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1

Iron oxyhydroxide mineralization on microbial extracellular polysaccharides  

NASA Astrophysics Data System (ADS)

Iron biominerals can form in neutral pH microaerophilic environments where microbes both catalyze iron oxidation and create polymers that localize mineral precipitation. In order to classify the microbial polymers that influence FeOOH mineralogy, we studied the organic and mineral components of biominerals using scanning transmission X-ray microscopy (STXM), micro X-ray fluorescence (?XRF) microscopy, and high-resolution transmission electron microscopy (HRTEM). We focused on iron microbial mat samples from a creek and abandoned mine; these samples are dominated by iron oxyhydroxide-coated structures with sheath, stalk, and filament morphologies. In addition, we characterized the mineralized products of an iron-oxidizing, stalk-forming bacterial culture isolated from the mine. In both natural and cultured samples, microbial polymers were found to be acidic polysaccharides with carboxyl functional groups, strongly spatially correlated with iron oxyhydroxide distribution patterns. Organic fibrils collect FeOOH and control its recrystallization, in some cases resulting in oriented crystals with high aspect ratios. The impact of polymers is particularly pronounced as the materials age. Synthesis experiments designed to mimic the biomineralization processes show that the polysaccharide carboxyl groups bind dissolved iron strongly but release it as mineralization proceeds. Our results suggest that carboxyl groups of acidic polysaccharides are produced by different microorganisms to create a wide range of iron oxyhydroxide biomineral structures. The intimate and potentially long-term association controls the crystal growth, phase, and reactivity of iron oxyhydroxide nanoparticles in natural systems.

Chan, Clara S.; Fakra, Sirine C.; Edwards, David C.; Emerson, David; Banfield, Jillian F.

2009-07-01

2

Insights into the Global Microbial Community Structure Associated with Iron Oxyhydroxide Minerals Deposited in the Aerobic Biogeosphere  

Microsoft Academic Search

Over the last decade or so, several studies have investigated the formation, mineralogy and microbial composition of iron oxyhydroxides. Here, we focus on the exploration of the microbial community structure of iron oxyhydroxide minerals that often occur in tight association with microbial life, which are referred to as Biogenic Iron Oxyhydroxides (BIOS). BIOS deposits host a wide range of microbial

Ernest Chi Fru; Paul Piccinelli; Danielle Fortin

2012-01-01

3

Electrolyte ion binding at iron oxyhydroxide mineral surfaces.  

PubMed

Electrolyte ion loadings at the surfaces of synthetic goethite (?-FeOOH) and lepidocrocite (?-FeOOH) particles that were pre-equilibrated in aqueous solutions of 10 mM NaCl and NaClO4 at 25 °C were investigated by cryogenic X-ray photoelectron spectroscopy (XPS). Atomic concentrations of Cl(-), ClO4(-), and Na(+) were correlated to potential determining ion (pdi; H(+), OH(-)) loadings obtained by potentiometric titrations. While Cl(-) promoted more pdi adsorption than ClO4(-), due to its greater charge-to-size ratio, both ions followed the same loading dependence on pdi adsorption, in contrast to previous studies supporting the concept for negligible perchlorate adorption. Lepidocrocite particles exhibited a stronger response of electrolyte adsorption to pdi loadings due electrolyte ion adsorption on the proton inactive (010) plane. These particles also acquired greater sodium loadings than goethite. These loadings were moreover considerably enhanced by perchlorate adsorption, possibly due to a thickening of the interfacial region in NaClO4 on the (010) plane. Finally, goethite particles with rougher surfaces acquired greater pdi and ion loadings than on those with smoother surfaces. No strong differences could be discerned between Cl(-) and ClO4(-) loadings on these materials. This work thus identified key aspects underpinning the relationship between pdi and electrolyte loadings at FeOOH mineral surfaces of environmental and technological importance. PMID:24050677

Kozin, Philipp A; Shchukarev, Andrey; Boily, Jean-François

2013-09-19

4

Simulated atmospheric processing of iron oxyhydroxide minerals at low pH: Roles of particle size and acid anion in iron dissolution  

PubMed Central

A number of recent studies have shown that iron dissolution in Fe-containing dust aerosol can be linked to source material (mineral or anthropogenic), mineralogy, and iron speciation. All of these factors need to be incorporated into atmospheric chemistry models if these models are to accurately predict the impact of Fe-containing dusts into open ocean waters. In this report, we combine dissolution measurements along with spectroscopy and microscopy to focus on nanoscale size effects in the dissolution of Fe-containing minerals in low-pH environments and the importance of acid type, including HNO3, H2SO4, and HCl, on dissolution. All of these acids are present in the atmosphere, and dust particles have been shown to be associated with nitrate, sulfate, and/or chloride. These measurements are done under light and dark conditions so as to simulate and distinguish between daytime and nighttime atmospheric chemical processing. Both size (nano- versus micron-sized particles) and anion (nitrate, sulfate, and chloride) are found to play significant roles in the dissolution of ?-FeOOH under both light and dark conditions. The current study highlights these important, yet unconsidered, factors in the atmospheric processing of iron-containing mineral dust aerosol.

Rubasinghege, Gayan; Lentz, Robert W.; Scherer, Michelle M.; Grassian, Vicki H.

2010-01-01

5

Magnetic birefringence of iron oxyhydroxide nanoparticles stabilised by sucrose  

NASA Astrophysics Data System (ADS)

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 2-5 nm particles. The mineral form of the iron-core is suggested to be akaganeite. Anisotropy of the optical polarizability and magnetic susceptibility of akaganeite nanoparticles are calculated. The permanent dipole moment obtained for the nanoparticles studied was found to be negligible, in agreement with the characteristic superparamagnetic behaviour of the magnetic nanoparticles observed at room temperature. The Neel temperature of these nanoparticles is estimated as below 276 K. The results obtained are discussed against a background of the earlier studies of similar nanoscale systems.

Koralewski, M.; Pochylski, M.; Gierszewski, J.

2011-05-01

6

Biomimetic lithography and deposition kinetics of iron oxyhydroxide thin films  

SciTech Connect

Heterogeneous nucleation and crystal growth on functionalized organic substrates is a critical step in biological hard tissue formation. Self assembled monolayers can be derivatized with various organic functional groups to mimic the ``nucleation proteins`` for induction of mineral growth. Studies of nucleation and growth on SAMs can provide a better understanding of biomineralization and can also form the basis of a superior thin film deposition process. We demonstrate that micron-scale, electron and ion beam, lithographic techniques can be used to pattern SAMs with functional organic groups that either inhibit or promote mineral deposition. Patterned films of iron oxyhydroxide were deposited on the areas patterned with nucleation sites. Studies of the deposition kinetic of these films show that indeed the surface induces heterogeneous nucleation and that film formation does not occur via absorption of polymers or colloidal material formed homogeneously in solution. The nucleus interfacial free energy was calculated to be 24 mJ/m2 on a SAM surface composed entirely of sulfonate groups.

Rieke, P.C.; Wood, L.L.; Marsh, B.M.; Fryxell, G.E.; Engelhard, M.H.; Baer, D.R. [Pacific Northwest Lab., Richland, WA (United States); Tarasevich, B.J. [Pacific Northwest Lab., Richland, WA (United States)]|[Pennsylvania State Univ., University Park, PA (United States). Dept. of Chemistry; John, C.M. [Shaman Pharmaceuticals, San Francisco, CA (United States)

1993-12-01

7

Spectroscopic Evidence for Ni(Ii) Surface Speciation at the Iron Oxyhydroxides-Water Interface  

SciTech Connect

Understanding in situ metal surface speciation on mineral surfaces is critical to predicting the natural attenuation of metals in the subsurface environment. In this study, we have demonstrated the novel Ni K-edge X-ray absorption spectroscopy (XAS) measurements needed to understand Ni(II) surface speciation in three synthetic iron oxyhydroxides (ferrihydrite, goethite, and hematite). The adsorption of Ni gradually increases with increasing pH from 5 to 8, and the adsorption edge appears at near the point of zero salt effect (PZSE) of the solids. The results of XAS analysis indicate four different Ni inner-sphere surface species are present. While total Ni surface species in hematite at pH 6.85 surfaces consist of {approx}63% face-sharing (interatomic distance of Ni-Fe (R{sub Ni-Fe}) {approx}2.9 {angstrom}) and {approx}37% corner-sharing (R{sub Ni-Fe} 4.0 {angstrom}) surface species on iron octahedra, a combination of two different edge-sharing (between NiO{sub 6} and FeO{sub 6} octahedra, in chains or in rows) and corner-sharing surface species are observed in goethite and ferrihydrite at pH 5.09-6.89. In ferrihydrite, approximately 70% of surface species are edge-sharing surface species (in chains) (R{sub Ni-Fe} 3.0 {angstrom}), followed by {approx}30% of edge-sharing species (in rows) (R{sub Ni-Fe} {approx}3.2 {angstrom}) and {approx}3-5% of corner-sharing surface species (R{sub Ni-Fe} 4.0{angstrom}). Goethite contains {approx}54% edge-sharing (R{sub Ni-Fe} 3.0 {angstrom}), {approx}26% edge-sharing (R{sub Ni-Fe} {approx}3.2 {angstrom}), and 20% corner-sharing surface species. These findings indicate that the reactivity and surface speciation of Ni are sensitive to the crystallinity of iron oxyhydroxides. The spectroscopic evidence for multi-Ni surface speciation should be factored into predictions of the transport of Ni in soil-water environments.

Arai, Y.

2009-05-11

8

Molecular Mechanisms of Iron Oxyhydroxide Biomineralization  

NASA Astrophysics Data System (ADS)

Neutrophilic iron-oxidizing microbes such as Gallionella and PV-1 (Emerson and Moyer, 1997) extrude polymers that become encrusted with iron oxides. Little is known about the identity of these polymers, their biological function and the roles they play in mineralization. To this end, we are investigating iron oxidizers in natural terrestrial iron-rich microbial mat communities, culturing and characterizing them in the laboratory and performing abiotic synthesis experiments based on the natural mineralization processes. Our sampling site is in a flooded former lead-zinc mine in Tennyson, WI, which is host to thick reddish-orange microbial mats. Scanning and transmission electron microscopy studies show that the mat is composed of iron oxide-covered stalks and sheaths (like those formed by Gallionella and Leptothrix spp.), as well as tangled masses of mineralized filaments. There is evidence of polymer influence on mineral phase and morphology in the form of extremely thin (few-unit cell wide), microns-long akaganeite (? -FeOOH) crystals at the center of these mineralized filaments. We are using synchrotron-based X-ray spectromicroscopy (PEEM-photoelectron emisson microscopy and STXM-scanning transmission X-ray microscopy), which has the ability to give chemical information on heterogenous samples at high spatial resolutions. Both PEEM and STXM show that these filaments contain polysaccharides, which are likely templating the akaganeite formation. Initial iron oxide synthesis experiments using model microbial polysaccharides support this hypothesis. Further synthesis and characterization by X-ray absorption and infrared spectroscopy methods is being performed in order to elucidate the molecular mechanisms of mineral nucleation and growth.

