather a united system constantly in association and interactions with each other in the terrestrial environment. Interactions of these components mediated by soil solution and atmosphere govern mechanisms of mineral weathering reactions, formation of short-range ordered (SRO) metal

P. M. Huang

2004-01-01

121

A simple method to determine mineralization of (14) C-labeled compounds in soil.  

PubMed

Degradation of organic compounds in soil is often determined by measuring the decrease of the parent compound and analyzing the occurrence of its metabolites. However, determining carbon species as end products of parent compound dissipation requires using labeled materials that allow more accurate determination of the environmental fate of the compound of interest. The current conventional closed system widely used to monitor degradation of (14) C-labeled compounds in soil is complex and expensive and requires a specialized apparatus and facility. In the present study, the authors describe a simple system that facilitates measurement of mineralization of (14) C-labeled compounds applied to soil samples. In the system, soda lime pellets to trap mineralized (14) C-carbon species, including carbon dioxide, were placed in a cup, which was then inserted above the treated soil sample in a tube. Mineralization of [(14) C]2,4-D applied to soil samples in the simple system was compared with that in the conventional system. The simple system provided an equivalent detection of (14) C-carbon species mineralized from the parent compound. The results demonstrate that this cost- and space-effective simple system is suitable for examining degradation and mineralization of (14) C-labeled compounds in soil and could potentially be used to investigate their mineralization in other biological matrices. PMID:24677225

Myung, Kyung; Madary, Michael W; Satchivi, Norbert M

2014-06-01

122

Resources for a lunar base: Rocks, minerals, and soil of the Moon  

NASA Astrophysics Data System (ADS)

The rocks and minerals of the Moon will be included among the raw materials used to construct a lunar base. The lunar regolith, the fragmental material present on the surface of the Moon, is composed mostly of disaggregated rocks and minerals, but also includes glassy fragments fused together by meteorite impacts. The finer fraction of the regolith (i.e., less than 1 cm) is informally referred to as soil. The soil is probably the most important portion of the regolith for use at a lunar base. For example, soil can be used as insulation against cosmic rays, for lunar ceramics and abodes, or for growing plants. The soil contains abundant solar-wind-implanted elements as well as various minerals, particularly oxide phases, that are of potential economic importance. For example, these components of the soil are sources of oxygen and hydrogen for rocket fuel, helium for nuclear energy, and metals such as Fe, Al, Si, and Ti.

Taylor, Lawrence A.

1992-09-01

123

Impact of activated carbon, biochar and compost on the desorption and mineralization of phenanthrene in soil.  

PubMed

Sorption of PAHs to carbonaceous soil amendments reduces their dissolved concentrations, limiting toxicity but also potentially biodegradation. Therefore, the maximum abiotic desorption of freshly sorbed phenanthrene (?5 mg kg(-1)) was measured in three soils amended with activated carbon (AC), biochar or compost. Total amounts of phenanthrene desorbed were similar between the different soils, but the amendment type had a large influence. Complete desorption was observed in the unamended and compost amended soils, but this reduced for biochar (41% desorbed) and AC (8% desorbed). Cumulative amounts mineralized were 28% for the unamended control, 19% for compost, 13% for biochar and 4% for AC. Therefore, the effects of the amendments in soil in reducing desorption were also reflected in the extents of mineralization. Modeling was used to analyze key processes, indicating that for the AC and charcoal treatments bacterial activity did not limit mineralization, but rather desorption into the dissolved phase. PMID:23871817

Marchal, Geoffrey; Smith, Kilian E C; Rein, Arno; Winding, Anne; Wollensen de Jonge, Lis; Trapp, Stefan; Karlson, Ulrich G

2013-10-01

124

Resources for a lunar base: Rocks, minerals, and soil of the Moon  

NASA Technical Reports Server (NTRS)

The rocks and minerals of the Moon will be included among the raw materials used to construct a lunar base. The lunar regolith, the fragmental material present on the surface of the Moon, is composed mostly of disaggregated rocks and minerals, but also includes glassy fragments fused together by meteorite impacts. The finer fraction of the regolith (i.e., less than 1 cm) is informally referred to as soil. The soil is probably the most important portion of the regolith for use at a lunar base. For example, soil can be used as insulation against cosmic rays, for lunar ceramics and abodes, or for growing plants. The soil contains abundant solar-wind-implanted elements as well as various minerals, particularly oxide phases, that are of potential economic importance. For example, these components of the soil are sources of oxygen and hydrogen for rocket fuel, helium for nuclear energy, and metals such as Fe, Al, Si, and Ti.

Taylor, Lawrence A.

1992-01-01

125

Mineral Soil Carbon in Managed Hardwood Forests of the Northeastern US  

NASA Astrophysics Data System (ADS)

New England is characterized by extensive forest cover and large reservoirs of soil carbon (C). In northern hardwood forests, mineral soil C can account for up to 50% of total ecosystem C. There has been an increasing demand for forests to serve both as a C sink and a renewable energy source, and effective management of the ecosystem C balance relies on accurate modeling of each compartment of the ecosystem. However, the dynamics of soil C storage with respect to forest use are variable and poorly understood, particularly in mineral soils. For example, current regional models assume C pools after forest harvesting do not change, while some studies suggest that belowground mineral soil C pools can be affected by disturbances at the soil surface. We quantified mineral soil C pools in previously clear-cut stands in seven research or protected forests across New York, New Hampshire, Massachusetts, and Vermont. The ages of the sites sampled ranged from recently cleared to those with no disturbance history, with 21 forest stands represented in the study. Within each research forest studied, physical parameters such as soil type, forest type, slope and land-use history (aside from forest harvest) did not vary between the stands of different ages. Soil samples were collected to a depth of 60 cm below the mineral-organic boundary using a gas-powered augur and 9.5-cm diameter drill bit. Samples were collected in 10-cm increments in shallow mineral soil and 15-cm increments from 30-60 cm depth. Carbon, nitrogen (N), pH, texture and soil mineralogy were measured across the regional sites. At Bartlett Experimental Forest (BEF) in New Hampshire, mineral soil biogeochemistry in cut and uncut sites was studied at a finer scale. Measurements included soil temperature to 55 cm depth, carbon compound analyses using Py-GCMS and soil microbial messenger RNA extractions from mineral soil. Finally, we simulated C dynamics after harvesting by building a model in Stella, with a particular interest in the role that priming effects may play if C is transported from organic to mineral soil layers after forest harvest. Laboratory analyses were conducted at Dartmouth College and at the University of New Hampshire. For the regional study, mineral soil C and N concentrations, and in some cases, pools were highest at locations that had never been harvested. Although sites represented different stages of succession after clearing, there were no significant patterns over time since harvest. At BEF, soil temperature at 55 cm depth in a recently cleared stand was on average 1.5° C higher than surrounding forested sites between June and September, and shallower depths had greater temperature discrepancies. Our model, which was parameterized using published field data from Bartlett and Hubbard Brook forests, showed that inputs of labile C to mineral soil after harvest could prime the decomposition of preexisting mineral soil C and account for up to 40% of the observed difference in C pools between harvested and undisturbed sites.

Vario, C.; Friedland, A.; Hornig, C.

2013-12-01

126

Effects of redox conditions on the adsorption of dissolved organic matter to soil minerals and differently aged paddy soils  

NASA Astrophysics Data System (ADS)

Effects of redox conditions on the adsorption of dissolved organic matter to soil minerals and differently aged paddy soils Meike Sauerwein1, Alexander Hanke2, Klaus Kaiser3, Karsten Kalbitz2 1) Dept. of Soil Ecology, Bayreuth Centre of Ecology and Environmental Research (BayCEER), University of Bayreuth, 95440 Bayreuth, Germany, meike.sauerwein@gmail.com 2) Institute of ecosystem dynamics and biodiversity, University of Amsterdam, 1018 WV, Netherlands, a.hanke@uva.nl, k.kalbitz@uva.nl 3) Soil Sciences, Martin Luther University Halle, 06099 Halle, Germany, klaus.kaiser@landw.uni-halle.de Current knowledge on dissolved organic matter (DOM) in soils is based mainly on observations and experiments in aerobic environments. Adsorption to soil minerals is an important mechanism of DOM retention and stabilization against microbial decay under oxic conditions. Under anoxic conditions where hydrous iron oxides, the potential main adsorbents of DOM, possibly dissolve, the importance of adsorption seems questionable. Therefore, we studied the adsorption of DOM to selected soil minerals and to mineral soils under oxic and anoxic conditions. In detail, we tested the following hypotheses: 1. Minerals and soils adsorb less DOM under anoxic conditions than under oxic ones. 2. The reduced adsorption under anoxic conditions is result of the smaller adsorption to hydrous Fe oxides whereas adsorption to clay minerals and Al hydroxides is not sensitive to changes in redox conditions 3. DOM adsorption will increase with the number of redox cycles, thus time of soil formation, due to increasing contents of poorly crystalline Fe oxides. This will, however, cause a stronger sensitivity to redox changes as poor crystalline Fe oxides are more reactive. 4. Aromatic compounds, being preferentially adsorbed under oxic conditions, will be less strongly adsorbed under anoxic conditions. We chose paddy soils as models because their periodically and regular exposure to changing redox cycles, with anoxic conditions during the rice growing period and oxic conditions during harvest and growth of other crops. Soils of a unique chronosequence of paddy soils (50, 300, 700 and 2000 years) in China were studied in direct comparison to non-paddy soils of the same age. In additions, selected soil minerals (goethite, ferrihydrite, amorphous Al hydroxide, hydrobiotite, nontronite and ripodolite), differing in their response to changes in redox conditions, were studied in order to indentify those mineral constituents responsible for redox-induced changes in DOM adsorption to the test soils. The DOM for the adsorption was extracted from composted rice straw as a surrogate for DOM percolating in paddy soils. Batch adsorption experiments were carried out with DOM pre-incubated to give oxic and anoxic conditions and maintaining these redox conditions during the whole procedure. The redox potential resulting from anoxic pre-incubation was about 100 mV, thus in the range of Fe reduction. Besides of dissolved organic carbon (DOC), we determined changes in the composition of DOM by the specific UV absorbance. We also analyzed main cations, anions and redox-sensitive elements to give a comprehensive picture of the effects of changing redox conditions on the dynamics of organic C, N, P, S, Fe and Al. First results indicated indeed less adsorption of DOM to Fe oxides under anoxic than under oxic conditions, with a more pronounced effect for ferrihydrite than for goethite. Maximum adsorption of DOM was more than 50% larger under oxic than under anoxic conditions. The effect was less pronounced but still detectable for clay minerals such as hydrobiotite, nontronite, and ripodolite. The specific UV absorbance of DOM contact with minerals was 20-50% stronger under anoxic than under oxic conditions. These changes in DOM composition indicated that preferential adsorption of aromatic compounds might be limited to aerated soils. We conclude that adsorption, although less strong than under oxic conditions, is an important mechanism of DOM retention also under anoxic conditions. Decreasi

Sauerwein, Meike; Hanke, Alexander; Kaiser, Klaus; Kalbitz, Karsten

2010-05-01

127

DIVISION S-10--WETLAND SOILS Carbon Accumulation and Storage in Mineral Subsoil beneath Peat  

E-print Network

DIVISION S-10--WETLAND SOILS Carbon Accumulation and Storage in Mineral Subsoil beneath Peat Tim R subsoil (Turunen and Moore, 2003). TheyWe showed that sandy subsoils beneath peat near Ramsey Lake AND METHODS DOC under anoxic conditions. Study Area The soils were collected from near Ramsay Lake, upper

Moore, Tim

128

Soil mineral genesis and distribution in a saline lake landscape of the Pantanal Wetland, Brazil  

E-print Network

Soil mineral genesis and distribution in a saline lake landscape of the Pantanal Wetland, Brazil S Geografia, Universidade de SĂŁo Paulo, SĂŁo Paulo, Brazil b Soil & Water Sciences Program, Department) and alkalinity appear to be geochemically controlled during the concentration of waters and may be involved

Ahmad, Sajjad

129

SULFUR DYNAMICS IN MINERAL HORIZONS OF TWO NORTHERN HARDWOOD SOILS A COLUMN STUDY WITH 35S  

EPA Science Inventory

Sulfur dynamics of two Spodosols were ascertained using soil columns constructed from homogenized mineral soil from northern hardwood ecosystems at the Huntington Forest (HF) in the Adirondack Mountains of New York and Bear Brook Watershed in Maine (BBWM). olumns were leached for...

130

Clay Mineral Formation and Transformation in Rocks and Soils  

Microsoft Academic Search

Three mechanisms for clay mineral formation (inheritance, neoformation, and transformation) operating in three geological environments (weathering, sedimentary, and diagenetic-hydrothermal) yield nine possibilities for the origin of clay minerals in nature. Several of these possibilities are discussed in terms of the rock cycle. The mineralogy of clays neoformed in the weathering environment is a function of solution chemistry, with the most

D. D. Eberl; V. C. Farmer; R. M. Barrer

1984-01-01

131

Potential C and N mineralization and microbial biomass from intact and increasingly disturbed soils of varying texture  

Microsoft Academic Search

Potential C and N mineralization and soil microbial biomass C were determined following disturbance (i.e. drying and sieving) pretreatments in five soils varying in texture (30–350 mg clay g?1 soil) from the southern Piedmont USA. Soil disturbance by drying (i.e. rewetting following drying at 55°C for 72 h) of intact soil cores resulted in a flush of C mineralization (70%

A. J. Franzluebbers

1999-01-01

132

Screening rhizosphere soil samples for the ability to mineralize elevated concentrations of atrazine and metolachlor  

Microsoft Academic Search

Rhizosphere soils from several plant species were tested for their ability to mineralize atrazine (2?chloro?4?ethylamino?6?isopropylamino?s?triazine) or metolachlor (2?chloro?N?(2?ethyl?6?methylphenyl)?N?(2?methoxy?1?methylethyl)acetamide) at concentrations typical of point?source contamination (50 ?g\\/g). Rhizosphere soils were collected from the root zone of plants in areas with previous herbicide exposure. Several rhizosphere soils tested positive for C?atrazine mineralization (? 8.5%) including kochia (Kochia scoparia), lambsquarters (Chenopodium berlandieri), foxtail

T. A. Anderson; J. R. Coats

1995-01-01

133

Shedding light on carbon-mineral complexation in the soil environment: impacts on C sequestration and cycling  

E-print Network

42 Shedding light on carbon-mineral complexation in the soil environment: impacts on C sequestration and cycling Sparks, D.L. & C. Chen Department of Plant and Soil Sciences and Delaware@udel.edu) Abstract Organic matter (OM)-mineral complexation plays a critical role in soil carbon (C) stabilization

Sparks, Donald L.

134

Mineral Contamination from Cemetery Soils: Case Study of Zandfontein Cemetery, South Africa  

PubMed Central

The burial of coffins may pose an environmental and health hazard since the metals that are used in coffin-making may corrode or degrade into harmful toxins. These may leach into the surrounding soils and groundwater. Very little research has been conducted world-wide on the mineral contamination potential of cemeteries, and virtually none in South Africa. The aim of the study is to determine whether burial practices affect the mineral content of soils in cemeteries. This was done by comparing the mineral concentrations of soils within the Zandfontein Cemetery in Tshwane (Gauteng, South Africa) to those off-site as well as those in zones with high burial loads with those zones with fewer burials. Twenty three soil samples were collected from various sites on- and off-site and analyzed for 31 minerals using ICP-AES. It was found that mineral concentrations of soils within the Zandfontein Cemetery were considerably higher than those off-site. Soil samples in multiple burials blocks also have elevated metal concentrations. These excess metals are probably of anthropogenic origin associated with burial practices and could pose an environmental and human health hazard. Strict monitoring of water quality in boreholes in the vicinity of the cemetery is recommended. PMID:22470306

Jonker, Cornelia; Olivier, Jana

2012-01-01

135

Mineralization of organic contaminants under aerobic and anaerobic conditions in sludge-soil mixtures  

Microsoft Academic Search

Background and Main Features  The mineralization of eight organic chemicals (surfactants, substituted aromatic compounds, di(2-ethylhexyl)phthalate and\\u000a phenanthrene) was examined in sludge-soil mixtures under aerobic, denitrifying and methanogenic conditions.\\u000a \\u000a \\u000a \\u000a Results and Discussion  Most of the chemicals were extensively or partially mineralized under aerobic conditions with mineralization half-lives between\\u000a 1.5 and 12.5 days. Linear tridecyl tetra ethoxylate, di(2-ethylhexyl)phthalate and 2,4-dinitrophenol were also mineralized\\u000a partially

Bo Gejlsbjerg; Trine T. Andersen; Torben Madsen

2004-01-01

136

Recovery of Minerals in Martian Soils Via Supercritical Fluid Extraction  

NASA Astrophysics Data System (ADS)

We are investigating the use of supercritical fluids to extract mineral and/or carbonaceous material from Martian surface soils and its igneous crust. Two candidate supercritical fluids are carbon dioxide and water. The Martian atmosphere is composed mostly of carbon dioxide (approx. 95.3%) and could therefore provide an in-situ source of carbon dioxide. Water, although present in the Martian atmosphere at only approx. 0.03%, is also a candidate supercritical solvent. Previous work done with supercritical fluids has focused primarily on their solvating properties with organic compounds. Interestingly, the first work reported by Hannay and Hogarth at a meeting of the Royal Society of London in 1879 observed that increasing or decreasing the pressure caused several inorganic salts e.g., cobalt chloride, potassium iodide, and potassium bromide, to dissolve or precipitate in supercritical ethanol. In high-pressure boilers, silica, present in most boiler feed waters, is dissolved in supercritical steam and transported as dissolved silica to the turbine blades. As the pressure is reduced the silica precipitates onto the turbine blades eventually requiring the shutdown of the generator. In supercritical water oxidation processes for waste treatment, dissolved salts present a similar problem. The solubility of silicon dioxide (SiO2) in supercritical water is shown. The solubility curve has a shape characteristic of supercritical systems. At a high pressure (greater than 1750 atmospheres) increasing the temperature results in an increase in solubility of silica, while at low pressures, less than 400 atm., the solubility decreases as temperature increases. There are only a few studies in the literature where supercritical fluids are used in extractive metallurgy. Bolt modified the Mond process in which supercritical carbon monoxide was used to produce nickel carbonyl (Ni(CO)4). Tolley and Tester studied the solubility of titanium tetrachloride (TiCl4) in supercritical CO2. They reported complete miscibility of TiCl4 with supercritical CO2 (infinite solubility). At 1500 psig, TiCl4 and CO2 form a single liquid phase below 50 C. Tolley et al. also reported on the solubility and thermodynamics of tin tetrachloride in supercritical CO2. Some of their data for TiC14 are shown. Three criteria have been suggested to predict which materials are suitable for supercritical extraction: 1) Hydrocarbons or lipophilic compounds of low molecular weight and polarity are easily extracted with supercritical CO2. 2) Compounds with polar groups are not easily extracted with supercritical CO2. 3) Separation of mixtures is facilitated if components differing mass, vapor pressure, or polarity.

Debelak, Kenneth A.; Roth, John A.

2001-03-01

137

Comparison of soil CO2 emission in poorly and well-drained mineral soil at a small agricultural hillside scale  

NASA Astrophysics Data System (ADS)

The increase of greenhouse gases (GHG) in the atmosphere and the climate change which results from it, will have major effects in the 21th century. In agricultural landscapes and others ecosystems, soil CO2 emissions are controlled by thermal and hydrological regimes, but their relative importance seems to be dependant of soil drainage conditions. The purpose of this study was to measure and model soil CO2 emissions at the scale of a hillslope presenting a gradient of soil drainage conditions. The studied hillslope is located in the Kervidy-Naizin headwater catchment (Brittany, France, 48°00'N 2°50W) and corresponds to an agricultural field cropped in a maize / winter wheat rotation. Soil CO2 emissions were measured once per week from February 2013 to March 2014, in two locations contrasting by soil drainage condition: (1) well-drained mineral (WDM) soil classified as Cambisol in upslope position, (2) poorly-drained mineral (PDM) soil classified as Haplic Albeluvisol and which undergoes continuous or periodic saturation and reduction conditions in downslope position. The measurement sites of 9m2 were equipped for continuous measurement of soil water content (TDR probes) and soil temperature. Soil CO2 emissions were measured with the infrared gas analyzer (IRGA) Li-8100A (Li-Cor, Lincoln, USA) until now. Results showed that PDM soils were waterlogged in winter and autumn inducing a low CO2 emission (average of 1.1±0.2µmol.m-2.s-1) which was two times lower than CO2 emissions in WDM soil. A shift of soil moisture to field capacity leading to an availability of oxygen in soil in the spring and summer induced an increase of soil CO2 emissions in PDM soil with a maximum of 5.03±0.5µmol.m-2.s-1 at the end of July. In WDM soil, CO2 emissions were high at the end of spring (average of 7µmol.m-2.s-1) and decreased of 65% at the end of summer because of the drought conditions. The modeling of temporal variability of soil CO2 emission by temperature and moisture empirical functions showed that the combined effect of soil temperature and soil moisture explained 77% (61% by T° and 39% by SWC) of soil CO2 emission variability in PDM soil, against 63% (53% by T° and 47% by SWC) in WDM soil. Others factors such as C input, and oxygen availability due to soil management may also controlled soil CO2 emission and mostly in WDM soil. The integration of these factors in model could help to well understand the difference in soil CO2 emission in Poorly-drained mineral soil compared with well-drained soil at agricultural hillside scale.

TETE, Emmanuel; Viaud, Valerie; Flechard, Chris; Walter, Christian

2014-05-01

138

Correlation of the Abundance of Betaproteobacteria on Mineral Surfaces with Mineral Weathering in Forest Soils  

PubMed Central

Pyrosequencing-based analysis of 16S rRNA gene sequences revealed a significant correlation between apatite dissolution and the abundance of betaproteobacteria on apatite surfaces, suggesting a role for the bacteria belonging to this phylum in mineral weathering. Notably, the cultivation-dependent approach demonstrated that the most efficient mineral-weathering bacteria belonged to the betaproteobacterial genus Burhkolderia. PMID:22798365

Lepleux, C.; Turpault, M. P.; Oger, P.; Frey-Klett, P.

2012-01-01

139

Effects of flooding and warming on soil organic matter mineralization in Avicennia germinans mangrove forests and Juncus roemerianus salt marshes  

NASA Astrophysics Data System (ADS)

Under a changing climate, coastal wetlands experience sea level rise, warming, and vegetation change, all of which may influence organic matter mineralization. In coastal wetlands of subtropical west-central Florida (USA), we investigated how soil carbon (C) and nitrogen (N) mineralization respond to soil water, temperature, and ecosystem type (Avicennia germinans mangrove forest vs. Juncus roemerianus salt marsh). We evaluated how soil respiration and mineral N concentration varied along a soil moisture gradient, and whether these relationships differed between ecosystem types. Then, we manipulated soils in a 28-d laboratory incubation to evaluate how potentially mineralizable C and N respond to temperature (23 vs. 27 °C), soil hydroperiod (inundated 4 vs. 20 h/d), and soil source. Soil saturation and inundation suppressed short-term (minutes to weeks) C mineralization from near-surface soils. Soil CO2 efflux declined by 65% as soil moisture increased from 75% to 85%, and potentially mineralizable C was 18% lower with a 20-h hydroperiod than with a 4-h hydroperiod. Organic C quality appears to be greater in A. germinans than in J. roemerianus soils, as A. germinans soils had higher field CO2 efflux rates and greater mineralizable C:N (despite lower total C:N). Increasing incubation temperature from 23 to 27 °C elevated potentially mineralizable C by 40%, indicating that two symptoms of climate change (increased inundation from sea level rise, and warming) may have opposing effects on soil C mineralization. Temperature sensitivity of C mineralization was high for long-hydroperiod soils, however, suggesting that protection of soil organic matter (SOM) due to prolonged inundation will be undermined by warming. Potentially mineralizable N was greater in J. roemerianus soils, although in situ mineral N was not different between ecosystems, instead correlating positively with SOM. These results indicate that models forecasting soil elevation responses to climate change might include inundation effects on mineralization rates.

Lewis, David Bruce; Brown, Jewel A.; Jimenez, Kristine L.

2014-02-01

140

Microbes residing in young organic rich Alaskan soils contain older carbon than those residing in old mineral high Arctic soils  

NASA Astrophysics Data System (ADS)

Arctic soils range from very organic rich to low carbon and mineral-dominated soils. At present, we do not yet fully understand if all carbon in the Arctic is equally vulnerable to mineralization in a warmer climate. Many studies have demonstrated that ancient carbon is respired when permafrost has thawed, yet our understanding of the active layer and permafrost carbon dynamics is still emerging. In an effort to remedy this disconnect between our knowledge of surface fluxes and below ground processes, we used radiocarbon to examine the microbial carbon dynamics in soil cores from organic rich soils near Barrow, Alaska and mineral soils from the Canadian high Arctic. Specifically, we compared the microbial community using lipid biomarkers, the inputs of carbon using n-alkanes and measured the 14C of both the bulk organic carbon and of the microbial lipids. In theory, the microbial lipids (phospholipid fatty acids, PLFA) represent the viable microbial community, as these lipids are hydrolyzed quickly after cell death. Variations in the PLFA distributions suggested that different microbial communities inhabit organic rich Alaskan soils and those of the Canadian high Arctic. When the PLFA concentrations were converted to cellular concentration, they were within the same order of magnitude (1 to 5 x 108 cells/g dry soil) with slightly higher cell concentrations in the organic rich Alaskan soils. When these cellular concentrations were normalized to the organic carbon content, the Canadian high Arctic soils contained a greater proportion of microbes. Although bulk organic carbon 14C of Alaskan soils indicated more recent carbon inputs into the soil than the Canadian high Arctic soils, the 14C of the PLFA revealed the opposite. For corresponding depth horizons, microbes in Alaskan soils were consuming carbon 1000 to 1500 years older than those in the Canadian high Arctic. Differences between the 14C content of bulk organic carbon and the microbial lipids were much smaller in Alaskan soil than that of the Canadian high Arctic soil, indicating that Alaskan microbes were interacting with the bulk organic carbon pool and Canadian high Arctic soil microbes were disconnected from the bulk organic carbon pool. Additionally, dissimilarities in the n-alkane distributions suggest vastly different carbon sources to these different soils. Collectively, these results suggest that (a) these Arctic soils contain a comparable abundance of microbes, (b) the organic carbon being accumulated in the Alaskan soil is likely from recent biomass, (c) mineral soil accumulation in the Canadian high Arctic is likely due to erosional inputs of ancient carbon and (d) the carbon stocks in Alaskan soils are more bioavailable to the microbes than those in mineral soils of the Canadian high Arctic. Incubation studies that incorporate gas fluxes and proteomics may tease apart if the observed differences in bioavailability are a function of temperature, substrate availability or some other variable.

Ziolkowski, L. A.; Slater, G. F.; Onstott, T. C.; Whyte, L.; Townsend-Small, A.

2013-12-01

141

High temperature and salinity enhance soil nitrogen mineralization in a tidal freshwater marsh.  

PubMed

Soil nitrogen (N) mineralization in wetlands is sensitive to various environmental factors. To compare the effects of salinity and temperature on N mineralization, wetland soils from a tidal freshwater marsh locating in the Yellow River Delta was incubated over a 48-d anaerobic incubation period under four salinity concentrations (0, 10, 20 and 35‰) and four temperature levels (10, 20, 30 and 40°C). The results suggested that accumulated ammonium nitrogen (NH4+-N) increased with increasing incubation time under all salinity concentrations. Higher temperatures and salinities significantly enhanced soil N mineralization except for a short-term (?10 days) inhibiting effect found under 35‰ salinity. The incubation time, temperature, salinity and their interactions exhibited significant effects on N mineralization (P<0.001) except the interactive effect of salinity and temperature (P>0.05), while temperature exhibited the greatest effect (P<0.001). Meanwhile, N mineralization processes were simulated using both an effective accumulated temperature model and a one-pool model. Both models fit well with the simulation of soil N mineralization process in the coastal freshwater wetlands under a range of 30 to 40°C (R2?=?0.88-0.99, P<0.01). Our results indicated that an enhanced NH4+-N release with increasing temperature and salinity deriving from the projected global warming could have profound effects on nutrient cycling in coastal wetland ecosystems. PMID:24733366

Gao, Haifeng; Bai, Junhong; He, Xinhua; Zhao, Qingqing; Lu, Qiongqiong; Wang, Junjing

2014-01-01

142

High Temperature and Salinity Enhance Soil Nitrogen Mineralization in a Tidal Freshwater Marsh  

PubMed Central

Soil nitrogen (N) mineralization in wetlands is sensitive to various environmental factors. To compare the effects of salinity and temperature on N mineralization, wetland soils from a tidal freshwater marsh locating in the Yellow River Delta was incubated over a 48-d anaerobic incubation period under four salinity concentrations (0, 10, 20 and 35‰) and four temperature levels (10, 20, 30 and 40°C). The results suggested that accumulated ammonium nitrogen (NH4+-N) increased with increasing incubation time under all salinity concentrations. Higher temperatures and salinities significantly enhanced soil N mineralization except for a short-term (?10 days) inhibiting effect found under 35‰ salinity. The incubation time, temperature, salinity and their interactions exhibited significant effects on N mineralization (P<0.001) except the interactive effect of salinity and temperature (P>0.05), while temperature exhibited the greatest effect (P<0.001). Meanwhile, N mineralization processes were simulated using both an effective accumulated temperature model and a one-pool model. Both models fit well with the simulation of soil N mineralization process in the coastal freshwater wetlands under a range of 30 to 40°C (R2?=?0.88–0.99, P<0.01). Our results indicated that an enhanced NH4+-N release with increasing temperature and salinity deriving from the projected global warming could have profound effects on nutrient cycling in coastal wetland ecosystems. PMID:24733366

Gao, Haifeng; Bai, Junhong; He, Xinhua; Zhao, Qingqing; Lu, Qiongqiong; Wang, Junjing

2014-01-01

143

Thermal properties of peat, marshy and mineral soils in relation to soil moisture status in Polesie and Biebrza wetlands  

NASA Astrophysics Data System (ADS)

Knowledge of thermal properties of soil helps in estimating heat fluxes as an important component of the heat balance. The research was conducted to evaluate spatial distribution of the soil thermal properties (thermal conductivity, heat capacity and thermal diffusivity) in relation to soil wetness and bulk density in wetland soils of Polesie and Biebrza regions (Poland). Soil moisture content and bulk density together with soil temperature and texture data, were used for determination of thermal properties. The thermal conductivity was measured, by KD2 Pro Decagon, and calculated by the physical-statistical model of Usowicz, and the heat capacity - was calculated with empirical formulae, and the thermal diffusivity was determined by the ratio of thermal conductivity to the heat capacity. The thermal conductivity of wetland and marsh soils increases with increasing moisture content and density of the soil to higher extent in soils richer in minerals - mostly quartz. Maximum thermal conductivity of the wetland soils at different density did not exceed the value of the thermal conductivity of water. However, for mineral soil at the natural density (1.31 Mg m-3) and with the quartz content of 96%, the thermal conductivity is about four times greater than the thermal conductivity of water. This is due to that the thermal conductivity of quartz is sixteen times greater than that of water. Dependence of the soil thermal conductivity on moisture content is non-linear and the shape of the non-linearity largely depends on the density of the soil. Particular components of soil bring their contribution to the conductivity respectively to their fractions and compounds being dominant in the ground contribute mostly to the effective slope of the thermal conductivity versus the water content at a given soil density. The heat capacity of the soil substrate is linearly dependent on the water content. Soils containing more organic matter within low specific densities, usually are characterized by less or minimal available heat capacity values in dry conditions, while they can also be characterized by highest or maximal heat capacity values, in highly wet conditions approaching the saturation with water. The increase in soil density caused a parallel shift of the characteristics of the heat capacity in the direction of higher values. This was associated with an increase in solids content per unit volume of the substrate and the reduction of the water content and the specific heat capacity of the individual components of the soil. Thermal diffusivity of soils exhibits characteristic extremes. In organic soils characteristic minimal or maximal extremes may occur, while mineral soils achieve only maximal diffusivity values on regular basis. Extremes of the thermal diffusivity are mainly due to the changes in the intensity of the thermal conductivity of the substrate due to change in soil moisture content and density. The heat capacity of the soil increases with increasing moisture content at the constant rate. The value of soil thermal diffusivity depends highly on quartz content. Thermal diffusivity of the soil with the same moisture content was greater for the higher densities, and minimum or maximum thermal diffusivity tends to move toward the lower moisture content for higher densities. The observed extremes are so distinctive that they determine the value of soil moisture and density, at which the temperature wave travels the slowest and the fastest in the soil. The question of determining and sensing the water capacity is also affected by the texture and porosity. Simple volumetric measures of porosity are used, but with distinguishing the volume of pores filled by air and other part filled with water. Practically, porosity is treated simply and is included to assessments by effects on the thermal properties. We prove that thermal properties are very good variables for a sensitive indicator of the water content, and accounting the impact from porosity. Thermal properties gather effects from the texture and porosity cumulatively. Therefo

Usowicz, Boguslaw; ?ukowski, Mateusz; Marczewski, Wojciech; Usowicz, Jerzy B.; Lipiec, Jerzy; Stankiewicz, Krystyna

2013-04-01

144

Comparison of different methodologies for field measurement of net nitrogen mineralization in pasture soils under different soil conditions  

Microsoft Academic Search

Net mineralization was measured in free-draining and poorly drained pasture soils using three different field incubation\\u000a methodologies. Two involved the use of enclosed incubation vessels (jar or box) containing C2H2 as a nitrification inhibitor. The third method confined soil cores in situ in an open tube in the ground, with an anion-exchange\\u000a resin at the base to retain leached NO3

D. J. Hatch; A. Bhogal; R. D. Lovell; M. A. Shepherd; S. C. Jarvis

2000-01-01

145

Forest type affects the coupled relationships of soil C and N mineralization in the temperate forests of northern China  

PubMed Central

Decomposition of soil organic matter (SOM) is sensitive to vegetation and climate change. Here, we investigated the influence of changes in forest types on the mineralization of soil carbon (C) and nitrogen (N), and their temperature sensitivity (Q10) and coupling relationships by using a laboratory soil incubation experiments. We sampled soils from four forest types, namely, a primary Quercus liaotungensis forest (QL), Larix principis-rupprechtii plantation (LP), Pinus tabulaeformis plantation (PT), and secondary shrub forest (SS) in temperate northern China. The results showed that soil C and N mineralization differed significantly among forest types. Soil C and N mineralization were closely coupled in all plots, and C:N ratios of mineralized SOM ranged from 2.54 to 4.12. Forest type significantly influenced the Q10 values of soil C and N mineralization. The activation energy (Ea) of soil C and N mineralization was negatively related to the SOM quality index in all forest types. The reverse relationships suggested that the carbon quality-temperature (CQT) hypothesis was simultaneously applicable to soil C and N mineralization. Our findings show that the coupled relationships of soil C and N mineralization can be affected by vegetation change. PMID:25322802

Quan, Quan; Wang, Changhui; He, Nianpeng; Zhang, Zhen; Wen, Xuefa; Su, Hongxin; Wang, Qing; Xue, Jingyue

2014-01-01

146

Forest type affects the coupled relationships of soil C and N mineralization in the temperate forests of northern China  

NASA Astrophysics Data System (ADS)

Decomposition of soil organic matter (SOM) is sensitive to vegetation and climate change. Here, we investigated the influence of changes in forest types on the mineralization of soil carbon (C) and nitrogen (N), and their temperature sensitivity (Q10) and coupling relationships by using a laboratory soil incubation experiments. We sampled soils from four forest types, namely, a primary Quercus liaotungensis forest (QL), Larix principis-rupprechtii plantation (LP), Pinus tabulaeformis plantation (PT), and secondary shrub forest (SS) in temperate northern China. The results showed that soil C and N mineralization differed significantly among forest types. Soil C and N mineralization were closely coupled in all plots, and C:N ratios of mineralized SOM ranged from 2.54 to 4.12. Forest type significantly influenced the Q10 values of soil C and N mineralization. The activation energy (Ea) of soil C and N mineralization was negatively related to the SOM quality index in all forest types. The reverse relationships suggested that the carbon quality-temperature (CQT) hypothesis was simultaneously applicable to soil C and N mineralization. Our findings show that the coupled relationships of soil C and N mineralization can be affected by vegetation change.

Quan, Quan; Wang, Changhui; He, Nianpeng; Zhang, Zhen; Wen, Xuefa; Su, Hongxin; Wang, Qing; Xue, Jingyue

2014-10-01

147

Forest type affects the coupled relationships of soil C and N mineralization in the temperate forests of northern China.  

PubMed

Decomposition of soil organic matter (SOM) is sensitive to vegetation and climate change. Here, we investigated the influence of changes in forest types on the mineralization of soil carbon (C) and nitrogen (N), and their temperature sensitivity (Q10) and coupling relationships by using a laboratory soil incubation experiments. We sampled soils from four forest types, namely, a primary Quercus liaotungensis forest (QL), Larix principis-rupprechtii plantation (LP), Pinus tabulaeformis plantation (PT), and secondary shrub forest (SS) in temperate northern China. The results showed that soil C and N mineralization differed significantly among forest types. Soil C and N mineralization were closely coupled in all plots, and C:N ratios of mineralized SOM ranged from 2.54 to 4.12. Forest type significantly influenced the Q10 values of soil C and N mineralization. The activation energy (Ea) of soil C and N mineralization was negatively related to the SOM quality index in all forest types. The reverse relationships suggested that the carbon quality-temperature (CQT) hypothesis was simultaneously applicable to soil C and N mineralization. Our findings show that the coupled relationships of soil C and N mineralization can be affected by vegetation change. PMID:25322802

Quan, Quan; Wang, Changhui; He, Nianpeng; Zhang, Zhen; Wen, Xuefa; Su, Hongxin; Wang, Qing; Xue, Jingyue

2014-01-01

148

Iron Redox Cycling Drives Decomposition of Mineral-Associated C in Humid Tropical Forest Soils  

NASA Astrophysics Data System (ADS)

The stabilization of soil carbon (C) by reactive minerals and an inhibition of decomposition due to oxygen (O2) limitation (reducing conditions) have been proposed as drivers of the high soil C concentrations characteristic of humid tropical forests, which constitute a major terrestrial C reservoir. Here, we examined relationships between these factors and spatial patterns of C concentrations and C turnover (using radiocarbon modeling) in surface soils of the Luquillo Experimental Forest, Puerto Rico. We used concentrations of reduced iron (Fe(II)) as an index of reducing conditions given the importance of Fe reduction to anaerobic metabolism in these soils. Concentrations of Fe(II), reactive iron and aluminum (Al) minerals, interactions between Fe(II) and Al, and live fine root biomass explained most variation in C concentrations across the landscape (pseudo R2 = 0.84). Carbon increased with chelatable "poorly crystalline" Fe, in agreement with previous research, but C decreased with citrate/ascorbate extractable Fe, an index of Fe oxides susceptible to microbial reduction. We suggest that availability of Fe oxides to sustain anaerobic respiration partially offsets soil C accumulation in these ecosystems, despite the role of a subset of reactive Fe in promoting C stabilization. We estimated decomposition rates of mineral-associated C using 14C content of the heavy soil density fraction from a subset of samples. Turnover times averaged 108 years but decreased with Fe(II) concentrations. Thus, our data suggest that Fe redox cycling in soil microsites is associated with increased turnover of mineral-associated C in this fluctuating-oxygen environment, implying that the capacity of reactive metals to stabilize C may be partially contingent on O2 dynamics. Our results suggest a multifaceted role for reactive minerals in soil C cycling, emphasizing the importance of ecosystem-scale interactions among geochemical, physical, and biological factors.

Hall, S. J.; Mcnicol, G.; Silver, W. L.

2013-12-01

149

Soil sorption and leaching of active ingredients of Lumax® under mineral or organic fertilization.  