Chan, C. S.; Fakra, S.; de Stasio, G.; Banfield, J. F.

2003-12-01

9

Antagonistic effects of humic acid and iron oxyhydroxide grain-coating on biochar nanoparticle transport in saturated sand.  

PubMed

Biochar land application may result in multiple agronomic and environmental benefits (e.g., carbon sequestration, improving soil quality, and immobilizing environmental contaminants). However, our understanding of biochar particle transport is largely unknown in natural environments with significant heterogeneity in solid (e.g., patches of iron oxyhydroxide coating) and solution chemistry (e.g., the presence of natural organic matter), which represents a critical knowledge gap in assessing the environmental impact of biochar land application. Transport and retention kinetics of nanoparticles (NPs) from wheat straw biochars produced at two pyrolysis temperatures (i.e., 350 and 550 °C) were investigated in water-saturated sand columns at environmentally relevant concentrations of dissolved humic acid (HA, 0, 1, 5, and 10 mg L(-1)) and fractional surface coverage of iron oxyhydroxide coatings on sand grains (?, 0.16, 0.28, and 0.40). Transport of biochar NPs increased with increasing HA concentration, largely because of enhanced repulsive interaction energy between biochar NPs and sand grains. Conversely, transport of biochar NPs decreased significantly with increasing ? due to enhanced electrostatic attraction between negatively charged biochar NPs and positively charged iron oxyhydroxides. At a given ? of 0.28, biochar NPs were less retained with increasing HA concentration due to increased electrosteric repulsion between biochar NPs and sand grains. Experimental breakthrough curves and retention profiles were well described using a two-site kinetic retention model that accounted for Langmuirian blocking or random sequential adsorption at one site. Consistent with the blocking effect, the often observed flat retention profiles stemmed from decreased retention rate and/or maximum retention capacity at a higher HA concentration or smaller ?. The antagonistic effects of HA and iron oxyhydroxide grain-coating imparted on the mobility of biochar NPs suggest that biochar colloid transport potential will be dependent on competitive influences exerted by a number of environmental factors (e.g., natural organic matter and metal oxides). PMID:23614641

Wang, Dengjun; Zhang, Wei; Zhou, Dongmei

2013-05-07

10

Lead coprecipitation with iron oxyhydroxide nano-particles  

NASA Astrophysics Data System (ADS)

Pb2+ and Fe3+ coprecipitation was studied with sorption edge measurements, desorption experiments, sorbent aging, High Resolution Transmission and Analytical Electron Microscopy (HR TEM-AEM), and geochemical modeling. Companion adsorption experiments were also conducted for comparison. The macroscopic chemical and near atomic scale HRTEM data supplemented our molecule scale analysis with EXAFS (Kelly et al., 2008). Coprecipitation of Pb2+ with ferric oxyhydroxides occurred at ˜pH 4 and is more efficient than adsorption in removing Pb2+ from aqueous solutions at similar sorbate/sorbent ratios and pH. X-ray Diffraction (XRD) shows peaks of lepidocrocite and two additional broad peaks similar to fine particles of 2-line ferrihydrite (2LFh). HRTEM of the Pb-Fe coprecipitates shows a mixture of 2-6 nm diameter spheres and 8-20 by 200-300 nm needles, both uniformly distributed with Pb2+. Geochemical modeling shows that surface complexation models fit the experimental data of low Pb:Fe ratios when a high site density is used. Desorption experiments show that more Pb2+ was released from loaded sorbents collected from adsorption experiments than from Pb to Fe coprecipitates at dilute EDTA concentrations. Desorbed Pb2+ versus dissolved Fe3+ data show a linear relationship for coprecipitation (CPT) desorption experiments but a parabolic relationship for adsorption (ADS) experiments.Based on these results, we hypothesize that Pb2+ was first adsorbed onto the nanometer-sized, metastable, iron oxyhydroxide polymers of 2LFh with domain size of 2-3 nm. As these nano-particles assembled into larger particles, some Pb2+ was trapped in the iron oxyhydroxide structure and re-arranged to form solid solutions. Therefore, the CPT contact method produced more efficient removal of Pb2+ than the adsorption contact method, and Pb2+ bound in CPT solids represent a more stable sequestration of Pb2+ in the environment than Pb2+ adsorbed on iron oxyhydroxide surfaces.

Lu, Peng; Nuhfer, Noel T.; Kelly, Shelly; Li, Qin; Konishi, Hiromi; Elswick, Erika; Zhu, Chen

2011-08-01

11

The nanosphere iron mineral(s) in Mars soil  

Microsoft Academic Search

A series of surface-modified clays containing nanophase (np) iron\\/oxyhydroxides of extremely small particle sizes, with total iron contents as high as found in Mars soil, were prepared by iron deposition on the clay surface from ferrous chloride solution. Comprehensive studies of the iron mineralogy in these 'Mars-soil analogs' were conducted using chemical extractions, solubility analyses, pH and redox, x ray

A. Banin; T. Ben-Shlomo; L. Margulies; D. F. Blake; R. L. Mancinelli; A. U. Gehring

1993-01-01

12

Oxygen and hydrogen isotope compositions of pedogenic phyllosilicates and iron oxyhydroxides: Development of modern surface domain arrays and implications for paleotemperature reconstructions  

NASA Astrophysics Data System (ADS)

Mineralogic, chemical, and oxygen and hydrogen isotope compositions of 68 different modern soil and paleosol phyllosilicate and iron oxyhydroxide samples are presented. The chemical and mineralogic data are used in conjunction with published thermodynamic data to calculate hydrogen and oxygen isotope fractionation factors for each sample. These temperature-dependent fractionation values are then combined with modern global oxygen and hydrogen isotope compositions of meteoric water and temperature data from the IAEA database to construct modern surface domains (MSD) for each phyllosilicate and iron oxyhydroxide sample with the coordinates dD and d18O. The hydrogen isotopic compositions of the phyllosilicates range from -108S to -24S, whereas the oxygen isotopic compositions range from +10.2S to +22.7S. The hydrogen isotopic compositions of the iron oxyhydroxides range from -113S to -154S, whereas the oxygen isotopic compositions range from +3.1S to -3.2S. All of the phyllosilicate samples from modern soils plot within the MSD and yield equilibrium temperatures of formation similar to measured temperatures at each respective site. These results suggest that published thermodynamic data provide good estimates of natural systems. Paleo-equatorial Permo-Pennsylvanian phyllosilicates and iron oxyhydroxides plot within the MSD, or at slightly higher temperatures than MSD values (25 to 35° C). Eocene kaolinites plot within the MSD with equilibrium temperatures above modern temperatures (22°). Late Triassic iron oxyhydroxides from Argentina plot within the modern surface domain at temperatures of 12° C. However, the phyllosilicate data points plot well outside their respective MSDs, suggesting the phyllosilicate ? D values of these Triassic samples have likely been altered by proton-diffusion.

Tabor, N. J.; Montanez, I. P.

2002-12-01

13

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

14

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

NASA Astrophysics Data System (ADS)

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 (?XRF), X-ray absorption spectroscopy (??XAFS), and X-ray diffraction (?XRD) in conjunction with focused ion beam (FIB) sectioning, and high resolution 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 (Fe 1-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 ?EXAFS spectroscopy and ?XRD measurements indicate that the dominant form of biofilm Fe is a short-range ordered Fe oxyhydroxide characterized by pervasive edge-sharing Fe-O 6 octahedral linkages. Double corner-sharing Fe-O 6 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.

2009-01-01

15

Trace metals in oxic lake sediments: possible adsorption onto iron oxyhydroxides  

Microsoft Academic Search

Apparent overall equilibrium constants for the adsorption of Cd, Cu, Ni, Pb and Zn onto natural iron oxyhydroxides have been calculated from the partitioning of these trace metals in oxic lake sediments and the in situ measurement of trace metal concentrations in the associated pore waters. Such values obtained from lakes of various pH located on the Precambrian Shield, in

A. Tessier; F. Rapin; R. Carignan

1985-01-01

16

Adsorption\\/coprecipitation of trace elements from water with iron oxyhydroxide  

Microsoft Academic Search

This study has examined the adsorptive\\/coprecipitation behavior of several inorganic cations and anions in systems containing freshly precipitated x-ray amorphous iron oxyhydroxide. The project examined experimentally several simple, well-characterized model systems to establish type behavior in sufficient detail to allow interpretation of subsequent experimental work on less well-characterized waste materials. A prominent feature of this project was evaluation of the

J. O. Leckie; M. M. Benjamin; K. Hayes; G. Kaufman; S. Altmann

1980-01-01

17

Synthesis of LiFePO 4\\/polyacenes using iron oxyhydroxide as an iron source  

Microsoft Academic Search

LiFePO4\\/polyacenes (PAS) composite is synthesized by iron oxyhydroxide as a new raw material and phenol–formaldehyde resin as both reducing agent and carbon source. The mechanism of the reaction is outlined by the analysis of XRD, FTIR as well as TG\\/DSC. The results show that the formation of LiFePO4 is started at 300°C, and above 550°C, the product can be mainly

Guiling Yang; Xianfa Zhang; Jing Liu; Xingguang He; Jiawei Wang; Haiming Xie; Rongshun Wang

2010-01-01

18

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

SciTech Connect

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. - Graphical abstract: The transformation of various iron oxyhydroxides in the presence of trace Fe(II) was compared based on experimental results, thermodynamic stability, crystalline structure, and transformation mechanism. Highlights: > Fe(II) can accelerate the transformation from akaganeite to hematite. > Small particles of goethite can transform to hematite in the presence of Fe(II). > Some hematite particles were found to be embedded within the crystal of goethite. > The relationship between structure and transformation mechanism was revealed.

Lu Bin [College of Physics Science and Information Engineering, Hebei Normal University, Shijiazhuang 050016 (China); College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050016 (China); Guo Hui; Li Ping [College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050016 (China); Liu Hui, E-mail: liuhuicn@126.com [College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050016 (China); Wei Yu, E-mail: weiyu@mail.hebtu.edu.cn [College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050016 (China); Hou Denglu [College of Physics Science and Information Engineering, Hebei Normal University, Shijiazhuang 050016 (China)

2011-08-15

19

Chromate adsorption on amorphous iron oxyhydroxide in the presence of major groundwater ions  

Microsoft Academic Search

Chromate adsorption on amorphous iron oxyhydroxide was investigated in dilute iron suspensions as a single solute and in solutions of increasing complexity containing CO2(g), SO4S (aq), H4SiO4(aq), and cations (K , MgS , CaS (aq)). In paired-solute systems (e.g., CrO4S -H2CO3*), anionic cosolutes markedly reduce CrO4S adsorption through a combination of competitive and electrostatic effects, but cations exert no appreciable

John M. Zachara; Donald C. Girvin; Ronald L. Schmidt; C. Thomas. Resch

1987-01-01

20

Experimental study of the stability of metals associated with iron oxyhydroxides precipitated in acid mine drainage  

Microsoft Academic Search

Iron oxyhydroxide precipitates associated with acid mine drainage (AMD) from the Stearns Coal Zone in southeastern Kentucky\\u000a were analyzed for their metal (Al, Cu, Pb, Mn, Ni, and Zn) content. The most concentrated metals within these sediments are\\u000a nickel (27–32×103?mol\\/kg), manganese (16–29×103?mol\\/kg), and aluminum (13–22×103?mol\\/kg) as determined by HCl-HNO3 digestion. Metal concentrations associated with the organic fraction as determined by

S. Rose; A. M. Ghazi

1998-01-01

21

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

22

Soils of Mars.  