PubMed

The study describes the soil sorption of the herbicide Lumax®, composed of S-metolachlor (MTC), terbuthylazine (TBZ), and mesotrione (MST), as influenced by mineral and organic fertilizers. The investigation was performed on a sandy soil of an agricultural area designated as a Nitrate Vulnerable Zone, where mineral and organic fertilizers were applied for many years. Two organic fertilizers, cattle manure and slurry, respectively, and a mineral fertilizer with a nitrification inhibitor, Entec®, were compared. According to the experiments, performed with a batch method, the sorption conformed to Freundlich model. The extent of sorption of Lumax® ingredients was closely related to their octanol-water partition coefficient Kow. The respective desorption was hysteretic. Leaching trials were carried out by using water or solutions of DOM or Entec® as the eluants. Only the elution with the mineral fertilizer promoted the leaching of Lumax® active ingredients. PMID:24997942

Pinna, Maria Vittoria; Roggero, Pier Paolo; Seddaiu, Giovanna; Pusino, Alba

2014-09-01

150

Effects of amendment of different biochars on soil physical and biological properties related to carbon mineralization  

NASA Astrophysics Data System (ADS)

Biochar addition to soils potentially affects various soil properties, and these effects are dependent on biochars derived from different feedstock materials and pyrolysis processes. The objective of this study was to investigate the effects of amendment of different biochars on soil physical and biological properties. Biochars were produced with dairy manure and woodchip at temperatures of 300, 500, and 700°C, respectively. Each biochar was mixed at 5% (w/w) with a forest soil and the mixture was incubated for 180 days, during which soil physical and biological properties, and soil respiration rates were measured. Results showed that the biochar addition significantly enhanced the formation of soil macroaggregates at the early incubation time. The biochar application significantly reduced soil bulk density, increased the amount of soil organic matter, and stimulated microbial activity and soil respiration rates at the early incubation stage. Biochar applications improved water retention capacity, with stronger effects by biochars produced at higher pyrolysis temperatures. At the same suction, the soil with woodchip biochars possessed higher water content than with the dairy manure biochars. Biochar addition significantly affected the soil physical and biological properties, which resulted in different soil carbon mineralization rates.

Zhang, Renduo; Zhu, Shuzhi; Ouyang, Lei

2014-05-01

151

Refinements to an In-Situ Soil Core Technique for Measuring Net Nitrogen Mineralization in Moist, Fertilized Agricultural Soil  

Microsoft Academic Search

were made to the ISC\\/IERB technique, which ultimately resulted in reduced sample variability. Following the refinements, a significant tribute to errors in quantifying the initial inorganic N N fertilization effect was shown for the most variable period of the content of the fertilized soil adjacent to the core before growing season where net N mineralization rates for N-fertilized corn incubation.

Kristofor R. Brye; John M. Norman; Erik V. Nordheim; S. Thompson Gower; Larry G. Bundy

2002-01-01

152

Soil nitrogen mineralization in plantations of Juglans nigra interplanted with actinorhizal Elaeagnus umbellata or Alnus glutinosa  

Microsoft Academic Search

Nitrogen mineralization rates were estimated in 19-year-old interplantings of black walnut (Juglans nigra L.) with dinitrogen fixing autumn-olive (Elaeagnus umbellata Thunb.) or black alder (Alnus glutinosa L. Gaertn.) and in pure walnut plantings at two locations in Illinois USA. N mineralization rates were measured repeatedly over a one year period usingin situ incubations of soil cores in oxygen-permeable polyethylene bags

Mark W. Paschke; Jeffrey O. Dawson; Mark B. David

1989-01-01

153

Specific 137 Cs-sorption capacity parameters of soils and mineral sorbents  

Microsoft Academic Search

The selective sorption of cesium by some soils, minerals, and natural mineral sorbents was studied using new methodological\\u000a and experimental approaches. It was found that the total capacity of two types of highly selective sorption sites significantly\\u000a differing (by several orders of magnitude) in the selectivity coefficients of Cs-K ion exchange makes up 0.5–6% of the total\\u000a capacity of the

S. V. Kruglov; V. S. Anisimov; L. N. Anisimova; R. M. Aleksakhin

2008-01-01

154

Limitations to carbon mineralization in litter and mineral soil of young and old ponderosa pine forests  

Microsoft Academic Search

Summer drought is a feature of the semi-arid region of central Oregon, USA, where vegetation naturally develops into ponderosa pine (Pinus ponderosa var. Laws) forest. Forest management consists of clearcut harvest and natural regeneration. Soil microbial activity is interconnected with forest processes because substrate quality and availability can be important driving variables. Stand development influences the soil water regime, and

F. m. Kelliher; D. j. Ross; B. e. Law; D. d. Baldocchi; N. j. Rodda

2004-01-01

155

Changes in the Mineral Assemblage of Paddy Soils upon Redox Cycles  

NASA Astrophysics Data System (ADS)

Rice is one of the major cereal crops of global agriculture. World wide more than 10% of the arable land is used for rice production, mainly under temporarily waterlogged conditions. This leads to distinct redox cycles, governing the biogeochemistry of paddy soils. Yet, long-term effects of alternating redox conditions on the soil mineral matrix and properties are still not fully understood. The objective of the project is to elucidate the processes of mineral transformation as related to changing redox conditions and to time of rice cultivation. Long-term effects of rice cultivation on the mineral assemblage were studied along a chronosequence of paddy soils (100, 700 and 2000a paddy soils) developed in comparable parent material in the province of Zhejiang, China. Top soils were analysed for the mineral assemblage and physicochemical properties using x-ray diffraction and chemical analyses, respectively. All studied clay fractions showed a similar clay mineral assemblage (illite, chlorite, kaolinite, vermiculite, smectite). Differences among the paddy sites though could not be related to the time of cultivation. The CECpot of the clay fraction slightly increased from 100 to 2000 a paddy usage, which was partly attributed to a concurrent increase of Corg. With age the Feo/Fed-ratio in both the Alp and Ardp-horizon increased, with a maximum in the Ardp of the 2000 a paddy field. We conclude, that due to an increasing number of redox-cycles, long-term cultivation enhances the formation of microcrystalline Fe-hydroxides in the A-horizons of paddy soils. Chronological changes in the clay mineral assemblage could not be observed in this study.

Vogelsang, Vanessa; Fiedler, Sabine; Jahn, Reinhold

2010-05-01

156

Microbial Composition in Decomposing Pine Litter Shifts in Response to Common Soil Secondary Minerals  

NASA Astrophysics Data System (ADS)

A range of environmental and biotic factors have been identified that drive microbial community structure in soils - carbon substrates, redox conditions, mineral nutrients, salinity, pH, and species interactions. However, soil mineralogy has been largely ignored as a candidate in spite of recent studies that indicate that minerals have a substantial impact on soil organic matter stores and subsequent fluxes from soils. Given that secondary minerals and organic colloids govern a soil's biogeochemical activity due to surface area and electromagnetic charge, we propose that secondary minerals are a strong determinant of the communities that are responsible for process rates. To test this, we created three microcosms to study communities during decomposition using pine forest litter mixed with two common secondary minerals in soils (goethite and gibbsite) and with quartz as a control. Changes in bacterial and fungal communities were tracked over the 154-day incubation by pyrosequencing fragments of the bacterial 16S and fungal 18S rRNA genes. Ordination using nonmetric multidimensional scaling showed that bacterial communities separated on the basis of minerals. Overall, a single generalist - identified as an Acidobacteriaceae isolate - dominated all treatments over the course of the experiment, representing roughly 25% of all communities. Fungal communities discriminated between the quartz control alone and mineral treatments as a whole. Again, several generalists dominated the community. Coniochaeta ligniaria dominated communities with abundances ranging from 29 to 40%. The general stability of generalist populations may explain the similarities between treatment respiration rates. Variation between molecular fingerprints, then, were largely a function of unique minor members with abundances ranging from 0.01 to 8%. Carbon availability did not surface as a possible mechanism responsible for shifts in fingerprints due to the relatively large mass of needles in the incubation. Other possible mechanisms include the presence of soluble Fe as an alternative energy source in the goethite treatment, the presence of toxic soluble Al in the gibbsite treatment, the loss of available phosphorus in the secondary mineral treatments due to sorption by secondary mineral surfaces, and variations in mineral surfaces as microhabitats. These findings suggest that Al and Fe oxides, such as goethite or gibbsite, are a factor in determining microbial community structure.

Welty-Bernard, A. T.; Heckman, K.; Vazquez, A.; Rasmussen, C.; Chorover, J.; Schwartz, E.

2011-12-01

157

Recovery of microbially mediated processes in soil augmented with a pentachlorophenol-mineralizing bacterium.  

PubMed

Specific physiological groups can be used to evaluate the recovery of soil microbial communities following disturbance. In this study, soil was contaminated with pentachlorophenol (PCP) to assess the resiliency of microorganisms responsible for carbon and nitrogen cycling. Methane fluxes were monitored in soil microcosms to evaluate the effects of contamination and augmentation on microbial populations involved in carbon cycling. The addition of a PCP-mineralizing bacterium, Sphingomonas chlorophenolica strain RA2, enhanced the recovery of methane-oxidizing capacity relative to uninoculated treatments when soil was contaminated with low concentrations of PCP (10 and 50 microg/g soil, ppm). At the highest level of PCP contamination tested (300 ppm), there was no recovery of methane-oxidizing capacity whether or not the PCP-mineralizing bacterium was added to soil. The nitrogen-cycling capacity of contaminated and augmented soil was tested by measuring nitrification potentials. The addition of PCP resulted in a concentration-dependent reduction in nitrification rates. After three months of incubation, all augmented soils had nitrification rates equivalent to the uncontaminated control, and the uninoculated soils contaminated with 100 and 300 ppm PCP still were impaired in their nitrification potentials. These results indicate that biological removal of a contaminant has the potential to restore microbially mediated processes to levels observed prior to contamination. PMID:16152961

Colores, Gregory M; Schmidt, Steven K

2005-08-01

158

Minerals  

NSDL National Science Digital Library

This interactive lesson on minerals starts with a definition of minerals and compares crystalline and amorphous minerals. The composition is discussed and a chart shows the relative amounts of elements in minerals. Next, there is a discussion of the characteristics by which minerals are identified including luster, color, streak, hardness, and cleavage and fracture along with special properties such as magnetism. The characteristics of calcite, talc, hematite, magnetite, and galena are then observed.

159

Kinetics of carbon mineralization of biochars compared with wheat straw in three soils.  

PubMed

Application of biochars to soils may stabilize soil organic matter and sequester carbon (C). The objectives of our research were to study in vitro C mineralization kinetics of various biochars in comparison with wheat straw in three soils and to study their contribution to C stabilization. Three soils (Oxisol, Alfisol topsoil, and Alfisol subsoil) were incubated at 25°C with wheat straw, charcoal, hydrothermal carbonization coal (HTC), low-temperature conversion coal (LTC), and a control (natural organic matter). Carbon mineralization was analyzed by alkali absorption of CO released at regular intervals over 365 d. Soil samples taken after 5 and 365 d of incubation were analyzed for soluble organic C and inorganic N. Chemical characterization of biochars and straw for C and N bonds was performed with Fourier transformation spectroscopy and with the N fractionation method, respectively. The LTC treatment contained more N in the heterocyclic-bound N fraction as compared with the biochars and straw. Charcoal was highly carbonized when compared with the HTC and LTC. The results show higher C mineralization and a lower half-life of straw-C compared with biochars. Among biochars, HTC showed some C mineralization when compared with charcoal and LTC over 365 d. Carbon mineralization rates were different in the three soils. The half-life of charcoal-C was higher in the Oxisol than in the Alfisol topsoil and subsoil, possibly due to high Fe-oxides in the Oxisol. The LTC-C had a higher half-life, possibly due to N unavailability. We conclude that biochar stabilization can be influenced by soil type. PMID:22751064

Qayyum, Muhammad Farooq; Steffens, Diedrich; Reisenauer, Hans Peter; Schubert, Sven

2012-01-01

160

The use of micro-FTIR to characterize soil minerals and Boron adsorption S. Pittiglio and H.E. Doner  

E-print Network

the composition of the soil matrix and possibly the form and location of B in the soil matrix. METHODS PedsThe use of micro-FTIR to characterize soil minerals and Boron adsorption S. Pittiglio and H to obtain direct structural information of adsorbed boron on the solid surfaces of soil material (clays

161

Impact of clay mineral on air oxidation of PAH-contaminated soils.  

PubMed

This work investigated the impact of a clay mineral (bentonite) on the air oxidation of the solvent extractable organic matters (EOMs) and the PAHs from contaminated soils. EOMs were isolated from two coking plant soils and mixed with silica sand or bentonite. These samples, as well as raw soils and bentonite/soil mixtures, were oxidized in air at 60 and 100 °C for 160 days. Mineralization was followed by measuring the CO2 produced over the experiments. EOM, polycyclic aromatic compound (PAC), including PAH, contents were also determined. Oxidation led to a decrease in EOM contents and PAH concentrations, these diminutions were enhanced by the presence of bentonite. Transfer of carbon from EOM to insoluble organic matter pointed out a condensation phenomenon leading to a stabilization of the contamination. Higher mineralization rates, observed during the oxidation of the soil/bentonite mixtures, seem to indicate that this clay mineral had a positive influence on the transformation of PAC into CO2. PMID:24816462

Biache, Coralie; Kouadio, Olivier; Lorgeoux, Catherine; Faure, Pierre

2014-09-01

162

Organic matter mineralization in frozen boreal soils-environmental constraints on catabolic and anabolic microbial activity  

NASA Astrophysics Data System (ADS)

Heterotrophic microbial mineralization of soil organic matter (SOM) and associated production and emission of atmospheric trace gases proceed during the winter months in the frozen soils of high latitude ecosystems. However, in what ways this microbial activity is constrained by the environmental conditions prevailing in a frozen soil matrix is uncertain. This presentation will address how temperature, water availability and substrate availability combine to regulate rates of microbial activity at below freezing temperatures and the implications of this activity for SOM mineralization in the surface layers of boreal forest soils experiencing seasonal freezing. We show that the amount and availability of liquid water is an integral factor regulating rates of microbial activity in the frozen soil matrix and can also explain frequently observed deviations in the temperature responses of biogenic CO2 production in frozen soils, as compared to unfrozen soils. Using stable isotope labeling (13C) we also show that the partitioning of substrate carbon, in the form of monomeric sugar (glucose), for catabolic and anabolic metabolism remain constant in the temperature range of -4C to 9C. This confirms that microbial growth may proceed even when soils are frozen. In addition we present corresponding data for organisms metabolizing polymeric substrates (cellulose) requiring exoenzymatic activity prior to substrate uptake. We conclude that the metabolic response of soil microorganism to controlling factors may change substantially across the freezing point of soil water, and also the patterns of interaction among controlling factors are affected. Thus, it is evident that metabolic response functions derived from investigations of unfrozen soils cannot be superimposed on frozen soils. Nonetheless, the soil microbial population appear very adapted to seasonal freezing with respect to their metabolic performance.

Oquist, Mats G.; Sparrman, Tobias; Schleucher, Jürgen; Nilsson, Mats B.

2014-05-01

163

Clay minerals as a factor influencing the biochemical activity of soil microorganisms  

Microsoft Academic Search

The results of the study confirm the significance of clay minerals as a factor influencing the biochemical activity of soil\\u000a microorganisms. The soil microflora is influenced both by the direct effect of clays on the microbial cells and indirectly,\\u000a by their effect on the environment. The direct effect is projected into fundamental processes of the cycle of biogenic elements,\\u000a including

Z. Filip

1973-01-01

164

Reversibility of soil forming clay mineral reactions induced by plant - clay interactions  

NASA Astrophysics Data System (ADS)

Recent data based upon observations of field experiments and laboratory experiments suggest that changes in phyllosilicate mineralogy, as seen by X-ray diffraction analysis, which is induced by plant action can be reversed in relatively short periods of time. Changes from diagenetic or metamorphic mineral structures (illite and chlorite) to those found in soils (mixed layered minerals in the smectite, hydroxy-interlayer mineral and illites) observed in Delaware Bay salt marsh sediments in periods of tens of years and observed under different biologic (mycorhize) actions in coniferous forests in the soil environment can be found to be reversed under other natural conditions. Reversal of this process (chloritisation of smectitic minerals in soils) has been observed in natural situations over a period of just 14 years under sequoia gigantia. Formation of smectite minerals from illite (potassic mica-like minerals) has been observed to occur under intensive agriculture conditions over periods of 80 years or so under intensive zea mais production. Laboratory experiments using rye grass show that this same process can be accomplished to a somewhat lesser extent after one growing season. However experiments using alfalfa for 30 year growing periods show that much of the illite content of a soil can be reconstituted or even increased. Observations on experiments using zea mais under various fertilizer and mycorhize treatments indicate that within a single growing season potassium can be extracted from the clay (illite layers) but at the end of the season the potassium can be restored to the clay structures and more replaced that extracted. Hence it is clear that the change in clay mineralogy normally considered to be irreversible, illite to smectite or chlorite to smectite observed in soils, is a reversible process where plant systems control the soil chemistry and the soil mineralogy. The changes in clay mineralogy concern mostly the chemical composition of the interlayer ion population of a 2:1 clay structure. However the differences in interlayer ion chemistry give us such mineral names as chloritic hydroxyinterlayered mineral (Mg, OH interlayer), illite (K interlayer), and smectite (essentially hydrated Ca interlayer ions). Extraction of these interlayer ions can be reversed by chemistry engendered by plant regimes.

Barré, P.; Velde, B.

2012-04-01

165

Stable isotope geochemistry of sulfur bearing minerals and clay mineralogy of some soils and sediments in Loot Desert, central Iran  

E-print Network

Stable isotope geochemistry of sulfur bearing minerals and clay mineralogy of some soils Desert Stable isotope geochemistry is a unique technique to study the source of salts in soils and sediments. In the present research, sources of gypsum and other sulfur bearing minerals using stable isotope

Ahmad, Sajjad

166

Amino acid, peptide and protein mineralization dynamics in a taiga forest soil David L. Jones a,*, Knut Kielland b  

E-print Network

Amino acid, peptide and protein mineralization dynamics in a taiga forest soil David L. Jones a that the block in N mineralization in taiga forest soils is the transformation of high MW DON to low MW DON successional gradients in taiga forest systems (Vance and Chapin, 2001). The cycling of the diverse N

Wagner, Diane

167

Potassium Fixation and Supply by Soils with Mixed Clay Minerals.  

E-print Network

clay. If the sequence of weathering on these soils is Illite+Montmorillonite, these data suggest that the use of fixed K by plants proceeds at a faster rate than the decrease in K fixing capacity brought about by the weather- ing process. TABLE 2... clay. If the sequence of weathering on these soils is Illite+Montmorillonite, these data suggest that the use of fixed K by plants proceeds at a faster rate than the decrease in K fixing capacity brought about by the weather- ing process. TABLE 2...

Hipp, Billy W.

1969-01-01

168

Adsorption of Trametes versicolor laccase to soil iron and aluminum minerals: enzyme activity, kinetics and stability studies.  

PubMed

Laccases play an important role in the degradation of soil phenol or phenol-like substance and can be potentially used in soil remediation through immobilization. Iron and aluminum minerals can adsorb extracellular enzymes in soil environment. In the present study, we investigated the adsorptive interaction of laccase, from the white-rot fungus Trametes versicolor, with soil iron and aluminum minerals and characterized the properties of the enzyme after adsorption to minerals. Results showed that both soil iron and aluminum minerals adsorbed great amount of laccase, independent of the mineral specific surface areas. Adsorbed laccases retained 26-64% of the activity of the free enzyme. Compared to the free laccase, all adsorbed laccases showed higher Km values and lower Vmax values, indicating a reduced enzyme-substrate affinity and a lower rate of substrate conversion in reactions catalyzed by the adsorbed laccase. Adsorbed laccases exhibited increased catalytic activities compared to the free laccase at low pH, implying the suitable application of iron and aluminum mineral-adsorbed T. versicolor laccase in soil bioremediation, especially in acid soils. In terms of the thermal profiles, adsorbed laccases showed decreased thermal stability and higher temperature sensitivity relative to the free laccase. Moreover, adsorption improved the resistance of laccase to proteolysis and extended the lifespan of laccase. Our results implied that adsorbed T. versicolor laccase on soil iron and aluminum minerals had promising potential in soil remediation. PMID:24225344

Wu, Yue; Jiang, Ying; Jiao, Jiaguo; Liu, Manqiang; Hu, Feng; Griffiths, Bryan S; Li, Huixin

2014-02-01

169

Reactive Clay Minerals in a land use sequence of disturbed soils of the Belgian Loam Belt  

NASA Astrophysics Data System (ADS)

Clay minerals play a key role in soil biogeochemistry. They can stabilize organic matter, improve water storage, increase cation exchange capacity of the soil (CEC) and lower nutrient leaching. Phytoliths - the biogenic silica bodies (BSi) deposited in cell walls of plants - are important Si pools in soil horizons due to their higher solubility compared to minerals. They provide the source of Si for plant uptake in short time scales, as litter dissolves within soils. In a recent study, we analyzed the BSi pool differences across a set of different land uses (forests, pastures, croplands) in 6 long-term disturbed (multiple centuries) soil sites in the Belgium Loam Belt. Results from a simultaneous chemical extraction in 0.5M NaOH of Si and Al, showed that soils were depleted in the BSi pool while showing high levels of reactive secondary clay minerals, mainly in the deeper horizons and especially in the forests and the croplands. During the extraction, clays were similar in reactivity to the biogenic pool of phytoliths. In order to study the kinetics in a more natural environment, batch dissolution experiments were conducted. Samples from different soil depths for each land use site (0.5 g) were mixed with 0.5 L of demineralised water modified to pH 4, 7 and 10. Subsamples of 2 ml were taken during 3 months. In the end of the period, results for pH 7 showed that in the pastures, where reactive clays were almost absent, the ratio Si/RSi (defined as the Si concentration in the end of the batch experiment divided by the reactive silica extracted from the soil with the alkaline extraction) was lower than 0.005%. The same ratio was higher in the mineral horizons of forests (Si/RSi>0.01%) and croplands (0.005% < Si/RSi <0.01%) where clay minerals were the dominant fraction. These preliminary results highlight the clay minerals' strong potential for Si mobilization. More attention should be paid to this important fraction as it can contribute strongly to Si availability, in close competition with phytoliths and other soluble amorphous Si forms, strongly interfering with frequently applied methods to quantify biogenic Si in soils.

Barao, Lucia; Vandevenne, Floor; Ronchi, Benedicta; Meire, Patrick; Govers, Gerard; Struyf, Eric

2014-05-01

170

Origin and Reactivity of the Martian Soil: A 2003 Micromission  

NASA Technical Reports Server (NTRS)

The role of water in the development of the martian surface remains a fundamental scientific question. Did Mars have one or more "warm and wet" climatic episodes where liquid water was stable at the surface? If so, the mineral phases present in the soils should be consistent with a history of aqueous weathering. More generally, the formation of hydrated mineral phases on Mars is a strong indicator of past habitable surface environments. The primary purpose of this investigation is to help resolve the question of whether such aqueous indicators are present on Mars by probing the upper meter for diagnostic mineral species. According to Burns [1993], the formation of the ferric oxides responsible for the visible color of Mars are the result of dissolution of Fe (+2) phases from basalts followed by aqueous oxidation and precipitation of Fe" mineral assemblages. These precipitates likely included iron oxyhydroxides such as goethite (a-FeOOH) and lepidocrocite (g-FeOOH), but convincing evidence for these phases at the surface is still absent. The stability of these minerals is enhanced beneath the surface, and thus we propose a subsurface search for hydroxylated iron species as a test for a large-scale chemical weathering process based on interactions with liquid water. It is also possible that the ferric minerals on Mars are not aqueous alteration products of the rocks. A chemical study of the Pathfinder landing site concluded that the soils are not directly derived from the surrounding rocks and are enhanced in Mg and Fe. The additional source of these elements might be from other regions of Mars and transported by winds, or alternatively, from exogenic sources. Gibson [1970] proposed that the spectral reflectivity of Mars is consistent with oxidized meteoritic material. Yen and Murray [1998] further extend Gibson's idea and show, in the laboratory, that metallic iron can be readily oxidized to maghemite and hematite under present-day martian surface conditions (in the absence of liquid water). A test for a meteoritic component of the soil can be conducted, as described below, by searching for the presence of Ni at the martian surface. The average abundance of nickel in an Fe-Ni meteorite is about 7% and, if present at measurable levels in the soil, would be indicative of an exogenic contribution. In addition, it may be possible to directly search for mineral phases common in meteorites. An understanding of the formation and evolution of the martian soil would not be complete without addressing the unusual reactivity discovered by the Viking Landers The presence of an inorganic oxidant, possibly one produced as a results of photochemical processes, is the most widely accepted explanation of the Viking results. Are these chemical species simply adsorbed on soil grains, or have they reacted with the metal oxide substrates and altered the mineral structures? Could a completely different (non-photochemical) process be responsible for the soil reactivity? The various ideas for the nature of this putative oxidant could be constrained by a measurement of the change in reactivity with depth. Different compositions will have different lifetimes and mobilities and thus will have different vertical profiles. Because the oxidizing compounds are believed to actively destroy organic molecules, determination of the reactivity gradient also has significant implications for the search for life on Mars. A DS2-based microprobe system can be instrumented for a 2003 micromission to investigate the origin and reactivity of the martian soil. These measurements would provide invaluable information regarding the climate history and exobiological potential of the planet. The NMR, X ray and chemiresistor measurement approach described embodies a highly synergistic and general set of soil interrogation methods for elements, compounds, and crystal structures and can also be applied to other geologic questions of interest. For example, if the capability for precise targeting of the probes is available, then in-situ investigations of suspec

Yen, Albert S.; Kim, S. Sam; Marshall, John; Murray, Bruce C.

1999-01-01

171

Soil organic nitrogen mineralization across a global latitudinal gradient  

Microsoft Academic Search

Understanding and accurately predicting the fate of carbon and nitrogen in the terrestrial biosphere remains a central goal in ecosystem science. Amino acids represent a key pool of C and N in soil, and their availability to plants and microorganisms has been implicated as a major driver in regulating ecosystem functioning. Because of potential differences in biological diversity and litter

D. L. Jones; K. Kielland; R. A. Dahlgren; K. K. Newsham; J. F. Farrar; D. V. Murphy

2009-01-01

172

The effects of soil mineral phases on the abiotic degradation of selected organic compounds. [Tetraphenylboron  

SciTech Connect

Tetraphonylboron (TPB) will be used to precipitate radioactive 137Cs from high level nuclear waste water, at the Defense Waste Processing Facility (DWPF) which is operated by the US Department of Energy (US DOE), at the Savannah River Site (SRS), Aiken, SC. The decontaminated wastewater will contain millimolar quantities of TPB that will be processed into salt concretions. The waste processing operations will require about 3[times]l0[sup 5] kg/yr of TPB during its full scale operation. The transportation and use of large amounts of TPB can potentially result in the release of TPB into soil or aquatic environments where its degradation will take place. Previous studies have shown that TPB degrades abiotically in soils; however, the role of specific mineral surfaces in mediating the reaction kinetics and mechanisms for the abiotic degradation of TPB are not clearly known. Laboratory studies have been undertaken to evaluate the surface facilitated degradation of TPB by aluminum silicate clay minerals-kaolinite and montmorillonite. Preliminary results indicate that the rate of degradation of TPB is much higher in kaolinite-a single layer mineral-than in montmorillonite - a double layer mineral- and Orangeburg loamy soil. The initial products of TPB degradation in both minerals are diphenylboric acid (DPBA) and biphenyl. However, HPLC monitoring of degradation products of TPB in montmorillonite appears to indicate the presence of phenol and monophenyboric acid (MPBA).

Sandu, S.S.

1992-06-01

173

Molecular-Level Analysis of Organic Matter Structure and Composition from Different Soil Mineral Fractions  

NASA Astrophysics Data System (ADS)

The formation and turnover of soil organic matter (SOM) depends on the inherent chemical characteristics of biomolecular inputs (lignin, proteins, carbohydrates, macromolecular lipids, etc.) as well as the interactions between biomolecules and soil mineral fractions. The objective of this study is to characterize organic matter associated with the light, sand, silt and clay fractions of a Canadian agricultural soil. And, because lignin is believed to be a major contributor in SOM formation and preservation, the oxidation state of lignin in the different mineral fractions was measured using mild alkaline copper oxidation and gas chromatography - mass spectrometery which releases lignin phenols that are indicative of lignin sources and stage of degradation. For example, an increase in the acid/aldehyde (Ad/Al) ratio of lignin phenols has been observed with increased lignin degradation (and oxidation). In this study, lignin phenols from organic matter associated with the clay fraction had higher Ad/Al ratios for both syringyl and vanillyl lignin monomers when compared to that associated with silt, sand and the whole soil. These results suggest that either lignin degradation is enhanced by SOM association with clay surfaces or that oxidized lignin is preserved on clay mineral surfaces via sorption after partial degradation has occurred. The structural characteristics of organic matter from the soil fractions will also be examined by solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Organic matter associated with each mineral fraction will be extracted with NaOH for high resolution solution-state NMR spectroscopy. Results from NMR analysis will determine the relative abundance of functional groups (alkane, aromatic, carbonyl, alkoxy) in each of the soil fractions. Relative intensities of the functional groups are indicative of relative contributions of biomolecular classes such as lipids, lignin, fatty acids, and sugars to the organic matter associated with each fraction. The study comprises our initial steps in characterizing protection mechanisms responsible for the long-term retention and stability of biomolecules and their degradation intermediates in soil.

Clemente, J. S.; Gregorich, E. G.; Simpson, A. J.; Simpson, M. J.

2009-05-01

174

Molecular-level analysis of organic matter structure and composition from different soil mineral fractions  

NASA Astrophysics Data System (ADS)

The formation and turnover of soil organic matter (SOM) depends on the inherent chemical characteristics of biomolecular inputs (lignin, proteins, carbohydrates, macromolecular lipids, etc.) as well as the interactions between biomolecules and soil mineral fractions. The objective of this study is to characterize organic matter associated with the light, sand, silt and clay fractions of a Canadian agricultural soil. And, because lignin is believed to be a major contributor in SOM formation and preservation, the oxidation state of lignin in the different mineral fractions was measured using mild alkaline copper oxidation and gas chromatography - mass spectrometery which releases lignin phenols that are indicative of lignin sources and stage of degradation. For example, an increase in the acid/aldehyde (Ad/Al) ratio of lignin phenols has been observed with increased lignin degradation (and oxidation). In this study, lignin phenols from organic matter associated with the clay fraction had higher Ad/Al ratios for both syringyl and vanillyl lignin monomers when compared to that associated with silt, sand and the whole soil. These results suggest that either lignin degradation is enhanced by SOM association with clay surfaces or that oxidized lignin is preserved on clay mineral surfaces via sorption after partial degradation has occurred. The structural characteristics of organic matter from the soil fractions will also be examined by solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Organic matter associated with each mineral fraction will be extracted with NaOH for high resolution solution-state NMR spectroscopy. Results from NMR analysis will determine the relative abundance of functional groups (alkane, aromatic, carbonyl, alkoxy) in each of the soil fractions. Relative intensities of the functional groups are indicative of relative contributions of biomolecular classes such as lipids, lignin, fatty acids, and sugars to the organic matter associated with each fraction. The study comprises our initial steps in characterizing protection mechanisms responsible for the long-term retention and stability of biomolecules and their degradation intermediates in soil.

Clemente, J. S.; Gregorich, E. G.; Simpson, A. J.; Simpson, M. J.

2009-04-01

175

Plant Root Responses to Three Abundant Soil Minerals: Silicon, Aluminum and Iron  

Microsoft Academic Search

Silicon (Si), aluminum (Al), and iron (Fe) are the three most abundant minerals in soil; however, their effects on plants differ because they are beneficial, toxic, and essential to plant growth, respectively. High accumulation of silicon in the shoots helps some plants to overcome a range of biotic and abiotic stresses. However, plants vary in their ability to take up

Jian Feng Ma

2005-01-01

176

Minerals  

NSDL National Science Digital Library

This page is from James Madison University's Department of Geology and Environmental Science. It provides an introduction to minerals, an alphabetical list of minerals and dichotomous keys to identifying minerals in PDF. There are also links to other department pages on igneous, sedimentary, and metamorphic rocks.

Fichter, Lynn S.

2000-09-13

177

Minerals  

NSDL National Science Digital Library

This slide show provides students with basic information on mineralogy. It explains how the term "mineral" is defined, the properties that are used to identify minerals, their importance in daily life, and some general facts. For each identifying property, an example mineral and photograph are provided. Addresses to websites with additional information are also included.

Passow, Michael

178

Minerals  

NSDL National Science Digital Library

Create a poster about minerals! Directions: Make a poster about minerals. (20 points) Include at least (1) large picture (15 points) on your poster complete with labels of every part (10 points). (15 points) Include at least three (3) facts about minerals. (5 points each) (15 points) Write at ...

Walls, Mrs.

2011-01-30

179

Persistence of four pyrethroid insecticides in a mineral and an organic soil.  

PubMed

Permethrin, cypermethrin, fenpropanate and fenvalerate (emulsifiable concentrates) were applied at 280 g AI/ha and incorporated into mineral and organic soil contained in small field plots. Radishes and carrots were grown to serve as indicators of insecticide uptake. Similar plots were treated with the same insecticides at 140 g AI/ha and the soil surface was left undisturbed following application. Soil cores were removed at appropriate intervals and the crops were harvested when mature. The insecticide concentration in all samples was determined by gas-liquid chromatography. The amount of insecticide in the soil declined rapidly to less than 50% of the initial value in 1 month or less for most material-soil-treatment combinations and within 2 months for all cases. Concentrations remained in excess of 0.01 ppm in the organic soil for at least six months for all material-treatment combinations but fell below this level over 2-5 months in the mineral soils. Organic soil incorporated fenvalerate was the most persistent combination overall with 25, 17 and 7% remaining at 6, 18 and 28 months respectively. The trans-isomers of permethrin and cypermethrin disappeared more quickly than the cis-isomers but the insecticidally active IR isomers were not preferentially degraded relative to the inactive 1S. No residues (less than 0.01 ppm) were found in the radish or carrot crops. First order disappearance rates were not constant for any of the combinations. A comparison of partial rate constants showed: 1) 0-1 mo rates were generally greater in mineral than organic soil, 2) 1-6 mo rates in organic soil were lower than 0-1 mo rates, 3) 1-6 mo rates for surface applications to organic soil were generally less than for incorporated applications. In laboratory experiments, 0-1 mo rates for fenvalerate disappearance in a mineral soil were 2-3x greater for 0.5 ppm than for 10 ppm while 1-6 mo rates were independent of insecticide concentration but were 1.5x greater for 0.5% moisture than for 5%. PMID:7299074

Chapman, R A; Harris, C R

1981-01-01

180

The Accumulation of Organic Carbon in Mineral Soils by Afforestation of Abandoned Farmland  

PubMed Central

The afforestation of abandoned farmland significantly influences soil organic carbon (OC). However, the dynamics between OC inputs after afforestation and the original OC are not well understood. To learn more about soil OC dynamics after afforestation of farmland, we measured the soil OC content in paired forest and farmland plots in Shaanxi Province, China. The forest plots had been established on farmland 18, 24, 48, 100, and 200 yr previously. The natural 13C abundance of soil organic matter was also analyzed to distinguish between crop- and forest-derived C in the afforested soils. We observed a nonlinear accumulation of total OC in the 0–80 cm depth of the mineral soil across time. Total soil OC accumulated more rapidly under forest stands aged 18 to 48 yr than under forest stands aged 100 or 200 yrs. The rate of OC accumulation was also greater in the 0–10 cm depth than in the 10–80 cm depth. Forest-derived OC in afforested soils also accumulated nonlinearly across time, with the greatest increase in the 0–20 cm depth. Forest-derived OC in afforest soils accounted for 52–86% of the total OC in the 0–10 cm depth, 36–61% of the total OC in the 10–20 cm depth, and 11–50% of the total OC in the 20–80 cm depth. Crop-derived OC concentrations in the 0–20 cm depth decreased slightly after afforestation, but there was no change in crop-derived OC concentrations in the 20–80 cm depth. The results of our study support the claim that afforestation of farmland can sequester atmospheric CO2 by increasing soil OC stocks. Changes in the OC stocks of mineral soils after afforestation appear to be influenced mainly by the input of forest-derived C rather than by the loss of original OC. PMID:22412854

Wei, Xiaorong; Qiu, Liping; Shao, Mingan; Zhang, Xingchang; Gale, William J.

2012-01-01

181

Mineral composition and charcoal determine the bacterial community structure in artificial soils.  

PubMed

To study the influence of the clay minerals montmorillonite (M) and illite (I), the metal oxides ferrihydrite (F) and aluminum hydroxide (A), and charcoal (C) on soil bacterial communities, seven artificial soils with identical texture provided by quartz (Q) were mixed with sterilized manure as organic carbon source before adding a microbial inoculant derived from a Cambisol. Bacterial communities established in artificial soils after 90 days of incubation were compared by DGGE analysis of bacterial and taxon-specific 16S rRNA gene amplicons. The bacterial community structure of charcoal-containing soils highly differed from the other soils at all taxonomic levels studied. Effects of montmorillonite and illite were observed for Bacteria and Betaproteobacteria, but not for Actinobacteria or Alphaproteobacteria. A weak influence of metal oxides on Betaproteobacteria was found. Barcoded pyrosequencing of 16S rRNA gene amplicons done for QM, QI, QIF, and QMC revealed a high bacterial diversity in the artificial soils. The composition of the artificial soils was different from the inoculant, and the structure of the bacterial communities established in QMC soil was most different from the other soils, suggesting that charcoal provided distinct microenvironments and biogeochemical interfaces formed. Several populations with discriminative relative abundance between artificial soils were identified. PMID:23289489

Ding, Guo-Chun; Pronk, Geertje Johanna; Babin, Doreen; Heuer, Holger; Heister, Katja; Kögel-Knabner, Ingrid; Smalla, Kornelia

2013-10-01

182

Passive sequestration of atmospheric CO2 through coupled plant-mineral reactions in urban soils.  

PubMed

Photosynthetic removal of CO(2) from the atmosphere is an important planetary carbon dioxide removal mechanism. Naturally, an amount equivalent to all atmospheric carbon passes through the coupled plant-soil system within 7 years. Plants cycle up to 40% of photosynthesized carbon through their roots, providing a flux of C at depth into the soil system. Root-exuded carboxylic acids have the potential to supply 4-5 micromoles C hr(-1)g(-1) fresh weight to the soil solution, and enhance silicate mineral weathering. Ultimately, the final product of these root-driven processes is CO(2), present in solution as bicarbonate. This combines with Ca liberated by corrosion associated with silicate mineral weathering to enter the soil-water system and to produce pedogenic calcium carbonate precipitates. Combining understanding of photosynthesis and plant root physiology with knowledge of mineral weathering provides an opportunity to design artificial soils or to plan land use in ways that maximize removal and sequestration of atmospheric CO(2) through artificially enhanced pedogenic carbonate precipitation. This process requires relatively low energy and infrastructure inputs. It offers a sustainable carbon dioxide removal mechanism analogous to the use of constructed wetlands for the passive remediation of contaminated waters, and is likely to achieve wide public acceptance. PMID:22616942

Manning, David A C; Renforth, Phil

2013-01-01

183

Calculating carbon mass balance from unsaturated soil columns treated with CaSO4-minerals: Test of soil carbon sequestration.  

PubMed

Renewed interest in managing C balance in soils is motivated by increasing atmospheric concentrations of CO2 and consequent climate change. Here, experiments were conducted in soil columns to determine C mass balances with and without addition of CaSO4-minerals (anhydrite and gypsum), which were hypothesized to promote soil organic carbon (SOC) retention and soil inorganic carbon (SIC) precipitation as calcite under slightly alkaline conditions. Changes in C contents in three phases (gas, liquid and solid) were measured in unsaturated soil columns tested for one year and comprehensive C mass balances were determined. The tested soil columns had no C inputs, and only C utilization by microbial activity and C transformations were assumed in the C chemistry. The measurements showed that changes in C inventories occurred through two processes, SOC loss and SIC gain. However, the measured SOC losses in the treated columns were lower than their corresponding control columns, indicating that the amendments promoted SOC retention. The SOC losses resulted mostly from microbial respiration and loss of CO2 to the atmosphere rather than from chemical leaching. Microbial oxidation of SOC appears to have been suppressed by increased Ca(2+) and SO4(2)(-) from dissolution of CaSO4 minerals. For the conditions tested, SIC accumulation per m(2) soil area under CaSO4-treatment ranged from 130 to 260gCm(-1) infiltrated water (20-120gCm(-1) infiltrated water as net C benefit). These results demonstrate the potential for increasing C sequestration in slightly alkaline soils via CaSO4-treatment. PMID:24974014

Han, Young-Soo; Tokunaga, Tetsu K

2014-12-01

184

Persistence of chlorpyrifos in a mineral and an organic soil.  

PubMed

Chlorpyrifos (Lorsban emulsifiable concentrate) was applied at 3.4 kg AI/ha and incorporated into sand and muck soil contained in small field plots. Soil samples were taken at intervals over 2 yr. Radishes and carrots, seeded yearly, served as indicator crops for absorption of insecticide residues. Samples were extracted and analyzed, by gas-liquid chromatography, for chlorpyrifos, oxychlorpyrifos, and 3,5,6-trichloro-2-pyridinol. Chlorpyrifos residues declined rapidly, with 50% of the initial application remaining after 2 and 8 wk in sand and muck, respectively, and 4 and 9% after 1 yr. Pyridinol residues increased to 13 and 39% of the initial chlorpyrifos application in sand and muck after 1 and 8 wk, respectively, and declined thereafter. Oxychlorpyrifos was detected in the 2 soils at very low levels only in immediate posttreatment samples. In the first year of the study low levels (less than 0.1 ppm) of chlorpyrifos and the pyridinol were detected in radishes and carrots. PMID:6153667

Chapman, R A; Harris, C R

1980-01-01

185

[Soil organic carbon mineralization of Black Locust forest in the deep soil layer of the hilly region of the Loess Plateau, China].  

PubMed

The deep soil layer (below 100 cm) stores considerable soil organic carbon (SOC). We can reveal its stability and provide the basis for certification of the deep soil carbon sinks by studying the SOC mineralization in the deep soil layer. With the shallow soil layer (0-100 cm) as control, the SOC mineralization under the condition (temperature 15 degrees C, the soil water content 8%) of Black Locust forest in the deep soil layer (100-400 cm) of the hilly region of the Loess Plateau was studied. The results showed that: (1) There was a downward trend in the total SOC mineralization with the increase of soil depth. The total SOC mineralization in the sub-deep soil (100-200 cm) and deep soil (200-400 cm) were equivalent to approximately 88.1% and 67.8% of that in the shallow layer (0-100 cm). (2) Throughout the carbon mineralization process, the same as the shallow soil, the sub-deep and deep soil can be divided into 3 stages. In the rapid decomposition phase, the ratio of the mineralization or organic carbon to the total mineralization in the sub-deep and deep layer (0-10 d) was approximately 50% of that in the shallow layer (0-17 d). In the slow decomposition phase, the ratio of organic carbon mineralization to total mineralization in the sub-deep, deep layer (11-45 d) was 150% of that in the shallow layer (18-45 d). There was no significant difference in this ratio among these three layers (46-62 d) in the relatively stable stage. (3) There was no significant difference (P > 0.05) in the mineralization rate of SOC among the shallow, sub-deep, deep layers. The stability of SOC in the deep soil layer (100-400 cm) was similar to that in the shallow soil layer and the SOC in the deep soil layer was also involved in the global carbon cycle. The change of SOC in the deep soil layer should be taken into account when estimating the effects of soil carbon sequestration in the Hilly Region of the Loess Plateau, China. PMID:23323422

Ma, Xin-Xin; Xu, Ming-Xiang; Yang, Kai

2012-11-01

186

[Soil nitrogen mineralization and primary productivity in Rhododendron aureum community of snowpacks in alpine tundra of Changbai Mountain].  

PubMed

Based on continuous observation of soil temperature and in situ incubation, this paper studied the effects of snow packs on soil temperature, soil nitrogen (N) mineralization, and primary productivity of Rhododendron aureum community alpine tundra in Changbai Mountain. During the snow-covered period of non-growth season (from last October to early May), test soil had an increasing N content, and accumulated sufficient mineralized N for plant growth in the coming year. The soil under snow packs in snow-covered period had a mean temperature -3.0 degrees C, and its N mineralization was more vigorous, with available N increased by 3.88 g x m(-2); while the soil with no snowpack had a mean temperature -7.5 degrees C, and the available N only increased by 1.21 g x m(-2). During growth season (from mid May to late August), soil N content decreased. In autumn when plants stopped growing, soil available N content tended to increase. In winter, the soil temperature under snowpacks kept at around 0 degrees C or a little lower, which promoted soil N mineralization, while that with no snowpack was in a frozen status. The difference in soil N mineralization was the key factor resulting in the higher primary productivity of snowpack Rh. aureum community and the driving force for the spatial variation of vegetation. PMID:21265136

Zhang, Guo-chun; Liu, Qi-jing; Xu, Qian-qian; Liu, Yan

2010-09-01

187

A general evaluation of the frequency distribution of clay and associated minerals in the alluvial soils of ceylon  

USGS Publications Warehouse

Clay mineral analyses were made of several alluvial clay materials from Ceylon. These studies show that the soil materials can be divided into 3 clay mineral provinces on the basis of the frequency distribution of clay and associated minerals. The provinces closely follow the climatic divisions. The characteristic feature of this classification is the progressive development of gibbsite from Dry to Wet Zone areas. Gibbsite has been used as a reliable indicator mineral. ?? 1971.

Herath, J. W.; Grimshaw, R. W.

1971-01-01

188

Low dissolved organic carbon input from fresh litter to deep mineral soils  

SciTech Connect

Dissolved organic carbon (DOC) leached from recent litter in the forest floor has been suggested to be an important source of C to the mineral soil of forest ecosystems. In order to determine the rate at which this flux of C occurs we have taken advantage of a local release of 14C at Oak Ridge National Laboratory Reservation, USA (latitude N 35 58'; longitude W 84 16'). Eight replicate 7x7 m plots were estab lished at four field sites on the reservation in an upland oak forest setting. Half of the plots were provided with 14C-enriched litter (?14C ?1000 ), and the other half with near-background litter (?14C ?220 ) over multiple years. Differences in the labeled leaf litter were used to quantify the movement of litter derived DOC through the soil profile. Soil solutions were collected over several years with tension lysimeters at 15 and 70 cm depth and measured for DOC concentration and 14C abundance. The net amount of DOC retained between 15 and 70 cm was 1.5-6 g m-2 y-1. There were significant effects of the litter additions on the 14C abundance in the DOC, but the net transport of 14C from the added litter was small. The difference in ?14C between the treatments with enriched and near-background litter was only about 130 at both depths, which is small compared with the difference in ?14C in the added litter. The primary source of DOC within the mineral soil must therefore have been either the Oe/Oa horizon or the organic matter in the mineral soil. Over a 2-year time frame, leaching of DOC from recent litter did not have a major impact on the C stock in the mineral soil below 15 cm in this ecosystem.

Froeberg, Mats J [ORNL; Jardine, Philip M [ORNL; Hanson, Paul J [ORNL; Swanston, Christopher [ORNL; Todd Jr, Donald E [ORNL; Phillips, Jana Randolph [ORNL; Garten Jr, Charles T [ORNL

2007-01-01

189

Factors driving carbon mineralization priming effect in a soil amended with different types of biochar  

NASA Astrophysics Data System (ADS)

The effect of biochar on soil carbon mineralization priming effect depends on the characteristics of the raw materials, production method and pyrolysis conditions. The goal of the present study is to evaluate the impact of three different types of biochar on soil CO2 emissions and in different physicochemical properties. For this purpose, a sandy-loam soil was amended with the three biochars (BI, BII and BIII) at a rate of 8 wt % and soil CO2 emissions were measured for 45 days. BI is produced from a mixed wood sieving's from wood chip production, BII from a mixture of paper sludge and wheat husks and BIII from sewage sludge. Cumulative CO2 emissions of biochars, soil and amended soil were well fit to a simple first-order kinetic model with correlation coefficients (r2) greater than 0.97. Results shown a negative priming effect in the soil after addition of BI and a positive priming effect in the case of soil amended with BII and BIII. These results can be related with different biochar properties such as ash content, volatile matter, fixed carbon, organic carbon oxidised with dichromate, soluble carbon and metal and phenolic substances content in addition to surface biochar properties. Three biochars increased the values of soil field capacity and wilting point, while effects over pH and cation exchange capacity were not observed.

Cely, P.; Tarquis, A. M.; Paz-Ferreiro, J.; Méndez, A.; Gascó, G.

2014-03-01

190

Mineralization of 13C glucose in three fine textured soils from the western boreal forest  

NASA Astrophysics Data System (ADS)

Microbial composition is known, on similar soil types, to vary based on differing organic matter inputs, or stand composition. Dominating western upland boreal forests are fine textured soils with a canopy cover of aspen (Populus tremuloides Michx.), white spruce (Picea glauca (Moench) Voss or a mixture of the two. These soils then reflect different belowground biogeochemical processing of organic matter. Anthropogenic soils, formed from a combination of peat litter and fine textured mineral soil, are now also a part of the landscape in the western boreal. This study set out to determine if a simple labelled compound (13C glucose) was processed differently between soils from the two dominant stand types (aspen and spruce) and a soil from an anthropogenic (constructed) site. Results indicate that while all three soils rapidly incorporated, and respired, the labelled carbon each maintained a distinct microbial community structure (as evidenced by phospholipid fatty acid analysis) throughout the 300 hour experiment. Therefore soils with different microbial communities from varied organic matter inputs decompose organic carbon by different processes, even in the case of simple labile compounds.

Norris, C. E.; Quideau, S. A.; Macey, D. E.

2012-04-01

191

Watershed-Scale Geochemical Inventory of Soils by Portable X-Ray Fluorescence  

NASA Astrophysics Data System (ADS)

Spatial databases of geochemical data are an excellent source of point-scale information on naturally occurring toxic elements (arsenic, selenium or radon), contamination from industrial processes (lead, mercury, or cesium), mineralogical variability, and the fate of toxic compounds (i.e. sorption of pesticides to iron oxyhydroxide minerals) in soil. Sample preparation time, safety concerns associated with HF or HNO3 acid dissolution, instrument availability, and cost are all common constraints that limit the scale at which new geochemical surveys can be conducted. We used a Thermo-Fisher Niton portable X-Ray fluorescence (XRF) meter to perform comparatively rapid geochemical surveys in soils of two (35 ha) watersheds. The watersheds have contrasting parent materials, one formed from metavolcanic rock and the other from granite. The X-Ray fluorescence inventory of genetic soil horizons (n=660) was used to identify trends in soil development and landscape processes. Since soil samples are usually sieved and ground for standard laboratory characterization, the additional time required to prepare samples for XRF analysis was minimal, approximately 2 minutes for sample preparation and 6 minutes for machine scan time per sample. Preliminary analysis of the resulting geochemical data show strong spatial trends in watershed- and hillslope-scale variability in weathering indices (FeCBD:FeTotal and K:Ti), inferred mineralogy (Si:Al, Si:Al+Fe), and geologic signatures (multivariate analysis of 20 common elements). Depth trends and spatial patterns were correlated with common terrain-shape indices (slope, upslope contributing area, surface curvatures, local prominence, etc.), degree of soil development, parent material, and hydrological conditions. For example, Si:Al was higher in soils with greater upslope contributing area, and in seasonally saturated soils (Fig 1). Our findings demonstrate that portable XRF technology is a promising new tool for rapid lab-based and in situ geochemical surveys of soils. Ratio of silicon to aluminum (molecular mass) at six depth ranges, within a Sierra Foothill watershed. Watershed area is approximately 35ha, north is aligned with the y-axis.

Beaudette, D. E.; Stupi, L. K.; Swarowsky, A.; O'Geen, A. T.; Chang, J. F.; Gallagher, B.

2009-12-01

192

Isolation and characterization of an isoproturon mineralizing Sphingomonas sp. strain SH from a French agricultural soil.  

PubMed

The phenylurea herbicide isoproturon, 3-(4-isopropylphenyl)-1,1-dimethylurea (IPU), was found to be rapidly mineralized in an agricultural soil in France that had been periodically exposed to IPU. Enrichment cultures from samples of this soil isolated a bacterial strain able to mineralize IPU. 16S rRNA sequence analysis showed that this strain belonged to the phylogeny of the genus Sphingomonas (96% similarity with Sphingomonas sp. JEM-14, AB219361) and was designated Sphingomonas sp. strain SH. From this strain, a partial sequence of a 1,2-dioxygenase (catA) gene coding for an enzyme degrading catechol putatively formed during IPU mineralization was amplified. Phylogenetic analysis revealed that the catA sequence was related to Sphingomonas spp. and showed a lack of congruence between the catA and 16S rRNA based phylogenies, implying horizontal gene transfer of the catA gene cluster between soil microbiota. The IPU degrading ability of strain SH was strongly influenced by pH with maximum degradation taking place at pH 7.5. SH was only able to mineralize IPU and its known metabolites including 4-isopropylaniline and it could not degrade other structurally related phenylurea herbicides such as diuron, linuron, monolinuron and chlorotoluron or their aniline derivatives. These observations suggest that the catabolic abilities of the strain SH are highly specific to the metabolism of IPU. PMID:21110068

Hussain, Sabir; Devers-Lamrani, Marion; El Azhari, Najoi; Martin-Laurent, Fabrice

2011-06-01

193

Ectomycorrhizal Influence on Particle Size, Surface Structure, Mineral Crystallinity, Functional Groups, and Elemental Composition of Soil Colloids from Different Soil Origins  

PubMed Central

Limited data are available on the ectomycorrhizae-induced changes in surface structure and composition of soil colloids, the most active portion in soil matrix, although such data may benefit the understanding of mycorrhizal-aided soil improvements. By using ectomycorrhizae (Gomphidius viscidus) and soil colloids from dark brown forest soil (a good loam) and saline-alkali soil (heavily degraded soil), we tried to approach the changes here. For the good loam either from the surface or deep soils, the fungus treatment induced physical absorption of covering materials on colloid surface with nonsignificant increases in soil particle size (P > 0.05). These increased the amount of variable functional groups (O–H stretching and bending, C–H stretching, C=O stretching, etc.) by 3–26% and the crystallinity of variable soil minerals (kaolinite, hydromica, and quartz) by 40–300%. However, the fungus treatment of saline-alkali soil obviously differed from the dark brown forest soil. There were 12–35% decreases in most functional groups, 15–55% decreases in crystallinity of most soil minerals but general increases in their grain size, and significant increases in soil particle size (P < 0.05). These different responses sharply decreased element ratios (C?:?O, C?:?N, and C?:?Si) in soil colloids from saline-alkali soil, moving them close to those of the good loam of dark brown forest soil. PMID:23766704

Li, Yanhong; Wang, Huimei; Wang, Wenjie; Yang, Lei; Zu, Yuangang

2013-01-01

194

WEATHERING OF IRONBEARING MINERALS IN SOILS AND SAPROLITE ON THE NORTH CAROLINA BLUE RIDGE FRONT: II. CLAY MINERALOGY  

Microsoft Academic Search

The mineralogy of the clay fraction was studied for soils and saprolite on two Blue Ridge Front mountain slopes. The clay fraction contained the weathering products of primary minerals in the mica gneiss and schist parent rocks. Gibbsite is most abundant in the saprolite and residual soil horizons, where only chemical weathering has been operable. In colluvial soil horizons, where

D. D. AMARASIRIWARDENA; S. W. BUOL

195

Effects of Biological Soil Crusts on Seedling Growth and Mineral Content of Four Semiarid Herbaceous Plant Species  

Microsoft Academic Search

A growing body of evidence indicates that biological soil crusts of arid and semiarid lands contribute significantly to ecosys- tem stability by means of soil stabilization, nitrogen fixation, and improved growth and establishment of vascular plant species. In this study, we examined growth and mineral content of Bromus tectorum, Elymus elymoides, Gaillardia pulchella, and Sphaeralcea munroana grown in soil amended

R. L. Pendleton; B. K. Pendleton; G. L. Howard; S. D. Warren

196

From bulk soil to intracrystalline investigation of plant-mineral interaction  

NASA Astrophysics Data System (ADS)

Understanding the controls and feedbacks regulating the flux of matter between bio-geochemical reservoirs in forest ecosystems receives a fast growing interest for the last decades. A complex question is to understand how minerals and vegetation interact in soils to sustain life and, to a broader scope, how forest ecosystems may respond to human activity (acid rain, harvesting,...) and climate perturbations (temperature, precipitation,...). Many mineralogical and biogeochemical approaches have longtime been developed, and occasionally coupled, in order to investigate the mechanisms by which chemical elements either are exchanged between soil particles and solutions, or are transferred to plants or to deeper soil layers and finally leave the system. But the characterization of particular processes like the contribution of minor reactive minerals to plant nutrition and global fluxes or the mechanisms by which biology can modify reaction rates and balance the bioavailability of nutrients in response to environmental perturbation sometimes fails because of the lack of suitable tracers. Recent analytical and conceptual advances have opened new perspectives for the use of light "non traditional" stable isotopes. Showing a wild range of concentrations and isotopic compositions between biogeochemical reservoirs in forest ecosystem, boron has physico-chemical properties particularly relevant to the investigation of water/rock interactions even when evolving biologically-mediated reactions. In this study, we focused on the distribution of boron isotopes from intracrystalline to bulk soil scales. An overview of the boron distribution and annual fluxes in the soil-plant system clearly indicates that the vegetation cycling largely controls the mobility of boron. We also observe that the mineral and biological B pools have drastically different isotopic signature that makes the transfer of B between them very easy to follow. In particular, the podzol soil we analyzed shows a clear contribution of vegetation-recycled B to neoformed mineral phases, whereas B in minerals from the brown acidic soil rather indicates predominant mineral dissolution with little or even no B supply from the soil solution. If B isotopes thus proved their sensitivity to the soil forming conditions, a simple isotopic budget also demonstrates that the isotopic signature shown by the vegetation cannot result from fractionation during boron absorption. Analyses of B isotopes within intracrystalline phyllosilicate minerals further identify the interfoliar layers as the major source of B during plant nutrition. Additionally, weathering experiments placing phyllosilicates in contact with various alteration agents (protons, organic acid or siderophore) point to the role of the latters as likely responsible for the boron liberation from the phyllosilicate interfoliar layers. This scenario gives the phyllosilicate interfoliar layers a central function in the plant nutrition in context studied here of soils developed on granitic bedrocks. It also implies a very dynamic system in which plants and minerals can exchange matter over very short periods of time.

Lemarchand, D.; Voinot, A.; Chabaux, F.; Turpault, M.

2011-12-01

197

Potential linkages between mineral magnetic measurements and urban roadside soil pollution (part 2).  

PubMed

Use of mineral magnetic concentration parameters (?LF, ?ARM and SIRM) as a potential pollution proxy for soil samples collected from Wolverhampton (UK) is explored. Comparison of soil-related analytical data by correlation analyses between each magnetic parameter and individual geochemical classes (i.e. Fe, Pb, Ni, Zn, Cd), are reported. ?LF, ?ARM and SIRM parameters reveal significant (p < 0.001 n = 60), strong (r = 0.632-0.797), associations with Fe, Cu, Zn and Pb. Inter-geochemical correlations suggest anthropogenic influences, which is supported by low ?FD% measurements that infer an influence of multi-domain mineralogy are indicative of anthropogenic combustion processes. Results indicate mineral magnetic measurements could potentially be used as a geochemical indicator for soils in certain environments and/or specific settings that are appropriate for monitoring techniques. The mineral magnetic technique offers a simple, reliable, rapid, sensitive, inexpensive and non-destructive approach that could be a valuable pollution proxy for soil contamination studies. PMID:24463607

Crosby, C J; Fullen, M A; Booth, C A

2014-03-01

198

Sorption and Transport of Pharmaceutical chemicals in Organic- and Mineral-rich Soils  

NASA Astrophysics Data System (ADS)

Pharmaceutical, active ingredients in personal care products (PhACs), and their derivative compounds are increasingly ubiquitous in surface waters across the world. Sorption and transport of four relatively common PhACs (naproxen, ibuprofen, cetirizine, and triclosan) in different natural soils was measured. All of these compounds are relatively hydrophobic (log KOW>2) and have acid/base functional groups, including one compound that is zwitterionic (cetirizine.) The main goal of this study was to correlate organic matter (OM) and clay content in natural soils and sediment with sorption and degradation of PhACs and ultimately their potential for transport within the subsurface environment. A- and B-horizon soils were collected from four sub-regions within a pristine managed forested watershed near Charleston, SC, with no apparent sources of anthropogenic contamination. These four soil series had varying OM content (fOC) between 0.4-9%, clay mineral content between 6-20%, and soil pH between 4.5-6. The A-horizon soils had higher fOC and lower clay content than the B-horizon soils. Sorption isotherms measured from batch sorption experimental data indicated a non-linear sorption relationship in all A- and B-horizon soils - stronger sorption was observed at lower PhAC concentrations and lower sorption at higher concentrations. Three PhACs (naproxen, ibuprofen, and triclosan) sorbed more strongly with higher fOC A-horizon soils compared with the B-horizon soils. These results show that soil OM had a significant role in strongly binding these three PhACs, which had the highest KOW values. In contrast, cetirizine, which is predominantly positively charged at pH below 8, strongly sorbed to soils with higher clay mineral content and least strongly to higher fOC soils. All sorption isotherms fitted well to the Freundlich model. For naproxen, ibuprofen, and triclosan, there was a strong and positive linear correlation between the Freundlich adsorption constant, Kf, and fOC, again indicating that these PhACs preferentially partition into the soil OM. Such a correlation was absent for cetirizine. Breakthrough curves of PhACs measured in homogeneous packed soil columns indicated that PhAC transport was affected by chemical nonequilibrium processes depending on the soil and PhAC chemistry. The shape of the breakthrough curves indicated that there were two distinct sorption sites - OM and clay minerals - which influence nonequilibrium transport of these compounds. The retardation factor estimated using the distribution coefficient, Kd, measured from the sorption experiments was very similar to the measured value. While the sorption and transport data do not provide mechanistic information regarding the nature of PhAC interaction with chemical reactive components within geological materials, they do provide important information regarding potential fate of such compounds in the environment. The results also show the role that soil OM and mineral surfaces play in sequestering or transporting these chemicals. These insights have implications to the quality of the water resources in our communities.

Vulava, V. M.; Schwindaman, J.; Murphey, V.; Kuzma, S.; Cory, W.

2011-12-01

199

Linking Annual N2O Emission in Organic Soils to Mineral Nitrogen Input as Estimated by Heterotrophic Respiration and Soil C/N Ratio  

PubMed Central

Organic soils are an important source of N2O, but global estimates of these fluxes remain uncertain because measurements are sparse. We tested the hypothesis that N2O fluxes can be predicted from estimates of mineral nitrogen input, calculated from readily-available measurements of CO2 flux and soil C/N ratio. From studies of organic soils throughout the world, we compiled a data set of annual CO2 and N2O fluxes which were measured concurrently. The input of soil mineral nitrogen in these studies was estimated from applied fertilizer nitrogen and organic nitrogen mineralization. The latter was calculated by dividing the rate of soil heterotrophic respiration by soil C/N ratio. This index of mineral nitrogen input explained up to 69% of the overall variability of N2O fluxes, whereas CO2 flux or soil C/N ratio alone explained only 49% and 36% of the variability, respectively. Including water table level in the model, along with mineral nitrogen input, further improved the model with the explanatory proportion of variability in N2O flux increasing to 75%. Unlike grassland or cropland soils, forest soils were evidently nitrogen-limited, so water table level had no significant effect on N2O flux. Our proposed approach, which uses the product of soil-derived CO2 flux and the inverse of soil C/N ratio as a proxy for nitrogen mineralization, shows promise for estimating regional or global N2O fluxes from organic soils, although some further enhancements may be warranted. PMID:24798347

Mu, Zhijian; Huang, Aiying; Ni, Jiupai; Xie, Deti

2014-01-01

200

Light-catalyzed chromium(VI) reduction by organic compounds and soil minerals.  

PubMed

Detoxification of Cr(VI) through reduction has been considered an effective method for reclaiming Cr-contaminated soil, sediment, and waste water. Organic matter is widely distributed in soil and aquatic systems; however, low Cr(VI) reduction rates inhibit the adoption of Cr reduction technologies by industry. Scientists have been aware of Cr(VI) reduction catalyzed by soil minerals; however, most of the studies focused on using semiconductors as catalysts with UV irradiation to accelerate the redox reactions. The objective of this study was to evaluate the rates of Cr(VI) reduction by fluorescence light in the presence of organic materials with or without specific soil minerals. Experimental results showed that dissolved organic compounds reduced Cr(VI) slowly under laboratory light; however, Cr(VI) reduction was greatly enhanced when growth chamber light was applied. Low photon flux (i.e., laboratory light) only enhanced Cr(VI) reduction by organics when Fe(III) was also present, because the Fe(II)-Fe(III) redox couple accelerated electron transfer and decreased electrostatic repulsion between reactants. Laboratory light was required to initiate Cr(VI) reduction catalyzed by TiO2; nonetheless, light-catalyzed Cr(VI) reduction by smectite and ferrihydrite could occur only when greater light energy was provided with a growth chamber light. Our results suggest a potential pathway for Cr(VI) reduction using naturally occurring organic compounds and colloids in acidic water systems or in surface soils when light is available. PMID:14674529

Tzou, Y M; Loeppert, R H; Wang, M K

2003-01-01

201

Contents of minerals in green leafy vegetables cultivated in soil fortified with different chemical fertilizers.  

PubMed

Content of selected minerals in spinach (Spinacea oleracea) and ambat chuka (Rumex vesicarius) cultivated in soil fortified with different chemical fertilizers was determined in a pot experiment. Addition of NPK (Nitrogen, Phosphorus and Potassium) fertilizer along with micronutrients, iron and zinc, enhanced the concentration of zinc, iron and magnesium in selected green leafy vegetables markedly (p < 0.05), while the concentration of copper was not altered significantly (p > 0.05). Potassium content in the green leafy vegetables was not affected (p > 0.05) by the addition of chemical fertilizers to soil. Spinach and ambat chuka differed remarkably in their mineral contents. Contents of potassium, zinc and copper were significantly high in spinach, while the contents of magnesium and iron were markedly high in ambat chuka (p < 0.05). PMID:11213164

Reddy, N S; Bhatt, G

2001-01-01

202

Soft X-ray spectromicroscopy study of mineral-organic matter associations in pasture soil clay fractions.  

PubMed

There is a growing acceptance that associations with soil minerals may be the most important overarching stabilization mechanism for soil organic matter. However, direct investigation of organo-mineral associations has been hampered by a lack of methods that can simultaneously characterize organic matter (OM) and soil minerals. In this study, STXM-NEXAFS spectroscopy at the C 1s, Ca 2p, Fe 2p, Al 1s, and Si 1s edges was used to investigate C associations with Ca, Fe, Al, and Si species in soil clay fractions from an upland pasture hillslope. Bulk techniques including C and N NEXAFS, Fe K-edge EXAFS spectroscopy, and XRD were applied to provide additional information. Results demonstrated that C was associated with Ca, Fe, Al, and Si with no separate phase in soil clay particles. In soil clay particles, the pervasive C forms were aromatic C, carboxyl C, and polysaccharides with the relative abundance of carboxyl C and polysaccharides varying spatially at the submicrometer scale. Only limited regions in the soil clay particles had aliphatic C. Good C-Ca spatial correlations were found for soil clay particles with no CaCO3, suggesting a strong role of Ca in organo-mineral assemblage formation. Fe EXAFS showed that about 50% of the total Fe in soils was contained in Fe oxides, whereas Fe-bearing aluminosilicates (vermiculite and Illite) accounted for another 50%. Fe oxides in the soil were mainly crystalline goethite and hematite, with lesser amounts of poorly crystalline ferrihydrite. XRD revealed that soil clay aluminosilicates were hydroxy-interlayered vermiculite, Illite, and kaolinite. C showed similar correlation with Fe to Al and Si, implying a similar association of Fe oxides and aluminosilicates with organic matter in organo-mineral associations. These direct microscopic determinations can help improve understanding of organo-mineral interactions in soils. PMID:24837340

Chen, Chunmei; Dynes, James J; Wang, Jian; Karunakaran, Chithra; Sparks, Donald L

2014-06-17

203

Organo-mineral associations of Fe oxides and soil organic matter: Formation, properties and functions.  

NASA Astrophysics Data System (ADS)

In many soils, Fe oxides and oxyhydroxides are assumed to be the most important substrates for the formation of organo-mineral associations. While field studies often report correlations between organic C and the amount of Fe oxides, laboratory experiments confirm high organic matter loadings on Fe oxides and different possible interaction mechanisms. In spite of their small mass proportion within soils, the particular importance of Fe oxides as organic matter carriers might be explained by their usual occurrence as poorly crystalline, nanoparticulate minerals: This leads to large specific surface areas of 100-700 m2 g-1, which may dominate a soils total mineral surface area. Another reason for their high reactivity towards organic matter is seen in the fact that the surface of Fe oxides is covered by conditionally charged hydroxyl groups. Implications of the formation of Fe-oxide organic matter associations for pedogenesis are manifold and severe. On one hand, it will influence organic matter composition and development. Dissolved organic matter and extracellular polymeric substances are believed to be important sources for mineral associated organic matter. These complex mixtures usually fractionate during their association with Fe oxides. The associated fraction is supposed to be stabilized, whereas the non-associated fraction remains mobile and available to degradation by microorganisms. On the other hand, the organic coating will completely change the interface properties of Fe oxides such as solubility, charge and hydrophobicity. This in turn will affect their reactivity towards nutrients and pollutants, adsorption of new organic matter, the availability of ferric Fe towards microorganisms, the aggregation behavior and mobility of Fe oxides. In other words, for many soil forming processes it makes a big difference, whether the Fe oxide surfaces are coated by organic matter or not.

Eusterhues, Karin; Totsche, Kai Uwe

2013-04-01

204

Measuring the specific caesium sorption capacity of soils, sediments and clay minerals  

Microsoft Academic Search

Two methods to quantify the specific Cs sorption capacity of soils and sediments, which is generally believed to be associated with the Frayed Edge Sites (FES) of illitic clay minerals, are described in detail and are critically reviewed. The first method is a direct measurement of the FES capacity, while the second quantifies the combined parameter KDCs×[K+](=KC(K?Cs)×[FES]), i.e. the product

A. de Koning; A. V. Konoplev; R. N. J. Comans

2007-01-01

205

[Effect of mineral and organic fertilizers on algal growth on soddy-podzol soil].  

PubMed

The effect of various fertilizers and lime on the composition of algae and their content in soil was studied both in the field and laboratory conditions. The maximum yield of the algae was found upon continuous combined introduction of organic and mineral fertilizers, especially together with lime. In short-term experiments, the maximum yield was also registered upon combined introduction of the fertilizers and lime. PMID:1226149

Balezina, L S

1975-01-01

206

Formation of nitrous oxide (N2O) hydrate in soil mineral suspensions with electrolytes  

NASA Astrophysics Data System (ADS)

We have identified the effects of solid surface (illite, nontronite, sphalerite, kaolinite) and electrolyte (NaCl, KCl, CaCl2, MgCl2) types on the formation of N2O hydrate in this study. The hydrate formation experiments were conducted at hydrate forming condition (273.3K and 30 bar) by injecting N2O gas into the soil mineral suspensions with and without electrolytes in a 50mL pressurized vessel. The formation of N2O hydrate in aqueous electrolyte solutions was slower than that in deionized water. Ion charge and size were significant factors affecting N2O hydrate formation kinetic in electrolytes solutions. The addition of soil mineral suspensions accelerated the formation of N2O hydrate in the electrolyte solutions. Surface area and ionic strength of soil minerals highly influenced on formation kinetic of N2O hydrate. The hydrate formation times in the solid suspensions without electrolytes were very similar to that in the deionized water. The results obtained from this research could be indirectly applied to the fate of N2O sequestered into geological formations as well as its storage as a form of N2O hydrate.

Kyung, D.; Enkh-Amgalan, T.; Lee, W.

2013-05-01

207

Adsorption of iron cyanide complexes onto clay minerals, manganese oxide, and soil.  

PubMed

The adsorption characteristics of an iron cyanide complex, soluble Prussian blue KFe(III)[Fe(II)(CN)(6)], were evaluated for representative soil minerals and soil at pH 3.7, 6.4 and 9.7. Three specimen clay minerals (kaolinite, montmorillonite, and illite), two synthesized manganese oxides (birnessite and cryptomelane), and a Drummer soil from Indiana were used as the adsorbents. Surface protonation of variable charge sites increased with decreasing pH yielding positively charged sites on crystal edges and enhancing the attractive force between minerals and iron cyanide complexes. Anion adsorption on clays often is correlated to the metal content of the adsorbent, and a positive relationship was observed between iron or aluminum content and Prussian blue adsorption. Illite had high extractable iron and adsorbed more ferro-ferricyande anion, while kaolinite and montmorillonite had lower extractable iron and adsorbed less. However, less pH effect was observed on the adsorption of iron cyanide to manganese oxides. This may due to the manganese oxide mediated oxidation of ferrocyanide [Fe(II)(CN)(6)(4-)], to ferricyanide [Fe(III)(CN)(6)(3-)], which has a low affinity for manganese oxides. PMID:20665323

Kang, Dong-Hee; Schwab, A Paul; Johnston, C T; Banks, M Katherine

2010-09-01

208

Mineralization of nitrogen compounds in the soil under the bilberry-sphagnum birch forest (Yaroslavl Oblast)  

NASA Astrophysics Data System (ADS)

Net mineralization of nitrogen was measured in the horizons of peaty podzolic gley soil (At1, 0-6 cm, At2, 6-10 cm, and A2, 10-20 cm) of the bilberry-sphagnum birch forest from May to the beginning of November in 2011 and 2012; it comprised 2.1 ± 0.4, 2.7 ± 0.4, 1.2 ± 0.4, and 1.9 ± 0.2, 1.9 ± 0.2, 0.8 ± 0.15 g N/m2, respectively. The total of 6 ± 0.7 and 4.6 ± 0.3 g N/m2 were mineralized in the soil profile in the years 2011 and 2012, respectively, with the contribution of ammonification being more than 99%. The seasonal variations in nitrogen mineralization correlated with the temperature and soil moisture content in At1 and At2 horizons. The efficiency of nitrogen mineralization in soil horizons under the birch forest was expressed by similar values, namely, 0.005 ± 0.0008, 0.0064 ± 0.0008, and 0.003 ± 0.001 mg N/g C per day, and this suggests a high efficiency of substrate utilization in the eluvial part of the soil profile. The seasonal variation of carbon dioxide production correlated with the ammonification in the At1 horizon with r = 0.85 and p = 0.03 in 2011 and 2012, and in the At2 horizon with r = 0.65 and p = 0.16 in 2012. Over the studied period, production of ammonia depended on soil moistening in the dry year of 2011 ( r = 0.91; p = 0.01) and soil temperature in the wet year of 2012 ( r = 0.78; p = 0.06). The productivity of the process equaled 3 ± 0.9 mg N/m2, or 30 g N/ha in both years of observation.

Razgulin, S. M.

2014-02-01

209

Pristine soils mineralize 3-chlorobenzoate and 2,4-dichlorophenoxyacetate via different microbial populations.  

PubMed Central

Biodegradation of two chlorinated aromatic compounds was found to be a common capability of the microorganisms found in the soils of undisturbed, pristine ecosystems. We used 2,4-dichlorophenoxyacetate (2,4-D) and 3-chlorobenzoate (3CBA) as enrichment substrates to compare populations of degrading bacteria from six different regions making up two ecosystems. We collected soil samples from four Mediterranean (California, central Chile, the Cape region of South Africa, and southwestern Australia) and two boreal (northern Saskatchewan and northwestern Russia) ecosystems that had no direct exposure to pesticides or to human disturbance. Between 96 and 120 samples from each of the six regions were incubated with 50 ppm of [U-14C]2,4-D or [U-14C]3CBA. Soils from all regions samples mineralized both 2,4-D and 3CBA, but 3CBA was mineralized without a lag period, while 2,4-D was generally not mineralized until the second week. 3CBA degradative capabilities were more evenly distributed spatially than those for 2,4-D. The degradative capabilities of the soils were readily transferred to fresh liquid medium. 3CBA degraders were easily isolated from most soils. We recovered 610 strains that could release carbon dioxide from ring-labeled 3CBA. Of these, 144 strains released chloride and degraded over 80% of 1 mM 3CBA in 3 weeks or less. In contrast, only five 2,4-D degraders could be isolated, although a variety of methods were used in an attempt to culture the degraders. The differences in the distribution and culturability of the bacteria responsible for 3CBA and 2,4-D degradation in these ecosystems suggest that the two substrates are degraded by different populations. We also describe a 14C-based microtiter plate method that allows efficient screening of a large number of samples for biodegradation activity. PMID:8919776

Fulthorpe, R R; Rhodes, A N; Tiedje, J M

1996-01-01

210

[Characteristics of soil net nitrogen mineralization in subalpine/alpine forests of west Sichuan, Southwest China during seasonal freeze-thaw period].  

PubMed

Seasonal freeze-thaw cycle and its change pattern under the scenarios of climate warming might exert strong effects on the soil nitrogen mineralization in alpine forests. In this paper, intact soil cores were collected from the subalpine/alpine forests along an altitudinal gradient in west Sichuan, and an incubation test was conducted to study the soil net nitrogen mineralization rate and the amount of soil mineralized nitrogen in the forests during growth season and seasonal freeze-thaw period under simulated scenarios of global warming. In the test soils, the NH(4+)-N and NO(3-)-N contents both showed a clear tendency of decreased in the period from growth season to the onset stage of freezing, increased at deep freezing stage, and decreased again at the early stage of thawing. The soil net nitrogen mineralization rate and the amount of soil mineralized nitrogen were significantly lower in freeze-thaw period than in growth season, and the soil inorganic nitrogen was obviously immobilized. The soil nitrogen immobilization was stronger at middle altitudes but weaker at high altitudes, as compared with that at low altitudes, possibly due to the variation of soil temperature and its induced different freeze-thaw cycle. During growth period, the soil net nitrogen mineralization rate and the amount of soil mineralized nitrogen showed an obvious increasing trend with the decrease of altitude, and the soil nitrogen mineralization was the strongest at low altitudes, implying that under the scenarios of climate warming, the increase of soil temperature promoted the soil nitrogen mineralization during growth season, and affected the soil nitrogen mineralization rate by increasing the frequency of freeze-thaw cycle and shortening the time period of freeze-thaw. Soil micro-environment could also affect the soil nitrogen mineralization in alpine forest regions. PMID:22720601

Liu, Jin-Ling; Wu, Fu-Zhong; Yang, Wan-Qin; Shi, Pei-Li; Wang, Ao; Yang, Yu-Lian; Wu, Zhi-Chao

2012-03-01

211

Nitrogen and carbon mineralization of semi-arid shrubland soil exposed to long-term atmospheric nitrogen deposition  

Microsoft Academic Search

Anthropogenic N-deposition represents a significant input of N into semi-arid chaparral and coastal sage scrub (CSS) shrublands\\u000a of southern California. High levels of atmospheric N deposition have the potential to increase soil C and N mineralization,\\u000a and we hypothesize that semi-arid shrubland soil exposed to long-term (decades) high N deposition will have significantly\\u000a higher C and N mineralization potentials. This

George L. Vourlitis; Gypsi Zorba

2007-01-01

212

Mineralization and changes in microbial biomass in water-saturated soil amended with some tropical plant residues  

Microsoft Academic Search

An incubation experiment was conducted in the laboratory at 25 and 35°C during 56 d to analyze the mineralization patterns and the changes in microbial biomass in water-saturated soils amended with 6 types of organic materials (O.M.) including residues from 4 tropical plants. C and N mineralization in amended and non-amended soils was influenced by the temperature, A significantly positive

Abul Kalam Mohammad Azmal; Takuya Marumoto; Hamo Shindo; Masaya Nishiyama

1996-01-01

213

Effect of organic residue amendments and soil moisture on N mineralization, maize (Zea mays L.) dry biomass and nutrient concentration  

Microsoft Academic Search

Greenhouse pot experiments with four tropical soils were conducted to measure the effect of crop residues on nitrogen mineralization\\/immobilization and growth of maize plants at two soil moisture regimes (pF2.5 and pF3.5). The nitrogen rich residues of pigeon pea (PP, Cajanus cajan (L.) Millps, C\\/N, 18.8) enhanced plant growth and increased the assimilation of mineral elements (N, P and K)

Girma Abera; Endalkachew Wolde-meskel; Lars R Bakken

2012-01-01

214

Minerals vs. Microbes: Biogeochemical Controls on Carbon Storage in Humid Tropical Forest Soils  

NASA Astrophysics Data System (ADS)

Humid tropical forest soils contain a substantial portion (~500 Pg) of the terrestrial carbon (C) pool, yet their response to climate change remains unclear due to mechanistic uncertainty in the biogeochemical controls on soil C storage in these ecosystems. Poorly-crystalline minerals have long been known to stabilize soil C, but few studies have explored their relative importance in comparison with other likely controls such as rhizosphere processes, oxygen deficiency (anaerobiosis), and C quality. We examined relationships among soil C and a suite of biogeochemical variables measured in 162 samples from surface soils (ultisols and oxisols) collected over scales of landforms to landscapes (m - km) in the Luquillo Experimental Forest, Puerto Rico. We measured iron (Fe), aluminum (Al), and manganese (Mn) oxides in 0.5M hydrochloric acid (HCl), sodium citrate/ascorbic acid (CA), and citrate/dithionite (CD) extractions, along with clay content, root biomass, C quality (C/N ratios), and anaerobiosis using HCl-extractable reduced iron (Fe(II)) concentrations as a proxy. We used mixed-effects models to compare the relative importance of the above variables (normalized by mean and standard deviation) as predictors of soil C, with random effects to account for spatial structure. Poorly-crystalline Al oxide concentrations (CA extraction), soil C/N ratio, and Fe(II) concentrations each had highly significant (p < 0.0001) positive relationships with soil C concentrations that conveyed equivalent explanatory power, assessed by comparing standardized regression coefficients. The optimal mixed model explained 82 % of the variation of the residual sum of squares of soil C concentrations, which varied between 2 - 20 % C among samples. Fine root biomass had a weak but significantly positive association with soil C concentrations (p < 0.05), while crystalline Fe oxide concentrations (CD extraction) displayed a negative correlation (p < 0.01), and clay contents had no significant relationship. The latter results are surprising given the documented role of Fe oxides and clay minerals in C stabilization, yet may indicate the importance of C supply via roots in controlling C concentrations in humid tropical ecosystems. Samples associated with high concentrations of crystalline Fe and high clay contents may represent soils from deeper in the soil profile exposed by landslides, characterized by poorly-developed aggregate structure and fewer C inputs since disturbance. Our optimal mixed model suggested an equivalent importance of soil mineralogy, anaerobiosis, and C quality as correlates of soil C concentrations across tropical forest ecosystems varying in temperature, precipitation, and community composition. Whereas soil mineralogy may be relatively static over timescales of years to decades, O2 availability and the chemical composition of soil C inputs and can potentially vary more rapidly. Our model suggests that changes in temperature and precipitation regimes that alter O2 availability and/or increase the lability of C inputs may lead to decreased soil C storage in humid tropical forest soils.