National Technical Information Service (NTIS)

A mineralogical model for the Mars fine soil that includes as major components smectite clays absorbed and coated with amorphous iron oxyhydroxides and perhaps mixed with small amounts of better-crystalized iron oxides as separate phases is proposed. Also...

A. Banin

1988-01-01

23

Soil organic matter mineralization in frozen soils  

NASA Astrophysics Data System (ADS)

Boreal forest soils are frozen for a large part of the year and soil organic matter mineralization during this period has been shown to significantly influence the C balance of boreal forest ecosystems. Mineralization proceeds through heterotrophic microbial activity, but the understanding of the environmental controls regulating soil organic matter mineralization under frozen conditions is poor. Through a series of investigations we have addressed this issue in order to elucidate to what extent a range of environmental factors control mineralization processes in frozen soils and also the microbial communities potential to oxidize organic substrates and grow under such conditions. The unfrozen water content in the frozen soils was shown to be an integral control on the temperature response of biogenic CO2 production across the freezing point of bulk soil water. We found that osmotic potential was an important contributor to the total water potential and, hence, the unfrozen water content of frozen soil. From being low and negligible in an unfrozen soil, the osmotic potential was found to contribute up to 70% of the total water potential in frozen soil, greatly influencing the volume of liquid water. The specific factors of how soil organic matter composition affected the unfrozen water content and CO2 production of frozen soil were studied by CP-MAS NMR. We concluded that abundance of aromatics and recalcitrant compounds showed a significant positive correlation with unfrozen water content and these were also the major soil organic fractions that similarly correlated with the microbial CO2 production of the frozen soils. Thus, the hierarchy of environmental factors controlling SOM mineralization changes as soils freeze and environmental controls elucidated from studies of unfrozen systems can not be added on frozen conditions. We have also investigated the potential activity of soil microbial communities under frozen conditions in order to elucidate temperature limitations on soil organic matter mineralization. The carbon mineralization was found to proceed down to -4°C and the soil microbial communities were growing at this temperature. At -9°C, the carbon mineralization was insignificant. 13C NMR revealed that the soil microorganisms were able to produce ethylene glycol (anti-freeze medium) under frozen conditions (-4°C). The production of ethylene glycol coincided with an increase in CO2 production that took place after a lag-phase of ca. 41 days. 13C NMR also confirmed that soil microbial anabolic processes continued under frozen conditions. At -4°C, 23% of the used substrate was respired as CO2 and 77% were converted and assimilated by the organisms as e.g. lipids and polysaccharides. This is contradicting to earlier studies that suggest that mainly processes yielding CO2 occurs in soils at <0°C.

Harrysson Drotz, S.; Sparrman, T.; Schleucher, J.; Nilsson, M.; Öquist, M. G.

2009-12-01

24

The soils of Mars  

NASA Astrophysics Data System (ADS)

A mineralogical model for the Mars fine soil that includes as major components smectite clays absorbed and coated with amorphous iron oxyhydroxides and perhaps mixed with small amounts of better-crystalized iron oxides as separate phases is proposed. Also present as accessory minerals are sulfate minerals such as kieserite (MgSO4.H2O) and/or anhydrite (CaSO4), rutile (TiO2), and maghemite (Fe2O3) or magnetite (Fe3O4), the last two as magnetic components. Carbonates may be present at low concentrations only (less than 1 to 2 pct). However, a prime question to be addressed by a Mars Sample Return Mission shall be related to the mineralogical composition of the soil, and its spatial variability.

Banin, A.

25

Mineral Abundances in Martian Soils  

NASA Astrophysics Data System (ADS)

Using traditional geochemical calculations with in situ Martian cosmochemical data researchers Harry (Hap) McSween Jr. and Ian McGlynn (University of Tennessee) and Deanne Rogers (SUNY at Stony Brook) have developed a method for identifying the major and minor minerals in soils at the Mars Exploration Rovers (MER) landing sites. The team used information from the MER Athena instrument package operating on Mars since January, 2004. They created two models using MiniTES spectra, Alpha Particle X-ray Spectrometer (APXS) data, and Mossbauer spectrometer data to calculate the mineralogy of average dark soils on the Gusev crater plains and on Meridiani Planum, located on opposite sides of Mars. Soils at both locations are similarly composed of minerals derived from the comminution of basalts (about three quarters by weight) and other minerals derived from rocks altered by chemical weathering (about one quarter by weight). This mixture of possibly unrelated materials (primary and altered) might mean that the alteration of soil did not occur in place and that the basaltic and alteration suites of minerals came from different sources. The nearly identical modal mineralogy at two widely-separated locations on the planet supports a previous hypothesis based on comparable chemical compositions that soils have been homogenized, if not globally then at least over large areas of the Martian surface. Yet, global maps of orbital remote sensing data have not shown surface abundances of alteration minerals as high as those in the Martian soils.

Martel, L. M. V.

2011-01-01

26

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

Microsoft Academic Search

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

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

2008-01-01

27

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

Microsoft Academic Search

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

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

2009-01-01

28

Oxygen K-Edge Emission And Absorption Spectroscopy of Iron Oxyhydroxide Nanoparticles  

SciTech Connect

Transition metal oxide and oxyhydroxide nanoparticles are the focus of considerable current interest in geochemistry. Much progress has been made in understanding the structure and phase relationships in mineral nanoparticles, but the effects of small size and modified surface structure on reactivity remains an outstanding problem. Common environmental nanoparticles have been shown to exhibit enhanced chemical reactivity relative to bulk mineral surfaces, but the origin of this behavior is not well established. We studied the electronic structure component of mineral reactivity by comparing soft x-ray absorption and emission spectra of bulk goethite ({alpha}-FeOOH) with spectra obtained from {approx}6 nm FeOOH nanoparticles and larger FeOOH nanoparticles obtained by hydrothermal coarsening. The semiconductor band gap is reduced in the FeOOH nanoparticles, mainly due to the presence of additional states in the upper valence band. We performed ab initio simulation of the electronic structure of oxygen sites at the 010 surface of goethite, and observe that oxygen sites with reduced metal coordination contribute to the O 2p DOS at higher binding energy. Hence we conclude that FeOOH nanoparticle surfaces are more disordered than the surfaces of goethite, and that this structural component is likely the dominant cause of enhanced rates of reductive dissolution.

Gilbert, B.; Kim, C.S.; Dong, C.-L.; Guo, J.; Nico, P.S.; Shuh, D.K.

2009-06-04

29

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

30

Nitrogen mineralization in tropical wetland rice soils  

Microsoft Academic Search

To study the effect of temperature on the soil organic N mineralization of tropical flooded rice soils, laboratory incubation experiments using 30 flooded rice soils from the Philippines, Indonesia, Malaysia, and Thailand were conducted under flooded conditions at 25 and 30°C. The rate of N mineralization was determined every week, but the data at 56 and 112 d were presented

Ireneo J. Manguiat; Iwao Watanabe; Grace B. Mascariña; Jasper G. Tallada

1996-01-01

31

Transformations of mercury, iron, and sulfur during the reductive dissolution of iron oxyhydroxide by sulfide  

NASA Astrophysics Data System (ADS)

Methylmercury can accumulate in fish to concentrations unhealthy for humans and other predatory mammals. Most sources of mercury (Hg) emit inorganic species to the environment. Therefore, ecological harm occurs when inorganic Hg is converted to methylmercury. Sulfate- and iron-reducing bacteria (SRB and FeRB) methylate Hg, but the effects of processes involving oxidized and reduced forms of sulfur and iron on the reactivity of Hg, including the propensity of inorganic Hg to be methylated, are poorly understood. Under abiotic conditions, using a laboratory flow reactor, bisulfide (HS-) was added at 40 to 250 ?M h-1 to 5 g L-1 goethite (?-FeOOH) suspensions to which Hg(II) was adsorbed (30 100 nmol m-2) at pH 7.5. Dissolved Hg initially decreased from 103 or 104 nM (depending on initial conditions) to 10-1 nM, during which the concentration of Hg(II) adsorbed to goethite decreased by 80% and metacinnabar (?-HgS(s)) formed, based on identification using Hg LIII-edge extended X-ray absorption fine structure (EXAFS) spectroscopic analysis. The apparent coordination of oxygens surrounding Hg(II), measured with EXAFS spectroscopy, increased during one flow experiment, suggesting desorption of monodentate-bound Hg(II) while bidentate-bound Hg(II) persisted on the goethite surface. Further sulfidation increased dissolved Hg concentrations by one to two orders of magnitude (0.5 to 10 nM or 30 nM), suggesting that byproducts of bisulfide oxidation and Fe(III) reduction, primarily polysulfide and potentially Fe(II), enhanced the dissolution of ?-HgS(s) and/or desorption of Hg(II). Rapid accumulation of Fe(II) in the solid phase (up to 40 ?mol g-1) coincided with faster elevation of dissolved Hg concentrations. Fe(II) served as a proxy for elemental sulfur [S(0)], as S(0) was the dominant bisulfide oxidation product coupled to Fe(III) reduction, based on sulfur K-edge X-ray absorption near edge structure (XANES) spectroscopy. In one experiment, dissolved Hg concentrations tracked those of all sulfide species [S(-II)]. These results suggest that S(-II) reacted with S(0) to form polysulfide, which then caused the dissolution of ?-HgS(s). A secondary Fe-bearing phase resembling poorly formed green rust was observed in sulfidized solids with scanning electron microscopy, although there was no clear evidence that either surface-bound or mineralized Fe(II) strongly affected Hg speciation. Examination of interrelated processes involving S(-II) and Fe(III) revealed new modes of Hg solubilization previously not considered in Hg reactivity models.

Slowey, Aaron J.; Brown, Gordon E.

2007-02-01

32

Biological Control on Mineral Transformation in Soils ?  

NASA Astrophysics Data System (ADS)

Weathering of primary minerals is commonly linked to biological processes through the production of carbonic and organic acids. Plants can also play a role in weathering by removing soluble constituents and enhancing diffusion gradients within the soil. Here we investigate the synthesis of secondary minerals and the role of plants in removing elements that act as building blocks for these minerals. In order to minimize losses from leaching, we have sampled a chronosequence of soils forming on lava flows on Hawaii Island that receive about 200 mm of rain annually and have never been subjected to high levels of rainfall. The P concentration in the soils drops from almost 3000 mg/kg on a 1.5 ky lava flow to around 1000 mg/kg on a 350 ky lava flow. This loss of P can only be ascribed to P-uptake by plants with subsequent removal through the loss of above ground biomass through fire and/or wind removal. Over the same time frame the amount of plagioclase in the soils drops from around 22% of the <2 mm soil fraction on the youngest lava flow to virtually 0% on the 350 ky flow, suggesting a substantial release of Si. Elevated silicon in arid, basaltic soil environments often leads to formation of smectite, a feature not observed along the chronosequence. In fact, plagioclase is replaced by the kaolin mineral halloysite with allophane as an apparent precursor. Kaolin minerals are associated with moderate to intense leaching environments rather than the mild leaching conditions that influence these soils. We selected an intermediate age soil profile (170 ky lava flow) to conduct an in-depth investigation of the soil mineral composition. We detected a strong dominance of halloysite, the presence of gibbsite, but no smectite. Secondary halloysite formation is preferred over smectite formation when Si activities are relatively low, and the pH is acidic rather than alkaline. Although this mineral assemblage seems to imply formation under a wetter climatic regime, the oxygen isotopic composition of the halloysite suggests formation under soil environmental conditions similar to the present. The Si concentration in grass and tree leaves in the vicinity of the soil contain between 3 and 8% Si. Loss of these leaves to the nearby ocean (either as dried or burned residue) could be responsible for considerable Si removal in a manner similar to the P-removal. The resulting Si-deficient soil-water favors the formation of halloysite over smectite as is demonstrated by construction of mineral stability diagrams using the soil-water data from the soils along the chronosequence.

Ziegler, K.; Hsieh, J. C.; Chadwick, O. A.; Kelly, E. F.

2001-12-01

33

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

34

Mineralization of metsulfuron-methyl in Chinese paddy soils  

Microsoft Academic Search

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 14C mineralized after 84d of incubation at 15°C. The mineralization of MSM was

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

2010-01-01

35

Recycling Ni from Contaminated and Mineralized Soils.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Rare plant species accumulate potentially valuable concentrations of some metals. Alyssum murale readily accumulates over 2% Ni in aboveground dry matter when grown on Ni-mineralized serpentine soils in Oregon, allowing production of “hay” biomass with at least 400 kg Ni ha-1 with low levels of fer...

36

Potential anthropogenic mobilisation of mercury and arsenic from soils on mineralised rocks, Northland, New Zealand.  

PubMed

Eroded roots of hot spring systems in Northland, New Zealand consist of mineralised rocks containing sulfide minerals. Marcasite and cinnabar are the dominant sulfides with subordinate pyrite. Deep weathering and leached soil formation has occurred in a warm temperate to subtropical climate with up to 3 m/year rainfall. Decomposition of the iron sulfides in natural and anthropogenic rock exposures yields acid rock drainage with pH typically between 2 and 4, and locally down to pH 1. Soils and weathered rocks developed on basement greywacke have negligible acid neutralisation capacity. Natural rainforest soils have pH between 4 and 5 on unmineralised greywacke, and pH is as low as 3.5 in soils on mineralised rocks. Roads with aggregate made from mineralised rocks have pH near 3, and quarries from which the rock was extracted can have pH down to 1. Mineralised rocks are enriched in arsenic and mercury, both of which are environmentally available as solid solution impurities in iron sulfides and phosphate minerals. Base metals (Cu, Pb, Zn) are present at low levels in soils, at or below typical basement rock background. Decomposition of the iron sulfides releases the solid solution arsenic and mercury into the acid rock drainage solutions. Phosphate minerals release their impurities only under strongly acid conditions (pH<1). Arsenic and mercury are adsorbed on to iron oxyhydroxides in soils, concentrated in the C horizon, with up to 4000 ppm arsenic and 100 ppm mercury. Waters emanating from acid rock drainage areas have arsenic and mercury below drinking water limits. Leaching experiments and theoretical predictions indicate that both arsenic and mercury are least mobile in acid soils, at pH of c. 3-4. This optimum pH range for fixation of arsenic and mercury on iron oxyhydroxides in soils is similar to natural pH at the field site of this study. However, neutralisation of acid soils developed on mineralised rocks is likely to decrease adsorption and enhance mobility of arsenic and mercury. Hence, development of farmland by clearing forest and adding agricultural lime may mobilise arsenic and mercury from underlying soils on mineralised rocks. In addition, arsenic and mercury release into runoff water will be enhanced where sediment is washed off mineralised road aggregate (pH 3) on to farm land (pH>6). The naturally acid forest soils, or even lower pH of natural acid rock drainage, are the most desirable environmental conditions to restrict dissolution of arsenic and mercury from soils. This approach is only valid where mineralised soils have low base metal concentrations. PMID:15644268

Craw, D

2004-12-15

37

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

2009-11-10

38

The nanophase iron mineral(s) in Mars soil.  

PubMed

A series of surface-modified clays containing nanophase (np) iron oxide/oxyhydroxides of extremely small particle sizes, with total iron contents as high as found in Mars soil, were prepared by iron deposition on the clay surface from ferrous chloride solution. Comprehensive studies of the iron mineralogy in these "Mars-soil analogs" were conducted using chemical extractions, solubility analyses, pH and redox, x ray and electron diffractometry, electron microscopic imaging, specific surface area and particle size determinations, differential thermal analyses, magnetic properties characterization, spectral reflectance, and Viking biology simulation experiments. The clay matrix and the procedure used for synthesis produced nanophase iron oxides containing a certain proportion of divalent iron, which slowly converts to more stable, fully oxidized iron minerals. The clay acted as an effective matrix, both chemically and sterically, preventing the major part of the synthesized iron oxides from ripening, i.e., growing and developing larger crystals. The precipitated iron oxides appear as isodiametric or slightly elongated particles in the size range 1-10 nm, having large specific surface area. The noncrystalline nature of the iron compounds precipitated on the surface of the clay was verified by their complete extractability in oxalate. Lepidocrocite (gamma-FeOOH) was detected by selected area electron diffraction. It is formed from a double iron Fe(II)/Fe(III) hydroxy mineral such as "green rust," or ferrosic hydroxide. Magnetic measurements suggested that lepidocrocite converted to the more stable maghemite (gamma-Fe2O3) by mild heat treatment and then to nanophase hematite (alpha-Fe2O3) by extensive heat treatment. After mild heating, the iron-enriched clay became slightly magnetic, to the extent that it adheres to a hand-held magnet, as was observed with Mars soil. The chemical reactivity of the iron-enriched clays strongly resembles, and offers a plausible mechanism for, the somewhat puzzling observations of the Viking biology experiments. Their unique chemical reactivities are attributed to the combined catalytic effects of the iron oxide/oxyhydroxides and silicate phase surfaces. The reflectance spectrum of the clay-iron preparations in the visible range is generally similar to the reflectance curves of bright regions on Mars. This strengthens the evidence for the predominance of nanophase iron oxides/oxyhydroxides in Mars soil. The mode of formation of these nanophase iron oxides on Mars is still unknown. It is puzzling that despite the long period of time since aqueous weathering took place on Mars, they have not developed from their transitory stage to well-crystallized end-members. The possibility is suggested that these phases represent a continuously on-going, extremely slow weathering process. PMID:11539182

Banin, A; Ben-Shlomo, T; Margulies, L; Blake, D F; Mancinelli, R L; Gehring, A U

1993-11-25

39

Enhancing pyrene mineralization in contaminated soil by the addition of humic acids or composted contaminated soil  

Microsoft Academic Search

The addition of composted PAH-contaminated soil to PAH-contaminated soil spiked with 14C-labeled pyrene resulted in rapid mineralization of pyrene (more than 57% after 21 days compared with 3.4% in unamended soil). The addition of the humic acid fraction of the composted soil also increased the mineralization potential of the soil significantly, but to a lesser extent (37.5% mineralization after 106

A. Haderlein; R. Legros; B. Ramsay

2001-01-01

40

Carbon and nitrogen mineralization in subarctic agricultural and forest soils  

Microsoft Academic Search

C and N mineralization potentials were determined, in a 12-week laboratory incubation study, on soil samples obtained from recently cleared land which had been cropped to barley for 4 years (field soils) and from nearby undisturbed taiga (forest soils). Treatments for the cropped soils were conventional and no-tillage with and without crop residues removed. An average of about 3% of

S. D. Sparrow; V. L. Cochran

1988-01-01

41

Ammonium fixation by soil and pure clay minerals  

Microsoft Academic Search

Fixation of the ammonium ion (NH4 ) by clay minerals is an alternate way of building the nitrogen (N) pool in soil to optimize N crop recovery and minimize losses. Clay minerals (illite, montmorillonite, and vermiculite) and an illitic Portnoeuf soil were used to compare NH4 fixation abilities. Total N determination and X?ray diffraction analysis were performed on each of

Martha Mamo; Robert W. Taylor; James W. Shuford

1993-01-01

42

Hydrogeomorphology influences soil nitrogen and phosphorus mineralization in floodplain wetlands  

USGS Publications Warehouse

Conceptual models of river–floodplain systems and biogeochemical theory predict that floodplain soil nitrogen (N) and phosphorus (P) mineralization should increase with hydrologic connectivity to the river and thus increase with distance downstream (longitudinal dimension) and in lower geomorphic units within the floodplain (lateral dimension). We measured rates of in situ soil net ammonification, nitrification, N, and P mineralization using monthly incubations of modified resin cores for a year in the forested floodplain wetlands of Difficult Run, a fifth order urban Piedmont river in Virginia, USA. Mineralization rates were then related to potentially controlling ecosystem attributes associated with hydrologic connectivity, soil characteristics, and vegetative inputs. Ammonification and P mineralization were greatest in the wet backswamps, nitrification was greatest in the dry levees, and net N mineralization was greatest in the intermediately wet toe-slopes. Nitrification also was greater in the headwater sites than downstream sites, whereas ammonification was greater in downstream sites. Annual net N mineralization increased with spatial gradients of greater ammonium loading to the soil surface associated with flooding, soil organic and nutrient content, and herbaceous nutrient inputs. Annual net P mineralization was associated negatively with soil pH and coarser soil texture, and positively with ammonium and phosphate loading to the soil surface associated with flooding. Within an intensively sampled low elevation flowpath at one site, sediment deposition during individual incubations stimulated mineralization of N and P. However, the amount of N and P mineralized in soil was substantially less than the amount deposited with sedimentation. In summary, greater inputs of nutrients and water and storage of soil nutrients along gradients of river–floodplain hydrologic connectivity increased floodplain soil nutrient mineralization rates.