Hall, S. J.; Silver, W. L.

2012-12-01

215

Sequential extraction method for speciation of arsenate and arsenite in mineral soils.  

PubMed

A novel sequential extraction method for the speciation of As(III) and As(V) in oxic and anoxic mineral soils was developed and tested. The procedure consists of seven extraction steps targeting various As pools ranging from weakly adsorbed to well-crystalline species. Each step was specifically designed to preserve the As(III) and As(V) redox states, e.g., by complexation of As(III) with diethyldithiocarbamate or pyrrolidinedithiocarbamate, using mild reductive (NH(2)OH.HCl) or oxidative (hot HNO(3)) extractions, and complexing (Fe(3+) with Cl(-), acetate, and oxalate) or precipitating (S(2-) with Hg(2+)) matrix elements, which may cause As redox transformations. Using high-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) for the quantification of dissolved As(III) and As(V) in the extracts, the detection limit for each step was in the range of 1.0-75 ng As/g, depending on the extraction matrix. Thus, the procedure is also well-suited for As speciation in soils or sediments with low As concentrations, where analyses by X-ray absorption spectroscopy (XAS) may be difficult. The entire extraction sequence can be performed under normal atmosphere, which greatly simplifies sample handling. The proposed method was tested using model minerals spiked with As(III) or As(V), two strongly As-polluted soil previously characterized for As speciation by XAS, and three less-polluted soils. PMID:20524641

Huang, Jen-How; Kretzschmar, Ruben

2010-07-01

216

Carbon Mineralization of Soils from Native Evergreen Broadleaf Forest and Three Plantations in Mid?subtropic China  

Microsoft Academic Search

Mineralization of soil organic carbon (C) plays a key role in supplying nutrient elements essential to plant growth. Changes of C mineralization of mixed stands of Chinese fir and Michelia macclurei (a broadleaf tree), pure M. macclurei stands, and pure Chinese fir (Cunninghamia lanceolata) stands established in 1983 after clear?felling of a first?generation Chinese fir forest were analyzed in Huitong,

Jian Zhang

2009-01-01

217

Kinetics and mechanisms of metal sorption at the soil mineral/water interface: The continuum from adsorption to  

E-print Network

GEOC 36 Kinetics and mechanisms of metal sorption at the soil mineral/water interface mechanisms at the mineral/water interface. For example, it has been shown that metal sorption often results, Newark, DE 19717-1303 A basic understanding of the kinetics and mechanisms of metal sorption on natural

Sparks, Donald L.

218

Mineral stress: the missing link in understanding how global climate change will affect plants in real world soils  

Microsoft Academic Search

Many natural and agricultural ecosystems are characterized by sub-optimal availability of mineral nutrients and ion toxicities. Mineral stresses are likely to have important, complex, and poorly understood interactions with global climate change variables. For example, most terrestrial vegetation is supported by weathered soils with some combination of low P, low Ca, Al toxicity, and Mn toxicity. Each of these stresses

Jonathan P. Lynch; Samuel B. St. Clair

2004-01-01

219

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. ???, XXXX, DOI:10.1029/, Impact of surface roughness and soil texture on mineral dust  

E-print Network

texture on mineral dust emission fluxes modeling Laurent MENUT1 , Carlos P´EREZ2,3 , Karsten HAUSTEIN4 to estimate vertical fluxes of mineral dust aerosols over arid regions need accurate data on soil and surface properties. The LISA dataset was developed for Northern Africa, Middle East and East Asia. This regional

Menut, Laurent

220

Effects of belowground litter addition, increased precipitation and clipping on soil carbon and nitrogen mineralization in a temperate steppe  

NASA Astrophysics Data System (ADS)

Soil carbon (C) and nitrogen (N) cycling are sensitive to changes in environmental factors and play critical roles in the responses of terrestrial ecosystems to natural and anthropogenic perturbations. This study was conducted to quantify the effects of belowground particulate litter (BPL) addition, increased precipitation and their interactions on soil C and N mineralization in two adjacent sites where belowground photosynthate allocation was manipulated through vegetation clipping in a temperate steppe of northeastern China from 2010 to 2011. The results show that BPL addition significantly increase soil C mineralization rate (CMR) and net N mineralization rate (NMR). Although increased precipitation-induced enhancement of soil CMR essentially ceased after the first year, stimulation of soil NMR and net nitrification rate continued into the second year. Clipping only marginally decreased soil CMR and NMR during the two years. There were significant synergistic interactions between BPL addition (and increased precipitation) and clipping on soil CMR and NMR, likely to reflect shifts in soil microbial community structure and a decrease in arbuscular mycorrhizal fungi biomass due to the reduction of belowground photosynthate allocation. These results highlight the importance of plants in mediating the responses of soil C and N mineralization to potentially increased BPL and precipitation by controlling belowground photosynthate allocation in the temperate steppe.

Ma, L.; Guo, C.; Xin, X.; Yuan, S.; Wang, R.

2013-11-01

221

Bioremediation of experimental petroleum spills on mineral soils in the Vestfold Hills, Antarctica  

SciTech Connect

The effect of nutrient and water enhancement on the biodegradation of petroleum was tested in Antarctic mineral soils. Nitrogen, phosphorus and potassium were applied in solution, with or without gum xanthan or plastic covers, to sites artificially contaminated with distillate. The effectiveness of these procedures was assessed by measuring changes in total petroleum hydrocarbons; heptadecane/pristane and octadecane/phytane ratios; in concentrations of major hydrocarbon components and in microbial numbers and activity. Significantly lower hydrocarbon concentration were recorded after one year in soils treated with fertilizer solutions, but only in the surface 3 cm. These soils also showed lowered heptadecane/pristane and octadecane/phytane ratios and had the highest levels of microbial activity relative to other plots. Soils treated with gum xanthan or covered with plastic had the highest residual hydrocarbon levels. Both treatments inhibited evaporative loss of hydrocarbon, and there were indications that gum xanthan was utilized by the microbiota as an alternative carbon source to distillate. Higher temperatures were recorded under the plastic but no stimulation of biodegradation was detected. Estimated numbers of metabolically active bacteria were in the range 10[sup 7] to 10[sup 8] g[sup [minus]1] dry weight of soil, with an estimated biomass of 0.03 to 0.26 mg g[sup [minus]1] soil. Estimated numbers of amoebae were in the range 10[sup 6] 10[sup 7] g[sup [minus]1] soil (biomass of 2 to 4 mg g[sup [minus]1]). The highest populations were recorded in fertilized, contaminated soils, the only soils where petroleum degradation was demonstrated. 23 refs., 1 fig., 4 tabs.

Kerry, E. (Univ. of Tasmania (Australia))

1993-01-01

222

Response of maize yield, nitrate leaching, and soil nitrogen to pig slurry combined with mineral nitrogen.  

PubMed

The application of pig (Sus scrofa) slurry (PS) is a common fertilization practice that may affect nitrate concentrations and loads in drainage and receiving water bodies. To protect water resources, many agricultural areas are being designated as vulnerable to nitrate contamination, and there is a need for scientific data aiming at reducing nitrate exports from these vulnerable zones by optimizing N fertilization strategies. The objective of this work, conducted in drainage lysimeters in a 4-yr monoculture maize (Zea mays L.) crop, is to assess the effects of four fertilization strategies combining PS (30, 60, 90, and 120 t ha(-1)) and mineral N on yield, changes in soil mineral N, and concentration and mass of nitrate in drainage waters. Grain yield was not affected by treatments in the four experimental years, nor was the soil mineral N at the end of the experiment. Effects of fertilization strategies on nitrate concentration and mass in drainage waters were detected only after 3 yr of repeated PS applications. The mass of nitrate leached over the 4 yr was positively related to the total amount of N applied, either organic or mineral. In year 2003, precipitation in spring reduced N availability for the crop in treatments with rates > or = 60 t PS ha(-1). The N-budget revealed that the transport pathways for 25% of N inputs to the system are unknown. The presowing application of pig slurry at 30 t ha(-1) complemented with mineral N at side-dressing, was the most efficient from an environmental standpoint (4-yr average of 145 kg grain yield kg(-1) N leached). PMID:20176841

Yagüe, María R; Quílez, Dolores

2010-01-01

223

Influence of pH and electrolyte composition on adsorption of poliovirus by soils and minerals.  

PubMed Central

The pH and the nature an concentration of simple electrolytes influenced the interaction of poliovirus type 2 with three soils, a sand, and a clay mineral. In electrolytes above pH 9 the virus was not adsorbed extensively to the substrates, but below pH 7 almost all virus was bound. For each adsorbent there was a characteristic pH region of transition from strong to weak uptake. Differences between the soils in virus uptake were shown to parallel their pH-dependent mineral. In electrolytes above pH 9 the virus was not adsorbed extensively to the substrates, but below pH 7 almost all virus was bound. For each adsorbent there was a characteristic pH region of transition from strong to weak uptake. Differences between the soils in virus uptake were shown to parallel their pH-dependent mineral. In electrolytes above pH 9 the virus was not adsorbed extensively to the substrates, but below pH 7 almost all virus was bound. For each adsorbent there was a characteristic pH region of transition from strong to weak uptake. Differences between the soils in virus uptake were shown to parallel their pH-dependent charge properties, as determined by whole-particle microelectrophoresis. Only when the pH was close to or above the critical region was uptake increased with electrolyte concentration. The transition region for all substrates was above pH 7.5 the isoelectric point of the virus. Thus, it appears that when both the virus and substrate are highly negative charged, repulsive electrostatic effects may exceed inherent attractive interactions, thereby inhibiting adsorption. PMID:6274260

Taylor, D H; Moore, R S; Sturman, L S

1981-01-01

224

Nitrous oxide emissions respond differently to mineral and organic nitrogen sources in contrasting soil types.  

PubMed

The use of various animal manures for nitrogen (N) fertilization is often viewed as a viable replacement for mineral N fertilizers. However, the impacts of amendment type on NO production may vary. In this study, NO emissions were measured for 2 yr on two soil types with contrasting texture and carbon (C) content under a cool, humid climate. Treatments consisted of a no-N control, calcium ammonium nitrate, poultry manure, liquid cattle manure, or liquid swine manure. The N sources were surface applied and immediately incorporated at 90 kg N ha before seeding of spring wheat ( L.). Cumulative NO-N emissions from the silty clay ranged from 2.2 to 8.3 kg ha yr and were slightly lower in the control than in the fertilized plots ( = 0.067). The 2-yr mean NO emission factors ranged from 2.0 to 4.4% of added N, with no difference among N sources. Emissions of NO from the sandy loam soil ranged from 0.3 to 2.2 kg NO-N ha yr, with higher emissions with organic than mineral N sources ( = 0.015) and the greatest emissions with poultry manure ( < 0.001). The NO emission factor from plots amended with poultry manure was 1.8%, more than double that of the other treatments (0.3-0.9%), likely because of its high C content. On the silty clay, the yield-based NO emissions (g NO-N kg grain yield N) were similar between treatments, whereas on the sandy loam, they were greatest when amended with poultry manure. Our findings suggest that, compared with mineral N sources, manure application only increases soil NO flux in soils with low C content. PMID:22370405

Pelster, David E; Chantigny, Martin H; Rochette, Philippe; Angers, Denis A; Rieux, Christine; Vanasse, Anne

2012-01-01

225

Beryllium geochemistry in soils: Evaluation of 10Be/9Be ratios in authigenic minerals as a basis for age models  

USGS Publications Warehouse

Soils contain a diverse and complex set of chemicals and minerals. Being an 'open system', both in the chemical and nuclear sense, soils have defied quantitative nuclear dating. However, based on the published studies of the cosmogenic atmospheric 10Be in soils, its relatively long half-life (1.5 Ma), and the fact that 10Be gets quickly incorporated in most soil minerals, this radionuclide appears to be potentially the most useful for soil dating. We therefore studied the natural variations in the specific activities of 10Be with respect to the isotope 9Be in mineral phases in eight profiles of diverse soils from temperate to tropical climatic regimes and evaluated the implications of the data for determining the time of formation of soil minerals, following an earlier suggestion [Lal et al., 1991. Development of cosmogenic nuclear methods for the study of soil erosion and formation rates. Current Sci. 61, 636-639.]. We find that the 10Be/9Be ratios in both bulk soils and in the authigenic mineral phases are confined within a narrower range than in 10Be concentrations. Also, the highest 10Be/9Be ratios in authigenic minerals are observed at the soil-rock interface as predicted by the model. We present model 10Be/9Be ages of the B-horizon and the corresponding soil formation rates for several soil profiles. The present study demonstrates that the 10Be/9Be ratios in the authigenic phases, e.g. clay and Fe-hydroxides, can indeed be used for obtaining useful model ages for soils younger than 10-15 Ma. However, the present work has to be pushed considerably further, to take into account more realistic age models in which, for instance, downward transport of 10Be and clays, and in-situ dissolution of clay minerals at depths, altering the 10Be/9Be ratios of the acidic solutions, are included. We show that in the case of younger soils (< 1 Ma) studied here, their 10Be inventories and 10Be/9Be ratios have been significantly disturbed possibly by mixing with transported soils. ?? 1997 Elsevier Science B.V.

Barg, E.; Lal, D.; Pavich, M.J.; Caffee, M.W.; Southon, J.R.

1997-01-01

226

DIVISION S-4—SOIL FERTILITY & PLANT NUTRITION Evaluating Chemical and Physical Indices of Nitrogen Mineralization Capacity with an Unequivocal Reference  

Microsoft Academic Search

likely to be unable to selectively extract the fraction of biologically labile soil organic N (Bundy and Mei- After decades of searching for a rapid method to estimate the N singer, 1994). mineralization capacity of soil, there is still no consistent recommenda- Though the concept of a mineralizable N pool has tion. It is legitimate to examine the causes for

Weijin Wang; Chris J. Smith; Phillip M. Chalk; Deli Chen

227

Effects of organic management on water-extractable organic matter and C mineralization in European arable soils  

Microsoft Academic Search

In this study we tested the hypothesis that water-extractable organic carbon (WEOC) content and its properties can be used to distinguish conventionally (CONV) from organically (ORG) managed arable soils as responsible for C mineralization. We sampled soils at three different European sites located in Mediterranean (Italy) and continental (Switzerland) regions under conventional and organic management. The Mediterranean sites are here

S. Marinari; K. Liburdi; A. Fliessbach; K. Kalbitz

2010-01-01

228

Mineral?nutrient concentrations in the mountain mahogany species Cercocarpus montanus and Cercocarpus intricatus and in their associated soils  

Microsoft Academic Search

Data taken from study sites in northeastern Utah and northeastern Arizona were used to describe the mineral?nutrient relationships of C. montanus and C. intricatus. General habitat and soil relationships are discussed as well as nutrient dynamics with respect to beneath and between plants, uptake patterns ?soil to plant, transfer within the plant and ideas of leaf duration (evergreen vs. deciduous)

Jack D. Brotherson

1992-01-01

229

Accumulation and turnover of carbon in organic and mineral soils of the BOREAS northern study area  

USGS Publications Warehouse

Rates of input, accumulation, and turnover of C differ markedly within soil profiles and in soils with different drainage in the BOREAS northern study area. Soil C storage increases from ???3 kg C m-2 in well-drained, sandy soils to greater than 100 kg C m-2 in wetlands. Two modes of C accumulation were observed in upland soil profiles. Large annual C inputs (0.06-0.1 kg C m-2 yr-1) and slow decomposition (turnover times of 6-250 years) lead to rapid C accumulation in regrowing surface moss and detrital layers following fire. Deep organic layers that have accumulated over the millennia since the initiation of soil development, and are located below the most recent charred horizon, show slower rates of input (0.015-0.03 kg C m-2 yr-1) and turnover (100-1600 years) and accumulate C about 10 times slower than surface detrital layers. Rates of C input to soils derived from C and 14C data were in accord with net primary production estimates, with highest rates of input (0.14-0.6 kg C m-2 yr-1) in wetlands. Turnover times for C in surface detrital layers were 6-15 years for well-drained sand soils that showed highest soil temperatures in summer, 30-40 years for wetlands, and 36-250 years for uplands with thick moss cover and black spruce trees. Long (>100 years) turnover times in upland black spruce/clay soils most likely reflect the influence of woody debris incorporated into detrital layers. Turnover times for deep organic and mineral layer C were controlled by drainage, with fastest turnover (80-130 years) in well-drained sand soils and slowest turnover (>3000 years) in wetlands. Total C accumulation rates, which account for C losses from both deep organic and surface detrital layers, are close to zero for sand/jack pine soils, 0.003-0.01 kg C m-2 yr-1 for moderately to poorly drained sites in mature forest stands, and 0.03 kg C m-2 yr-1 for a productive fen. Decomposition of organic matter more than several decades old accounts for 9-22% of total heterotrophic respiration at these sites. The rates of C accumulation derived here are decadal averages for specific stands and will vary as stands age or undergo disturbance. Extrapolation to larger regions and longer timescales, where burning offsets C gains in moss layers, will yield smaller rates of C storage.

Trumbore, S. E.; Harden, J. W.

1997-01-01

230

[Spatial heterogeneity of surface soil mineral components in a small catchment in Karst peak-cluster depression area, South China].  

PubMed

A total of 163 soil samples (0-20 cm layer) were collected from the grid sampling plots (80 m x 80 m) in Huanjiang Observation and Research Station of Karst Ecosystem in a small catchment in Karst cluster-peak depression area, South China. By using classical statistics and geostatistics, the spatial heterogeneity of mineral components (SiO2, Fe2O3, CaO, MgO, Al2O3, MnO, and TiO2) in the soils were studied. The contents of the seven soil mineral components in the study area differed greatly, being in the order of SiO2 > Al2O3 > CaO > MgO > Fe2O3 > TiO2 > MnO, and the variance coefficients also varied obviously, in the order of CaO > MgO > Fe2O3 > TiO2 > SiO2 > Al2O3 > MnO. The seven mineral components accounted for 69.4% of the total soil mass. The spatial patterns and the fittest models of the seven soil mineral components differed from each other. All the seven soil mineral components had a strong spatial autocorrelation, with shorter variation ranges and stronger spatial dependence. The Kriging contour maps indicated that the distribution patterns of soil SiO2, Fe2O3, Al2O3, MnO, and TiO2 were similar, being higher in south and east, lower in north and west, higher in depression, and lower in slope, while the distribution patterns of soil CaO and MgO were in adverse. Natural conditions (vegetation, bare rock rate, slope degree, and slope aspect, etc. ) and human disturbance were the most important factors affecting the spatial patterns of the soil mineral components. PMID:24564147

Gao, Peng; Fu, Tong-Gang; Wang, Ke-Lin; Chen, Hong-Song; Zeng, Fu-Ping

2013-11-01

231

Mineral cycling in soil and litter arthropod food chains. Progress report, November 1, 1979-October 31, 1980  

SciTech Connect

Recent progress and current status are reported for research concerned with mineral element dynamics in soil arthropod food chains. Research is performed within the larger context of terrestrial decomposition systems, in which soil arthropods may act as regulators of nutrient dynamics during decomposition. Research is measuring rates of nutrient accumulation and excretion by using radioactive tracer techniques with radioactive analogs of nutrients. Experimental measurement of radioactive tracer excretion and nutrient element pools are reported for soil microarthropods, using new methods of counting and microprobe elemental analysis. Research on arthropod-fungal relations is utilizing high-efficiency extraction followed by dissection of 13 x 13 cm soil blocks. A two-component excretion model is reported for Cobalt-60 in earthworms (Eisenia foetida), demonstrating that no assimilation of cobalt occurs from the mineral soil fraction but is entirely from organic matter. Collection of data sets on soil arthropod communities and abundances is completed.

Crossley, Jr, D A

1980-08-01

232

Stimulating effect of earthworm excreta on the mineralization of nitrogen compounds in soil  

NASA Astrophysics Data System (ADS)

The effect of excreta of earthworm species Aporrectodea caliginosa and Eisenia fetida on the mineralization of nitrogen compounds in soils has been studied. A single application of excreta obtained from three earthworms in one day increased the formation of nitrate nitrogen compounds in the soil by 10 50%. The application of ammonium nitrogen (in the form of NH4Cl) in amounts equivalent to the ammonium nitrogen content in the daily excreta of three earthworms had the same effect on the mineralization of nitrogen compounds. The effect of earthworm excreta, as well as the effect of ammonium nitrogen, on the nitrification process was an order of magnitude higher than their contribution to the formation of nitrates due to the oxidation of the introduced ammonium. Hence, ammonium—an important component of the earthworm excreta—can exert a stimulating effect on nitrification processes in the soil and produce long-term cumulative effects that are much more significant than the direct effect of this nitrogen compound.

Bityutskii, N. P.; Solov'eva, A. N.; Lukina, E. I.; Oleinik, A. S.; Zavgorodnyaya, Yu. A.; Demin, V. V.; Byzov, B. A.

2007-04-01

233

Temperature-Dependent Near-Infrared Spectral Properties of Minerals, Meteorites, and Lunar Soil  

NASA Astrophysics Data System (ADS)

The near-IR spectral properties of minerals, meteorites, and lunar soil vary with temperature. The manner in which these materials vary is diagnostic of aspects of their composition. We quantify the spectral dependence on temperature by reporting the change in relative reflectance with temperature as a function of wavelength. We call this quantity, ?R/?T (in units of K-1), as a function of temperature the “thermo-reflectance spectrum.” The thermo-reflectance spectra of olivine and pyroxene are distinct, and most of the observable structure in thermo-reflectance spectra of the ordinary and carbonaceous chondrites can be understood in terms of a mixture of the thermo-reflectance spectra of olivine and pyroxene. The magnitude of thermo-reflectance spectra of meteorites and lunar soils is much less than that of pure minerals. Lunar soils are particularly subdued. While conventional analysis of remotely obtained spectra of the Moon can neglect temperature effects, spatially resolved measurements of the surface of the asteroid Vesta will likely have a strong temperature-dependent component based on measurements of a eucrite and a howardite.

Hinrichs, John L.; Lucey, Paul G.

2002-01-01

234

Carbon and nitrogen mineralization in a vineyard soil amended with grape marc vermicompost.  

PubMed

Vineyard soils in many areas suffer from low organic matter contents, which can be the cause of negative effects such as increasing the risk of erosion, so the use of organic amendments must be considered a good agricultural practice. Even more, if grape marc is recycled as a soil amendment in the vineyards, benefits from a good waste management strategy are also obtained. In the present study, a grape marc from the wine region of Valdeorras (north-west Spain) was used for the production of vermicompost, and this added to a vineyard soil of the same area in a laboratory study. Mixtures of soil and grape marc vermicompost (2 and 4%, dry weight) were incubated for ten weeks at 25°C and the mineralization of C and N studied. The respiration data were fitted to a first-order kinetic model. The rates of grape marc vermicompost which should be added to the vineyard soil in order to maintain the initial levels of organic matter were estimated from the laboratory data, and found to be 1.7?t?ha(-1)?year(-1) of bulk vermicompost (if the present mean temperature is considered) and 2.1?t?ha(-1)?year(-1) of bulk vermicompost (if a 2°C increment in temperature is considered), amounts which could be obtained recycling the grape marc produced in the exploitation. PMID:20837558

Paradelo, Remigio; Moldes, Ana Belén; Barral, María Teresa

2011-11-01

235

Spatial variation in 2-methyl-4-chlorophenoxyacetic acid mineralization and sorption in a sandy soil at field level.  

PubMed

The phenoxyacetic acid herbicide MCPA (2-methyl-4-chlorophenoxyacetic acid) is frequently detected in groundwater beneath Danish agricultural fields. We investigated spatial variation in microbial MCPA mineralization potential in a flat agricultural field of fine sandy soil (USDA classification: Humic Dystrudept) located on the Yoldia plains of Northern Jutland, Denmark. Samples for determination of MCPA mineralization and sorption were collected from the Ap and Bs horizons at 51 sampling sites located in a 200 x 220 m grid. Spatial variation in sorption was low in both horizons (distribution coefficient, 0.36-4.16 L kg(-1)). Sorption correlated strongly with soil organic carbon content in both horizons (CV, 93 and 83%, respectively) and negatively with soil pH. [Ring-(14)C]-MCPA mineralized readily in the Ap horizon, with 49 to 62% of the (14)C-MCPA being converted to (14)CO(2) during the 67-d incubation period. With the subsoil, mineralization of (14)C-MCPA varied considerably between samples (0.5-72.8%). At neither depth was there correlation between (14)C-MCPA mineralization and sorption, soil pH, organic carbon content, clay content, number of colony-forming units (CFU), pseudomonad CFU, or any of the four microbial activity parameters measured. The presence of microbial genes encoding for the TfdA enzyme was quantified using real-time polymerase chain reaction. No correlation was found between MCPA mineralization potential and the natural background number of tfdA genes present in the soil samples. The degradation kinetics suggests that the high (14)C-MCPA mineralization rate detected in soil samples was linked to growth of the MCPA-degrading soil microbial community. PMID:18689753

Fredslund, L; Vinther, F P; Brinch, U C; Elsgaard, L; Rosenberg, P; Jacobsen, C S

2008-01-01

236

Arsenate adsorption structures on aluminum oxide and phyllosilicate mineral surfaces in smelter-impacted soils.  

PubMed

A clearer understanding of arsenic (As) retention and transport in forest soils impacted by copper smelter emissions may reduce risks to human health and provide insight into As behavior in the vadose zone. On Vashon-Maury Island in Puget Sound, As is predominantly associated with the fine (< 63 microm) fraction of surficial soils. X-ray diffraction of oriented samples from the < 2 microm size fraction indicate that clinochlore isthe dominant phyllosilicate. X-ray absorption spectroscopy (XAS) was employed to examine As oxidation state and local coordination environment in impacted soil samples. Arsenic is present as As(V) in tetrahedral coordination with oxygen, associated with aluminum (Al) octahedra in bidentate binuclear (bridging) structures with As-Al distances of 3.15 - 3.16 angstroms. Including multiple scattering (MS) paths derived from the arsenate tetrahedron in esperanzaite significantly improved the match between XAS fine structure (EXAFS) data and models generated from theoretical phase and amplitude functions. The data are interpreted to indicate arsenate adsorption onto poorly crystalline aluminum oxyhydroxides and/or the edges of clinochlore interlayer hydroxyl sheets with constrained geometries causing MS to be important This implies that As initially released from the smelter as particulate As(III) and As(V) oxides was oxidized, dissolved, and adsorbed onto soil minerals and colloids; no evidence for relic arsenic oxide was observed. Physical transport of arsenic oxide particles and As adsorbed on soil colloids may account for limited downward migration of As within the soil column. The oxidizing and mildly acidic pH conditions in the upper vadose zone promote stable sorption complexes; barring substantial changes in soil chemistry, As is not expected to experience significant mobilization. PMID:15952360

Beaulieu, Brett T; Savage, Kaye S

2005-05-15

237

Geoarchaeological conclusions through investigating sediments, soils and minerals in karst depressions in Mount Ida, Central Crete  

NASA Astrophysics Data System (ADS)

The investigation of sediments, soils and minerals can provide important information for the reconstruction of past landscapes and the human impact on the environment. In this context, sediment-filled karst depressions function as archives as their different sediment structures reflect various superficial conditions and associated man-made changes in the environmental system. The study area, namely the doline of Zominthos, is located at 1200 m a.s.l. in the Ida Mountains in Central Crete and is known for its remnants of a late Minoan settlement complex (Neopalatial Period, ~1600 BC). Our purpose is to help understand the past human-environmental interactions in the Central Cretan highlands through the use of several sedimentological and mineralogical methods including percussion drilling and subsequent analysis with polarisation microscopy, SEM, EPMA and XRD investigations. The macroscopic evaluation of the core profiles and the micromorphological studies of thin sections give evidence of colluvial sediments within the doline which are interbedded with fine-grained, graded horizons featuring clearly fluvial textures. They must be considered with regard to intense landuse and deforestation of the surrounding escarpments. The mineralogical investigations show the coincident abundance of well-preserved angular minerals on the one side and heavily weathered minerals on the other side. This leads to the assumption of at least two different generations of minerals that underwent a various history of subaerial exposure. The vast majority of heavy minerals (e.g. carpholites, chloritoid, garnets, spinels) cannot derive from the limestone bedrock and must stem from allochthonous sources. They originate from metamorphic rocks that do not outcrop in the catchment area of Zominthos. However, they must have existed here in former times when klippes provided the concerning minerals for the buildup of the soil cover. Hence, the palaeorelief must have been different with divergent lithology. Considerable amounts of volcanogenic pyroxenes and amphiboles have been found, which can clearly be connected with the Thera eruption of Santorini 1620 BC. They have been found all over the core profiles and thus provide a time marker for the intense man-made geomorphodynamics since the date of the intense ash fallout over Crete. More than 10 up to 15 metres of pedosediments have been deposited in the Zominthos doline in the last 3400 years. Furthermore, large amounts of remarkable and very rare mineral species have been detected within the pedosediments, e.g. ferrocarpholite. The observed light minerals, respectively diverse quartz grains, show varied grain morphologies that indicate fluvial, aeolian as well as tectonic impacts. The clay mineralogy of the limestone residues and the pedosediments was investigated, showing significant amounts of kaolinite within the latter, which can be attributed to strong southern wind regimes that transported the particles from the Sahara into the study area. In contrast, the bedrock lacks completely in this allochthonous aeolian dust component. In addition, the strong polygenetic nature of the sediment fills has to be stated. The prevalent assumption of an autochthonous thin and clayey residue in karst depressions can not be confirmed. The human impact on this landscape is crucial and plays a major role regarding the composition and genesis of the sedimentary fills. The application of combined sedimentological and mineralogical investigations for (geo)archaeological purposes is still a quite exceptional approach. As shown by the results, it can deliver important information for the reconstruction of past human-environmental systems, which are encoded in minerals, sediments and soil properties.

Holzhauer, I.; Siart, C.; Meyer, H. P.; Schukraft, G.; Altherr, R.; Eitel, B.

2009-04-01

238

Effects of temperature on microbial C metabolism in peat and mineral soil  

NASA Astrophysics Data System (ADS)

Microbial metabolism, the main mechanism responsible for soil CO2 emissions, plays an important role in the global C cycle. Increased temperature generally stimulates decomposition and respiration, indicative of increased microbial C metabolism and possibly greater energy demand by microbes for growth and maintenance. Changes in microbial metabolism with temperature may manifest differently in microbial communities from soils with different C availability because it is generally expected that when more organic C is present, carbon use efficiency (CUE) will be lower and more CO2 will be released per unit C assimilated by microbes than when less C substrate is available. In this study we examined the effect of temperature on C processing in peat and mineral soil from the Marcel Experimental Forest in Minnesota. Samples were incubated for 7 days at 5, 10, 15, and 20°C. We used position-specific 13C-labeled tracers to model C flux through the central C metabolic network (i.e. glycolysis, pentose phosphate pathway, and the citric acid cycle) and to asses the CUE of microbial communities. We also measured total CO2 production and microbial biomass, and we calculated the metabolic quotient (qCO2), which is the rate of CO2, respired per unit of microbial biomass. We found that temperature and soil type did not affect CUE and patterns of C flow through the central C metabolic network. Increased temperature stimulated respiration and decreased qCO2 in peat more than the mineral soil. These results suggest temperature affects rate of C cycling, but does not alter the relative demand for energy production and biosynthesis per unit substrate-C. This implies, in contrast to expectations that at higher temperatures more substrate will be used to offset greater demand for maintenance energy, warmer temperatures will not alter the balance of growth and maintenance energy by soil microbes. Moreover, substrate availability did not result in ';wasteful' C use, but increased C cycling rates. These findings may simplify the modeling of soil respiration with climatic warming.

Hagerty, S.; Dijkstra, P.; Miller, E.; Schwartz, E.; KOCH, G. W.; Hungate, B. A.

2013-12-01

239

Phosphate-Based Mineralization of Arsenic in Contaminated Soil: A Potential Remediation Method for Soil and Groundwater  

NASA Astrophysics Data System (ADS)

Soil arsenic contamination resulting from the use of arsenical compounds is a widespread environmental problem. A phosphate-based remediation method which has the potential to immobilize arsenic in both oxidizing and reducing subsurface systems is under laboratory investigation. Although phosphate treatments have been reported to be effective in removal of arsenic from contaminated water, its use in contaminated soils has not been tested. This study aims to (1) determine the competitive adsorption/desorption of arsenate and phosphate at surfaces of ferric hydroxide coated sand in the absence or presence of calcium ions, and (2) develop a method of arsenic fixation which involves phosphoric acid flushing of arsenic from contaminated soil and precipitation of arsenic as apatite-like phases. Ferric hydroxide is a significant arsenic sequestering constituent in soil. Phosphate competes with arsenate for adsorption sites on the ferric hydroxide surface. Batch adsorption experiments conducted using ferric hydroxide coated sand have indicated similar pH-controlled adsorption mechanisms for both arsenate and phosphate. The data obtained from the adsorption experiments is being used to guide the development of a phosphate-based method for soil and groundwater arsenic remediation. Batch experiments were performed using 3g of contaminated soil in contact with 45 ml of treatment fluid (a dilute phosphoric acid and calcium hydroxide solution). Solution samples were collected at 24, 72, 144, 312, and 384 hours, with continuous agitation at 200 rpm. Solution concentrations of phosphorus and calcium generally decreased with time and were primarily controlled by pH. It has been experimentally demonstrated that solution arsenic concentrations can be lowered by maintaining high pH with adequate calcium supply. A batch experiment conducted at pH > 11, using 1 kg of soil in contact with 1 liter of 0.25% H3PO4, precipitated a white material giving an XRD signature indicative of brushite, an apatite precursor phase. Additional experiments will be performed to determine the optimum conditions for arsenic mineralization as apatite-like phases for both oxidizing and reducing subsurface environments.

Neupane, G.; Donahoe, R. J.

2009-12-01

240

A mineral support and biotic catalyst are essential in the formation of highly polymeric soil humic substances  

NASA Astrophysics Data System (ADS)

The hypothesis was proposed that highly polymeric humic substances in the mineral horizons of soils in a temperate humid climate originate from polymerization of water-soluble structural precursors directly on mineral surfaces under the catalytic effect of immobilized phenoloxidases (heterophasic biocatalysis). This hypothesis was confirmed by a laboratory experiment using a mixture of monomeric phenols and nitrogenous compounds as structural precursors, fungal laccase as a biotic catalyst, and a hydroxyaluminum-kaolinite complex as a mineral support. Enzymic oxidation of phenolic precursors on the mineral surface was substantially more rapid than abiotic oxidation and led to synthesis of a highly polymeric fraction with a molecular weight over 75 kDa. These products were not produced on the mineral with an absence of laccase (abiotic catalysis) or in solution without the mineral matrix (homogeneous catalysis).

Zavarzina, A. G.

2006-12-01

241

Development of bulk density, total C distribution and OC saturation in fine mineral fractions during paddy soil evolution  

NASA Astrophysics Data System (ADS)

Paddy soils are described as important accumulator for OM (Zhang and He, 2004). In southeast China, paddy soils have the second highest OM stocks (Zhao et al, 1997) and thus a large proportion of the terrestrial carbon is conserved in wetland rice soils. The paddy soil management is believed to be favorable for accumulation of organic matter, as its content in paddy soils is statistically higher than that of non-paddy soils (Cai, 1996). However, the mechanism of OM storage and the development of OM distribution during paddy soil evolution is largely unknown. The aim of the project is to identify the role of organo-mineral complexes for the stabilization of organic carbon during management-induced paddy soil formation in a chronosequence ranging from 50 to 2000 years of paddy soil use. The soil samples were analysed for bulk density, total organic carbon (TOC) and total inorganic carbon (TIC) concentrations of bulk soils and the concentration of organic carbon as well as the organic carbon stocks of physical soil fractions. First results indicate distinctly different depth distributions between paddy and non-paddy (control) sites. The paddy soils are characterized by relatively low bulk densities in the puddled layer (between 0.9 and 1.3 g cm-3) and high values in the plough pan (1.4 to 1.6 g cm-3) and the non-paddy soils by relatively homogeneous values throughout the profiles (1.3 to 1.4 g cm-3). In contrast to the carbonate-rich non-paddy sites, we found a significant loss of carbonates during paddy soil formation, resulting in decalcification of the upper 20 cm after 100 yr of paddy soil use, and decalcification of the total soil profile in 700, 1000 and 2000 yr old paddy soils. The calculation of the organic carbon stocks of each horizon indicate that paddy sites always have higher values in topsoils compared to non-paddy sites, and show increasing values with increasing soil age. The capacity of fine mineral fractions to preserve OC was calculated according to Hassink (1997). The potential capacity of paddy soil fraction to preserve OC is independently from soil age between 30 and 35.4 g OC (kg soil)-1. However, the calculated saturation level increases from 11.7 to 19.9 g OC (kg soil)-1 from 50 to 2000 y old paddy sites respectively. With increasing duration of paddy soil use, the fine fractions indicate an increasing saturation level from 33.1% to 56.2% of the potential capacity to preserve OC. This underlines the importance of fine fractions for increasing OC storage during paddy soil evolution. Conclusively, paddy soil management leads to an accelerated soil development compared to non-irrigated cropland sites. In addition, increasing OC stocks, especially in the fine mineral associated OM fractions underline the relevance of paddy soil management for OC sequestration. References Cai Z. (1996). Effect of land use on organic carbon storage in soils in eastern China. Water Air Soil Pollut 91, 383-393. Hassink J. (1997). The capacity of soil to preserve organic C and N by their association with clay and silt particles. Plant and Soil 191, 77-87. Zhang M., He Z. (2004). Long-term changes in organic carbon and nutrients of an Ultisol under rice cropping in southeast China. Geoderma 118, 167-179. Zhao C. (1996). Effect of land use on organic carbon storage in soils in eastern China. Water Air Soil Pollut 91, 383-393.

Wissing, Livia; Kölbl, Angelika; Cao, Zhi-Hong; Kögel-Knabner, Ingrid

2010-05-01

242

Acetochlor mineralization and fate of its two major metabolites in two soils under laboratory conditions.  

PubMed

The degradation of the herbicide acetochlor, in a neoluvisol and in a calcosol were studied as a function of depth (0-25cm and 25-50cm) and temperature (25 degrees C and 15 degrees C) under controlled laboratory conditions during 58 and 90 days, respectively. The surface and sub-surface soil samples were respectively spiked with 1 and 0.01mgkg(-1) of 14C-acetochlor, the concentrations observed in previous field monitoring. The half-lives (DT50) varied from 1.4 to 14.9 days depending on the soil, temperature and applied concentration. The maximal mineralization (24%) was observed for the surface calcosol at 25 degrees C. The comparison of results obtained for sterilized and non-sterilized soils, the decrease of DT50 with the increase of temperature, the shape of CO2 emissions and the increase of number of aerobic endogenous microflora through the experiment suggested that biological process are dominant in degradation. A particular attention was paid to the formation and dissipation of metabolites ESA (ethanesulphonic acid) and OA (oxanilic acid) during the whole experiment. At 25 degrees C, ESA and OA were observed after three days, but as ESA concentration decreased over time in surface calcosol, it remained constant in surface neoluvisol. A difference in ESA/OA ratio depends on the soil with a predominance of OA in surface neoluvisol and a disappearance of OA in surface calcosol. PMID:18078980

Dictor, Marie-Christine; Baran, Nicole; Gautier, Anne; Mouvet, Christophe

2008-03-01

243

minerals  

NASA Astrophysics Data System (ADS)

Polarized electronic absorption spectra of colourless chalcocyanite, CuSO4, have been measured using microscope-spectrometric techniques. The spectra are characterized by a structured and clearly polarized band system in the near-infrared spectral range with components centred at 11,720, 10,545, 9,100, and 7,320 cm-1, which have been assigned to crystal field d- d transitions of Cu2+ cations in pseudo-tetragonally elongated CuO6 polyhedra with point symmetry C i (). The polarization behaviour is interpreted based on a D 2( C 2?) pseudo-symmetry. Crystal field calculations were performed for the actual triclinic point symmetry by applying the Superposition Model of crystal fields, as well as in terms of a `classic' pseudo-tetragonal crystal field approach yielding the parameters Dq (eq) = 910, Dt = 395, and Ds = 1,336 cm-1, corresponding to a cubically averaged Dq cub = 679 cm-1. A comparative survey on crystal fields in Cu2+ minerals shows that the low overall crystal field strength in chalcocyanite, combined with a comparatively weak pseudo-tetragonal splitting of energy levels, is responsible for its unique colourless appearance among oxygen-based Cu2+ minerals. The weak crystal field in CuSO4 can be related to the lower position of the SO4 2- anion compared to, e.g. the H2O molecule in the spectrochemical series of ligands.

Wildner, Manfred; Giester, Gerald; Kersten, Monika; Langer, Klaus

2014-10-01

244

Long-term fertilization of a boreal Norway spruce forest increases the temperature sensitivity of soil organic carbon mineralization  

PubMed Central

Boreal ecosystems store one-third of global soil organic carbon (SOC) and are particularly sensitive to climate warming and higher nutrient inputs. Thus, a better description of how forest managements such as nutrient fertilization impact soil carbon (C) and its temperature sensitivity is needed to better predict feedbacks between C cycling and climate. The temperature sensitivity of in situ soil C respiration was investigated in a boreal forest, which has received long-term nutrient fertilization (22 years), and compared with the temperature sensitivity of C mineralization measured in the laboratory. We found that the fertilization treatment increased both the response of soil in situ CO2 effluxes to a warming treatment and the temperature sensitivity of C mineralization measured in the laboratory (Q10). These results suggested that soil C may be more sensitive to an increase in temperature in long-term fertilized in comparison with nutrient poor boreal ecosystems. Furthermore, the fertilization treatment modified the SOC content and the microbial community composition, but we found no direct relationship between either SOC or microbial changes and the temperature sensitivity of C mineralization. However, the relation between the soil C:N ratio and the fungal/bacterial ratio was changed in the combined warmed and fertilized treatment compared with the other treatments, which suggest that strong interaction mechanisms may occur between nutrient input and warming in boreal soils. Further research is needed to unravel into more details in how far soil organic matter and microbial community composition changes are responsible for the change in the temperature sensitivity of soil C under increasing mineral N inputs. Such research would help to take into account the effect of fertilization managements on soil C storage in C cycling numerical models. PMID:24455147

Coucheney, Elsa; Stromgren, Monika; Lerch, Thomas Z; Herrmann, Anke M

2013-01-01

245

Pig slurry and mineral fertilization strategies' effects on soil quality: macroaggregate stability and organic matter fractions.  

PubMed

Applying pig slurry to the land as fertilizer at appropriate agronomic rates is important to close nutrient cycles and optimize the value of organic matter. However a long-term discussion has taken place about its effects on soil quality. In the north-east of Spain, eight fertilization strategies were evaluated on the soil quality parameters' aggregate stability, soil organic matter (SOM) physical fractions and soil microbial biomass (SMB). Six strategies used different pig slurries (PS) which provided organic matter from 1.7 to 2.6 t ha(-1)yr(-1), the rest (mineral N fertilization and a control) did not. Pig slurries were applied at sowing and/or at cereal tillering, as sidedressing. Field experiments were maintained for an 8-year period, in a silty loam soil devoted to a rainfed winter cereal. Soil samples were taken once, before the last sidedressing in 2011. Aggregate stability was quantified using the standard water-stable aggregate method but including a modification which meant that pre-wetting was avoided (WSA(MOD)). When using the WSA(MOD) method, we found a tendency for the percentage of water-stable aggregates to increase due to PS application (differences of up to 74% in the increment) and it was more marked the nearer they were measured to the application time (3 months vs. 12 months). The strategies which include PS show a positive effect on the SOM amount, mainly in the 0.05-0.2 mm light fraction, which increased by up to 34% with every 10 t ha(-1) organic C applied, and on SMB (up to 53% increment). There is a positive and significant linear relationship (p < 0.05, R(2) = 0.75) between the SOM light fraction (%) and the water-stable aggregates soil content (%, WSA(MOD)). Thus, the introduction of PS in fertilization strategies improves soil quality parameters. However, the soil quality benefits need to be balanced with any other potential environmental impact. PMID:23000547

Yagüe, María R; Bosch-Serra, Ŕngela D; Antúnez, Montserrat; Boixadera, Jaume

2012-11-01

246

Models of compacted fine-grained soils used as mineral liner for solid waste  

NASA Astrophysics Data System (ADS)

To prevent the leakage of pollutant liquids into groundwater and sublayers, the compacted fine-grained soils are commonly utilized as mineral liners or a sealing system constructed under municipal solid waste and other containment hazardous materials. This study presents the correlation equations of the compaction parameters required for construction of a mineral liner system. The determination of the characteristic compaction parameters, maximum dry unit weight ( ? dmax) and optimum water content ( w opt) requires considerable time and great effort. In this study, empirical models are described and examined to find which of the index properties correlate well with the compaction characteristics for estimating ? dmax and w opt of fine-grained soils at the standard compactive effort. The compaction data are correlated with different combinations of gravel content ( G), sand content ( S), fine-grained content (FC = clay + silt), plasticity index ( I p), liquid limit ( w L) and plastic limit ( w P) by performing multilinear regression (MLR) analyses. The obtained correlations with statistical parameters are presented and compared with the previous studies. It is found that the maximum dry unit weight and optimum water content have a considerably good correlation with plastic limit in comparison with liquid limit and plasticity index.

Sivrikaya, Osman

2008-02-01

247

Extraction Pattern of Arsenic Species with Mineral Composition in Contaminated Soils in Korea  

NASA Astrophysics Data System (ADS)

Specific determination of various arsenic species is gaining increasing attention because the toxicity of arsenic differs with chemical forms such as organic (MMA, DMA) or inorganic (arsenite, arsenate). Knowledge of extraction method for arsenic speciation in contaminated soils then notified and tested by many researchers. However, the analytical technique for separation of different arsenic species has been always challenging in different environmental samples. A achieving correct analytical results and resolving the lowest detection limit is also desirable. Extraction method for arsenic speciation have been studied by many researchers with the use of a variety of extractants such as H3PO4, HCl, Na2CO3, EDTA 'in soils and sediments including plenty of clay. We, in this study, reported a benign extraction method and presented the pattern of arsenic in contaminated soils of different mineral compositions. Soil samples were collected from tailings of 2 places (Kyungbuk, Jeonnam); both were from abandoned metal mines in Korea. Samples were air dried at room temperature and separated by mechanical sieving to three fractions (2mm_200 ?m, 200_64?m, <64?m). Prepared samples were examined for total arsenic analysis used by KBSI method and modified Garcia-Manyes method for arsenic speciation. We extracted arsenic species from the soils by using a mixture of 1M phosphoric acid and 0.1% ascorbic acid. 0.2g of sample was placed in microwave digestion vessels along with 10ml extraction solution and treated for 15min at 60w microwave power. After the microwave stage, the contents were transferred to 30ml sample bottles and diluted to 16ml with deionized water, then centrifuged for 15min at 2500rpm. Total arsenic concentration of sample was analyzed by using ICP-AES (ICP-OES, Ultima2C, Jobin Yvon) and the arsenic species were analyzed by hyphenated system, SPE-HG-ICP-AES. To identify the mineral phases in bulk soil samples, we used XRD (Phillips X'Pert MPD) under 40kV/30mA condition. XRD data was collected between 5 and 70° 2theta values using CuK? target.

Park, M.; Shin, M.; Yoon, H.; Kim, Y.; Kim, K.; Ko, I.

2006-12-01

248

Soil Mineral Composition Matters: Response of Microbial Communities to Phenanthrene and Plant Litter Addition in Long-Term Matured Artificial Soils  

PubMed Central

The fate of polycyclic aromatic hydrocarbons (PAHs) in soil is determined by a suite of biotic and abiotic factors, and disentangling their role in the complex soil interaction network remains challenging. Here, we investigate the influence of soil composition on the microbial community structure and its response to the spiked model PAH compound phenanthrene and plant litter. We used long-term matured artificial soils differing in type of clay mineral (illite, montmorillonite) and presence of charcoal or ferrihydrite. The soils received an identical soil microbial fraction and were incubated for more than two years with two sterile manure additions. The matured artificial soils and a natural soil were subjected to the following spiking treatments: (I) phenanthrene, (II) litter, (III) litter + phenanthrene, (IV) unspiked control. Total community DNA was extracted from soil sampled on the day of spiking, 7, 21, and 63 days after spiking. Bacterial 16S rRNA gene and fungal internal transcribed spacer amplicons were quantified by qPCR and subjected to denaturing gradient gel electrophoresis (DGGE). DGGE analysis revealed that the bacterial community composition, which was strongly shaped by clay minerals after more than two years of incubation, changed in response to spiked phenanthrene and added litter. DGGE and qPCR showed that soil composition significantly influenced the microbial response to spiking. While fungal communities responded only in presence of litter to phenanthrene spiking, the response of the bacterial communities to phenanthrene was less pronounced when litter was present. Interestingly, microbial communities in all artificial soils were more strongly affected by spiking than in the natural soil, which might indicate the importance of higher microbial diversity to compensate perturbations. This study showed the influence of soil composition on the microbiota and their response to phenanthrene and litter, which may increase our understanding of complex interactions in soils for bioremediation applications. PMID:25222697

Babin, Doreen; Vogel, Cordula; Zuhlke, Sebastian; Schloter, Michael; Pronk, Geertje Johanna; Heister, Katja; Spiteller, Michael; Kogel-Knabner, Ingrid; Smalla, Kornelia

2014-01-01

249

Soil mineral composition matters: response of microbial communities to phenanthrene and plant litter addition in long-term matured artificial soils.  

PubMed

The fate of polycyclic aromatic hydrocarbons (PAHs) in soil is determined by a suite of biotic and abiotic factors, and disentangling their role in the complex soil interaction network remains challenging. Here, we investigate the influence of soil composition on the microbial community structure and its response to the spiked model PAH compound phenanthrene and plant litter. We used long-term matured artificial soils differing in type of clay mineral (illite, montmorillonite) and presence of charcoal or ferrihydrite. The soils received an identical soil microbial fraction and were incubated for more than two years with two sterile manure additions. The matured artificial soils and a natural soil were subjected to the following spiking treatments: (I) phenanthrene, (II) litter, (III) litter + phenanthrene, (IV) unspiked control. Total community DNA was extracted from soil sampled on the day of spiking, 7, 21, and 63 days after spiking. Bacterial 16S rRNA gene and fungal internal transcribed spacer amplicons were quantified by qPCR and subjected to denaturing gradient gel electrophoresis (DGGE). DGGE analysis revealed that the bacterial community composition, which was strongly shaped by clay minerals after more than two years of incubation, changed in response to spiked phenanthrene and added litter. DGGE and qPCR showed that soil composition significantly influenced the microbial response to spiking. While fungal communities responded only in presence of litter to phenanthrene spiking, the response of the bacterial communities to phenanthrene was less pronounced when litter was present. Interestingly, microbial communities in all artificial soils were more strongly affected by spiking than in the natural soil, which might indicate the importance of higher microbial diversity to compensate perturbations. This study showed the influence of soil composition on the microbiota and their response to phenanthrene and litter, which may increase our understanding of complex interactions in soils for bioremediation applications. PMID:25222697

Babin, Doreen; Vogel, Cordula; Zühlke, Sebastian; Schloter, Michael; Pronk, Geertje Johanna; Heister, Katja; Spiteller, Michael; Kögel-Knabner, Ingrid; Smalla, Kornelia

2014-01-01

250

Mineral cycling in soil and litter arthropod food chains. Annual progress report, February 1, 1983-January 31, 1984  

SciTech Connect

This annual report describes progress in research on the influence of soil fauna on the general process of terrestrial decomposition. The major goal is to investigate the regulation of decomposition by soil arthropods. Methods have included radioactive tracer measurements of food chain dynamics, rates of nutrient or mineral element flow during decomposition, and simulation modeling. This year's report describes significant progress in defining the influence of soil arthropods in stimulating microbial immobilization of nutrients. Preliminary efforts to define the importance of the soil-litter macroarthropods are also reported.

Crossley, D.A. Jr.

1983-09-30

251

Potential for Rapid Physical Protection of Wood and Pyrolyzed Carbon in the Mineral Soil Matrix: Effects of Soil Type, Depth, and Temperature  

NASA Astrophysics Data System (ADS)

To determine how soil type, depth, and temperature affect the stabilization of biochar and wood in soils, we conducted an incubation study using soils from a moist tropical forest in Tabonuco, Puerto Rico and from a Mediterranean grassland in Hopland, California, collected from surface and from deep horizons. To these four soil types we added ground 13C-labeled biochar (or the wood from which it was derived) and incubated at ambient (14 °C for the Hopland and 20 °C for the Tabonuco soil) and elevated (ambient +6 °C) temperatures at field gravimetric moisture content (20% for Hopland and 80% for Tabonuco) for 13 months. Preliminary analysis of the 13CO2 evolution from these soils indicates that wood was mineralized faster than biochar. Differences in the matrix of the soils - greater clay and iron oxide content in the Tabonuco Oxisol than in the Hopland Ultisol, but also greater clay and iron oxide content in the deep compared to the surface Hopland soil - lead to the expectation that the potential for physical protection of organic carbon substrates from mineralization is greater in the tropical soils and also greater in the deeper horizons. Here we present results from 13C analyses of density fractionations conducted on the soils after they incubated for 13 months, and thereby quantify the extent to which the introduced 13C was mobilized from the free particulate fraction, where it was added, to the intra-aggregate particulate fraction and the mineral-associated fraction. Our results will enable better predictions of the environmental conditions under which biochar (and wood) is more likely to contribute to stable soil carbon pools.

Castanha, C.; Tas, N.; Reichl, K.; Jansson, J. K.; Brodie, E. L.; Fischer, M. L.; Torn, M. S.

2012-12-01

252

Tracking rainfall variations in the late Pleistocene using U isotopes in dated secondary soil minerals  

NASA Astrophysics Data System (ADS)

Past changes in rainfall are an important indicator of variations in atmospheric circulation. However, there are very few approaches that are uniquely sensitive to past changes in rainfall and use common materials that can be accurately dated. Secondary minerals in arid soils form directly from rainfall and can precipitate continuously over hundreds of thousands of years. Previous studies have used stable isotope measurements of soil carbonates to look at a variety of processes such as precipitation source and amount, evaporation, temperature, and vegetation. Often, the challenge with stable isotope approaches is to distinguish between these factors. In addition, stable isotope studies have not traditionally used high-resolution analytical techniques to capture the temporal variations within a given sample. The development of alternative isotopic systems that more directly reflect rainfall would provide a complimentary tool to more traditional strategies. In order to evaluate whether widely observed variations in the calculated initial U isotopic composition of dated soil minerals (e.g. (234U/238U)0) reflect changes in past rainfall, we sampled modern soil pore waters, soils and dust from a rainfall gradient in Fish Lake Valley, NV. In situ ion microprobe (SHRIMP-RG) techniques were used to determine the 230Th-U ages and (234U/238U)0 from uranium-rich soil opal collected at three field sites in western North America. Modern pore waters in desert soils from Fish Lake Valley, NV show systematic decreases in (234U/238U) with increasing rainfall. This is attributed to increasing infiltration flux and chemical weathering at higher rainfall rates, as the eolian influence should likely remain the same across the rainfall gradient. Although changes in the uranium concentration and isotopic composition of dust through time may also influence the (234U/238U) of soil water, these changes are likely minimal relative to changes in infiltration flux. The variations in (234U/238U)0 obtained from 230Th-U dating of soil opal span approximately the last 5-60 kyrs. Based on the modern pore water data, we interpret low (234U/238U)0 to indicate periods of higher rainfall, and high (234U/238U)0 to indicate periods of reduced rainfall. We observe nearly synchronous shifts during the last glacial-interglacial transition along the latitudinal transect of our field sites. Our initial results show that the transition from MIS 3 to 2 was likely characterized by increasing precipitation, with peak rainfall at the beginning of MIS 2. This corresponds to generally decreasing SST off of the California coast and rainier periods in speleothem records from the southwestern United States. Additionally (234U/238U)0 from our soil opal records co-varies with fluctuations in lake levels of large pluvial lake systems in western North America. The synchronous signal of increased rainfall during MIS 2 is consistent with a southward-shift in westerly storm tracks at the LGM. Our approach demonstrates an alternative method for increasing the spatial coverage and chronology of climate records in arid regions.

Ibarra, D. E.; Oster, J. L.; Maher, K.

2011-12-01

253

Substrate quality alters microbial mineralization of added substrate and soil organic carbon  

NASA Astrophysics Data System (ADS)

The rate and extent of decomposition of soil organic carbon (SOC) is dependent on substrate chemistry and microbial dynamics. Our objectives were to understand the influence of substrate chemistry on microbial processing of carbon (C), and to use model fitting to quantify differences in pool sizes and mineralization rates. We conducted an incubation experiment for 270 days using four uniformly-labeled 14C substrates (glucose, starch, cinnamic acid and stearic acid) on four different soils (a temperate Mollisol, a tropical Ultisol, a sub-arctic Andisol, and an arctic Gelisol). The 14C labeling enabled us to separate CO2 respired from added substrates and from native SOC. Microbial gene copy numbers were quantified at days 4, 30 and 270 using quantitative polymerase chain reaction (qPCR). Substrate C respiration was always higher for glucose than other substrates. Soils with cinnamic and stearic acid lost more native SOC than glucose- and starch-amended soils, despite an initial delay in respiration. Cinnamic and stearic acid amendments also exhibited higher fungal gene copy numbers at the end of incubation compared to unamended soils. We found that 270 days was sufficient to model decomposition of simple substrates (glucose and starch) with three pools, but was insufficient for more complex substrates (cinnamic and stearic acid) and native SOC. This study reveals that substrate quality imparts considerable control on microbial decomposition of newly added and native SOC, and demonstrates the need for multi-year incubation experiments to constrain decomposition parameters for the most recalcitrant fractions of SOC and added substrates.

Jagadamma, S.; Mayes, M. A.; Steinweg, J. M.; Schaeffer, S. M.

2014-03-01

254

Substrate quality alters the microbial mineralization of added substrate and soil organic carbon  

NASA Astrophysics Data System (ADS)

The rate and extent of decomposition of soil organic carbon (SOC) is dependent, among other factors, on substrate chemistry and microbial dynamics. Our objectives were to understand the influence of substrate chemistry on microbial decomposition of carbon (C), and to use model fitting to quantify differences in pool sizes and mineralization rates. We conducted an incubation experiment for 270 days using four uniformly labeled 14C substrates (glucose, starch, cinnamic acid and stearic acid) on four different soils (a temperate Mollisol, a tropical Ultisol, a sub-arctic Andisol, and an arctic Gelisol). The 14C labeling enabled us to separate CO2 respired from added substrates and from native SOC. Microbial gene copy numbers were quantified at days 4, 30 and 270 using quantitative polymerase chain reaction (qPCR). Substrate C respiration was always higher for glucose than other substrates. Soils with cinnamic and stearic acid lost more native SOC than glucose- and starch-amended soils. Cinnamic and stearic acid amendments also exhibited higher fungal gene copy numbers at the end of incubation compared to unamended soils. We found that 270 days were sufficient to model the decomposition of simple substrates (glucose and starch) with three pools, but were insufficient for more complex substrates (cinnamic and stearic acid) and native SOC. This study reveals that substrate quality exerts considerable control on the microbial decomposition of newly added and native SOC, and demonstrates the need for multi-year incubation experiments to constrain decomposition parameters for the most recalcitrant fractions of SOC and complex substrates.

Jagadamma, S.; Mayes, M. A.; Steinweg, J. M.; Schaeffer, S. M.

2014-09-01

255

Interactions between arsenic and iron oxyhydroxides in lacustrine sediments  

Microsoft Academic Search

Arsenic and iron concentrations were measured in surficial sediments and in interstitial and overlying waters at 22 littoral stations of 16 lakes. The lakes were chosen to cover values of pH between 4.0 and 8.4 and various As concentrations. Depth-distributions of dissolved As and Fe concentrations suggest a close association of both elements in a dissolution-diffusion-precipitation cycle for Fe and

N. Belzile; A. Tessier

1990-01-01

256

Characterization of mineral phosphate solubilization traits from a barley rhizosphere soil functional metagenome  

PubMed Central

Mineral phosphate solubilization (MPS) microorganisms are important for their provision of orthophosphate anions for plant growth promotion activity in soil. In this study, we applied a functional metagenomic approach to identify this trait directly from the microbiome in barley rhizosphere soil that had not received P fertilizer over a 15-year period. A fosmid system was used to clone the metagenome of which 18,000 clones (?666 Mb of DNA) was screened for MPS. Functional assays and High Performance Liquid Chromatography analysis recognized gluconic acid production and MPS activity in the range 24.8–77.1 mmol/L and 27.6–38.16 ?g/mL, respectively, when screened in an Escherichia coli host (at frequency of one MPS-positive clone hit per 114 Mb DNA tested). The MPS clones (with average insert size of ?37 kb) were analysed by 454 Roche sequencing and annotated. A number of genes/operons with homology to Phosphorous (P) uptake, regulatory and solubilization mechanisms were identified, linking the MPS function to the uncultivated microbiome present in barley rhizosphere soil. PMID:23894099

Chhabra, Sagar; Brazil, Dina; Morrissey, John; Burke, James I; O'Gara, Fergal; N Dowling, David

2013-01-01

257

Nitrogen mineralization and transformation from composts and biosolids during field incubation in a sandy soil  

SciTech Connect

Field evaluation of nutrient release from composts is important to estimate nutrient contribution to crops, potential leaching of nutrients, and, ultimately, to determine optimum application rates, timing, and placement of composts. Field incubation and laboratory analyses were conducted to evaluate the mineralization rate and transformation of N in biosolids (BSD), yard waste (YW), and West Palm Beach co-compost (WPCC). Each of the composts or biosolids was packed into PVC columns and inserted vertically into the upper layer of an Oldsmar fine sand of raised citrus beds. The top end of the PVC column was capped to prevent excessive leaching of nutrients from the columns. The moisture equilibrium between the incubated sample and the soil in the field was attained through the bottom and four side holes of each column, which were separated from the contacting soil by 400-mesh nylon screen. A set of the incubated columns was removed at monthly intervals, and the soil underlying each column was sampled to analyze for KCl-extractable NH{sub 4}-N and NO{sub 3}-N. Total C and N of the incubated samples were determined at the end of the 1-year incubation.

He, Z.L.; Alva, A.K.; Yan, P.; Li, Y.C.; Calvert, D.V.; Stoffella, P.J.; Banks, D.J.

2000-02-01

258

Effect of basic slag addition on soil properties, growth and leaf mineral composition of beans in a Cu-contaminated soil  

E-print Network

1 Effect of basic slag addition on soil properties, growth and leaf mineral composition of beans in a Cu-contaminated soil NEGIM O.1 , ELOIFI B.1 , MENCH M.2 , BES C.2 , GASTE H.2 , MOTELICA-HEINO M.3, France. 3 ISTO, UMR 6113, CNRS Université d'Orléans, France. ABSTRACT Basic slag (BS) is an alkaline by

Paris-Sud XI, Université de

259

[Study on the determination of metsulfuron-methyl and its adsorption behavior on typical soils and minerals].  

PubMed

Adsorption behavior of metsulfuron-methyl on soils and minerals was investigated using batch experiment. The concentration of metsulfuron-methyl in supernatant was analyzed by capillary electrophoresis (CE) method. Metsulfuron-methyl, whose peak centered at 4.6 min in capillary electrophoresis chromatogram, was well separated from impurities in soil slurry. CE was shown to be fast with low operating cost in the routine determination of the herbicide, which was further confirmed by high performance liquid chromatograph (HPLC). Sorption isotherms were fitted to the Freundlich equation, where the parameter Kf was in the range of 0.82-199.69 for minerals and 1.97-10.48 for soils, respectively. Among the various factors influencing the sorption behavior of metsulfuron-methyl, soil pH appeared to be the most important one. The electrostatic interaction mechanism was applied in the explanation of the sorption behavior of metsulfuron-methyl. PMID:17633192

Zhu, You-feng; Xie, Zheng-miao; Xu, Jian-ming

2007-05-01

260

Isolation and characterization of 1,2,4-trichlorobenzene mineralizing Bordetella sp. and its bioremediation potential in soil  

Microsoft Academic Search

A soil which has been polluted with chlorinated benzenes for more than 25 years was used for isolation of adapted microorganisms able to mineralize 1,2,4-trichlorobenzene (1,2,4-TCB). A microbial community was enriched from this soil and acclimated in liquid culture under aerobic conditions using 1,2,4-TCB as a sole available carbon source. From this community, two strains were isolated and identified by

Fang Wang; Sabine Grundmann; Michael Schmid; Ulrike Dörfler; Stefanie Roherer; Jean Charles Munch; Anton Hartmann; Xin Jiang; Reiner Schroll

2007-01-01

261

Near infrared spectroscopy as a potential tool to monitor the mineralization of exogenous organic matter within the soil  

NASA Astrophysics Data System (ADS)

Many studies have shown that near infrared spectroscopy (NIRS) is an effective method to characterize various soil properties and endogenous or exogenous organic matter. However, the ability of NIRS to monitor the dynamics of organic matter incorporated into the soil has not yet been tested. This method has a great potential as it can be faster, cheaper and more accessible than conventional techniques dealing with this topic. The aim of this study was to evaluate the potential of the visible near infrared (Vis-NIR: 400-2500nm) to monitor the mineralization of organic matter added to the soil by quantifying, over time, its degradation products. This study focused on 2 types of soils, one from France (Neoluvisol developed on silt wind) and the other from Tunisia (Vertic Xerofluvents). Both soils received two types of organic input, poultry manure (C/N = 17.8) and composted pig manure on straw (C/N = 20.6). Moreover, a sample from each soil type, with no organic input, was kept as a reference. The samples were wetted up to field capacity and were incubated at 25°C during 58 days. Analytical data characterizing the mineralization of organic matter, as mineral carbon (C-CO2) and mineral nitrogen (N-NH4 and N-NO3) were collected following periodic measurements. The soil samples spectra were recorded at the same time using an ASD Fieldspec Pro (350-2500 nm). Principal components analysis (PCA) was performed with the analytical data and spectra to find correlations between the mineralization dynamics and changes of spectra, in relation to the exogenous organic matter degradation. Partial least squares (PLS) algorithm was used to calibrate models linking different mineralization parameters to spectral response. Owing to the low number of available samples (28 samples), the models were adjusted using leave one out cross-validation. Direct observation of the spectra as shown that the level of spectral reflectance of soil samples has evolved over time, which means that the state of degradation of organic matter affects soil reflectance in the Vis-NIR. PCA performed with the analytical data discriminates the time according to the 1st axis that explains 50.1% of the observed variance. PCA performed with the reflectance spectra did not show any significant correlation with the time parameter in the 1st factorial plane. However, the 2nd axis of this factorial plane differentiates between soil types. The models calibrated by the mean of PLS to predict direct analytical data (C-CO2, N-NH4 and N-NH3) were quite precise for the cumulative carbon and the mineral nitrogen produced after mineralization of the exogenous organic matter. The performance of these models were R˛=0.68-0.78, RMSE=64.92mg C/kg-109.91mg N/kg and ME=3.47mg C/kg-13.94mg N/kg, respectively. Moreover, we have calibrated models to predict the organic carbon (R˛ = 0.89, RMSE = 352.57 mg C / kg and ME = -50.16mg C / kg) and organic nitrogen (R˛ = 0.79, RMSE = 9.46% and ME = 0.69%) remaining in the soil samples. The predictions of these indirect variables related to mineralization process were satisfactory. These first results are promising towards the development of a non-intrusive, cheaper and flexible tool to monitor the mineralization of exogenous organic matter within the soil.

Fouad, Youssef; Walter, Christian; Morvan, Thierry; Zaouchi, Yousr; Sanaa, Mustapha

2010-05-01

262

Microbial weathering of apatite and wollastonite in a forest soil: Evidence from minerals buried in a root-free zone  

NASA Astrophysics Data System (ADS)

Mineral weathering is an important process in biogeochemical cycling because it releases nutrients from less labile pools (e.g., rocks) to the food chain. A field experiment was undertaken to determine the degree to which microbes - both fungi and bacteria - are responsible for weathering of Ca-bearing minerals. The experiment was performed at the Hubbard Brook Experimental Forest (HBEF) in the northeastern USA, where acid deposition has leached plant-available calcium from soils for decades. Trees obtain soil nutrients through root uptake as well as through mycorrhizal fungi with which they are symbiotically associated. These fungi extend their hyphae from the tree roots into the soil and exude organic acids that may enhance mineral dissolution. The two most common types of symbiotic fungal-tree associations are ectomycorrhizae, which are associated with spruce (Picea), fir (Abies), and beech (Fagus); and arbuscular mycorrhizae which are commonly associated with angiosperms, such as maples (Acer). To examine the role of fungi and bacteria in weathering of Ca- and/or P-bearing minerals, mesh bags containing sand-sized grains of quartz (as a control), quartz plus 1% wollastonite (CaSiO3), or quartz plus 1% apatite (Ca5(PO4)3F) were buried ~15 cm deep in mineral soil beneath American beech, sugar maple, and mixed spruce and balsam fir stands at the HBEF. Half of the bags were constructed of 50-?m mesh to exclude roots but allow fungal hyphae and bacteria to enter the bags; the remaining bags had 1-?m mesh to exclude fungi and roots but allow bacteria to enter. The bags were retrieved ~ 1, 2 or 4 years after burial. Microbial community composition and biomass in the mesh bags and surrounding soil were characterized and quantified using phospholipid fatty acid (PLFA) analysis. Fungal biomass in the soil and control bags did not differ significantly among stand types. In contrast, the degree of fungal colonization in apatite- and wollastonite-amended bags varied significantly, suggesting that microbial response was due to tree species, type of mycorrhizal fungi, nutrient status of the soils, and mineral composition of the mesh bags. Mineral surfaces were examined using scanning electron microscopy (SEM) to investigate the degree of mineral dissolution as a function of stand type, microbial composition, and time.

Nezat, C. A.

2011-12-01

263

Laccaria bicolor S238N improves Scots pine mineral nutrition by increasing root nutrient uptake from soil minerals but does not increase mineral weathering  

Microsoft Academic Search

The role of ectomycorrhizal fungi on mineral nutrient mobilization and uptake is crucial for tree nutrition and growth in\\u000a temperate forest ecosystems. By using a “mineral weathering budget” approach, this study aims to quantify the effect of the\\u000a symbiosis with the ectomycorrhizal model strain Laccaria bicolor S238N on mineral weathering and tree nutrition, carrying out a column experiment with a

Calvaruso Christophe; Turpault Marie-Pierre; Uroz Stéphane; Leclerc Elisabeth; Kies Antoine; Frey-Klett Pascale

2010-01-01

264

Kinetics of Ion Exchange on Clay Minerals and Soil: II. Elucidation of Rate-limiting Steps1 R. A. OGWADA ANDD. L. SPARKS2  

E-print Network

, diffusion, reaction kinetics, K-ion selective electrode, energies of activation. Ogwada, R.A., and DKinetics of Ion Exchange on Clay Minerals and Soil: II. Elucidation of Rate-limiting Steps1 R. A.L. Sparks. 1986. Kinetics of ion exchange on clay minerals and soil: II. Elucidation of rate-limiting steps

Sparks, Donald L.

265

Mobilization of Metals from Pristine Mineral Soil by Nitrifying and Sulfur-Oxidizing Bacteria – The Leaching Potential of Indigenous Culture Enrichments  

Microsoft Academic Search

Indigenous chemolithotrophic nitrifying and sulfur-oxidizing culture enrichments mobilized metals from pristine mineral soil under conditions of ammonium or thiosulfate supplementation in a laboratory experiment carried out over a period of 40 days. The average mineralogical composition of the mineral soil was quartz (62%), feldspar (20%), muscovite (6%), chlorite (2%), hornblende (2%), dolomite (4%), and calcium carbonate (4%). The leaching efficiency

Renate Sonnleitner; Bernhard Redl; Petra Merschak; Franz Schinner

2011-01-01

266

Session EP23A. Aeolian Processes and Desert Landscape Development Impact of surface roughness and soil texture on mineral dust emission fluxes modeling  

E-print Network

and soil texture on mineral dust emission fluxes modeling Laurent MENUT1 , Carlos PĂ?REZ2 , Karsten HAUSTEIN) used to estimate vertical fluxes of mineral dust aerosols over arid regions need accurate data on soil and surface properties. The LISA dataset was develo- ped for Northern Africa, Middle East and East Asia

Menut, Laurent

267

Post-Fire Spatial Patterns of Soil Nitrogen Mineralization and Microbial Abundance  

PubMed Central

Stand-replacing fires influence soil nitrogen availability and microbial community composition, which may in turn mediate post-fire successional dynamics and nutrient cycling. However, fires create patchiness at both local and landscape scales and do not result in consistent patterns of ecological dynamics. The objectives of this study were to (1) quantify the spatial structure of microbial communities in forest stands recently affected by stand-replacing fire and (2) determine whether microbial variables aid predictions of in situ net nitrogen mineralization rates in recently burned stands. The study was conducted in lodgepole pine (Pinus contorta var. latifolia) and Engelmann spruce/subalpine fir (Picea engelmannii/Abies lasiocarpa) forest stands that burned during summer 2000 in Greater Yellowstone (Wyoming, USA). Using a fully probabilistic spatial process model and Bayesian kriging, the spatial structure of microbial lipid abundance and fungi-to-bacteria ratios were found to be spatially structured within plots two years following fire (for most plots, autocorrelation range varied from 1.5 to 10.5 m). Congruence of spatial patterns among microbial variables, in situ net N mineralization, and cover variables was evident. Stepwise regression resulted in significant models of in situ net N mineralization and included variables describing fungal and bacterial abundance, although explained variance was low (R2<0.29). Unraveling complex spatial patterns of nutrient cycling and the biotic factors that regulate it remains challenging but is critical for explaining post-fire ecosystem function, especially in Greater Yellowstone, which is projected to experience increased fire frequencies by mid 21st Century. PMID:23226324

Smithwick, Erica A. H.; Naithani, Kusum J.; Balser, Teri C.; Romme, William H.; Turner, Monica G.

2012-01-01

268

Effect of soil-plant-animal mineral interactions in the genesis of puerperal haemoglobinuria in dairy animals  

E-print Network

in dairy animals SS Randhawa CL Arora BP Joshi 'Dept Vet Med ;2Deptt Soils, PAU Ludhiana 141004, Punjab ; 3 in high yielding dairy animals and has been reported from many parts of the world including India cases of PH, tentatively diagnosed in 82 dairy animals, were included for mineral analysis

Paris-Sud XI, Université de

269

Mineralization and microbial biomass formation in upland soil amended with some tropical plant residues at different temperatures  

Microsoft Academic Search

A model experiment was carried out at 15, 25, and 35°C to investigate the changes in microbial biomass and the pattern of mineralization in upland soil during 8 weeks following the addition of 8 organic materials including 6 tropical plant residues, ipil ipil (Leucaena leucocephala), azolla (Azolla pinnata), water hyacinth (Eichhornia crassipes), dhaincha (Sesbania rostrata), cowpea (Vigna unguiculata), and sunhemp

Abul Kalam Mohammad Azmal; Takuya Marumoto; Haruo Shindo; Masaya Nishiyama

1996-01-01

270

Metagenomes from Thawing Low-Soil-Organic-Carbon Mineral Cryosols and Permafrost of the Canadian High Arctic  

PubMed Central

Microbial release of greenhouse gases from thawing permafrost is a global concern. Seventy-six metagenomes were generated from low-soil-organic-carbon mineral cryosols from Axel Heiberg Island, Nunavut, Canada, during a controlled thawing experiment. Permafrost thawing resulted in an increase in anaerobic fermenters and sulfate-reducing bacteria but not methanogens. PMID:25414511

Chauhan, Archana; Layton, Alice C.; Vishnivetskaya, Tatiana A.; Williams, Daniel; Pfiffner, Susan M.; Rekepalli, Bhanu; Stackhouse, Brandon; Lau, Maggie C. Y.; Phelps, Tommy J.; Mykytczuk, Nadia; Ronholm, Jennifer; Whyte, Lyle; Onstott, Tullis C.

2014-01-01

271

Submicron mineral structures control the stabilization of litter-derived organic matter in soils - A NanoSIMS study  

NASA Astrophysics Data System (ADS)

The sequestration of carbon and nitrogen by clay-sized particles in soils is well established. However, in the most cases, the complex structure of the organo-mineral associations remain a black box due to the common measurements of soil fractions as a whole. By combining nano-scale secondary ion mass spectrometry (NanoSIMS) with isotopic tracing it is possible to study the formation and spatial heterogeneity of organo-mineral associations. NanoSIMS enables the detection of up to seven secondary ion species (e.g. 13C-, 12N15N-, 27Al16O-, 56Fe16O-) simultaneously, to generate a submicron-scale image of the elemental and isotopic composition (e.g. 13C, 15N, Al and Fe) down to a lateral resolution of ~150 nm. Therefore this technique can be used to study organo-mineral associations at the relevant scale. The aim of our study was to follow the formation of organo-mineral associations over different time steps and the distribution of C and N by imaging the complex arrangement between soil mineral surfaces and litter-derived organic matter (OM). Parallel to the determination of the isotopic N and C composition of bulk soil and soil fractions (combined density and particle size fractionation) using isotope ratio mass spectrometry (IRMS), the spatial distribution of the OM was investigated by NanoSIMS analysis of the clay-sized fraction. In our study we show that only some of the clay-sized surfaces bind OM. Surprisingly, less than 19% of the mineral areas visible by scanning electron microscopy and NanoSIMS show an OM attachment. We demonstrate that mineral clusters with rough surfaces exhibit the preferential binding spots for OM. By combining NanoSIMS and isotopic tracing, we distinguish between new labelled and pre-existing OM and show that new OM is preferentially attached to already present organo-mineral clusters. Vogel, C., Mueller, C.W., Höschen, C., Buegger, F., Heister, K., Schulz, S., Schloter, M., Kögel-Knabner, I., 2014. Submicron structures provide preferential spots for carbon and nitrogen sequestration in soils. Nature Communications 5. doi:10.1038/ncomms3947

Vogel, Cordula; Mueller, Carsten W.; Höschen, Carmen; Buegger, Franz; Heister, Katja; Schulz, Stefanie; Schloter, Michael; Kögel-Knabner, Ingrid

2014-05-01

272

2,4-D mineralization in unsaturated and near-saturated surface soils of an undulating, cultivated Canadian prairie landscape.  