Noe, Gregory B.; Hupp, Cliff R.; Rybicki, Nancy B.

2013-01-01

43

Quantifying soil water effects on nitrogen mineralization from soil organic matter and from fresh crop residues  

Microsoft Academic Search

A loamy sand was incubated with and without addition of carrot leaves at six different water contents ranging from 6% to 20% (g 100 g-1 dry soil) and N mineralization was monitored during 98 days. We calculated zero- and first-order rates for mineralization in the unamended soil and first-order rates for N mineralization in the residue-amended soil. Although N mineralization

Stefaan De Neve; Georges Hofman

2002-01-01

44

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.

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

1990-01-01

45

Mineral composition in arid soils: A global distribution (Invited)  

NASA Astrophysics Data System (ADS)

Dust storms and subsequent mineral aerosol transport and deposition are mainly driven by meso- and synoptic-scale atmospheric processes. It is therefore essential that dust aerosol process and background atmospheric conditions are observed and modeled spatially and temporally as better as possible. Behavior of dust in its interactions with the environment is to a large extent determined by mineral composition of dust particles. Fractions of various minerals in the aerosol are very much dependent on mineral composition of arid soils, therefore the requirement for high-resolution specification of mineral and physical properties in soil sources holds as well. Dust aerosol is a complex mixture of minerals having high variability of their physical and chemical properties. Current information on geographical distribution of minerals in arid soils is available with unsatisfactorily resolution and this work aims to improve it. In this work we generate a high-resolution global data set of effective mineral contents (GMINER30), as more suitable input for the regional dust/mineral modelling simulations. The mapped minerals considered here are eight minerals (illite, kaolinite, smectite, calcite, quartz, feldspar, hematite and gypsum) distributed over clay and silt populations. GMINER30 could be used as input data in atmospheric dust models to provide emission fluxes for various mineral fractions.

Nickovic, S.; Vukovic, A.; Vujadinovic, M.; Pejanovic, G.; Djurdjevic, V.; Dacic, M.

2010-12-01

46

Adsorption coefficients for TNT on soil and clay minerals  

Microsoft Academic Search

To understand the fate and transport mechanisms of TNT from buried landmines is it essential to determine the adsorption process of TNT on soil and clay minerals. In this research, soil samples from horizons Ap and A from Jobos Series at Isabela, Puerto Rico were studied. The clay fractions were separated from the other soil components by centrifugation. Using the

Rosángela Rivera; Julissa Pabón; Omarie Pérez; Miguel A. Muñoz; Nairmen Mina

2007-01-01

47

Nonlinear Dynamics of Soil Moisture and Mineral Nitrogen  

Microsoft Academic Search

We investigate the behavior of simple dynamical systems describing the temporal dynamics of soil moisture, plant growth, soil organic matter, and mineral nitrogen. The equilibrium condition of the deterministic system are analyzed as a function of the climate, soil, and vegetation parameters, along with the possible bifurcations of the system to regimes of periodic or aperiodic oscillations. Particular attention is

A. Porporato; P. D'Odorico; S. Manzoni; I. Rodriguez-Iturbe

2003-01-01

48

Review of XRD-based quantitative analyses of clay minerals in soils: the suitability of mineral intensity factors  

Microsoft Academic Search

The determination of the types and relative amounts of the minerals present in soil forms an essential component of most soil characterization efforts. This paper reviews protocols for XRD-based quantitative clay mineral analysis in soils, with emphasis on methods using mineral intensity factors in combination with the so-called 100% approach. We summarize methodological differences and characteristic features and give information

Maren Kahle; Markus Kleber; Reinhold Jahn

2002-01-01

49

Influence of soil compaction on carbon and nitrogen mineralization of soil organic matter and crop residues  

Microsoft Academic Search

We studied the influence of soil compaction in a loamy sand soil on C and N mineralization and nitrification of soil organic\\u000a matter and added crop residues. Samples of unamended soil, and soil amended with leek residues, at six bulk densities ranging\\u000a from 1.2 to 1.6?Mg m–3 and 75% field capacity, were incubated. In the unamended soil, bulk density within

S. De Neve; G. Hofman

2000-01-01

50

Soil nitrogen mineralization as affected by water and temperature interactions  

Microsoft Academic Search

The hypothesis that water and temperature interact to influence the rate of soil N mineralization was studied in laboratory incubation experiments with two contrasting soils. Small sample rings (10 mm tall, 50 mm diameter) were packed to uniform bulk density with 1–2 mm aggregates of Plano silt loam and Wacousta silty clay loam. Samples were brought to five different water

Eileen J. Kladivko; Dennis R. Keeney

1987-01-01

51

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

52

Picloram and Aminopyralid Sorption to Soil and Clay Minerals  

Technology Transfer Automated Retrieval System (TEKTRAN)

Aminopyralid sorption data are lacking, and these data are needed to predict off-target transport and plant available herbicide in soil solution. The objective of this research was to determine the sorption of picloram and aminopyralid to five soils and three clay minerals and determine if the pote...

53

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

54

Sorption of tebuconazole onto selected soil minerals and humic acids  

Microsoft Academic Search

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

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

2012-01-01

55

ANALYSIS OF MANURE AND SOIL NITROGEN MINERALIZATION DURING INCUBATION  

Technology Transfer Automated Retrieval System (TEKTRAN)

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 afte...

56

Stability of Soil Carbon Fractions - Aggregation Versus Mineral Association  

Microsoft Academic Search

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

C. W. Mueller; I. Koegel-Knabner

2007-01-01

57

Soil mineral surfaces of paddy soils are accessible for organic carbon accumulation after decalcification  

NASA Astrophysics Data System (ADS)

We studied organic carbon (OC) accumulation due to organo-mineral associations during soil development on calcareous parent material. Two chronosequences in Zhejiang Province, PR China, were investigated; one under paddy cultivation with a maximum soil age of 2000 years, and the other under upland crops where the oldest soil was 700 years old. Bulk soils and soil fractions of the uppermost A horizons were analyzed for OC concentrations and radio carbon contents. Total pedogenic iron (Fed) concentration was determined by dithionite extraction and the proportion of oxalate extractable iron (Feox) was extracted by using the method of Schwertmann (1964). The specific surface area (SSA) of soil minerals was measured by the BET-N2 method (Brunauer et al., 1938) under four conditions: untreated, after organic matter removal, after iron removal and after removal of both. Within 700/2000 years of pedogenesis, we observed no change in clay mineral composition and no additional formation of the SSA of soil minerals. But the soils differed in the degree of decalcification, OC accumulation and in the formation of iron. Paddy soil management led to an enhanced decalcification and larger OC accumulation. Management-induced redox cycles caused larger proportions of Feox in paddy soils. Their large SSA, added to the surface area of clay minerals, provided additional options for OC covering. Unexpectedly, there was no evidence of formation of secondary minerals during soil development, which could provide new surfaces for OC accumulation. However, the study revealed higher OC coverings of mineral surfaces after decalcification in paddy soils. As carbonate and Ca2+ ions seemed to interconnect clay minerals, making their surface accessible to OC, the faster dissolution of carbonate and leaching of Ca2+ ions in paddy soils made additional clay mineral surfaces available to OC. In contrast, the surface area of minerals in non-paddy soils, in which decalcification was much lower, seemed to be partly inaccessible for OC covering due to strong microaggregation by cementation with carbonate and Ca2+-bridging. The smaller accumulation of mineral-associated SOM in non-paddy soils was additionally confirmed by the retarded replacement of the inherited carbon. The accelerated decalcification of paddy soils led to enhanced accessibility of mineral surfaces for OC covering, which intensified OC accumulation from the early stages of soil formation onward. References Brunauer, S., Emmett, P.H., Teller, E., (1938). Adsorption of gases in multimolecular layers. J. Am. Chem. Soc. 60 (2), 309-319. Schwertmann, U., 1964. Differenzierung der Eisenoxide des Bodens durch Extraktion mit Ammoniumoxalat-Lösung. Zeitschrift für Pflanzenernährung, Düngung, Bodenkunde 105 (3), 194-202.

Wissing, Livia

2013-04-01

58

Effects of acidity on mineralization: pH-dependence of organic matter mineralization in weakly acidic soils  

Microsoft Academic Search

The literature is ambiguous regarding the influence of acidity on mineralization of soil organic matter. Although mineralization is often regarded as being relatively insensitive to acidity, reports of agronomically-significant increases in N mineralization after liming of acid soils are common. We analyzed 61 soils (pH 5.1–7.9), representing all agro-ecological zones of Saskatchewan, Canada, to determine the pH-dependence of N mineralization.

Denis Curtin; C. A. Campbell; Abdul Jalil

1998-01-01

59

Using soil temperature and moisture to predict forest soil nitrogen mineralization  

Microsoft Academic Search

Due to the importance of N in forest productivity ecosystem and nutrient cycling research often includes measurement of soil N transformation rates as indices of potential availability and ecosystem losses of N. We examined the feasibility of using soil temperature and moisture content to predict soil N mineralization rates (Nmin) at the Coweeta Hydrologic Laboratory in the southern Appalachians. We

Jennifer D. Knoepp; Wayne T. Swank

2002-01-01

60

Bacterial diversity in three different Antarctic Cold Desert mineral soils.  

PubMed

A bacterial phylogenetic survey of three environmentally distinct Antarctic Dry Valley soil biotopes showed a high proportion of so-called "uncultured" phylotypes, with a relatively low diversity of identifiable phylotypes. Cyanobacterial phylotypic signals were restricted to the high-altitude sample, whereas many of the identifiable phylotypes, such as the members of the Actinobacteria, were found at all sample sites. Although the presence of Cyanobacteria and Actinobacteria is consistent with previous culture-dependent studies of microbial diversity in Antarctic Dry Valley mineral soils, many phylotypes identified by 16S rDNA analysis were of groups that have not hitherto been cultured from Antarctic soils. The general belief that such "extreme" environments harbor a relatively low species diversity was supported by the calculation of diversity indices. The detection of a substantial number of uncultured bacterial phylotypes showing low BLAST identities (< 95%) suggests that Antarctic Dry Valley mineral soils harbor a pool of novel psychrotrophic taxa. PMID:16596438

Smith, Jacques J; Tow, Lemese Ah; Stafford, William; Cary, Craig; Cowan, Donald A

2006-04-05

61

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

62

Stability of ATP in Antarctic mineral soils  

Microsoft Academic Search

The stability of exogenous ATP in Antarctic Ross desert soils has been assessed using bioluminescence monitoring of ATP-supplemented\\u000a samples. Under typical east Antarctic dry valley summer conditions (?3 to +15°C), exogenous ATP was degraded with a half-life\\u000a of between 0.5 and 30 h. The rate of degradation was affected, in order of significance, by soil biomass levels, temperature\\u000a and water content.