PubMed

The herbicide 2,4-D [2,4-(dichlorophenoxy) acetic acid] is one of the most widely used pesticides in the Canadian prairies and is frequently detected as a ground and surface water contaminant. The objective of this paper was to determine the magnitude and extent of variation of 2,4-D mineralization in a cultivated undulating prairie landscape. Microcosm incubation experiments, using a 4 x 3 x 2 factorial experimental design (soil moisture, 4 levels: 60, 85, 110, 135% of field capacity; slope position, 3 levels: upper-, mid- and lower-slopes; soil depth, 2 levels: 0-5 and 5-15 cm), were used to assess 2,4-D mineralization. The first-order mineralization rate constant (k(1)) varied from 0.03 to 0.22 day(- 1), while total 2,4-D mineralization varied from 31 to 52%. At near-saturated conditions (110 and 135% of field capacity), the onset of 2,4-D degradation was delayed in soil obtained from the upper- and mid-slopes but not in soils obtained from the lower-slope position. The k(1) and total 2,4-D mineralization was significantly influenced by all three factors and their interactions. The Freundlich sorption coefficient of 2,4-D ranged from 0.83 to 2.46 microg (1-1/n)g(- 1) mL(1/n) and was significantly influenced by variations in soil organic carbon content across slope positions. The infield variability of 2,4-D sorption and mineralization observed across slope positions in this undulating field was comparable in magnitude and extent to the regional variability of 2,4-D sorption and mineralization observed in surface soils across Manitoba. The large variability of 2,4-D mineralization and sorption at different slope positions in this cultivated undulating field suggests that landform segmentation models, which are used to delineate slope positions, are important considerations in pesticide fate studies. PMID:18161571

Shymko, Janna L; Farenhorst, Annemieke

2008-01-01

273

DRIFT and HR MAS NMR characterization of humic substances from a soil treated with different organic and mineral fertilizers  

NASA Astrophysics Data System (ADS)

In this study, using DRIFT and HR MAS NMR, we analyzed the humic substances isolated from a soil treated, over 40 years, with different organic, mineral and organic plus mineral treatments and cultivated with maize as the main crop. As expected, the structure of humic substances was very complex but by combining both techniques (DRIFT and HR MAS NMR) additional information was obtained on aromatic and aliphatic components, the most recalcitrant parts of these macromolecules. In so doing we wanted to investigate the relationship between HS structure and long-term management practices. An elevated content of lignin, aminoacids, peptides and proteins was observed mainly for farmyard manure treatments with respect to mineral or liquid manure amendments; this supports how the different management practices have greatly influenced the humification process of cultivated soils.

Ferrari, Erika; Francioso, Ornella; Nardi, Serenella; Saladini, Monica; Ferro, Nicola Dal; Morari, Francesco

2011-07-01

274

Carbazole angular dioxygenation and mineralization by bacteria isolated from hydrocarbon-contaminated tropical African soil.  

PubMed

Four bacterial strains isolated from hydrocarbon-contaminated soils in Lagos, Nigeria, displayed extensive degradation abilities on carbazole, an N-heterocyclic aromatic hydrocarbon. Physicochemical analyses of the sampling sites (ACPP, MWO, NESU) indicate gross pollution of the soils with a high hydrocarbon content (157,067.9 mg/kg) and presence of heavy metals. Phylogenetic analysis of the four strains indicated that they were identified as Achromobacter sp. strain SL1, Pseudomonas sp. strain SL4, Microbacterium esteraromaticum strain SL6, and Stenotrophomonas maltophilia strain BA. The rates of degradation of carbazole by the four isolates during 30 days of incubation were 0.057, 0.062, 0.036, and 0.050 mg L(-1) h(-1) for strains SL1, SL4, SL6, and BA. Gas chromatographic (GC) analyses of residual carbazole after 30 days of incubation revealed that 81.3, 85, 64.4, and 76 % of 50 mg l(-1) carbazole were degraded by strains SL1, SL4, SL6, and BA, respectively. GC-mass spectrometry and high-performance liquid chromatographic analyses of the extracts from the growing and resting cells of strains SL1, SL4, and SL6 cultured on carbazole showed detection of anthranilic acid and catechol while these metabolites were not detected in strain BA under the same conditions. This study has established for the first time carbazole angular dioxygenation and mineralization by isolates from African environment. PMID:24728574

Salam, L B; Ilori, M O; Amund, O O; Numata, M; Horisaki, T; Nojiri, H

2014-08-01

275

Mineral cycling in soil and litter arthropod food chains. Progress report, November 1, 1980-October 31, 1981  

SciTech Connect

Progress and current status are reported for research projects concerned with mineral element and nutrient dynamics in soil arthropod food chains. Research is performed within the larger context of terrestrial decomposition, in which soil arthropods may act as regulators of nutrient dynamics during decomposition. Research is measuring rates of nutrient accumulation and excretion by using radioactive tracer analogs of nutrients. This year, emphasis has been placed on field work in which soil arthropod population size and nutrients inputs were varied experimentally. The presence of microarthropods in field microcosms increased the mineralization of N and P in each case, but rates were not correlated with arthropod densities. Experiments recently started are using both arthropod and microfloral inhibitors, in open systems on the forest floor, with the objective of quantifying arthropod enhancement of microbial immobilization of nutrients.

Crossley, D.A. Jr.

1980-06-15

276

Alaska Geochemical Database (AGDB)-Geochemical data for rock, sediment, soil, mineral, and concentrate sample media  

USGS Publications Warehouse

The Alaska Geochemical Database (AGDB) was created and designed to compile and integrate geochemical data from Alaska in order to facilitate geologic mapping, petrologic studies, mineral resource assessments, definition of geochemical baseline values and statistics, environmental impact assessments, and studies in medical geology. This Microsoft Access database serves as a data archive in support of present and future Alaskan geologic and geochemical projects, and contains data tables describing historical and new quantitative and qualitative geochemical analyses. The analytical results were determined by 85 laboratory and field analytical methods on 264,095 rock, sediment, soil, mineral and heavy-mineral concentrate samples. Most samples were collected by U.S. Geological Survey (USGS) personnel and analyzed in USGS laboratories or, under contracts, in commercial analytical laboratories. These data represent analyses of samples collected as part of various USGS programs and projects from 1962 to 2009. In addition, mineralogical data from 18,138 nonmagnetic heavy mineral concentrate samples are included in this database. The AGDB includes historical geochemical data originally archived in the USGS Rock Analysis Storage System (RASS) database, used from the mid-1960s through the late 1980s and the USGS PLUTO database used from the mid-1970s through the mid-1990s. All of these data are currently maintained in the Oracle-based National Geochemical Database (NGDB). Retrievals from the NGDB were used to generate most of the AGDB data set. These data were checked for accuracy regarding sample location, sample media type, and analytical methods used. This arduous process of reviewing, verifying and, where necessary, editing all USGS geochemical data resulted in a significantly improved Alaska geochemical dataset. USGS data that were not previously in the NGDB because the data predate the earliest USGS geochemical databases, or were once excluded for programmatic reasons, are included here in the AGDB and will be added to the NGDB. The AGDB data provided here are the most accurate and complete to date, and should be useful for a wide variety of geochemical studies. The AGDB data provided in the linked database may be updated or changed periodically. The data on the DVD and in the data downloads provided with this report are current as of date of publication.

Granitto, Matthew; Bailey, Elizabeth A.; Schmidt, Jeanine M.; Shew, Nora B.; Gamble, Bruce M.; Labay, Keith A.

2011-01-01

277

How biological crusts are stabilizing the soil surface? The devolpment of organo-mineral interactions in the initial phase  

NASA Astrophysics Data System (ADS)

First colonizers of new land surfaces are cryptogames which often form biological soil crusts (BSC) covering the first millimetre of the top soil in many ecosystems from polar to desert ecosystems. These BSC are assemblages of cyanobacteria, green algae, mosses, liverworts, fungi and/or lichens. The development of soil surface crusts plays a major role for the further vegetation pattern through changes to the physico-chemical conditions and influencing various ecosystem processes. We studied the development of BSC on quaternary substrate of an initial artificial water catchment in Lusatia, Germany. Due to lack of organic matter in the geological substrate, photoautotrophic organisms like green algae and cyanobacteria dominated the initial phases of ecosystem development and, hence, of organo-mineral ineractions. We combined SEM/EDX and FTIR microscopy to study the contact zone of extracellular polymeric substances (EPS) of green algae and cyanobacteria with quartz, spars and mica on a >40 µm scale in undisturbed biological soil crusts, which had a maximum thickness of approx. 2 mm. SEM/EDX microscopy was used to determine the spatial distribution of S, Ca, Fe, Al, Si and K in the profiles, organic compounds were identified using FTIR microscopy. Exudates of crust organisms served as cementing material between sand particles. The crust could be subdivided into two horizontal layers. The upper layer, which had a thickness of approx. 200 µm, is characterized by accumulation of Al and K, but absence of Fe in microbial derived organic matter, indicating capture of weathering products of feldspars and mica by microbial exudates. The pore space between mineral particles was entirely filled with organic matter here. The underlying layer can be characterized by empty pores and organo-mineral bridges between the sand particles. Contrarily to the upper layer of the crust, Fe, Al and Si were associated with organic matter here but K was absent. Highest similarity of the FTIR spectra of EPS was observed with carbohydrates, using cellulose, dextran and humic acid Na salt as controls. Obviously, humification does not play a key role during this initial phase of soil formation. It was hypothesized that biological soil crusts facilitate the weathering of mineral substrate by (I) circumventing loss of fine particles with erosion, (II) by chemical treatment of minerals and (III) by catching small mineral-particles by glutinous EPS on the soil surface from the surrounding area.

Fischer, T.; Veste, M.; Wiehe, W.; Lange, P.

2009-04-01

278

Factors driving the carbon mineralization priming effect in a sandy loam soil amended with different types of biochar  

NASA Astrophysics Data System (ADS)

The effect of biochar on the soil carbon mineralization priming effect depends on the characteristics of the raw materials, production method and pyrolysis conditions. The goal of the present study is to evaluate the impact of three different types of biochar on physicochemical properties and CO2 emissions of a sandy loam soil. For this purpose, soil was amended with three different biochars (BI, BII and BIII) at a rate of 8 wt% and soil CO2 emissions were measured for 45 days. BI is produced from a mixed wood sieving from wood chip production, BII from a mixture of paper sludge and wheat husks and BIII from sewage sludge. Cumulative CO2 emissions of biochars, soil and amended soil were well fit to a simple first-order kinetic model with correlation coefficients (r2) greater than 0.97. Results show a negative priming effect in the soil after addition of BI and a positive priming effect in the case of soil amended with BII and BIII. These results can be related to different biochar properties such as carbon content, carbon aromaticity, volatile matter, fixed carbon, easily oxidized organic carbon or metal and phenolic substance content in addition to surface biochar properties. Three biochars increased the values of soil field capacity and wilting point, while effects over pH and cation exchange capacity were not observed.

Cely, P.; Tarquis, A. M.; Paz-Ferreiro, J.; Méndez, A.; Gascó, G.

2014-06-01

279

[Distribution and accumulation of mineral nitrogen in apple orchard soils in dry plateau of eastern Gansu Province].  

PubMed

This paper studied the distribution and accumulation characteristics of mineral nitrogen in the soils of different years old apple orchards in dry plateau of eastern Gansu Province. The soil ammonium nitrogen content was increased with the increase of planting year. In the 2-3, 5, 10, 15, 20, and 22 years old apple orchards, the ammonium nitrogen content in 0-120 cm soil layer was 3.3, 5.8, 6.5, 9.1, 12.1, and 15.3 mg x kg(-1), respectively, and 0-60 cm soil layer had a higher ammonium nitrogen content than 60-120 cm soil layer. For all the apple orchards, the nitrate nitrogen content in 0-40 cm soil layer was relatively low, but increased with increasing depth. The soil nitrate nitrogen content also increased with the increase of planting year, which reached 2602.5 kg x hm(-2) in the 0-120 cm soil layer of 22 years old apple orchard. It was concluded that in the apple orchards in dry plateau of eastern Gansu Province, soil ammonium nitrogen was more accumulated in upper layers, while nitrate nitrogen was more accumulated in deeper layers. PMID:20560341

Liu, Xiao-Yong; Dong, Tie; Zhang, Kun; Zhang, Hui-Yuan; Wang, Fa-Lin

2010-03-01

280

Recent (<4 year old) Leaf Litter is Not a Major Source of Microbial Carbon in a Temperate Forest Mineral Soil  

SciTech Connect

Microbial communities in soil A horizons derive their carbon from several potential sources: organic carbon (C) transported down from overlying litter and organic horizons, root-derived C, or soil organic matter. We took advantage of a multi-year experiment that manipulated the {sup 14}C isotope signature of surface leaf litter inputs in a temperate forest at the Oak Ridge Reservation, Tennessee, USA, to quantify the contribution of recent leaf litter C to microbial respiration and biomarkers in the underlying mineral soil. We observed no measurable difference (< {approx}40{per_thousand} given our current analytical methods) in the radiocarbon signatures of microbial phospholipid fatty acids (PLFA) isolated from the top 10 cm of mineral soil in plots that experienced 3 years of litterfall that differed in each year by {approx}750{per_thousand} between high-{sup 14}C and low-{sup 14}C treatments. Assuming any difference in {sup 14}C between the high- and low-{sup 14}C plots would reflect C derived from these manipulated litter additions, we estimate that <6% of the microbial C after 4 years was derived from the added 1-4-year-old surface litter. Large contributions of C from litter < 1 year (or >4 years) old (which fell after (or prior to) the manipulation and therefore did not differ between plots) are not supported because the {sup 14}C signatures of the PLFA compounds (averaging 200-220{per_thousand}) is much higher that of the 2004-5 leaf litter (115{per_thousand}) or pre-2000 litter. A mesocosm experiment further demonstrated that C leached from {sup 14}C-enriched surface litter or the O horizon was not a detectable C source in underlying mineral soil microbes during the first eight months after litter addition. Instead a decline in the {sup 14}C of PLFA over the mesocosm experiment likely reflected the loss of a pre-existing substrate not associated with added leaf litter. Measured PLFA {Delta}{sup 14}C signatures were higher than those measured in bulk mineral soil organic matter in our experiments, but fell within the range of {sup 14}C values measured in mineral soil roots. Together, our experiments suggest that root-derived C is the major (>60%) source of C for microbes in these temperate deciduous forest soils.

Kramer, Christiane [University of California, Irvine; Trumbore, Susan E. [University of California, Irvine; Froberg, Mats J. [Sveriges Lantbruksuniversitet; Cisneros dozal, Luz Maria [Los Alamos National Laboratory (LANL); Zhang, Dachun [University of California, Irvine; Xu, Xiamei [University of California, Irvine; Santos, Guaciara [University of California, Irvine; Hanson, Paul J [ORNL

2010-01-01

281

[Temperature sensitivity of CO2 fluxes from rhizosphere soil mineralization and root decomposition in Pinus massoniana and Castanopsis sclerophylla forests].  

PubMed

Rhizospheric and non-rhizospheric soils and the absorption, transition, and storage roots were sampled from the mid-subtropical Pinus massoniana and Castanopsis sclerophylla forests to study the CO2 fluxes from soil mineralization and root decomposition in the forests. The samples were incubated in closed jars at 15 degrees C, 25 degrees C, 35 degrees C, and 45 degrees C, respectively, and alkali absorption method was applied to measure the CO2 fluxes during 53 days incubation. For the two forests, the rhizospheric effect (ratio of rhizospheric to non-rhizospheric soil) on the CO2 flux from soil mineralization across all incubation temperature ranged from 1.12 to 3.09, with a decreasing trend along incubation days. There was no significant difference in the CO2 flux from soil mineralization between the two forests at 15 degrees C, but the CO2 flux was significantly higher in P. massoniana forest than in C. sclerophylla forest at 25 degrees C and 35 degrees C, and in an opposite pattern at 45 degrees C. At all incubation temperature, the CO2 release from the absorption root decomposition was higher than that from the transition and storage roots decomposition, and was smaller in P. massoniana than in C. sclerophylla forest for all the root functional types. The Q10 values of the CO2 fluxes from the two forests were higher for soils (1.21-1.83) than for roots (0.96-1.36). No significant differences were observed in the Q10 values of the CO2 flux from soil mineralization between the two forests, but the Q10 value of the CO2 flux from root decomposition was significantly higher in P. massoniana than in C. sclerophylla forest. It was suggested that the increment of CO2 flux from soil mineralization under global warming was far higher than that from root decomposition, and for P. massoniana than for C. sclerophylla forest. In subtropics of China, the adaptability of zonal climax community to global warming would be stronger than that of pioneer community. PMID:24066532

Liu, Yu; Hu, Xiao-Fei; Chen, Fu-Sheng; Yuan, Ping-Cheng

2013-06-01

282

Isolation from Agricultural Soil and Characterization of a Sphingomonas sp. Able To Mineralize the Phenylurea Herbicide Isoproturon  

PubMed Central

A soil bacterium (designated strain SRS2) able to metabolize the phenylurea herbicide isoproturon, 3-(4-isopropylphenyl)-1,1-dimethylurea (IPU), was isolated from a previously IPU-treated agricultural soil. Based on a partial analysis of the 16S rRNA gene and the cellular fatty acids, the strain was identified as a Sphingomonas sp. within the ?-subdivision of the proteobacteria. Strain SRS2 was able to mineralize IPU when provided as a source of carbon, nitrogen, and energy. Supplementing the medium with a mixture of amino acids considerably enhanced IPU mineralization. Mineralization of IPU was accompanied by transient accumulation of the metabolites 3-(4-isopropylphenyl)-1-methylurea, 3-(4-isopropylphenyl)-urea, and 4-isopropyl-aniline identified by high-performance liquid chromatography analysis, thus indicating a metabolic pathway initiated by two successive N-demethylations, followed by cleavage of the urea side chain and finally by mineralization of the phenyl structure. Strain SRS2 also transformed the dimethylurea-substituted herbicides diuron and chlorotoluron, giving rise to as-yet-unidentified products. In addition, no degradation of the methoxy-methylurea-substituted herbicide linuron was observed. This report is the first characterization of a pure bacterial culture able to mineralize IPU. PMID:11722885

S?rensen, Sebastian R.; Ronen, Zeev; Aamand, Jens

2001-01-01

283

Leaf litter and roots as sources of mineral soil organic matter in temperate deciduous forest with and without earthworms  

NASA Astrophysics Data System (ADS)

We labeled sugar maple trees with 13C to quantify the separate contributions of decaying leaf litter and root turnover/rhizosphere C flux to mineral soil organic matter (SOM). Labeled leaf litter was applied to forest plots with and without earthworms and recovery of the label in SOM was quantified over three years. In parallel, label recovery was quantified in soils from the labeling chambers where all label was supplied by belowground C flux. In the absence of earthworms about half of the label added as leaf litter remained in the surface organic horizons after three years, with about 3% recovered in mineral SOM. The label was most enriched on silt + clay surfaces, representing precipitation of DOC derived from litter. Earthworms mixed nearly all the leaf litter into mineral soil within one year, and after two years the label was most enriched in particulate organic matter held within soil aggregates produced by worms. After three years 15-20% of the added label was recovered in mineral SOM. In the labeling chambers over 75% of belowground C allocation (BCA) was used in root and rhizosphere respiration in the first year after labeling. We recovered only 3.8% of estimated BCA in SOM after 3 years; however, expressed as a proportion of fine root production plus rhizosphere C flux, this value is 15.4%, comparable to that for leaf litter in the presence of earthworms. In conclusion, both roots and leaf litter contribute significantly to the formation of stabilized mineral SOM in temperate deciduous forests, and this process is profoundly altered by the invasion of lumbricid earthworms.

Fahey, T.; Yavitt, J. B.

2012-12-01

284

Integrating microbial physiology and physiochemical principles in soils with the MIcrobial-MIneral Carbon Stabilization (MIMICS) model  

NASA Astrophysics Data System (ADS)

Previous modeling efforts document divergent responses of microbial explicit soil biogeochemistry models when compared to traditional models that implicitly simulate microbial activity, particularly following environmental perturbations. However, microbial models are needed that capture current soil biogeochemical theories emphasizing the relationships between litter quality, functional differences in microbial physiology, and the physical protection of microbial byproducts in forming stable soil organic matter (SOM). To address these limitations we introduce the MIcrobial-MIneral Carbon Stabilization (MIMICS) model. In MIMICS, the turnover of litter and SOM pools are governed by temperature sensitive Michaelis-Menten kinetics and the activity of two physiologically distinct microbial functional types. The production of microbial residues through microbial turnover provides inputs to SOM pools that are considered physically or chemically protected. Soil clay content determines the physical protection of SOM in different soil environments. MIMICS adequately simulates the mean rate of leaf litter decomposition observed at a temperate and boreal forest sites, and captures observed effects of litter quality on decomposition rates. Initial results from MIMICS suggest that soil C storage can be maximized in sandy soils with low-quality litter inputs, whereas high-quality litter inputs may maximize SOM accumulation in finely textured soils that physically stabilize microbial products. Assumptions in MIMICS about the degree to which microbial functional types differ in the production, turnover, and stabilization of microbial residues provides a~mechanism by which microbial communities may influence SOM dynamics in mineral soils. Although further analyses are needed to validate model results, MIMICS allows us to begin exploring theoretical interactions between substrate quality, microbial community abundance, and the formation of stable SOM.

Wieder, W. R.; Grandy, A. S.; Kallenbach, C. M.; Bonan, G. B.

2014-01-01

285

Natural selection for 2,4,5-trichlorophenoxyacetic acid mineralizing bacteria in agent orange contaminated soil.  

PubMed

Agent Orange contaminated soils were utilized in direct enrichment culture studies to isolate 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) and 2,4-dichlorophenoxyacetic acid (2,4-D) mineralizing bacteria. Two bacterial cultures able to grow at the expense of 2,4,5-T and/or 2,4-D were isolated. The 2,4,5-T degrading culture was a mixed culture containing two bacteria, Burkholderia species strain JR7B2 and Burkholderia species strain JR7B3. JR7B3 was able to metabolize 2,4,5-T as the sole source of carbon and energy, and demonstrated the ability to affect metabolism of 2,4-D to a lesser degree. Strain JR7B3 was able to mineralize 2,4,5-T in pure culture and utilized 2,4,5-T in the presence of 0.01% yeast extract. Subsequent characterization of the 2,4-D degrading culture showed that one bacterium, Burkholderia species strain JRB1, was able to utilize 2,4-D as a sole carbon and energy source in pure culture. Polymerase chain reaction (PCR) experiments utilizing known genetic sequences from other 2,4-D and 2,4,5-T degrading bacteria demonstrated that these organisms contain gene sequences similar to tfdA, B, C, E, and R (Strain JRB1) and the tftA, C, and E genes (Strain JR7B3). Expression analysis confirmed that tftA, C, and E and tfdA, B, and C were transcribed during 2,4,5-T and 2,4-D dependent growth, respectively. The results indicate a strong selective pressure for 2,4,5-T utilizing strains under field condition. PMID:15865343

Rice, J F; Menn, F M; Hay, A G; Sanseverino, J; Sayler, G S

2005-12-01

286

A novel method for soil aggregate stability measurement by laser granulometry with sonication  

NASA Astrophysics Data System (ADS)

Regulatory authorities need to establish rapid, cost-effective methods to measure soil physical indicators - such as aggregate stability - which can be applied to large numbers of soil samples to detect changes of soil quality through monitoring. Limitations of sieve-based methods to measure the stability of soil macro-aggregates include: i) the mass of stable aggregates is measured, only for a few, discrete sieve/size fractions, ii) no account is taken of the fundamental particle size distribution of the sub-sampled material, and iii) they are labour intensive. These limitations could be overcome by measurements with a Laser Granulometer (LG) instrument, but this technology has not been widely applied to the quantification of aggregate stability of soils. We present a novel method to quantify macro-aggregate (1-2 mm) stability. We measure the difference between the mean weight diameter (MWD; ?m) of aggregates that are stable in circulating water of low ionic strength, and the MWD of the fundamental particles of the soil to which these aggregates are reduced by sonication. The suspension is circulated rapidly through a LG analytical cell from a connected vessel for ten seconds; during this period hydrodynamic forces associated with the circulating water lead to the destruction of unstable aggregates. The MWD of stable aggregates is then measured by LG. In the next step, the aggregates - which are kept in the vessel at a minimal water circulation speed - are subject to sonication (18W for ten minutes) so the vast majority of the sample is broken down into its fundamental particles. The suspension is then recirculated rapidly through the LG and the MWD measured again. We refer to the difference between these two measurements as disaggregation reduction (DR) - the reduction in MWD on disaggregation by sonication. Soil types with more stable aggregates have larger values of DR. The stable aggregates - which are resistant to both slaking and mechanical breakdown by the hydrodynamic forces during circulation - are disrupted only by sonication. We used this method to compare macro-aggregate (1-2 mm) stability of air-dried agricultural topsoils under conventional tillage developed from two contrasting parent material types and compared the results with an alternative sieve-based technique. The first soil from the Midlands of England (developed from sedimentary mudstone; mean soil organic carbon (SOC) 2.5%) contained a substantially larger amount of illite/smectite (I/S) minerals compared to the second from the Wensum catchment in eastern England (developed from sands and glacial deposits; mean SOC=1.7%). The latter soils are prone to large erosive losses of fine sediment. Both sets of samples had been stored air-dried for 6 months prior to aggregate analyses. The mean values of DR (n=10 repeated subsample analyses) for the Midlands soil was 178?m; mean DR (n=10 repeat subsample analyses) for the Wensum soil was 30?m. The large difference in DR is most likely due to differences in soil mineralogy. The coefficient of variation of mean DR for duplicate analyses of sub-samples from the two topsoil types is around 10%. The majority of this variation is likely to be related to the difference in composition of the sub-samples. A standard, aggregated material could be included in further analyses to determine the relative magnitude of sub-sampling and analytical variance for this measurement technique. We then used the technique to investigate whether - as previously observed - variations (range 1000 - 4000 mg kg-1) in the quantity of amorphous (oxalate extractable) iron oxyhydroxides in a variety of soil samples (n=30) from the Wensum area (range SOC 1 - 2%) could account for differences in aggregate stability of these samples.

Rawlins, B. G.; Lark, R. M.; Wragg, J.

2012-04-01

287

Little evidence for niche partitioning among ectomycorrhizal fungi on spruce seedlings planted in decayed wood versus mineral soil microsites.  

PubMed

Ectomycorrhizal fungal (EMF) communities vary among microhabitats, supporting a dominant role for deterministic processes in EMF community assemblage. EMF communities also differ between forest and clearcut environments, responding to this disturbance in a directional manner over time by returning to the species composition of the original forest. Accordingly, we examined EMF community composition on roots of spruce seedlings planted in three different microhabitats in forest and clearcut plots: decayed wood, mineral soil adjacent to downed wood, or control mineral soil, to determine the effect of retained downed wood on EMF communities over the medium and long term. If downed and decayed wood provide refuge habitat distinct from that of mineral soil, we would expect EMF communities on seedlings in woody habitats in clearcuts to be similar to those on seedlings planted in the adjacent forest. As expected, we found EMF species richness to be higher in forests than clearcuts (P ? 0.01), even though soil nutrient status did not differ greatly between the two plot types (P ? 0.05). Communities on forest seedlings were dominated by Tylospora spp., whereas those in clearcuts were dominated by Amphinema byssoides and Thelephora terrestris. Surprisingly, while substrate conditions varied among microsites (P ? 0.03), especially between decayed wood and mineral soil, EMF communities were not distinctly different among microhabitats. Our data suggest that niche partitioning by substrate does not occur among EMF species on very young seedlings in high elevation spruce-fir forests. Further, dispersal limitations shape EMF community assembly in clearcuts in these forests. PMID:23797413

Walker, Jennifer K M; Jones, Melanie D

2013-12-01

288

Microbial mineralization of biochar and wheat straw mixture in soil: A short-term study  

Microsoft Academic Search

A short-term incubation study was carried out to investigate the effect of biochar addition to soil on CO2 emissions, microbial biomass, soil soluble carbon (C) nitrogen (N) and nitrate–nitrogen (NO3–N). Four soil treatments were investigated: soil only (control); soil+5% biochar; soil+0.5% wheat straw; soil+5% biochar+0.5% wheat straw. The biochar used was obtained from hardwood by pyrolysis at 500°C. Periodic measurements

Costanza Zavalloni; Giorgio Alberti; Stefano Biasiol; Gemini Delle Vedove; Flavio Fornasier; Jie Liu; Alessandro Peressotti

2011-01-01

289

Oxygen isotope fractionation effects in soil water via interaction with cations (Mg, Ca, K, Na) adsorbed to phyllosilicate clay minerals  

NASA Astrophysics Data System (ADS)

In isotope-enabled hydrology, soil and vadose zone sediments have been generally considered to be isotopically inert with respect to the water they host. This is inconsistent with knowledge that clay particles possessing an electronegative surface charge and resulting cation exchange capacity (CEC) interact with a wide range of solutes which, in the absence of clays, have been shown to exhibit ?18O isotope effects that vary in relation to the ionic strength of the solutions. To investigate the isotope effects caused by high CEC clays in mineral-water systems, we created a series of monominerallic-water mixtures at gravimetric water contents ranging from 5% to 32%, consisting of pure deionized water of known isotopic composition with homoionic (Mg, Ca, Na, K) montmorillonite. Similar mixtures were also created with quartz to determine the isotope effect of non-, or very minimally-, charged mineral surfaces. The ?18O value of the water in these monominerallic soil analogs was then measured by isotope ratio mass spectrometry (IRMS) after direct headspace CO2 equilibration. Mg- and Ca-exchanged homoionic montmorillonite depleted measured ?18O values up to 1.55‰ relative to pure water at 5% water content, declining to 0.49‰ depletion at 30% water content. K-montmorillonite enriched measured ?18O values up to 0.86‰ at 5% water content, declining to 0.11‰ enrichment at 30% water. Na-montmorillonite produces no measureable isotope effect. The isotope effects observed in these experiments may be present in natural, high-clay soils and sediments. These findings have relevance to the interpretation of results of direct CO2-water equilibration approaches to the measurement of the ?18O value of soil water. The adsorbed cation isotope effect may bear consideration in studies of pedogenic carbonate, plant-soil water use and soil-atmosphere interaction. Finally, the observed isotope effects may prove useful as molecular scale probes of the nature of mineral-water interactions.

Oerter, Erik; Finstad, Kari; Schaefer, Justin; Goldsmith, Gregory R.; Dawson, Todd; Amundson, Ronald

2014-07-01

290

Influence of Environmental Factors on Antagonism of Fungi by Bacteria in Soil: Clay Minerals and pH  

PubMed Central

The soil replica plating technique was used to evaluate the influence of clay minerals and pH on antagonistic interactions between fungi and bacteria in soil. In general, the antagonistic activity of bacteria towards filamentous fungi was greater in soil than on agar. The spread of Aspergillus niger through soil was inhibited by Serratia marcescens when the organisms were inoculated into separate sites in soil, and this antagonistic effect was maintained when the soil was amended with 3, 6, 9, or 12% (vol/vol) montmorillonite, whereas the addition of kaolinite at a concentration of 3% reduced the antagonism and at 6, 9, or 12% totally eliminated it. Similar results were obtained with the inhibition of A. niger by Agrobacterium radiobacter and of Penicillium vermiculatum by either S. marcescens or Nocardia paraffinae. When A. niger and S. marcescens were inoculated into the same soil site, A. niger was inhibited in all soils, regardless of clay content, although the extent of inhibition was greater as the concentration of montmorillonite, but not of kaolinite, increased. A. niger was inhibited more when inoculated as spores than as mycelial fragments and when inoculated 96 h after S. marcescens, but a 1% glucose solution reduced the amount of inhibition when the fungus was inoculated 96 h after the bacterium. When the pH of the soil-clay mixtures was altered, the amount of antagonism usually increased as the pH increased. Antagonism appeared to be related to the cation-exchange capacity and the pH of the soil-clay mixtures. Bacillus cereus and another species of Bacillus showed no activity in soil towards A. niger under any of the environmental conditions tested, even though the Bacillus sp. significantly inhibited A. niger and seven other fungi on agar. PMID:16345477

Rosenzweig, William D.; Stotzky, G.

1979-01-01

291

[Mineralogy and genesis of mixed-layer clay minerals in the Jiujiang net-like red soil].  

PubMed

Mineralogy and genesis were investigated using X-ray diffraction (XRD), Fourier infrared absorption spectroscopy (FTIR) and high resolution transmission electron microscopy (HRTEM) to understand the mineralogy and its genesis significance of mixed-layer clay minerals in Jiujiang red soil section. XRD and FTIR results show that the net-like red soil sediments are composed of illite, kaolinite, minor smectite and mixed-layer illite-smectite and minor mixed-layer kaolinite-smectite. HRTEM observation indicates that some smectite layers have transformed into kaolinite layers in net-like red soil. Mixed-layer illite-smectite is a transition phase of illite transforming into smectite, and mixed-layer kaolinite-smectite is a transitional product relative to kaolinite and smectite. The occurrence of two mixed-layer clay species suggests that the weathering sequence of clay minerals in net-like red soil traversed from illite to mixed-layer illite-smectite to smectite to mixed-layer kaolinite-smectite to kaolinite, which indicates that net-like red soil formed under a warm and humid climate with strengthening of weathering. PMID:23285883

Yin, Ke; Hong, Han-Lie; Li, Rong-Biao; Han, Wen; Wu, Yu; Gao, Wen-Peng; Jia, Jin-Sheng

2012-10-01

292

Arsenic binding to iron(II) minerals produced by an iron(III)-reducing Aeromonas strain isolated from paddy soil.  

PubMed

An iron reducing bacterial strain was isolated from a paddy soil and identified as a member of the Aeromonas group by 16S rRNA gene sequence analysis. When the cells were growing with dissolved Fe(III) as electron acceptor in the presence of As(V), Fe(II) minerals (siderite and vivianite) were formed and dissolved As was removed efficiently from solution. When the cells were growing with the Fe(III) hydroxide mineral (ferrihydrite) as electron acceptor in the presence of As(V), ferrihydrite was reduced and dissolved As(V) concentrations decreased sharply. Our results demonstrated firstly that members of the Aeromonas group can reduce Fe(III) in paddy soils, and secondly that iron reduction does not necessarily lead to arsenic mobilization. However, As immobilization can occur in environments that contain significant concentrations of counter ions such as bicarbonate and phosphate. PMID:19572768

Wang, Xin-Jun; Chen, Xue-Ping; Kappler, Andreas; Sun, Guo-Xin; Zhu, Yong-Guan

2009-11-01

293

Low-temperature, mineral-catalyzed air oxidation: a possible new pathway for PAH stabilization in sediments and soils.  

PubMed

Reactivity of polycyclic aromatic hydrocarbons (PAHs) in the subsurface is of importance to environmental assessment, as they constitute a highly toxic hazard. Understanding their reactivity in the long term in natural recovering systems is thus a key issue. This article describes an experimental investigation on the air oxidation of fluoranthene (a PAH abundant in natural systems polluted by industrial coal use) at 100°C on different mineral substrates commonly found in soils and sediments (quartz sand, limestone, and clay). Results demonstrate that fluoranthene is readily oxidized in the presence of limestone and clay, leading to the formation of high molecular weight compounds and a carbonaceous residue as end product especially for clay experiments. As demonstrated elsewhere, the experimental conditions used permitted the reproduction of the geochemical pathway of organic matter observed under natural conditions. It is therefore suggested that low-temperature, mineral-catalyzed air oxidation is a mechanism relevant to the stabilization of PAHs in sediments and soils. PMID:20964431

Ghislain, Thierry; Faure, Pierre; Biache, Coralie; Michels, Raymond

2010-11-15

294

Impact of land-use types on soil nitrogen net mineralization in the sandstorm and water source area of Beijing, China  

Microsoft Academic Search

Changes of land-use type (LUT) can affect soil nutrient pools and cycling processes that relate long-term sustainability of ecosystem, and can also affect atmospheric CO2 concentrations and global warming through soil respiration. We conducted a comparative study to determine NH4+ and NO3? concentrations in soil profiles (0–200cm) and examined the net nitrogen (N) mineralization and net nitrification in soil surface

Lilin Yang; Fusuo Zhang; Qiang Gao; Renzhao Mao; Xiaojing Liu

2010-01-01

295

Influence of mineral weathering reactions on the chemical composition of soil water, springs, and ground water, Catoctin Mountains, Maryland  

USGS Publications Warehouse

During 1983 and 1984, wet precipitation was primarily a solution of dilute sulphuric acid, whereas calcium and bicarbonate were the major ions in springs and ground water in two small watersheds with a deciduous forest cover in central Maryland. Dominant ions in soil water were calcium, magnesium, and sulphate. The relative importance of mineral weathering reactions on the chemical composition of these subsurface waters was compared to the contribution from wet precipitation, biological processes, and road deicing salts. -from Author

Katz, B.G.

1989-01-01

296

Mineral cycling in soil and litter arthropod food chains. Three-year progress report, February 1, 1984-January 31, 1987  

SciTech Connect

This report summarizes progress in a three-year research project on the influence of soil arthropods (mites, collembolans, insects, millipedes and others) upon decomposition rates and nutrient dynamics in decaying vegetable matter. Research has concentrated on two aspects of elemental dynamics in decomposing organic matter: Effects of arthropods on rates of decomposition and nutrient loss (mineralization of carbon and other elements), and arthropod stimulation of microbial immobilization of nutrient elements during decomposition.

Crossley, D.A. Jr.

1986-08-29

297

Impact of the Invasive Alien Plant Solidago Gigantea on Primary Productivity, Plant Nutrient Content and Soil Mineral Nutrient Concentrations  

Microsoft Academic Search

Invasion by alien plants can alter ecosystem processes and soil properties. In this study, we compared aboveground productivity, nutrient pools in standing biomass and topsoil (0–0.10 m) mineral nutrient concentrations between plots invaded by Early Goldenrod (Solidago gigantea) and adjacent, uninvaded, vegetation at five sites in Belgium. The five sites were characterised by a resident perennial herbaceous vegetation and spanned a wide

Sonia Vanderhoeven; Nicolas Dassonville; Lydie Chapuis-Lardy; Matthieu Hayez; Pierre Meerts

2006-01-01

298

The nitrogen mineralization rate of legume residues in soil as influenced by their polyphenol, lignin, and nitrogen contents  

Microsoft Academic Search

A 12-week greenhouse experiment was conducted to determine the effect of the polyphenol, lignin and N contents of six legumes on their N mineralization rate in soil and to compare estimates of legume-N release by the difference and 15N-recovery methods. Mature tops of alfalfa (Medicago sativa L.), round leaf cassia (Cassia rotundifolia Pers., var. Wynn), leucaena (Leucaena leucocephala Lam., deWit),

R. H. Fox; R. J. K. Myers; I. Vallis

1990-01-01

299

IMMOBILIZATION OF HEAVY METALS IN SOILS AND WATER BY A MANGANESE MINERAL  

EPA Science Inventory

A synthesized Mn mineral used in study on adsorption of heavy metals from water has shown a great adsorption capability for Pb, Cu, Cd, Co, Ni and Zn on this mineral over a pH range from 2 to 8. The retention of Pb on this mineral was as high as 10% of its weight. Application of ...

300

The status of selected minerals in soil, forage and beef cattle tissues in a semi-arid region of Zimbabwe.  