Don A. Cowan; Ana Casanueva

2007-01-01

63

Mineral Control of Soil Carbon Dynamics in Forest Soils: A Lithosequence Under Ponderosa Pine  

NASA Astrophysics Data System (ADS)

The role of soil organic carbon in regulating atmospheric CO2 concentration has spurred interest in both quantifying existing soil C stocks and modeling the behavior of soil C under climate change scenarios. Soil parent material exerts direct control over soil organic carbon content through its influence on soil pH and mineral composition. Soil acidity and mineral composition also influence soil microbial community composition and activity, thereby controlling soil respiration rates and microbial biomass size. We sampled a lithosequence of four parent materials (rhyolite, granite, basalt, limestone) under Pinus ponderosa to examine the effects of soil mineralogy and acidity on soil organic carbon content and soil microbial community. Three soil profiles were examined on each parent material and analyzed by X-ray diffraction, pH, selective dissolution, C and N content, and 13C signature. Soils from each of the four parent materials were incubated for 40 days, and microbial communities were compared on the basis of community composition (as determined through T-RFLP analysis), specific metabolic activity, biomass, ?13C of respired CO2, and cumulative amount of C mineralized over the course of the incubation. Soil C content varied significantly among soils of different parent material, and was strongly and positively associated with the abundance of Al-humus complexes r2 = 0.71; P < 0.0001, Fe-humus complexes r2 = 0.74; P = 0.0003, and crystalline Fe-oxide content r2 = 0.63; P = 0.0023. Microbial community composition varied significantly among soils and showed strong associations with soil pH 1:1 in KCl; r2 = 0.87; P < 0.0001, concentration of exchangeable Al r2 = 0.81; P < 0.0001, amorphous Fe oxide content r2 = 0.59; P < 0.004, and Al-humus content r2 = 0.35; P < 0.04. Mineralization rates, biomass and ?13C of respired CO2 differed among parent materials, and also varied with incubation time as substrate quality and N availability changed. The results demonstrate that within a specific ecosystem type, soil parent material exerts significant control over the lability and bioavailability of soil C and soil microbial community composition. We suggest that soil parent material and mineralogy are critical parameters for predicting soil C dynamics and recalcitrance of soil C stocks.

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

2008-12-01

64

Bromide Adsorption by Reference Minerals and Soils  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bromide, Br-, adsorption behavior was investigated on amorphous Al and Fe oxide, montmorillonite, kaolinite, and temperate and tropical soils. Bromide adsorption decreased with increasing solution pH with minimal adsorption occurring above pH 7. Bromide adsorption was higher for amorphous oxides t...

65

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

66

Temperature and soil moisture interactively affected soil net N mineralization in temperate grassland in Northern China  

Microsoft Academic Search

Intact soil cores from three adjacent sites (Site A: grazed, Site B: fenced for 4 years, and Site C: fenced for 24 years) were incubated in the laboratory to examine effects of temperature, soil moisture, and their interactions on net nitrification and N mineralization rates in the Inner Mongolia grassland of Northern China. Incubation temperature significantly influenced net nitrification and

Changhui Wang; Shiqiang Wan; Xuerong Xing; Lei Zhang; Xingguo Han

2006-01-01

67

Interactions between carbon and nitrogen mineralization and soil organic matter chemistry in Arctic tundra soils  

Microsoft Academic Search

We used long term long-term lab incubations and chemical fractionation to characterize the mineralization dynamics of organic soils from tussock, shrub, and wet meadow tundra communities, to determine the relationship between soil organic matter (SOM) decomposition and chemistry, and to quantify the relative proportions of carbon (C) and nitrogen (N) in tundra SOM that are biologically available for decomposition. Despite

M. Weintraub; J. P. Schimel

2002-01-01

68

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

2012-07-01

69

Interactions between Carbon and Nitrogen Mineralization and Soil Organic Matter Chemistry in Arctic Tundra Soils  

Microsoft Academic Search

We used long-term laboratory incubations and chemical fractionation to characterize the mineralization dynamics of organic\\u000a soils from tussock, shrub, and wet meadow tundra communities, to determine the relationship between soil organic matter (SOM)\\u000a decomposition and chemistry, and to quantify the relative proportions of carbon (C) and nitrogen (N) in tundra SOM that are\\u000a biologically available for decomposition. In all soils

Michael N. Weintraub; Joshua P. Schimel

2003-01-01

70

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

2012-06-07

71

Mineralization of organic matter and the carbon sequestration capacity of zonal soils  

Microsoft Academic Search

The susceptibility of soil organic matter (SOM) to mineralization decreases in the following sequence of zonal soils: tundra\\u000a soil > soddy-podzolic soil > gray forest soil > chestnut soil > dark chestnut soil > chernozem. The content of potentially\\u000a mineralizable organic matter in the plowed soils is 1.9–3.9 times lower than that in their virgin analogues. The highest soil\\u000a carbon

V. M. Semenov; L. A. Ivannikova; T. V. Kuznetsova; N. A. Semenova; A. S. Tulina

2008-01-01

72

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

73

Polymer Mineralization in Soils: Effects of Cold Storage on Microbial Populations and Biodegradation Potential  

Microsoft Academic Search

Soil retrieval, processing and storage procedures can have a profound effect on soil microorganisms. In particular, changes in soil microbial populations may adversely affect the biological activity of a soil and drastically alter the soil's potential to mineralize added substrates. The effects of cold storage on the biodegradation of a series of test polymers was investigated using two soils—a synthetic

Jason S. Lee; Belinda L. Daniels; David T. Eberiel; Richard E. Farrell

2000-01-01

74

Development of a mineralogical matrix at the adsorption of polyelectrolytes on soil minerals and soils  

NASA Astrophysics Data System (ADS)

The formation of the adsorption layers of polyelectrolytes (PEs) with the development of a mineralogical matrix on the surface of soil minerals and soils (kaolinite, montmorillonite, quartz sand, gray forest soil, and a chernozem) were established on the basis of direct measurements and IR spectroscopy. The differences in the adsorption kinetics of polyacrylamide (PAM) and polyacrylic acid (PAA) were revealed depending on the mineral nature, which were confirmed by the calculated values of the effective adsorption constants. It was found that the limit values of the PAM and PAA adsorption derived from experimental measurements for all the minerals were significantly higher than the values calculated for the formation of a monomolecular layer, which indicated adsorption on the surface of not only separate macromolecules but also secondary PE structures such as packets or fibrils. The IR spectroscopy studies confirmed the differences in the adsorption mechanism of PEs on soil minerals (from physical adsorption to chemisorption with the formation of surface compounds due to polar groups of PEs and surface groups of mineral particles). As a result, a cluster-matrix structure controlling the physicochemical properties of the modified surface was developed on the surface of natural aluminosilicates and soils.

Kurochkina, G. N.; Pinskii, D. L.

2012-11-01

75

Kinetic study for adsorption humic acid on soil minerals.  

PubMed

Kinetics of humic acid (HA) adsorption onto soil minerals (kaolinite and hematite) has been investigated under various conditions. The influence of ionic strength, pH, and solution cations on the rate of adsorption has been studied. The rate and the amount of adsorbed humic acid onto soil minerals increased with increasing ionic strength, decreasing pH, and in the presence of Ca(2+) as background electrolyte. The adsorption equilibrium data showed that adsorption behavior of humic acid could be described more reasonably by Freundlich adsorption isotherm than Langmiur adsorption isotherm. Pseudo first order and pseudo second order kinetic models were used to evaluate the kinetic data and the rate constants. The results explained that humic acid adsorption on hematite and kaolinite was more conforming with pseudo second order kinetics. PMID:23075223

Shaker, Ali M; Komy, Zanaty R; Heggy, Said E M; El-Sayed, Mohamed E A

2012-11-05

76

Mineral Hosts for Uranium in Oak Ridge Soils  

NASA Astrophysics Data System (ADS)

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 and incorporation. The Department of Energy's (DOE) Field Research Center (FRC) in Oak Ridge, TN provides an opportunity to investigate such questions in natural samples contaminated with uranium-bearing wastes over decades long leakage from unlined storage ponds. Uranium- contaminated soils from the FRC have been investigated using electron microprobe analysis and transmission electron microscopy (TEM). Three categories of mineral hosts for uranium have been identified: 1) iron oxides; 2) mixed manganese-iron oxides; and 3) uranium phosphates. Uranium bearing iron oxides include ferrihydrite and goethite, and occur within chips of weathered shale, as well as on surface grains and in loose soil material. Their uranium concentrations are on the order of tenths of a weight percent. Mixed Mn-Fe oxides are found in loose soils and have similar uranium concentrations. Uranium phosphates occur in pore spaces in shale chips and their precipitation may result from local saturation of pore waters. These have a U:P molar ratio of 1:1, consistent with minerals of the autunite and meta-autunite groups. In all three hosts, uranium is associated with phosphorus. The ubiquitous U-P association highlights the influence of phosphate on the environmental fate of uranium. Although uptake by iron oxides is clearly important, the precipitation of uranium phosphates may also account for a significant portion of the uranium budget.

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

2006-05-01

77

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

NASA Astrophysics Data System (ADS)

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 zone were selected, and soils were sampled in three seasons (summer, autumn, and winter). A simple first-order exponential equation was used to calculate constant Q10 values for the C and N mineralization over the investigated temperature range (0-30°C). The Q10 values of the C mineralization (average 2.0) for all study sites were significantly higher than for the N mineralization (average 1.7). The Q10 values of both activities were significantly negatively related to a soil organic matter quality index calculated by the ratios of respiration to the organic soil carbon and mineralized N to the total soil nitrogen. The chemical soil properties or microbial biomass did not affect the Q10 values of C and N mineralization. Moreover, the Q10 values showed no distinct pattern according to sampling date, indicating that the substrate quality and other factors are more important. Using a flexible model function, the analysis of relative temperature sensitivity (RTS) showed that the temperature sensitivity of activities increased with decreasing temperature. The C and N mineralization and potential amino-peptidase activities (tyrosine and leucine) showed an almost constant temperature dependence over 0-30°C. In contrast, ß-glucosidase, ß-xylosidase, and N-acetyl-ß-glucosaminidase showed a distinctive increase in temperature sensitivity with decreasing temperature. Low temperature at the winter sampling date caused a greater increase in the RTS of all microbial activities than for the autumn and summer sampling dates. Our results indicate (1) a disproportion of the RTS for potential enzyme activities of the C and N cycle and (2) a disproportion of the RTS for easily degradable C compounds (ß-glucose, ß-xylose) compared with the C mineralization of soil organic matter. Thus temperature may play an important role in regulating the decay of different soil organic matter fractions due to differences in the relative temperature sensitivities of enzyme activities.

Koch, Oliver; Tscherko, Dagmar; Kandeler, Ellen

2007-12-01

78

Carbon and N mineralization as affected by soil cultivation and crop residue in a calcareous wetland ecosystem in Central Iran  

Microsoft Academic Search

Mineralization of soil organic matter plays a key role in supplying nutrient elements essential to plant growth. Soil cultivation and crop residue affect C mineralization and nutrient availability in wetland ecosystems. This study evaluated the combined impacts of soil cultivation and crop residue on C and N mineralization in a calcareous wetland soil (Luvic Calcisol) in Central Iran. Soil samples

Fayez Raiesi

2006-01-01

79

Changes in Soil Minerology Reduce Phosphorus Mobility During Anoxic Soil Conditions  

NASA Astrophysics Data System (ADS)

Phosphorus (P) transfer from the landscape to receiving waters is an important environmental concern because these diffuse losses may cause widespread water quality impairments which can accelerate freshwater eutrophication. Phosphorus (P) mobilization from soil to surface and subsurface flow paths is controlled by numerous factors, and thus it can vary greatly with time and landscape scale. To determine whether P mobilization during soil saturation in the landscape was caused or controlled by complexation, iron reduction or ligand exchange, experiments were carried out to better characterize the interrelationships of varying P sources with dissolved organic carbon (DOC) and soil anoxic conditions. The soil incubation experiments consisted of treatments with distilled water, 5 mM acetic acid (HAc), 0.05% humic acid (HA) and glucose (40 mM) at 26 o C under anaerobic conditions to isolate effects of the various P exchange processes. The experimental results suggest that during soil saturation, the loosely bound P, which is primarily associated with iron oxyhydroxides, was mobilized by both reduction and complexation processes. Good correlations were observed between ferrous iron (Fe+2) and DOC, and between total dissolved phosphorus (TDP) and DOC, facilitating P desorption to the soil water. The anaerobic soil conditions with different P sources also indicated that mineralization facilitated P mobility, mainly due to chelation (humics and metabolites) and as a result of the bio-reduction of iron when fresh litter and grass were present. The organic P sources which are rich in carbohydrate and cellulose and that undergo fermentation due to the action of lactate forming organisms also caused a release of P. The easily metabolizable DOC sources lead to intensive bio-reduction of soil with the release of Fe, however this did not necessarily appear to cause more TDP in the soil solution. The varying P additions in soils with water, HAc and glucose (40mm) before and after soil incubation showed higher P sorption than aerobic soil due to reduced iron (Fe+2) - P mineral formation. Some of the readily available P in the soil solution tended to co-precipitate quickly with Fe, Al, Ca, and Mn, but it also resulted in the formation of earthy masses of vivianite [Fe2+3(PO4)2 . 8 H20], thus almost completely immobilizing P. These findings suggest that where conditions in the landscape are saturated, but remain stagnant for extended time periods, P additions may not necessarily enhance leaching once hydrological transport resumes. The temporal nature of P mobilization processes combined with rapid (i.e., preferential flow) hydrological transport appears to have a more important role in controlling P transport through the landscape.

Giri, S. K.; Geohring, L. D.; Richards, B. K.; Walter, M.; Steenhuis, T. S.

2008-05-01

80

Effects of mineral and biofertilizers on barley growth on compacted soil  

Microsoft Academic Search

Biofertilizers are an alternative to mineral fertilizers for increasing soil productivity and plant growth in sustainable agriculture. The objective of this study was to evaluate possible effects of three mineral fertilizers and four plant growth promoting rhizobacteria (PGPR) strains as biofertilizer on soil properties and seedling growth of barley (Hordeum vulgare) at three different soil bulk densities, and in three

Mustafa Y. Canbolat; Kenan Barik; Ramazan Çakmakçi; Fikrettin ?ahin

2006-01-01

81

EVALUATION OF AN IN SITU NET SOIL NITROGEN MINERALIZATION METHOD IN DRYLAND AGROECOSYSTEMS.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Direct quantitative measurement of soil net N mineralization in agricultural soils under field conditions has not been widely used. A potential method of in situ net N mineralization was investigated in the fallow phase of 3-yr no-till crop rotation at two sites. Undisturbed soil cores (5 by 15 cm) ...

82

CHARACTERIZATION OF HUMIC ACID FRACTIONS IMPROVES ESTIMATES OF NITROGEN MINERALIZATION KINETICS FOR LOWLAND RICE SOILS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Total soil carbon (C) and nitrogen (N) are poor predictors of N mineralization in tropical paddy rice soils. To better understand mineralization dynamics, two distinct humic acid (HA) fractions were chemically extracted from lowland rice soils of Vietnam and the Philippines. The influence of the p...

83

Mineral materials as feasible amendments to stabilize heavy metals in polluted urban soils  

Microsoft Academic Search

Four minerals, agricultural limestone (AL), rock phosphate (RP), palygorskite (PG), and calcium magnesium phosphate (CMP), were evaluated by means of chemical fractions of heavy metals in soils and concentrations of heavy metals in leachates from columns to determine their ability to stabilize heavy metals in polluted urban soils. Two urban soils (calcareous soil and acidic soil) polluted with cadmium, copper,

Mingkui Zhang; Jincheng Pu

2011-01-01

84

Solubilization of iron-containing minerals by soil microorganisms.  

PubMed

Eighty-eight strains of microorganisms were isolated from soils collected in northern and southern Chile, and 10 fungi which showed the highest solubilizing action upon the iron in granodiorite were then selected. These fungi were incubated with the following iron-containing minerals: augite, hornblende, biotite, magnetite, hematite, and the igneous rock granodiorite. The solubility of iron in these minerals depended on their nature, crystalline structure, the concentration of metabolic products, or all three. Complex formation could be the mechanism involved, as a strong cation-exchange resin was not able to extract Fe from culture solutions. This conclusion is also confirmed by the R(F) values obtained by thin-layer chromatography of iron-containing culture solutions. PMID:5167095

Arrieta, L; Grez, R

1971-10-01

85

Solubilization of Iron-Containing Minerals by Soil Microorganisms  

PubMed Central

Eighty-eight strains of microorganisms were isolated from soils collected in northern and southern Chile, and 10 fungi which showed the highest solubilizing action upon the iron in granodiorite were then selected. These fungi were incubated with the following iron-containing minerals: augite, hornblende, biotite, magnetite, hematite, and the igneous rock granodiorite. The solubility of iron in these minerals depended on their nature, crystalline structure, the concentration of metabolic products, or all three. Complex formation could be the mechanism involved, as a strong cation-exchange resin was not able to extract Fe from culture solutions. This conclusion is also confirmed by the RF values obtained by thin-layer chromatography of iron-containing culture solutions.

Arrieta, Luis; Grez, Renato

1971-01-01

86

The origin of lead in the organic horizon of tundra soils: atmospheric deposition, plant translocation from the mineral soil or soil mineral mixing?  

PubMed

Knowledge of the anthropogenic contribution to lead (Pb) concentrations in surface soils in high latitude ecosystems is central to our understanding of the extent of atmospheric Pb contamination. In this study, we reconstructed fallout of Pb at a remote sub-arctic region by using two ombrotrophic peat cores and assessed the extent to which this airborne Pb is able to explain the isotopic composition ((206)Pb/(207)Pb ratio) in the O-horizon of tundra soils. In the peat cores, long-range atmospheric fallout appeared to be the main source of Pb as indicated by temporal trends that followed the known European pollution history, i.e. accelerated fallout at the onset of industrialization and peak fallout around the 1960s-70s. The Pb isotopic composition of the O-horizon of podzolic tundra soil ((206)Pb/(207)Pb=1.170 ± 0.002; mean ± SD) overlapped with that of the peat ((206)Pb/(207)Pb=1.16 ± 0.01) representing a proxy for atmospheric aerosols, but was clearly different from that of the parent soil material ((206)Pb/(207)Pb=1.22-1.30). This finding indicated that long-range fallout of atmospheric Pb is the main driver of Pb accumulation in podzolic tundra soil. In O-horizons of tundra soil weakly affected by cryoturbation (cryosols) however, the input of Pb from the underlying mineral soil increased as indicated by (206)Pb/(207)Pb ratios of up to 1.20, a value closer to that of local soil minerals. Nevertheless, atmospheric Pb appeared to be the dominant source in this soil compartment. We conclude that Pb concentrations in the O-horizon of studied tundra soils - despite being much lower than in boreal soils and representative for one of the least exposed sites to atmospheric Pb contaminants in Europe - are mainly controlled by atmospheric inputs from distant anthropogenic sources. PMID:21820157

Klaminder, Jonatan; Farmer, John G; MacKenzie, Angus B

2011-08-04

87

Does plant uptake or low soil mineral-N production limit mineral-N losses to surface waters and groundwater from soils under grass in summer?  

PubMed

Summer minima and autumn/winter maxima in nitrate concentrations in rivers are reputedly due to high plant uptake of nitrate from soils in summer. A novel alternative hypothesis is tested here for soils under grass. By summer, residual readily mineralizable plant litter from the previous autumn/winter is negligible and fresh litter input low. Consequently little mineral-N is produced in the soil. Water-soluble and KCl-extractable mineral N in fresh soils and soils incubated outdoors for 7 days have been monitored over 12 months for soil transects at two permanent grassland sites near York, UK, using 6 replicates throughout. Vegetation-free soil is shown to produce very limited mineral-N in summer, despite the warm, moist conditions. Litter accumulates in autumn/winter and initially its high C:N ratio favours N accumulation in the soil. It is also shown that mineral-N generated monthly in situ in soil substantially exceeds the monthly mineral-N inputs via wet deposition at the sites. PMID:23562960

Bhatti, Ambreen; McClean, Colin J; Cresser, Malcolm S

2013-04-09

88

In situ mineralization of nitorgen and phosphorus of arctic soils after perturbations simulating climate change  

Microsoft Academic Search

Seasonal net nitrogen (N) and phosphorus (P) mineralization was investigated at Abisko, Swedish Lapland in soils of a subarctic heath and in soils of a colder (by about 4° C), high altitude fellfield by (a) using in situ soil incubation in soils which had been shaded or subjected to two levels of increased temperature, combined with (b) reciprocal transplantation of

Sven Jonasson; Mats Havström; Michael Jensen; Terry V. Callaghan

1993-01-01

89

COMPARISON OF NUTRIENT SOURCES OF MINERAL SOIL NUTRITION IN FLORIDA SUGARCANE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Improving soil organic matter and soil fertility are important factors in the sustainability of sugarcane production on mineral soils. A trial was established in 2004 on a sandy Spodosol in Florida to compare the effect of organic and inorganic nutrient sources on soil fertility and sugarcane produ...