PubMed

Five districts in the Matabeleland region, an arid western area of Zimbabwe, were investigated for the status of Ca, P, Na, Cu and Zn in soil, forage and cattle during the wet and dry seasons over a period of one year. The cattle came from the natural grazing lands and were not supplemented at the time of sampling. Some deficiencies in soil Zn and P were found in the districts of Lupane and Bulilimamangwe, respectively. Dry season soil Ca, Cu and P concentrations were significantly higher (p < 0.05) than rainy season values owing to leaching in all five districts. Most forage samples had mineral concentrations below the critical levels known to be adequate for animal requirements. Forage levels of Ca, Na. Cu and Zn significantly increased (p < 0.05) with advancing maturity, while P significantly decreased (p < 0.05) in almost all the districts. Marked deficiencies of minerals were found in cattle tissues and these levels followed the seasonal trend seen in the forage. These results indicate that cattle in Matebeleland are deficient in P, Ca, Cu and Zn and that grazing areas in the region cannot provide adequate levels of the five minerals studied. PMID:16274010

Ndebele, N; Mtimuni, J P; Mpofu, I D T; Makuza, S; Mumba, P

2005-07-01

301

Integrating microbial physiology and physio-chemical principles in soils with the MIcrobial-MIneral Carbon Stabilization (MIMICS) model  

NASA Astrophysics Data System (ADS)

A growing body of literature documents the pressing need to develop soil biogeochemistry models that more accurately reflect contemporary understanding of soil processes and better capture soil carbon (C) responses to environmental perturbations. Models that explicitly represent microbial activity offer inroads to improve representations of soil biogeochemical processes, but have yet to consider relationships between litter quality, functional differences in microbial physiology, and the physical protection of microbial byproducts in forming stable soil organic matter (SOM). To address these limitations, we introduce the MIcrobial-MIneral Carbon Stabilization (MIMICS) model, and evaluate it by comparing site-level soil C projections with observations from a long-term litter decomposition study and soil warming experiment. In MIMICS, the turnover of litter and SOM pools is governed by temperature-sensitive Michaelis-Menten kinetics and the activity of two physiologically distinct microbial functional types. The production of microbial residues through microbial turnover provides inputs to SOM pools that are considered physically or chemically protected. Soil clay content determines the physical protection of SOM in different soil environments. MIMICS adequately simulates the mean rate of leaf litter decomposition observed at temperate and boreal forest sites, and captures observed effects of litter quality on decomposition rates. Moreover, MIMICS better captures the response of SOM pools to experimental warming, with rapid SOM losses but declining temperature sensitivity to long-term warming, compared with a more conventional model structure. MIMICS incorporates current microbial theory to explore the mechanisms by which litter C is converted to stable SOM, and to improve predictions of soil C responses to environmental change.

Wieder, W. R.; Grandy, A. S.; Kallenbach, C. M.; Bonan, G. B.

2014-07-01

302

Carbon Sequestration and Nitrogen Mineralization in Soil Cooperated with Organic Composts and Bio-char During Corn (Zea mays) Cultivation  

NASA Astrophysics Data System (ADS)

Objectives of this study were to estimate the carbon sequestration and to evaluate nitrogen mineralization and nitrification in soils cooperated with organic composts and bio-char during corn cultivation. For the experiment, the soil used in this study was clay loam types, and application rates of chemical fertilizer and bio-char were recommended amount after soil test and 2 % to soil weight, respectively. The soil samples were periodically taken at every 15 day intervals during the experimental periods. The treatments were consisted of non-application, cow manure compost, pig manure compost, swine digestate from aerobic digestion system, their bio-char cooperation. For the experimental results, residual amount of inorganic carbon was ranged from 51 to 208kg 10a-1 in soil only cooperated with different organic composts. However it was estimated to be highest at 208kg 10a-1 in the application plot of pig manure compost. In addition to bio-char application, it was ranged from 187.8 to 286kg 10a-1, but was greatest accumulated at 160.3kg 10a-1 in the application plot of cow manure compost. For nitrogen mineralization and nitrification rates, it was shown that there were generally low in the soil cooperated with bio-char compared to the only application plots of different organic composts except for 71 days after sowing. Also, they were observed to be highest in the application plot of swine digestate from aerobic digestion system. For the loss of total inorganic carbon (TIC) by run-off water, it was ranged from 0.18 to 0.36 kg 10a-1 in the different treatment plots. Also, with application of bio-char, total nitrogen was estimated to be reduced at 0.42(15.1%) and 0.38(11.8%) kg 10a-1 in application plots of the pig manure compost and aerobic digestate, respectively.

Shin, Joung-Du; Lee, Sun-Ill; Park, Wu-Gyun; Choi, Yong-Su; Hong, Seong-Gil; Park, Sang-Won

2014-05-01

303

Effects of multi-walled carbon nanotubes on mineralization and mobility of nonylphenol and sodium dodecyl sulfate in agricultural soils  

NASA Astrophysics Data System (ADS)

Nanotechnology is one of the major scientific research fields in this decade. One of the most wide-spread nanomaterials are carbon based nanoparticles (CNPs) which are increasingly be used in industry. Several studies shows that CNPs are interacting with other chemical compounds and organic pollutants in the environment. It is assumed that the interactions between CNPs and organic pollutants are affected by solution and aggregate behavior. Based on the knowledge of the behavior of CNPs and organic pollutants in aquatic systems the interactions of CNPs and organic pollutants in agricultural soils have to be studied. As organic pollutants two environmental substances, nonylphenol (NP) and sodium dodecyl sulfate (SDS) were selected as model substances. They occur frequently in aqueous systems and also show different solubility behavior. As CNP representatives, two different multi-walled carbon nanotubes (MWNT) were selected. They differed either in length or outer diameter. Conclusions therefrom are to be closed the influence of length and diameter of the sorption capacity of different organic pollutants. In addition, two agricultural soils (sandy and silty soil) and one forest soil (sandy soil) were chosen. Mineralization and sorption experiments were conducted to provide information about the degradation of organic pollutants in presence of multi-walled carbon nanotubes in soils. To analyze the CNPs mineralization potential, peroxidase activity was measured. Further extraction experiments were conducted to detect the extractable part of organic pollutants. The results show that the surface area of the MWNT has a significant impact on the sorption behav-ior of NP and SDS in soils. The sorption of NP and SDS is much higher than without MWNT. However, the properties of the organic pollutants (different water solubility and hydrophobicity) are equally important and should be noted. The degradation of both pollutants is influenced by MWNT. Due to the strong sorption of NP and SDS on the MWNT, the degradation of these pollutants in soils, is slower than without MWNT. The peroxidase activity did not contribute to NP and SDS degradation. But the peroxidase activity in agricultural soils is higher than in forest soils. The extractable fraction of NP and SDS is very low and amounts to a maximum of 2 %. Due to the lower degradation of NP and SDS in the presence of MWNT a longer retention of the substances in the soils and potential toxic effects for humans and animals, as a result of plant uptake may be taken into account.

Lillotte, Julia; Marschner, Bernd; Stumpe, Britta

2014-05-01

304

Mineralization and Nutrient Release of an Organic Fertilizer Made by Flour, Meat, and Crop Residues in Two Vineyard Soils with Different pH Levels  

Microsoft Academic Search

The mineralization and nutrient evolution of an organic fertilizer compost of flour, meat, and crop residues was evaluated in two vineyard soils. A lysimetric testing, using 2.2-L Büchner funnels, was carried out to study the evolution of pH, electrical conductivity, and nutrients during the 400-day experiment. The net mineralization for two different doses of the fertilizer mixed with the soils

E. Garzón; F. González-Andrés; V. M. García-Martínez; J. M. de Paz

2011-01-01

305

Secondary Mineral Genesis from Chlorite and Serpentine in an Ultramafic Soil Toposequence  

Microsoft Academic Search

synthesis of smectite in poorly drained soils. For exam- ple, Istok and Harward (1982) found smectite, chlorite, The origin of secondary phyllosilicates in serpentinitic soils of dif- and serpentine within poorly drained soils, but found fering moisture regimes is incompletely understood. The objective of only serpentine and chlorite in well-drained upland soils. this study was to determine the genesis of

B. D. Lee; S. K. Sears; R. C. Graham; C. Amrhein; H. Vali

2003-01-01

306

Start | View At a Glance | Author Index 151-2 Soil Organic Matter-Mineral Interactions Along Hillslope Transects: Importance of  

E-print Network

Share | Start | View At a Glance | Author Index 151-2 Soil Organic Matter-Mineral Interactions, Departmen of Land Use, Rostock, Germany, Anthony Aufdenkampe, Stroud Water Research Center, Avondale, PA of organic matter (OM) with minerals has been increasingly recognized as a major process for protecting

Sparks, Donald L.

307

JOURNAL OF GEOPHYSICAL RESEARCH: ATMOSPHERES, VOL. 118, 65056520, doi:10.1002/jgrd.50313, 2013 Impact of surface roughness and soil texture on mineral dust emission  

E-print Network

Impact of surface roughness and soil texture on mineral dust emission fluxes modeling Laurent Menut,1 production models (DPM) used to estimate vertical fluxes of mineral dust aerosols over arid regions need Atmospheriques (LISA) data set was developed for Northern Africa, the Middle East, and East Asia. This regional

Menut, Laurent

308

Climatic and Edaphic Effects on the Turnover and Composition of Mineral-Associated Soil Organic Matter in Temperate Deciduous Forests  

NASA Astrophysics Data System (ADS)

Soil organic matter (SOM) is the largest reservoir of carbon (C) in terrestrial ecosystems. But, efforts to predict future changes in soil C stocks are challenged by our incomplete understanding of how soil C pools stabilized by different mechanisms will respond to changing climatic conditions and other environmental forcing factors. One approach to quantifying soil C pools of differing stability is to physically fractionate SOM into (1) a free light fraction representing an unprotected C pool, (2) an occluded light fraction characterizing a pool physically protected within aggregates, and (3) a mineral-associated dense fraction approximating a pool stabilized by organomineral interactions. Although the two light fractions are generally considered to be relatively homogenous pools, any assumption that the dense fraction represents a homogenous pool is problematic. To explore the potential for reducing the heterogeneity within the dense fraction, we isolated acid-hydrolyzable and acid-resistant C pools from the dense fraction at four sites representing a range of soil types and the climatic extent of Eastern deciduous forest. Soils were collected from before and after 14C-enriched leaf-litter manipulations at each site. Across all sites, 50-75% of the C in the dense fraction was acid-hydrolyzable, and the mean turnover time of C in this fraction was 1-2 orders of magnitude faster (~35-350 y) than that of the acid-resistant fraction (~300-1500 y). Remarkably, in some cases leaf-derived 14C accounted for up to about 5% of the C in one or both dense fraction pools after only 2 years, demonstrating the existence of a very rapid turnover component within both pools at some sites. Characterization of these mineral-associated C pools by mid-infrared spectroscopy showed variations in C chemistry across sites and site differences in the types of C isolated by hydrolysis. Taken together, these results demonstrate considerable differences within the Eastern deciduous forest in the dynamics of mineral-associated soil C pools that can be related to variations in climate, soil texture, and bioturbation.

Jastrow, J. D.; Calderon, F. J.; McFarlane, K. J.; Porras, R. C.; Torn, M. S.; Guilderson, T. P.; Hanson, P. J.

2013-12-01

309

Effects of de-icing chemicals sodium chloride and potassium formate on cadmium solubility in a coarse mineral soil.  

PubMed

Excessive use of sodium chloride (NaCl) as de-icing chemical causes environmental problems, such as elevated chloride concentrations in groundwater. On vulnerable sites, this can be avoided by using alternative organic de-icing chemicals, such as potassium formate (KHCOO). The environmental impacts of KCHOO are, however, not well known. This study reports the potential effects of NaCl and KCHOO on mechanisms controlling the mobility of cadmium (Cd) in roadside soils as a result of vehicular traffic. Changes in the solubility of Cd in a coarse mineral soil treated with these two de-icing chemicals were studied in a 50-day incubation experiment under four different moisture and temperature combinations and an initial soil Cd concentration of 3 mg kg(-1). After incubation, the distribution of soil Cd into different fractions was analyzed using a sequential extraction method. Soil pH and soil redox potential were recorded and the occurrence of Cd-Cl complexes in the soil was estimated using published stability constants. During incubation, KCHOO lowered the soil redox potential, but this was not accompanied by a decrease in the sorption capacity of oxides and the release of oxide-bound Cd into soil solution. On the other hand, elevated pH (from 4.3 to 6.7-8.5) in the formate treatments increased the sorption of Cd onto the oxide surfaces (up to 80% of total sorbed Cd). In the NaCl treatments, cation competition and formation of Cd-Cl complexes increased the water-soluble Cd fraction. Consequently, the amount of bioavailable Cd was 3.5 times smaller in the KCHOO than in the NaCl treatments. PMID:16165192

Rasa, Kimmo; Peltovuori, Tommi; Hartikainen, Helinä

2006-08-01

310

Determination of the composition of the organic matter chemically stabilized by agricultural soil clay minerals: Spectroscopy and Density Fractionation  

NASA Astrophysics Data System (ADS)

The interactions between soil organic matter and clay minerals are considered important processes because of their ability to sequester C in soil for long periods of time, and hence control C in the global C cycle when present. However, differing results have been reported regarding the composition of the soil organic matter - aromatic fractions versus aliphatic fractions - associated with clay minerals. To clarify this critical issue and better understand the C sequestration process in soils, we aimed to determine the nature of the chemically bound natural organic matter on clay surfaces, and to probe the speciation and spatial distribution of C in the soil clay nanoparticles using direct spectroscopic measurements namely solid-state CP-MAS and DP-MAS 13C NMR spectroscopy, x-ray diffraction spectroscopy (XRD), and scanning transmission x-ray microscopy (STXM). We tested the hypotheses that peptides and polysaccharides are stabilized by the smectite-illite clay while the lipids and black carbon are a separate phase; and that they are evenly distributed on clay surfaces. A soil clay fraction (5.5% organic C) was isolated from the surface of a prairie soil (Mollisol) in southwestern Minnesota, characterized by a pH 6.0, 32.5% clay content, and 3.7% organic carbon, using a sonication-sedimentation-siphoning process in distilled water. Then was subjected to density separation combined with low energy ultrasonic dispersion to separate the free organic and black C (light fraction) from the chemically bound C (heavy fraction). The XRD results indicated a dominance of interstratified smectite-illite clays in soil. The 13C-NMR spectra of the soil clay fraction suggested that polysaccharides and polypeptides are the prevailing components of the organic matter associated with the mineral clay, with only a minor component of aromatic C. The light fraction has strong alkyl C-H bands characteristic of fatty acids plus strong C-O bands characteristic of polysaccharides, including the anomeric C band centered at 105 ppm. The aromatic band at 130 ppm and the phenolic C-O band at 150 pm are strong as well indicating the presence of black carbon and lignin-derived components, contrary to the heavy fraction where they are almost absent. STXM results indicated that the proteins are abundant in the soil clay fraction, separate from lipids, and partially associated with saccharides. The black carbon constitutes a separate phase, but is amply present with lipids and lignin-derived compounds in the light fraction. We conclude that (1) the smectite-illite sheets in our soils preferentially retain peptides, and polysaccharides favoring the protection of these normally readily biodegradable fractions relative to the lignin-derived phenolic components; (2) the black carbon constitutes a major component of the light fraction, and is partially attached to the organic matter bonded with the smectitic clays; and (3) the lipids are associated with soil clay fraction as a separate phase, but are not bound to clay minerals.

Oufqir, Sofia; Bloom, Paul; Toner, Brandy; Hatcher, Patrick

2014-05-01

311

Capacity of microorganisms to decompose organic carbon affected by an increasing content of reactive mineral phases in a podzolic soil chronosequence  

NASA Astrophysics Data System (ADS)

Soil organic matter stabilization has received considerable interest in the last decades due to the importance of the soil organic carbon (SOC) pool in the global C budget. There is increasing evidence that the formation of organo-mineral associations play a major role in the mechanisms of organic carbon stabilization, indicating that the persistence of organic matter in soils relates primarily to soil physico-chemical and biological conditions than to intrinsic recalcitrance. Al and Fe oxy-hydroxides and short-range ordered aluminosilicates are known for their high capacity to sorb organic carbon. However, the impact of the evolution of these reactive mineral phases over short time scale on the distribution of microorganisms and their ability to decompose SOC is still poorly understood. To further study the short-term evolution of organo-mineral associations, we investigated a 500-year podzolic soil chronosequence which is characterized by an increasing amount of secondary reactive mineral phases with pedogenesis and soil age, and thus by increased organo-mineral associations. In order to determine the impact of these secondary mineral phases on the degradation of SOC by microorganisms, an incubation experiment was carried out using soil horizons up to 1m deep from 6 profiles of different ages along the chronosequence. Furthermore, we used amino sugars and phospholipid fatty acids as tracers of dead and living microbial biomass, respectively, in the incubated samples. Our results show that SOC mineralization was significantly lower in the illuvial Bh/Bhs horizons (which contain more reactive mineral phases) compared to the surface E horizons (depleted in reactive mineral phases), although the content in amino sugars is similar in these horizons. In the deeper Bw and BC horizons, as well as in the young profiles (<300 yrs) that have not yet undergone podzolization and related formation of organo-mineral associations, SOC mineralization rates were the highest. These findings suggest that stabilization of OC through organo-mineral interactions with reactive mineral phases in our study site strongly controls the ability of microorganisms to decompose soil organic matter.

Vermeire, Marie-Liesse; Doetterl, Sebastian; Bode, Samuel; Delmelle, Pierre; Van Oost, Kristof; Cornelis, Jean-Thomas

2014-05-01

312

Dynamics of tundra ecosystems and their potential response to energy research development. Soil chemical aspects of plant nutrition in alpine tundra at Eagle Summit, Alaska. II. Exchange chemistry of mineral and organic soils from Eagle Summit, Alaska  

SciTech Connect

Some aspects of the nutrient status of an arctic organic soil and an arctic mineral soil are described and contrasted with emphasis on soil properties which may be important in the availability of nutrients to plants. Field conditions related to the exchange chemistry of calcium, magnesium, and potassium, pH dependency of cation exchange capacity, exchange isotherms, and soil buffering power for pH, calcium, magnesium and potassium are discussed.

Stuart, L.

1983-02-15

313

NUTRIENT MANAGEMENT & SOIL & PLANT ANALYSIS Assessing Indices for Predicting Potential Nitrogen Mineralization in Soils under Different Management Systems  

Microsoft Academic Search

A reliable laboratory index of N availability would be useful for making N recommendations, but no single approach has received broad acceptance across a wide range of soils. We compared several indices over a range of soil conditions to test the possibility of combining indices for predicting potentially mineralizable N (N0). Soils (0-5 and 5-15 cm) from nine tillage studies

Harry H. Schomberg; Sirio Wietholter; Timothy S. Griffi; D. Wayne Reeves; Miguel L. Cabrera; Dwight S. Fisher; Dinku M. Endale

314

Treatment of petroleum-contaminated soils using iron mineral catalyzed hydrogen peroxide  

Microsoft Academic Search

Naturally-occurring iron minerals, goethite and magnetite, were used to catalyze hydrogen peroxide and initiate Fenton-like reaction of silica sand contaminated with diesel and\\/or kerosene in batch system. Optimum reaction conditions were investigated by varying H2O2 concentrations (0, 1, 7, 15, and 35wt%) and iron mineral contents (0, 1, 5 and 10wt%). Contaminant degradation in silica sand-iron mineral-H2O2 system was identified

Sung-Ho Kong; Richard J. Watts; Jin-Ho Choi

1998-01-01

315

The role of reaction affinity and secondary minerals in regulating chemical weathering rates at the Santa Cruz Soil Chronosequence, California  

USGS Publications Warehouse

In order to explore the reasons for the apparent discrepancy between laboratory and field weathering rates and to determine the extent to which weathering rates are controlled by the approach to thermodynamic equilibrium, secondary mineral precipitation, and flow rates, a multicomponent reactive transport model (CrunchFlow) was used to interpret soil profile development and mineral precipitation and dissolution rates at the 226 ka Marine Terrace Chronosequence near Santa Cruz, CA. Aqueous compositions, fluid chemistry, transport, and mineral abundances are well characterized [White A. F., Schulz M. S., Vivit D. V., Blum A., Stonestrom D. A. and Anderson S. P. (2008) Chemical weathering of a Marine Terrace Chronosequence, Santa Cruz, California. I: interpreting the long-term controls on chemical weathering based on spatial and temporal element and mineral distributions. Geochim. Cosmochim. Acta 72 (1), 36-68] and were used to constrain the reaction rates for the weathering and precipitating minerals in the reactive transport modeling. When primary mineral weathering rates are calculated with either of two experimentally determined rate constants, the nonlinear, parallel rate law formulation of Hellmann and Tisserand [Hellmann R. and Tisserand D. (2006) Dissolution kinetics as a function of the Gibbs free energy of reaction: An experimental study based on albite feldspar. Geochim. Cosmochim. Acta 70 (2), 364-383] or the aluminum inhibition model proposed by Oelkers et al. [Oelkers E. H., Schott J. and Devidal J. L. (1994) The effect of aluminum, pH, and chemical affinity on the rates of aluminosilicate dissolution reactions. Geochim. Cosmochim. Acta 58 (9), 2011-2024], modeling results are consistent with field-scale observations when independently constrained clay precipitation rates are accounted for. Experimental and field rates, therefore, can be reconciled at the Santa Cruz site. Additionally, observed maximum clay abundances in the argillic horizons occur at the depth and time where the reaction fronts of the primary minerals overlap. The modeling indicates that the argillic horizon at Santa Cruz can be explained almost entirely by weathering of primary minerals and in situ clay precipitation accompanied by undersaturation of kaolinite at the top of the profile. The rate constant for kaolinite precipitation was also determined based on model simulations of mineral abundances and dissolved Al, SiO2(aq) and pH in pore waters. Changes in the rate of kaolinite precipitation or the flow rate do not affect the gradient of the primary mineral weathering profiles, but instead control the rate of propagation of the primary mineral weathering fronts and thus total mass removed from the weathering profile. Our analysis suggests that secondary clay precipitation is as important as aqueous transport in governing the amount of dissolution that occurs within a profile because clay minerals exert a strong control over the reaction affinity of the dissolving primary minerals. The modeling also indicates that the weathering advance rate and the total mass of mineral dissolved is controlled by the thermodynamic saturation of the primary dissolving phases plagioclase and K-feldspar, as is evident from the difference in propagation rates of the reaction fronts for the two minerals despite their very similar kinetic rate laws. ?? 2009 Elsevier Ltd.

Maher, K.; Steefel, C.I.; White, A.F.; Stonestrom, D.A.

2009-01-01

316

Spatial and temporal variability of arsenic solid-state speciation in historically lead arsenate contaminated soils.  

PubMed

The arsenic (As) solid-state speciation (i.e., oxidation state, precipitates, and adsorption complexes) is one of the most important factors controlling dissolved As concentrations at As contaminated sites. In this case study, two representative subsurface samples (i.e., oxidized and semi-reduced sites) from former lead arsenate contaminated soils in the northeastern United States were chosen to investigate the effects of aging on As retention mechanisms using multiscale spectroscopic techniques. X-ray powder diffraction (XRD), synchrotron based microfocused (micro) XRD, in situ micro-synchrotron based X-ray fluorescence spectroscopy (SXRF), and micro-X-ray absorption near edge structure (XANES) spectroscopy were used to compliment the final bulk X-ray absorption spectroscopy (XAS) analyses. In the sample from an oxic area, As is predominantly (approximately 71%) present as As(V) adsorbed onto amorphous iron oxyhydroxides with a residue (approximately 29%) of an original contaminant, schultenite (PbHAsO4). Contrarily, there is no trace of schultenite in the sample from a semi-reduced area. Approximately 25% of the total As is present as adsorbed phases on amorphous iron oxyhydroxide and amorphous orpiment (As2S3). The rest of the fractions (approximately 46%) were identified as As(V)-Ca coprecipitates. This study shows that aging effects can significantly alter the original chemical constituent (schultenite) in soils, resulting in multi and site-specific As solid-state speciation. The variability in spatial and temporal scale may be important in assessing the environmental risk and in developing in situ remediation technologies. PMID:16509302

Arai, Yuji; Lanzirotti, A; Sutton, S R; Newville, Matthew; Dyer, J; Sparks, D L

2006-02-01

317

INFLUENCE OF SOIL MINERAL COLLOIDS ON METABOLIC PROCESSES, GROWTH, ADHESION, AND ECOLOGY OF MICROBES AND VIRUSES  

EPA Science Inventory

Soil is an extremely complex habitat for microbes because of the heterogeneity of soil particulates, the constantly changing water and gas regimes, the discontinuity between microhabitats, the intermittent supply of nutrients, etc. The complexity of soil is reflected in the heter...

318

Soil Variability along a Nitrogen Mineralization and Nitrification Gradient in a Nitrogen-Saturated Hardwood Forest  

Microsoft Academic Search

ABSTRACT,soils to be related to leaf litter chemistry of contrasting tree species (Ferrari, 1999). Other studies suggest that Some N-saturated watersheds of the Fernow Experimental Forest spatial heterogeneity is largely determined by the direct (FEF), West Virginia, exhibit a high degree of spatial heterogeneity in soil N processing. We used soils from four sites at FEF representing effects of plants

Frank S. Gilliam; Nikki L. Lyttle; Ashley Thomas; Mary Beth Adams

319

Skylab S-192 ratio codes of soil, mineral, and rock spectra for ratio image selection and interpretation  

NASA Technical Reports Server (NTRS)

A limited theoretical systems study is made of the Skylab S-192 12-channel multispectral scanner's capabilities for geological remote sensing. Laboratory spectra of rocks, minerals, soils, and some vegetation were used to rank the twelve channels and the best twelve of the 66 possible nonreciprocal spectral ratios according to their ability to discriminate among 17 classes of geological targets. Environmental and instrumental noise sources were ignored. The S-192 should be most useful for discriminating minerals deposited by hydrothermal alteration, weathering, and evaporation. Discrimination of igneous rocks will be difficult. Ratio images are recommended over automatic discrimination methods for those geological targets that can be enhanced by ratio imaging. Ratio codes were found for the twelve highest ranked ratios, for use in selecting the ratio images which will best enhance a target of interest. They can also be searched for false alarm candidates for a given target.

Vincent, R. K.; Pillars, W. W.

1974-01-01

320

Mineral magnetic properties of surface soils and sands across four North African transects and links to climatic gradients  

NASA Astrophysics Data System (ADS)

In light of their earlier success in characterizing and differentiating soils, sediments and atmospheric particulates, magnetic measurements were carried out on samples of North African surface soils and sands. The main aims were to document spatial variations in magnetic properties, explore their possible links to climatic gradients and their likely basis, and thereby help to differentiate potential sources for Sahara/Sahel-derived dusts. Samples were collected along four broadly north-to-south orientated transects located in Egypt, Niger, Mali, and Benin and southern Togo. These transects cover major climatic gradients ranging from hyper-arid to tropical. Across the rainfall range spanned by the Niger and Mali Transects (<100 to >800 mm/yr) there are significant north-to-south gradients in magnetic mineral concentrations. This is seen most clearly in the concentrations of the finest ferrimagnetic minerals (magnetite/maghemite), which are strongly represented in the clay fraction. Concentrations of the imperfect antiferromagnetic minerals (predominantly haematite) also increase with increasing rainfall. By analogy with studies spanning a similar rainfall gradient in areas of more uniform lithology, we suggest that the most likely cause for these trends is increased chemical weathering linked to the progressively wetter climate across the Sahara/Sahel transition. Within the set of samples from Egypt (rainfall >100 to <5 mm/yr), there is a marked gradient in the coercivity of remanence in the antiferromagnetic minerals present, with coercivity increasing southwards, paralleling the trend toward increasing aridity. Given the strong spatial discrimination demonstrated, especially in the Niger and Mali transects, these potentially climate-linked gradients hold out the promise of discriminating between dust source regions.

Lyons, Richard; Oldfield, Frank; Williams, Earle

2010-08-01

321

Short-term effects of crop rotation, residue management, and soil water on carbon mineralization in a tropical cropping system  

Microsoft Academic Search

The purpose of this study was to investigate the short-term effects of maize (Zea mays)-fallow rotation, residue management, and soil water on carbon mineralization in a tropical cropping system in Ghana. After\\u000a 15 months of the trial, maize–legume rotation treatments had significantly (P?C\\u000a 0 (?g CO2–C g?1) than maize–elephant grass (Pennisetum purpureum) rotations. The C\\u000a 0 for maize–grass rotation treatments was

S. G. K. Adiku; S. Narh; J. W. Jones; K. B. Laryea; G. N. Dowuona

2008-01-01

322

Soil organic matter quality influences mineralization and GHG emissions in cryosols: a field-based study of sub- to high Arctic.  

PubMed

Arctic soils store large amounts of labile soil organic matter (SOM) and several studies have suggested that SOM characteristics may explain variations in SOM cycling rates across Arctic landscapes and Arctic ecosystems. The objective of this study was to investigate the influence of routinely measured soil properties and SOM characteristics on soil gross N mineralization and soil GHG emissions at the landscape scale. This study was carried out in three Canadian Arctic ecosystems: Sub-Arctic (Churchill, MB), Low-Arctic (Daring Lake, NWT), and High-Arctic (Truelove Lowlands, NU). The landscapes were divided into five landform units: (1) upper slope, (2) back slope, (3) lower slope, (4) hummock, and (5) interhummock, which represented a great diversity of Static and Turbic Cryosolic soils including Brunisolic, Gleysolic, and Organic subgroups. Soil gross N mineralization was measured using the (15) N dilution technique, whereas soil GHG emissions (N2 O, CH4 , and CO2 ) were measured using a multicomponent Fourier transform infrared gas analyzer. Soil organic matter characteristics were determined by (1) water-extractable organic matter, (2) density fractionation of SOM, and (3) solid-state CPMAS (13) C nuclear magnetic resonance (NMR) spectroscopy. Results showed that gross N mineralization, N2 O, and CO2 emissions were affected by SOM quantity and SOM characteristics. Soil moisture, soil organic carbon (SOC), light fraction (LF) of SOM, and O-Alkyl-C to Aromatic-C ratio positively influenced gross N mineralization, N2 O and CO2 emissions, whereas the relative proportion of Aromatic-C negatively influenced those N and C cycling processes. Relationships between SOM characteristics and CH4 emissions were not significant throughout all Arctic ecosystems. Furthermore, results showed that lower slope and interhummock areas store relatively more labile C than upper and back slope locations. These results are particularly important because they can be used to produce better models that evaluate SOM stocks and dynamics under several climate scenarios and across Arctic landscapes and ecosystems. PMID:23504890

Paré, Maxime C; Bedard-Haughn, Angela

2013-04-01

323

Characterization of mineral phases of agricultural soil samples of Colombian coffee using Mössbauer spectroscopy and X-ray diffraction  

NASA Astrophysics Data System (ADS)

Soil chemical analysis, X-ray diffraction (XRD) and Mössbauer spectrometry (MS) of 57Fe were used to characterize mineral phases of samples taken from the productive layer (horizon A) of agricultural coffee soil from Tolima (Colombia). Chemical analysis shows the chemical and textural parameters of samples from two different regions of Tolima, i.e., Ibagué and Santa Isabel. By XRD phases like illite (I), andesine (A) and quartz (Q) in both samples were identified. The quantity of these phases is different for the two samples. The MS spectra taken at room temperature were adjusted by using five doublets, three of them associated to Fe + 3 type sites and the other two to Fe + 2 type sites. According to their isomer shift and quadrupole splitting the presence of phases like illite (detected by DRX), nontronite and biotite (not detected by XRD) can be postulated.

Rodríguez, Humberto Bustos; Lozano, Dagoberto Oyola; Martínez, Yebrayl Antonio Rojas; Pinilla, Marlene Rivera; Alcázar, German Antonio Pérez

2012-03-01

324

Minerals Masquerading As Enzymes: Abiotic Oxidation Of Soil Organic Matter In An Iron-Rich Humid Tropical Forest Soil  

NASA Astrophysics Data System (ADS)

Oxidative reactions play an important role in decomposing soil organic matter fractions that resist hydrolytic degradation, and fundamentally affect the cycling of recalcitrant soil carbon across ecosystems. Microbial extracellular oxidative enzymes (e.g. lignin peroxidases and laccases) have been assumed to provide a dominant role in catalyzing soil organic matter oxidation, while other potential oxidative mechanisms remain poorly explored. Here, we show that abiotic reactions mediated by the oxidation of ferrous iron (Fe(II)) could explain high potential oxidation rates in humid tropical forest soils, which often contain high concentrations of Fe(II) and experience rapid redox fluctuations between anaerobic and aerobic conditions. These abiotic reactions could provide an additional mechanism to explain high rates of decomposition in these ecosystems, despite frequent oxygen deficits. We sampled humid tropical forest soils in Puerto Rico, USA from various topographic positions, ranging from well-drained ridges to riparian valleys that experience broad fluctuations in redox potential. We measured oxidative activity by adding the model humic compound L-DOPA to soil slurries, followed by colorimetric measurements of the supernatant solution over time. Dilute hydrogen peroxide was added to a subset of slurries to measure peroxidative activity. We found that oxidative and peroxidative activity correlated positively with soil Fe(II) concentrations, counter to prevailing theory that low redox potential should suppress oxidative enzymes. Boiling or autoclaving sub-samples of soil slurries to denature any enzymes present typically increased peroxidative activity and did not eliminate oxidative activity, further suggesting the importance of an abiotic mechanism. We found substantial differences in the oxidation products of the L-DOPA substrate generated by our soil slurries in comparison with oxidation products generated by a purified enzyme (mushroom tyrosinase). Tyrosinase generated a red compound (dopachrome) that is the target analyte of the traditional L-DOPA oxidative enzyme assay, whereas our soil slurries generated purple melanin-like compounds that were likely generated by more extensive oxidation. To investigate the importance of Fe(II) for L-DOPA oxidation, we added realistic concentrations of Fe(II) (equivalent to 10 - 500 ?g Fe g-1 soil) to an L-DOPA buffer solution under oxic conditions, and found rates of L-DOPA oxidation comparable to those from soil slurries. Molecular oxygen and Fe(II) are known to generate strong oxidants via Fenton reactions. We decreased L-DOPA oxidation rates in soil slurries by adding catalase and superoxide-dismutase enzymes to scavenge reactive oxygen species, suggesting that a free-radical mechanism contributed to L-DOPA oxidation. We obtained similar results using another humic model compound, tetramethylbenzidine (TMB). Although abiotic oxidative reactions involving iron have been employed to degrade anthropogenic organic contaminants, this study is among the first to demonstrate their potential importance for oxidizing organic matter in natural ecosystems. In soils rich in Fe(II), abiotic reactions could complement, or even obviate, the role of microbial oxidative enzymes in degrading recalcitrant organic compounds.

Hall, S. J.; Silver, W. L.

2010-12-01

325

Mineral Dissolution and Metal Mobility From Rhizosphere and Non-rhizosphere Soils by Low Molecular Weight Organic Acids  

NASA Astrophysics Data System (ADS)

This research is part of an ongoing investigation of micro-biogeochemistry in the rhizosphere of co-occurring Eucalyptus mannifera and Acacia falciformis on the Southern Tablelands of New South Wales, Australia. While there is still considerable controversy in the literature regarding the roles of low molecular weight organic acids in soil processes there is growing evidence suggesting low molecular weight compounds, especially di-carboxylic acids, have large impacts on mineral dissolution and metal mobility in the rhizosphere. Rhizosphere and non-rhizosphere samples from adjacent E. mannifera and A. falciformis trees were subjected to four separate treatments in sets of 3 replicates; +oxalic acid, +malic acid, +citric acid or +NaCl control solution. These three acids were chosen because they are produced by rhizosphere species and they form stable complexes with nutrient elements such as Phosphorus (P), Iron (Fe), and Calcium (Ca). Solution samples were collected at day 1, day 8 and day 15 for pH measurement and analysed for major and trace elements by ICP-AES and ICP-MS. The results of the preliminary dissolution experiments show that milli-molar concentrations of individual organic acids, malate and oxalate, and in particular citrate, greatly increase the release of major and trace metals to solution compared to inorganic controls. Concentrations of Al and Fe in organic acid solutions were up to 10 times greater than in the inorganic controls. Si concentrations were a factor of 2-5 greater in the organic acid solutions, suggesting preferential weathering of Fe and Al oxyhydroxide phases rather than primary silicate minerals. Dissolution of elements such as Si, Al and Fe from rhizosphere soils were about twice that observed from non-rhizosphere soils, further supporting this. Interestingly Ti and Zr, which are usually considered to be immobile during chemical weathering and are not usually taken up by plants, were also mobilised from the rhizosphere soils, especially in the citric acid solution.

Little, D. A.; Field, J. B.; Welch, S. A.

2005-12-01

326

Enhanced mineralization of lindane in soils supplemented with the white rot basidiomycete Phanerochaete chrysosporium  

Microsoft Academic Search

Biotransformation of the insecticide lindane was investigated in sterilized and non-sterilized soils, each supplemented or not by the white rot basidiomycete Phanerochaete chrysosporium. After spore inoculation of the sterilized soil, the fungal biomass increased rapidly during the first week, then proceeded at a lower rate during the following 8-wk. Conversely, only limited fungal growth was detected in non-sterile soils. Lindane

Christian Mougin; Claude Pericaud; Jaqueline Dubroca; Marcel Asther

1997-01-01

327

Usefulness of NIR spectroscopy for the estimation of the mineral composition and texture of soils and heavy metal uptake  

NASA Astrophysics Data System (ADS)

The accumulation of heavy metals in soils from different sources (atmospheric deposition, agricultural practices, urban-industrial activities, etc.) is of a great environmental concern. In this sense, there is a consensus in the literature that the total heavy metals in soil are not a suitable tool for risk assessment regarding heavy metal mobility and bioavailability. Several approaches have been proposed to estimate this bioavailability but controversy exists to define an universal method. The bioavailability is influenced, apart from other properties like pH, organic matter, etc., by the mineral fraction and texture of a soil. However, the determination of these parameters, especially the mineral composition, is laborious, expensive, and time consuming. Thus, the objectives of this work are the estimation of the texture and mineral components of contrasting soils and the heavy metal uptake (Cu, Zn, Pb, Ni, Cr, Cd) by barley after sewage sludge application using NIR spectroscopy. A set of 70 contrasting soils from different parts of Spain were used for the analysis of the texture and mineral composition. The mineralogical characterization of soil samples was carried out by X-ray diffraction (XRD) using whole soil random powder, oriented clay on ceramic plates, and clay random powder. Chung method was used for semi-quantitative interpretation of X-ray diffraction patterns of soils, obtaining the percentage of Calcite (Ca), Quartz (Q), Albite (Ab), Potassium Feldspar (FK), phyllosilicates (PS). For the prediction of heavy metal uptake, the 70 soils were divided in two separate sets of 36 (experiment 1) and 34 (experiment 2) soils. The methodology for both experiments, separated in time, was the same. The soils were amended with the same dose of sewage sludge (15.71 g dry weight kg-1) and placed in pots. In these pots, a bioassay with barley, under greenhouse conditions, was carried out. Eight weeks after sowing, the plants were harvested. Roots were dried in an oven at 65°C for 2 days, and total heavy metals were determined. The soil samples (air-dried and ground to pass through 2-mm sieve) were placed in glass Petri-dishes, and scanned on reflectance mode from 12000 to 3800 cm-1. For these measurements, a Fourier-Transform near infrared (FT-NIR) spectrophotometer (MPA, Bruker Optik GmbH, Germany) was used. Partial least squares (PLS) regressions were performed to relate the spectral information with the studied parameters. For the mineral parameters and texture, and according to the RPD value, the following models were obtained: excellent for Ca (R2=90.33; RPD=3.24) and Ab (R2=86.03; RPD=2.70), very good (where quantitative predictions are possible) for silt (R2=77.61; RPD=2.13), sand (R2=75.46; RPD=2.03), Q (R2=75.72; RPD=2.04) and FK (R2=78.97; RPD=2.20), and fair models which may be used for assessment and correlation for clay (R2=68.19; RPD=1.78) and PS (R2=67.63; RPD=1.77). For the case of the estimation of the heavy metal uptake, and using the results obtained in the experiment 1, very good models were obtained for Pb (R2=80.75; RPD=2.31), fair, where only high and low values are distinguishable, Ni (R2=50.13; RPD=1.43) and Cd (R2=57.65; RPD=1.56), and poor for Cu (R2=21.94; RPD=1.15), Zn (R2=1.03; RPD=1.02) and Cr (R2=46.01; RPD=1.38). The models developed with the results obtained in the experiment 2 were classified as follows: excellent for Zn (R2=87.62; RPD=2.89) and Ni (R2=85.67; RPD=2.68), very good for Pb (R2=75.08; RPD=2.04) and Cd (R2=77.37; RPD=2.13), good for Cu (R2=72.54; RPD=1.94), and fair for Cr (R2=54.9; RPD=1.51). Although satisfactory results were found for Cu and Zn in the experiment 2 (surprisingly, after the bad results of the experiment 1), they seemed not to be useful, since they were influenced by just one high value, very different to the rest. However, this was not the case of the rest of studied metals, which seemed to have similar patterns in both experiments, with logical differences due to the different ranges, soils, etc. The results indicate that NIR spectroscopy can be a very usef

Soriano-Disla, J. M.; Gómez, I.; Jordán, M. M.; Guerrero, C.; Navarro-Pedreńo, J.; Meseguer, S.; Sanfeliu, T.

2009-04-01

328

DEVELOPMENT OF MULTI-PHASE AND MULTI-COMPONENT FLOW MODEL WITH REACTION IN POROUS MEDIA FOR RISK ASSESSMENT ON SOIL CONTAMINATION DUE TO MINERAL OIL  

NASA Astrophysics Data System (ADS)

In late years, soil contamination due to mineral oil in vacant lots of oil factory and oil field has become obvious. Measure for soil contamina tion and risk assessment are neces sary for sustainable development of industrial activity. Especially, in addition to contaminated sites, various exposure paths for human body such as well water, soil and farm crop are supposed. So it is very important to comprehend the transport phenomena of contaminated material under the environments of soil and ground water. In this study, mineral oil as c ontaminated material consisting of mu lti-component such as aliphatic and aromatic series was modeled. Then numerical mode l for transport phenomena in surface soil and aquifer was constructed. On the basis of modeling for mineral oil, our numerical model consists of three-phase (oil, water and gas) forty three-component. This numerical model becomes base program for risk assessment system on soil contamination due to mineral oil. Using this numerical model, we carried out some numerical simulation for a laboratory-scale experiment on oil-water multi-phase flow. Relative permeability that dominate flow behavior in multi-phase condition was formulated and the validity of the numerical model developed in this study was considered.

Sakamoto, Yasuhide; Nishiwaki, Junko; Hara, Junko; Kawabe, Yoshishige; Sugai, Yuichi; Komai, Takeshi

329

CLAY MINERALS AND THE ACCUMULATION OF SOIL ORGANIC MATTER IN NORTHWESTERN U.S. FORESTS  

EPA Science Inventory

Globally soils are an important terrestrial reservoir of carbon, storing approximately 3 times the carbon held in vegetation and 2 times the amount contained in the atmosphere. With the potential for global climate change it is imperative that world soils continue to be a sink f...

330

Impact of Lead and Sewage Sludge on Soil Microbial Biomass and Carbon and Nitrogen Mineralization  

Microsoft Academic Search

Sewage sludge disposal on arable land is viewed as a method to reduce waste accumulation and to enrich soil fertility. However, such disposal can degrade soil ecosystems due to the presence of potentially harmful substances, such as heavy metals. Pb has assumed greater significance because currently its dispersal through anthropogenic activities has exceeded the inputs from natural sources by about

G. H. Dar

1997-01-01

331

The influence of biological soil crusts on mineral uptake by associated vascular plants  

Microsoft Academic Search

Soil surfaces dominated by cyanobacteria and cyanolichens (such as Collema sp.) are widespread in deserts of the world. The influence of these biological soil crusts on the uptake of bioessential elements is reported for the first time for six seed plants of the deserts of Utah. This sample almost doubles the number of species for which the influence of biological

Kimball T. Harper; Jayne BelnapK

2001-01-01

332

Effect of Simulated Acid Rain on Nitrification and Nitrogen Mineralization in Forest Soils.  

National Technical Information Service (NTIS)

To determine the possible microbiological changes in soil resulting from acid rain, columns containing samples of forest soils were leached with either a continuous application of 100cm of simulated acid rain (pH3.2-4.1) at 5 cm/hour or an intermittent 1....

R. F. Strayer, C. J. Lin, M. Alexander

1981-01-01

333

EFFECTS OF BACTERIAL LIGNIN PEROXIDASE ON ORGANIC CARBON MINERALIZATION IN SOIL, USING RECOMBINANT STREPTOMYCES STRAINS  

EPA Science Inventory

Purified lignin peroxidase was added to sterile and nonsterile silt loam soil to study the effects of bacterial lignin peroxidase ALip-P3 of Streptomyces viridosporus T7A on the rate of organic carbon turnover in soil. ignin peroxidase ALip-P3 appears to affect the short-term tur...

334

DETERMINATION OF KINETICS OF PHOSPHORUS MINERALIZATION IN SOILS UNDER OXIDIZING CONDITIONS  

EPA Science Inventory

In search of a better approach to predict phosphorus movement in soils from applied wastewaters, reactions of added orthophosphates were studied in 9 different soils with widely varying physical and chemical properties. Information obtained on the nature and rate of P reaction wi...

335

Carbon, nitrogen and phosphorus mineralization potential of semiarid Sahelian soils amended with native shrub residues  

Microsoft Academic Search

Two native shrubs (Piliostigma reticulatum and Guiera senegalensis) commonly coexist with crops in fields throughout the Sahel but aboveground residue is annually coppiced and burned. An alternative, with potential to improve soil quality, would be non-thermal return of residues to soils but information is needed on the potential of residues’ to provide nutrients before such systems can be adopted. The

E. L. Dossa; M. Khouma; I. Diedhiou; M. Sene; F. Kizito; A. N. Badiane; S. A. N. Samba; R. P. Dick

2009-01-01

336

The influence of water table position on soil microbial processes and carbon mineralization in a mid-latitude spruce peatland  

NASA Astrophysics Data System (ADS)

High latitude forest and peatland soils represent a major global carbon store sensitive to the impacts of global climate change. While increased temperatures may impact rates of microbial enzyme activity and greenhouse gas release from peat soils, the interaction between increased temperatures and changing precipitation patterns is projected to simultaneously reduce soil moisture and water table (WT) height in high latitude peatlands. WT reduction increases oxygen diffusion within the peat profile and potentially impacts (1) microbial activity and enzyme production, and (2) the rate of carbon mineralization and greenhouse gas emission. We performed an experiment investigating the influence temperature and available oxygen on rates of microbial enzyme activity and carbon mineralization across a 0-40 cm depth-to-water-table gradient in Caribou Bog, Orono, ME. We incubated peat samples acrotelm and catotelm peat samples at four temperatures and three oxygen concentrations for 28 days in order to investigate the temperature and oxygen sensitivity of extracellular enzyme activity and carbon gas emission. We assayed rates of four hydrolytic and two oxidative exoenzymes that depolymerize carbon (C), nitrogen (N), or phosphorus (P) and compared enzymatic activity to rates of carbon mineralization and CO2 production in incubated samples. Microbial biomass increased significantly with water table depth and incubation temperature, but did not vary significantly with sampling depth or [O2]. In contrast, hydrolytic and oxidative enzyme activity consistently decreased with sampling depth, but did not typically vary significantly with site water table position. The chitinase, N-acetyl-glucosaminidase, however, demonstrated significantly higher activity at low water table sites than high water table sites, potentially due to high fungal abundances at low water table height. Enzyme activity increased with temperature, although increases were not significant above 21°C and weakly increased with [O2]. CO2 mineralization increased with depth to water table, sampling depth, oxygen concentration, and incubation temperature, with microbial CO2 production most sensitive to increased temperature at the highest water table sites. Although total microbial biomass did not differ significantly between samples taken above and below the water table, CO2 production was significantly higher in the acrotolm and associated with higher rates of oxidative and hydrolytic enzyme activity. These distinct functional responses despite identical total biomass suggest microbial community-level differences driving distinct patterns in enzyme expression and C release. As peatland water tables fall, shifts in the proportion of catotelm-associated microbial communities to acrotelm-associated microbial communities could drive C losses and contribute to a reduction in the long-term peatland carbon store.

Gill, A. L.; Finzi, A.

2013-12-01

337

Biochemical resistance of pyrogenic organic matter in fire-affected mineral soils of Southern Europe  

NASA Astrophysics Data System (ADS)

Incorporated into the soil, naturally formed pyrogenic organic matter (PyOM) is considered as highly recalcitrant, but direct estimation of PyOM decomposition rates are scarce. With this aim in mind, we subjected organic matter (OM) of fire-affected and unaffected soils to biochemical degradation under laboratory conditions and monitored CO2 production over a period of seven months. The soils derived from fire affected and unaffected areas of the Sierra de Aznalcóllar and the Dońana National Park, Southern Spain. Virtual fractionation of the solid-state 13C nuclear magnetic resonance (NMR) spectra of the fire affected soils into fire-unaffected soil organic matter (SOM) and PyOM yielded charcoal C contributions of 30 to 50% to the total organic C (Corg) of the sample derived from the Aznalcóllar region. Fitting the respiration data with a double exponential decay model revealed a fast carbon flush during the first three weeks of the experiment. Solid-state 13C NMR spectroscopy evidenced the contribution of aromatic moieties of the PyOM to this initial carbon release and to the biosynthesis of new microbial biomass. The input of PyOM resulted in an increase of the mean residence time (MRT) of the slow OM pool of the soil by a factor of 3 to 4 to approximately 40 years which rises doubts rises doubts about the presumed big influence of PyOM as an additional C-sink in soils. On the other hand, although being small the difference in turnover rates is evident and has some major implication with respect to long-term alteration of the chemical composition of OM in fire-affected soils. Based on the obtained results and the analysis of PyOM in other soil systems, a conceptual model is presented which can explain the different behavior of PyOM under different soil conditions.

Knicker, H.; González Vila, F. J.; Clemente Salas, L.

2012-04-01

338

Soil application of meat and bone meal. Short-term effects on mineralization dynamics and soil biochemical and microbiological properties  

Microsoft Academic Search

Meat and bone meal (MBM) utilization for animal production was banned in the European Union since 2000 as a consequence of the appearance of transmissive spongiform encephalopathies. Soil application could represent a lawful and effective strategy for the sustainable recycling of MBM due to its relevant content of nutritive elements and organic matter. The effectiveness of MBM as organic fertilizer

Claudio Mondini; Maria Luz Cayuela; Tania Sinicco; Miguel Angel Sánchez-Monedero; Eleonora Bertolone; Laura Bardi

2008-01-01

339

SOIL LIMING AND MINERAL FERTILIZATION FOR ROOT NODULATION AND GROWTH OF FABA BEANS IN AN ACID SOIL IN TUNISIA  

Microsoft Academic Search

Faba beans (Vicia faba L) are grown in northern Tunisia where annual rainfall approaches 1200 mm and where the soil acidity is the most limiting factor for plant growth. Aluminum (Al) and manganese (Mn) toxicities provide a hostile environment to root growth. To alleviate such a problem, farmers use selected acid-tolerant species. However, crop yields remain far below their optimal

Sarra Ouertatani; Kamel Regaya; John Ryan; Azaiez Gharbi

2011-01-01

340

Extraordinary soils give insight into the role of non-crystalline minerals in soil carbon response to climate and land use changes (Invited)  

NASA Astrophysics Data System (ADS)

Volcanic ash-derived soils often have enormous capacity to store carbon (C) due to complex, amorphous mineralogy. On the Island of Hawaii, a series of acrudoxic Hydrudands present along the windward slopes of Mauna Kea underlie a mosaic of vegetation ranging from undisturbed native forest to grass-dominated pasture and managed Eucalyptus plantations. These soils demonstrate a particularly strong ability to store C, even under scenarios of climate and land use change. We tested the effect of mean annual temperature (MAT) on ecosystem C storage along a 5 °C gradient and found that although fluxes of C belowground increased with MAT, total C storage, radiocarbon-based mean residence time, distribution of C among pools, and temperature sensitivity of decomposition did not change with MAT. Instead of MAT controlling these factors belowground, we identified that organo-Al complexes that were abundant in many of the soils across the gradient were the dominant factor positively associated with exceptional C storage. Further, in a sorption study from the same gradient, these same complexes also were identified as the primary driver of dissolved organic matter retention and of preferential sorption of aromatic compounds. Adjacent to the undisturbed sites, we paired a series of pasture and Eucalyptus plantation plots to determine whether conversion between these land-uses impacted C storage. We found that 10 years of plantation on previous pasture increased total soil C storage by 14.8%. Significant increases in total C occurred in the 18-72 cm depth section, consistent with the tree rooting depth. Further, within this depth increment the C fraction dominated by organo-mineral association significantly increased with plantation. These results collectively suggest the capacity for these extraordinary soils to retain carbon lies within the complex non-crystalline mineralogy and likely will be retained under future scenarios of climate and land use change.

Crow, S. E.; Lazaro, M.; Reeves, M. I.; Litton, C. M.; Giardina, C. P.; Wells, J. M.

2013-12-01

341

Biogeochemistry of mineral–organic associations across a long-term mineralogical soil gradient (0.3–4100 kyr), Hawaiian Islands  

Microsoft Academic Search

Organic matter (OM) in mineral–organic associations (MOAs) represents a large fraction of carbon in terrestrial ecosystems which is considered stable against biodegradation. To assess the role of MOAs in carbon cycling, there is a need to better understand (i) the time-dependent biogeochemical evolution of MOAs in soil, (ii) the effect of the mineral composition on the physico-chemical properties of attached

Robert Mikutta; Gabriele E. Schaumann; Daniela Gildemeister; Steeve Bonneville; Marc G. Kramer; Jon Chorover; Oliver A. Chadwick; Georg Guggenberger

2009-01-01

342

Interactive effects of native and exotic earthworms on resource use and nutrient mineralization in a tropical wet forest soil of Puerto Rico  

Microsoft Academic Search

Investigation of single or mixed assemblages of native Estherella sp. and exotic Pontoscolex corethrurus from a rain forest in Puerto Rico was undertaken to understand resource use patterns, and linkages with C and N mineralization in a 19-day incubation. Resource use was explored with addition of 15N-enriched leaf litter and 13C-enriched glucose to reconstructed organic and mineral soil horizons. Juvenile

S. L. Lachnicht; P. F. Hendrix; X. Zou

2002-01-01

343

Eucalyptus development in degraded soil fertilized with sewage sludge and mineral fertilizer  

NASA Astrophysics Data System (ADS)

The aim of this study was to compare the development of eucalyptus in a degraded Oxisol with mineral fertilizer and sewage sludge. The study was conducted in Selviria, Mato Grosso do Sul, Brasil. The culture of eucalyptus was planted in 2003 at 2.0 m x 1.5 m spacing, with application of 60 Mg ha-1 of sewage sludge (dry basis) and mineral fertilizer. After five years (2008) the area received biosolids and mineral fertilizer, and after five months, were evaluated for height and diameter at breast height of Eucalyptus. The experimental design was randomized blocks with four treatments: T1 - control (without addition of inputs), T2 - Mineral fertilization (30 kg ha-1 N, 90 kg ha-1 of P2O5 and 60 kg ha-1 K2O), T3 - Reapplication of 4.64 Mg ha-1 of sewage sludge, dry basis, T4 - Reapplication of 9.28 Mg ha-1 of sewage sludge, dry basis. Before reapplication the biosolids plant height was higher in the eucalyptus with treatment 9.28 Mg ha-1 of sewage sludge (8.03 m) compared to control (5.75 m) and mineral fertilizer (5.91 m) and that treatment 4.64 Mg ha-1 of sewage sludge (6.34 m) did not differ from the previous three. For the diameter at breast height was the highest value for treatment with 9.28 Mg ha-1 (7.78 cm) compared to control (5.23 cm) and 4.64 Mg ha-1 (5.03 cm), and that of mineral fertilizer (5.96 cm) did not differ from all treatments. After reapplication of sludge plant height was higher in the eucalyptus treatment with 9.28 Mg ha-1 of sewage sludge (11.21 m) compared with control (7.51 m), mineral fertilizer (7.77 m) and 4 64 Mg ha-1 (8.07 m), which did not differ. The diameter at breast height had the same behavior before the application of biosolids in the highest value observed being 9.28 Mg ha-1 (8.46 cm) compared with control (5.75 cm) and 4.64 Mg ha-1 (5.03 cm) and that of mineral fertilizer (6.34 cm) did not differ from the others. Reapplication of the dose of 9.28 Mg ha-1 of sewage sludge in degraded Oxisol provided greater height and diameter at breast height from eucalyptus trees.

Rodrigues, R. A. F.; Santos, E. B.; Alves, M. C.; Arruda, O. G.

2012-04-01

344

Data compilation, synthesis, and calculations used for organic-carbon storage and inventory estimates for mineral soils of the Mississippi River Basin  

USGS Publications Warehouse

U.S. Geological Survey investigations of environmental controls on carbon cycling in soils and sediments of the Mississippi River Basin (MRB), an area of 3.3 x 106 square kilometers (km2), have produced an assessment tool for estimating the storage and inventory of soil organic carbon (SOC) by using soil-characterization data from Federal, State, academic, and literature sources. The methodology is based on the linkage of site-specific SOC data (pedon data) to the soil-association map units of the U.S. Department of Agriculture State Soil Geographic (STATSGO) and Soil Survey Geographic (SSURGO) digital soil databases in a geographic information system. The collective pedon database assembled from individual sources presently contains 7,321 pedon records representing 2,581 soil series. SOC storage, in kilograms per square meter (kg/m2), is calculated for each pedon at standard depth intervals from 0 to 10, 10 to 20, 20 to 50, and 50 to 100 centimeters. The site-specific storage estimates are then regionalized to produce national-scale (STATSGO) and county-scale (SSURGO) maps of SOC to a specified depth. Based on this methodology, the mean SOC storage for the top meter of mineral soil in the MRB is approximately 10 kg/m2, and the total inventory is approximately 32.3 Pg (1 petagram = 109 metric tons). This inventory is from 2.5 to 3 percent of the estimated global mineral SOC pool.

Buell, Gary R.; Markewich, Helaine W.

2004-01-01

345

Identifying soils with potential of expanding sulfate mineral formation using electromagnetic induction  

E-print Network

quantifying sulfate in soils that may be potentially used in highway construction using electromagnetic induction. The objectives are to: 1) document electrical conductivity (EC) variability within selected sites that contain sulfate-bearing materials, and 2...

Fox, Miranda Lynn

2004-11-15

346

Point of zero charge determination in soils and minerals via traditional methods and detection  

E-print Network

) potentiometric titration measuring the adsorption of H+ and OHĂ? on amphoteric surfaces in solutions of varying possessing amphoteric surfaces. This poses far-reaching implications for soil management in agriculture

Ma, Lena

347

Fine root biomass and tree species effects on potential N mineralization in afforested sodic soils  

Microsoft Academic Search

The study was carried out under three types of plantation forest of 40 years, growing on infertile sodic soils, poor in organic matter and N content, of Indogangetic alluvium at Lucknow (26°45' N; 80°53' E). Fine root biomass estimated under three forests did not differ much with season, or with species (106–113 g m-2) but varied with soil depth to

Bajrang Singh; K. P. Tripathi; R. K. Jain; H. M. Behl

2000-01-01

348

Effect of simulated acid rain on nitrification and nitrogen mineralization in forest soils  

Microsoft Academic Search

To determine the possible microbiological changes in soil resulting from acid rain, columns containing samples of forest soils were leached with either a continuous application of 100 cm of simulated acid rain (pH 3.2-4.1) at 5 cm\\/hour or an intermittent 1.5-hour application of 1.2 cm of simulated acid rain twice weekly for 19 weeks. The upper 1.0- to 1.5-cm portions

Richard F. Strayer; Chyi-Jiin Lin; Martin Alexander

1981-01-01

349

Relationship of physicochemical properties of rhizosphere soils with native population of mineral phosphate solubilizing fungi  

Microsoft Academic Search

Phosphate solubilizing fungi (PSF) were enumerated in 78 rhizosphere soil samples collected from various sites of Bhavnagar\\u000a district with agro climatic zone of hot, semi-arid region of Gujarat. 81% of samples were inhabited with indigenous PSF; the\\u000a count varied ranging from 0.01 to 90 × 103 PSF g?1. PSF population in the rhizosphere soils were maximal at pH 7.4–8.4, electrical

Varsha T. Narsian; H. H. Patel

2009-01-01

350

Nitrogen mineralization and availability of mixed leguminous and non-leguminous cover crop residues in soil  

Microsoft Academic Search

Whereas non-leguminous cover crops such as cereal rye (Secale cereale) or annual ryegrass (Lolium multiflorium) are capable of reducing nitrogen (N) leaching during wet seasons, leguminous cover crops such as hairy vetch (Vicia villosa) improve soil N fertility for succeeding crops. With mixtures of grasses and legumes as cover crop, the goal of reducing\\u000a N leaching while increasing soil N

S. Kuo; U. M. Sainju

1998-01-01

351

Effects of water amendment on basal and substrate-induced respiration rates of mineral soils  

Microsoft Academic Search

We studied the effects of amending soils with different volumes of water or glucose solution on respiration rates measured as CO2 evolution. Basal respiration was not significantly affected by the volume of water amendment, but substrate-induced respiration in static soil solutions was significantly reduced by increasing water contents. Inhibition of substrate-induced respiration was removed by continuously agitating the incubation vessels.

K. Ritz; R. E. Wheatley

1989-01-01

352

The effect of acid rain, soil temperature and humidity on C-mineralization rates in organic soil layers under spruce  

Microsoft Academic Search

The biological activity in organic soil layers under spruce was determined by measuring rates of carbon dioxide emission. Under laboratory conditions, biological activity was found to be optimal at temperatures ranging from 20°C to 35°C and at water contents ranging from 40% to 60%. Weakly acidic to neutral pH values of organic materials stimulated microbial CO2 formation whereas high acidity

Volker Wilhelmi; Gunter M. Rothe

1990-01-01

353

Net Nitrogen Mineralization or Immobilization Potential in a Residue-Amended Calcareous Soil  

Microsoft Academic Search

Developing more sustainable agricultural systems that are less dependent on external inputs such as inorganic nitrogen (N) fertilizer that may affect environmental quality requires alternative N sources such as plant residues. However, to be effective it is important to screen plant material for their potential to mineralize N during the decomposition. The objective of this study was to establish statistical

Farshid Nourbakhsh; Richard P. Dick

2005-01-01

354

Integrating plant-microbe interactions to understand soil C stabilization with the MIcrobial-MIneral Carbon Stabilization model (MIMICS)  

NASA Astrophysics Data System (ADS)

If soil organic matter is predominantly microbial biomass, plant inputs that build biomass should also increase SOM. This seems obvious, but the implications fundamentally change how we think about the relationships between plants, microbes and SOM. Plant residues that build microbial biomass are typically characterized by low C/N ratios and high lignin contents. However, plants with high lignin contents and high C/N ratios are believed to increase SOM, an entrenched idea that still strongly motivates agricultural soil management practices. Here we use a combination of meta-analysis with a new microbial-explicit soil biogeochemistry model to explore the relationships between plant litter chemistry, microbial communities, and SOM stabilization in different soil types. We use the MIcrobial-MIneral Carbon Stabilization (MIMICS) model, newly built upon the Community Land Model (CLM) platform, to enhance our understanding of biology in earth system processes. The turnover of litter and SOM in MIMICS are governed by the activity of r- and k-selected microbial groups and temperature sensitive Michaelis-Menten kinetics. Plant and microbial residues are stabilized short-term by chemical recalcitrance or long-term by physical protection. Fast-turnover litter inputs increase SOM by >10% depending on temperature in clay soils, and it's only in sandy soils devoid of physical protection mechanisms that recalcitrant inputs build SOM. These results challenge centuries of lay knowledge as well as conventional ideas of SOM formation, but are they realistic? To test this, we conducted a meta-analysis of the relationships between the chemistry of plant liter inputs and SOM concentrations. We find globally that the highest SOM concentrations are associated with plant inputs containing low C/N ratios. These results are confirmed by individual tracer studies pointing to greater stabilization of low C/N ratio inputs, particularly in clay soils. Our model and meta-analysis results suggest that current ideas about plant-microbe-SOM relationships are unraveling. If so, our reconsideration of the mechanisms stabilizing SOM will also challenge long-held views about how to optimize plant community management to increase SOM.

Grandy, Stuart; Wieder, Will; Kallenbach, Cynthia; Tiemann, Lisa

2014-05-01

355

A regional approach for mineral soil weathering estimation and critical load assessment in boreal Saskatchewan, Canada.  

PubMed

In boreal regions of the province of Saskatchewan, Canada, there is concern over emerging acid precursor emission sources associated with the oil sands industry. Base cation weathering rates (BC(w)) and steady-state critical loads of sulfur (CL(S)) were identified for upland forest soil plots (n=107) in 45 ecodistricts according to a new method for approximation of BC(w) in the region. This method was developed by regression of simple soil and site properties with BC(w) calculated through application of a soil chemical model (PROFILE). PROFILE was parameterized using detailed physicochemical data for a subset (n=35) of the sites. Sand content, soil moisture and latitude emerged as important predictive variables in this empirical regression approximation. Base cation weathering varied widely (0.1-8000 mmol(c) m(-3) yr(-1)) across the study sites, consistent with their contrasting soil properties. Several sites had lower rates than observed in other acid-sensitive regions of Canada owing to quartz dominated mineralogy and coarse-textured soils with very low surface area. Weathering was variable within ecodistricts, although rates were consistently low among ecodistricts located in the northwest of the province. Overall, half of the forest plots demonstrated CL(S) less than 45 mmol(c) m(-2) yr(-1). Historically, the acidification risk in this region has been considered low and monitoring has been limited. Given the very low CL(S) in many northern ecodistricts and the potential for increased acid deposition as oil sands activities expand, soil acidification in these regions warrants further study. PMID:22940479

Whitfield, Colin J; Watmough, Shaun A

2012-10-15

356

Natural immobilization of uranium by phosphate mineralization in an oxidizing saprolite–soil profile: chemical weathering of the Coles Hill uranium deposit, Virginia  

Microsoft Academic Search

Geochemical and mineralogical studies of the 15- to 20-m-thick soil and saprolite profile developed over the Coles Hill uranium deposit demonstrate that uranium transport may be inhibited or naturally attenuated by the precipitation of U(VI) phosphate minerals in oxidizing and saturated soil environments. This study examines geochemical conditions in which these secondary uranium phosphates are formed and remain stable for

J. L Jerden; A. K Sinha; L Zelazny

2003-01-01

357

Persistence of isofenphos and isazophos in a mineral and an organic soil.  

PubMed

Isofenphos (Amaze (R), Oftanol (R), BAY 92114, 1-methylethyl 2- [[ethoxy [(1-methylethyl)amino] phosphinothioyl] oxy] benzoate) (20% granular) and isazophos (Miral (R), CGA 12223, 0,0-diethyl 0- [1-isopropyl-5-chloro-1,2,4-triazolyl(3)] phosphorothioate) (50% emulsifiable concentrate) were applied at 3.4 Kg AI/ha and incorporated into sand and muck soil contained in small field plots. Soil samples were taken at intervals, extending over 2 yr in the case of isofenphos. Radishes and carrots served as indicator crops for absorption of insecticides. Soil and crop samples were extracted and analyzed for the insecticides by glc. Isazophos residues in soil declined rapidly with ca. 50% of the initial applications remaining after 2 and 5 wk in the sand and muck respectively, and less than 1 and 3% after 1 yr. Isofenphos residues declined slowly with ca. 50% of the initial application remaining at 12 wk in both soil types. Residues of isofenphos after 1 yr were 15 and 45% of the initial application to sand and muck, respectively, and after 2 yr they had declined to 4 and 14%, respectively. Residues of both materials in radishes and carrots generally did not exceed 0.04 ppm except for carrots grown the first yr in isofenphos treated sand, where 0.25 ppm was found. PMID:7108145

Chapman, R A; Harris, C R

1982-01-01

358

Biogeochemistry of mineral-organic associations across a long-term mineralogical soil gradient (0.3-4100 kyr), Hawaiian Islands  

NASA Astrophysics Data System (ADS)

Organic matter (OM) in mineral-organic associations (MOAs) represents a large fraction of carbon in terrestrial ecosystems which is considered stable against biodegradation. To assess the role of MOAs in carbon cycling, there is a need to better understand (i) the time-dependent biogeochemical evolution of MOAs in soil, (ii) the effect of the mineral composition on the physico-chemical properties of attached OM, and (iii) the resulting consequences for the stabilization of OM. We studied the development of MOAs across a mineralogical soil gradient (0.3-4100 kyr) at the Hawaiian Islands that derived from basaltic tephra under comparable climatic and hydrological regimes. Mineral-organic associations were characterized using biomarker analyses of OM with chemolytic methods (lignin phenols, non-cellulosic carbohydrates) and wet chemical extractions, surface area/porosity measurements (N 2 at 77 K and CO 2 at 273 K), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC). The results show that in the initial weathering stage (0.3 kyr), MOAs are mainly composed of primary, low-surface area minerals (olivine, pyroxene, feldspar) with small amounts of attached OM and lignin phenols but a large contribution of microbial-derived carbohydrates. As high-surface area, poorly crystalline (PC) minerals increase in abundance during the second weathering stage (20-400 kyr), the content of mineral-associated OM increased sharply, up to 290 mg C/g MOA, with lignin phenols being favored over carbohydrates in the association with minerals. In the third and final weathering stage (1400-4100 kyr), metastable PC phases transformed into well crystalline secondary Fe and Al (hydr)oxides and kaolin minerals that were associated with less OM overall, and depleted in both lignin and carbohydrate as a fraction of total OM. XPS, the N 2 pore volume data and OM-mineral volumetric ratios suggest that, in contrast to the endmember sites where OM accumulated at the surfaces of larger mineral grains, topsoil MOAs of the 20-400-kyr sites are composed of a homogeneous admixture of small-sized PC minerals and OM, which originated from both adsorption and precipitation processes. The chemical composition of OM in surface-horizon MOAs, however, was largely controlled by the uniform source vegetation irrespective of the substrate age whereas in subsoil horizons, aromatic and carboxylic C correlated positively with oxalate-extractable Al and Si and CuCl 2-extractable Al concentrations representing PC aluminosilicates and Al-organic complexes ( r2 > 0.85). Additionally, XPS depth profiles suggest a zonal structure of sorbed OM with aromatic carbons being enriched in the proximity of mineral surfaces and amide carbons (peptides/proteins) being located in outer regions of MOAs. Albeit the mineralogical and compositional changes of OM, the rigidity of mineral-associated OM as analyzed by DSC changed little over time. A significantly reduced side chain mobility of sorbed OM was, however, observed in subsoil MOAs, which likely arose from stronger mineral-organic bindings. In conclusion, our study shows that the properties of soil MOAs change substantially over time with different mineral assemblages favoring the association of different types of OM, which is further accentuated by a vertical gradient of OM composition on mineral surfaces. Factors supporting the stabilization of sorbed OM were (i) the surface area and reactivity of minerals (primary or secondary crystalline minerals versus PC secondary minerals), (ii) the association of OM with micropores of PC minerals (via 'sterically' enhanced adsorption), (iii) the effective embedding of OM in 'well mixed' arrays with PC minerals and monomeric/polymeric metal species, (iv) the inherent stability of acidic aromatic OM components, and (iv) an impaired segmental mobility of sorbed OM, which might increase its stability against desorption and microbial utilization.

Mikutta, Robert; Schaumann, Gabriele E.; Gildemeister, Daniela; Bonneville, Steeve; Kramer, Marc G.; Chorover, Jon; Chadwick, Oliver A.; Guggenberger, Georg

2009-04-01

359

The distribution of secondary mineral phases along an eroding hillslope and its effect on carbon stabilization mechanisms and the fate of soil carbon fractions  

NASA Astrophysics Data System (ADS)

Soil redistribution processes can change soil carbon (C) dynamics drastically by moving carbon from high decomposition and re-sequestration environments at the eroding hillslope to low decomposition and burial at the depositional footslope and valley basin. This leads to not only spatially diverse soil carbon storage throughout the landscape, but also to qualitative changes of the transported carbon and the mineral phase. The interaction between those parameters and the effect on stabilization mechanisms for soil C are still a matter of debate. Here, we present an analysis that aims to clarify the bio/geo-chemical and mineralogical components involved in stabilizing C at various depths along an eroding cropped slope and how this affects the abundance of microbial derived carbon. We use the results of an incubation experiment combined with the abundance of amino sugars in different isolated soil C fractions as a tracer for the stability of the respective fraction. We applied further (i) a sequential extraction of the reactive soil phase using pyrophosphate, oxalate and dithionite-citrate-bicarbonate, and (ii) a qualitative analysis of the clay mineralogy, to analyze the changes in the mineral phase for the different isolated fractions along the slope transect. Our results emphasize the importance of physical protection within microaggregates to stabilize buried, chemically labile C. Our data further indicates that the stability of these aggregates is related to the presence of organo-mineral associations and poorly crystalline minerals. However, decreasing contents of these minerals with depth indicate a temporal limitation of this stabilization mechanism. Non-expandable clay minerals experience a relative enrichment at the depositional site while expandable clay minerals experience the same at the eroding site. These changes in clay mineralogy along the slope are partly responsible for the abundance of silt and clay associated C and the effectiveness of the clay fractions to stabilize C. In summary, our data clearly show that a variety of stabilization mechanisms together with changes in the organic and the mineral phase of soils need to be considered to understand this highly dynamic environment.

Doetterl, Sebastian; Cornelis, Jean-Thomas; Opfergelt, Sophie; Boeckx, Pascal; Bodé, Samuel; Six, Johan; Van Oost, Kristof

2014-05-01

360

The effects of mineral fertilizer and organic manure on soil microbial community and diversity  

Microsoft Academic Search

The effects of mineral fertilizer (NPK) and organic manure on phospholipid fatty acid profiles and microbial functional diversity\\u000a were investigated in a long-term (21-year) fertilizer experiment. The experiment included nine treatments: organic manure\\u000a (OM), organic manure plus fertilizer NPK (OM + NPK), fertilizer NPK (NPK), fertilizer NP (NP), fertilizer NK (NK), fertilizer\\u000a N (N), fertilizer P (P), fertilizer K (K),

Wenhui Zhong; Ting Gu; Wei Wang; Bin Zhang; Xiangui Lin; Qianru Huang; Weishou Shen

2010-01-01

361

The influence on climate forcing of mineral aerosols from disturbed soils  

Microsoft Academic Search

AEROSOLS influence the global radiation budget1, and so changes in the atmospheric aerosol load due to either natural causes or human activity will contribute to climate change2. A large fraction of the mass of tropospheric aerosol is wind-blown mineral dust, and its contribution to radiative forcing can be locally significant3,22. Model calculations indicate that 50 +\\/- 20% of the total

Ina Tegen; Andrew A. Lacis; Inez Fung

1996-01-01

362

Coupling Sorption to Soil Weathering during Reactive Transport: Impacts of Mineral Transformation and Sorbate Aging on Contaminant Speciation and Mobility  

SciTech Connect

The Hanford subsurface has become contaminated with highly alkaline, radioactive waste generated as a result of weapons production. The radioactive brine was stored in underground storage tanks, a number of which developed leaks and contaminated the surrounding subsurface. The high pH and ionic strength of these wastes has been predicted to accelerate the degree of soil weathering to produce new mineral phases--cancrinite and sodalite among the most abundant. Previous work has demonstrated that Cs and Sr, which along with I represent the most radioactive components in the waste, are sequestered by these neo-formed solids. The present work is aimed at assessing the stability of these neo-formed solids, with special emphasis on the degree of Cs, Sr and I release under ambient (neutral pH, low ionic strength) conditions expected to return to the Hanford area after the caustic radioactive brine waste is removed.

Carl I. Steefel; Aaron Thompson; Jon Chorover

2006-06-01

363

Influence of mineral characteristics on soil organic matter stocks, composition and stability of topsoils under long-term arable and forest land use  

NASA Astrophysics Data System (ADS)

A land use change from arable to forest is discussed as an option to sequester carbon and mitigate climate change but land use specific mechanisms responsible for soil organic matter stabilization are still poorly understood. In this study we aimed to analyze the impact of soil mineral characteristics (clay content and composition, iron and aluminium oxide content and crystallinity, specific surface area, content of exchangeable cations) on organic carbon (OC) stocks (kg m-2) and on the composition as well as on the stability of mineral associated organic matter (OM) of arable and forest topsoils. We selected seven soil types of different mineral characteristics for this study. Topsoil samples of each soil type were taken from a deciduous forest and an adjacent arable site. The arable and forest sites have been used continuously for more than 100 years. The Na-pyrophosphate soluble OM fractions (OM(PY)), representing mineral associated OM, were sequentially extracted, analyzed on their OC and 14C content, and characterised by FTIR spectroscopy. We found land use effects on the soil OC stocks and OC amounts separated by OM(PY) (OCPY) (forest > arable) as well as on the stability of OM(PY) (arable > forest). For the forest and arable topsoils, respectively, a linear relationship was found between the stocks of OC and exchangeable Ca. Only for the arable topsoils (pH 6.7-7.5), correlation analyses indicate increasing OCPY contents with an increase in oxalate soluble Fe and Al, exchangable Ca, and Na-pyrophosphate soluble Mg and Fe contents. The stability of OM(PY) of the arable topsoils seems to increase with the specific surface area of soil minerals <2 ?m and the content of exchangeable Ca. For the acidic forest topsoils (pH <5) showing a ratio between soil organic carbon content and specific surface area of >1 g m-2, the stability of OM(PY) seems to increase with increasing pH, the C=O group content of OM(PY) and, the Na-pyrophosphate soluble Mg contents. We hypothesize cation bridging of OM to mineral surfaces in near neutral arable soils and OM-crosslinking in acidic forest soil as important mechanisms for OM(PY) stabilization.

Kaiser, M.; Ellerbrock, R. H.; Wulf, M.; Dultz, S.; Hierath, C.; Sommer, M.

2011-12-01

364

Rebuilding Peatlands on Mineral Soils Utilizing Lessons Learned from Past Peatland Initiation  

Microsoft Academic Search

Recent surveys of peatland initiation during the past 10,000 years in northeastern Alberta have revealed that nearly all peatlands, regardless of whether they are currently bogs and fens, were initiated by paludification, or swamping of upland soils. Terrestrialization (or infilling of water bodies) rarely if ever was involved in the initiation of peatlands across the mid boreal of Canada. Although

D. H. Vitt; S. C. Koropchak; B. Xu; R. Bloise; R. Wieder; S. Mowbray

2010-01-01

365

Peatland establishment on mineral soils: Effects of water level, amendments, and species after two growing seasons  

Microsoft Academic Search

Recent surveys of peatland initiation that occurred over the past 10,000 years in northeastern Alberta have revealed that most peatlands initiated by paludification, or swamping of upland soils. Peatland ecologists have long known the importance of the paludification process, but it has not been transferred to peatland restoration methodologies. We initiated this study to determine if wetland structure and function

Dale H. Vitt; R. Kelman Wieder; Bin Xu; Molly Kaskie; Sara Koropchak

2011-01-01

366

Gross N mineralization rates after application of composted grape marc to soil  

Microsoft Academic Search

Grape marc is a common waste product of the wine production industry. When partially composted and applied to soil it may contain enough N to affect vine growth and hence wine quality. Yet little is known about the quantity and timing of N release from composted grape marc. A laboratory incubation was conducted where composted grape marc amended and non-amended

T. C. Flavel; D. V. Murphy; B. M. Lalor; I. R. P. Fillery

2005-01-01

367

Noble gases from solar energetic particles revealed by closed system stepwise etching of lunar soil minerals  

Microsoft Academic Search

He, Ne, and Ar abundances and isotopic ratios in plagioclase and pyroxene separates from lunar soils were determined using a closed system stepwise etching technique. This method of noble gas release allows one to separate solar wind (SW) noble gases from those implanted as solar energetic particles (SEP). The major part of SEP-Ne possibly originates from solar \\

R. Wieler; H. Baur; P. Signer

1986-01-01

368

Carbon mineralization dynamics in soils amended with meat meals under laboratory conditions  

Microsoft Academic Search

Meat and bone meal (MBM) is obtained from the wastes produced during slaughtering operations. Its high concentration of N and P makes it interesting as an organic fertiliser but its use in soil has been barely studied previously. In this work four laboratory experiments were performed to study the influence of different variables (MBM composition, rate of application, temperature of

M. L. Cayuela; T. Sinicco; F. Fornasier; M. A. Sanchez-Monedero; C. Mondini

2008-01-01

369

Altered Snow Density and Chemistry Change Soil Nitrogen Mineralization and Plant Growth  

Microsoft Academic Search

Snow properties such as snow density will likely change in a warmer climate. Changes in depth and extent of snow cover have been shown to affect soil nutrient dynamics and plant growth; however, effects of a changed snow density have so far not been explicitly tested. We altered snow properties (especially depth and density according to those found on ski

Christian Rixen; Michele Freppaz; Veronika Stoeckli; Christine Huovinen; Kai Huovinen; Sonja Wipf

2008-01-01