90

Positive and negative carbon mineralization priming effects among a variety of biochar-amended soils  

Microsoft Academic Search

Pyrogenic carbon (biochar) amendment is increasingly discussed as a method to increase soil fertility while sequestering atmospheric carbon (C). However, both increased and decreased C mineralization has been observed following biochar additions to soils. In an effort to better understand the interaction of pyrogenic C and soil organic matter (OM), a range of Florida soils were incubated with a range

Andrew R. Zimmerman; Bin Gao; Mi-Youn Ahn

2011-01-01

91

Soil organic carbon quality in forested mineral wetlands at different mean annual temperature  

Microsoft Academic Search

Forested mineral soil wetlands (FMSW) store large stocks of soil organic carbon (SOC), but little is known on: (i) whether the quality of SOC stored in these soils (proportion of active versus more resistant SOC compounds) differs from SOC in upland soils; (ii) how the quality of SOC in FMSW varies with mean annual temperature (MAT); and (iii) whether SOC

Cinzia Fissore; Christian P. Giardina; Randall K. Kolka; Carl C. Trettin

2009-01-01

92

Soil Phosphorus Supply Under Different Soil Redox Conditions: Implications of Mineral Dissolution and Soil Organic Matter Turnover  

NASA Astrophysics Data System (ADS)

In humid tropical environments, phosphorus (P) limitation to net primary productivity (NPP) has been associated with the formation of secondary phosphate minerals with aluminum (Al) and iron (Fe) oxides. Under low oxygen (O2) availability, iron-reducing bacteria use Fe oxides and oxyhydroxides as the terminal electron acceptors for anaerobic respiration and phosphate ions that are associated with the mineral surfaces are released when the surface is reduced. Surface soils of humid tropical forests are often characterized by low and fluctuating O2 availability. In this study we examined the effect of soil O2 depletion on Fe-P relationships in humid tropical forest soils from Puerto Rico. Surface mineral soils (0-10 cm depth) were incubated under oxic (ambient air), suboxic (94% N2- 6% O2) and anoxic (100% N2) conditions for 39 days and analyzed periodically for P fractions and CO2 efflux. The moderately labile inorganic P fraction (NaOH-Pi ) was the most sensitive to changes in soil redox conditions showing a rapid increase over the first 2 days of incubation. Under suboxic and oxic conditions, NAOH-Pi increased after 25 days of incubation, and was correlated with soil CO2 efflux suggesting that mineralization of organic matter led to increased labile P in these samples. Under anoxic conditions HCl-Pi was correlated with the most labile P pool (water available Pi) suggesting that soil reduction causes a rapid pulse of P from the geochemical pool. This short term release of P is likely to be important in maintaining the high NPP characteristic of humid tropical forests.

Chacon, N.

2003-12-01

93

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

SciTech Connect

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 mineralization activity was described well by first-order kinetics, whereas mineralization in long-term incubations was described better by fractional power kinetics. The mineralization activity was much lower in the late phase presumably due to a decline in the bioavailability of DEHP caused by diffusion-limited desorption. The initial DEHP mineralization rate in sludge-amended soil varied between 3.7 and 20.3 ng of DEHP (g dw)[sup [minus]1]d[sup [minus]1] depending on incubation conditions. Aerobic DEHP mineralization was 4--5 times faster than anaerobic mineralization, DEHP mineralization in sludge-amended soil was much more temperature sensitive than was DEHP mineralization in soil without sludge. Indigenous microorganisms in the sewage sludge appeared to dominate DEHP degradation in sludge-amended soil. It was estimated that > 41% of the DEHP in sludge-amended soil will have escaped mineralization after 1 year. In the absence of oxygen, > 68% of the DEHP will not be mineralized within 1 year. Collectively, the data suggest that a significant fraction of the DEHP in sludge-amended soils may escape mineralization under in situ conditions.

Madsen, P.L.; Thyme, J.B.; Henriksen, K.; Moeldrup, P.; Roslev, P. (Aalborg Univ. (Denmark). Environmental Engineering Lab.)

1999-08-01

94

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...

95

LONG-TERM URANIUM MIGRATION IN AGRICULTURAL FIELD SOILS FOLLOWING MINERAL P FERTILIZATION  

Technology Transfer Automated Retrieval System (TEKTRAN)

To preserve soil fertility, organic and mineral fertilizers are often applied to agricultural fields. Mineral fertilizers such as phosphates and super phosphates contain a certain amount of long-lived alpha activity due to 238-U, 230-Th, amongst others. The fate of U in soil systems is quite complex...

96

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

97

Mineral elements in root of wild Saposhnikovia divaricata and its rhizosphere soil.  

PubMed

Mineral elements are important components of medicinal herbs, and their concentrations are affected by many factors. In this study, Ca, Mg, Na, K, Fe, Mn, Cu, and Zn concentrations in wild Saposhnikovia divaricata and its rhizosphere soil collected from seven locations at two different times in China were measured, and influences of rhizosphere soil on those minerals in plant were evaluated. The results showed that mean concentrations of eight minerals in plant samples decreased in the order: Ca > Mg > Na > K > Fe > Zn > Mn > Cu, and those in the soil samples followed the following order: Na > Fe > Ca > K > Mg > Mn > Zn > Cu. Mean concentrations of Ca, Na, Mg, and K in plants were higher than those in soils, while higher mean concentrations of the other four minerals were found in soils. It was found that there was a positive correlation of Mg, Na, and Cu concentrations in the plant with those in the soil respectively, but a negative correlation of Mn concentration in plant with that in the soil. Except Ca, K, and Mn, the other five minerals in plant were all directly affected by one or more chemical compositions of soil. The results also indicate that pH value and concentrations of total nitrogen, Mg, Mn, and Cu in soil had significant correlations with multimineral elements in plant. In a word, mineral elements uptake of S. divaricata can be changed by adjusting the soil fertility levels to meet the need of appropriate quality control of S. divaricata. PMID:23686562

Sun, Jing-Bo; Gao, Yu-Gang; Zang, Pu; Yang, He; Zhang, Lian-Xue

2013-05-21

98

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.

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

1991-01-01

99

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

2011-10-20

100

Interactions of aqueous U(VI) with soil minerals in slightly alkaline natural systems  

Microsoft Academic Search

Uranium (U) is a common contaminant at numerous surface and subsurface sites in proximity to areas involved with weapons manufacturing\\u000a and atomic energy related activities. This paper covers some important aspects of the aqueous hexavalent uranium [U(VI)] interactions\\u000a with soil minerals that are present in contaminated soils and sediments. The retention of U via interactions with soil minerals\\u000a has significant

Nikolla P. Qafoku; Jonathan P. Icenhower

2008-01-01

101

Hexadecane mineralization activity in ornithogenic soil from Seabee Hook, Cape Hallett, Antarctica  

Microsoft Academic Search

Ornithogenic soils that form in penguin rookeries contain high levels of organic carbon and nitrogen. On Seabee Hook, Cape\\u000a Hallett, Antartica, ornithogenic soil was contaminated with hydrocarbons following establishment of a scientific research\\u000a station. In these soils hydrocarbon biodegradation could be supported by available soil nitrogen. Hexadecane mineralization\\u000a activity was detected in vitro in ornithogenic soil when incubated at 5

Jackie Aislabie; Janine Ryburn; Ajit Sarmah

2008-01-01

102

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

103

[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

104

The effects of abiotic and biotic environmental components on the microbial mineralization of selected xenobiotic compounds in soils  

SciTech Connect

This research investigated the effects of environmental components on the microbial mineralization of xenobiotic compounds in soils. The soils' chemical and physical characteristics, microbial community structure, organic and inorganic components, and other associated biota (plants) were examined for their effects on the biodegradation process. The biodegradation of {sup 14}C foreign, synthetic ({double bond} xenobiotic) compounds was measured by quantifying {sup 14} CO{sub 2} production over time. Mineralization kinetics were estimated by first-order and 3/2 order mineralization models. The compounds displayed different mineralization kinetics in the different soils, which were due to nature of the xenobiotic chemical and to abiotic and biotic soil characteristics. Specific soil components (montmorillonite, humic acids and fulvic acids) inhibited mineralization. Other soil components (sand, illite, kaolinite) had less effect on the biodegradation process. Modified soil microbial communities mineralized the compounds differently. Bacteria-enhanced soils metabolized the compounds to greater extents than the fungi-enhanced soils, which both mineralized the compounds more than actinomycete-enhanced soils. However, the rates of mineralization were only significantly different between the bacteria-enhanced soils and the actinomycete-enhanced soil. Plants significantly increased soil microbial biomass and activity, and stimulated the rate of microbial mineralization of xenobiotic compounds. However, they had no effect on the total amounts of mineralization. In summary, these diverse abiotic and biotic environmental components exerted tremendous influences on the microbial turnover of xenobiotic compounds in soils. Therefore, these components should be considered when modeling the fate of xenobiotic chemicals in the environment.

Knaebel, D.B.

1990-01-01

105

A simple technique for determining mineralization of carbon during incubation of soils treated with organic materials  

Microsoft Academic Search

Summary A simple technique is described for determining the rate of mineralization of carbon (carbon dioxide release) during incubation of soils treated with organic materials. The moistened mixture of soil and organic material is contained in a closed test tube and a small vial containing barium peroxide and water rests on the soil. This mixture absorbs carbon dioxide and releases

A. H. Cornfield

1961-01-01

106

Indigenous and enhanced mineralization of pyrene, benzo(a)pyrene, and carbazole in soils  

SciTech Connect

The authors 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 {sup 14}C-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 (<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 they isolated were identified as a Mycobacterium sp. and Xanthamonas sp., respectively.

Grosser, R.J.; Warshawsky, D.; Vestal, J.R. (Univ. of Cincinnati, OH (United States))

1991-12-01

107

Global distribution of minerals in arid soils as lower boundary condition in dust models  

NASA Astrophysics Data System (ADS)

Mineral dust eroded from arid soils affects the radiation budget of the Earth system, modifies ocean bioproductivity and influences human health. Dust aerosol is a complex mixture of minerals. Dust mineral composition has several potentially important impacts to environment and society. Iron and phosphorus embedded in mineral aerosol are essential for the primary marine productivity when dust deposits over the open ocean. Dust also acts as efficient agent for heterogeneous ice nucleation and this process is dependent on mineralogical structure of dust. Recent findings in medical geology indicate possible role of minerals to human health. In this study, a new 1-km global database was developed for several minerals (Illite, Kaolinite, Smectite, Calcite, Quartz, Feldspar, Hematite and Gypsum) embedded in clay and silt populations of arid soils. For the database generation, high-resolution data sets on soil textures, soil types and land cover was used. Tin addition to the selected minerals, phosphorus was also added whose geographical distribution was specified from compiled literature and data on soil types. The developed global database was used to specify sources of mineral fractions in the DREAM dust model and to simulate atmospheric paths of minerals and their potential impacts on marine biochemistry and tropospheric ice nucleation.

Nickovic, Slobodan

2010-05-01

108

Protozoan predation in soil slurries compromises determination of contaminant mineralization potential.  

PubMed

Soil suspensions (slurries) are commonly used to estimate the potential of soil microbial communities to mineralize organic contaminants. The preparation of soil slurries disrupts soil structure, however, potentially affecting both the bacterial populations and their protozoan predators. We studied the importance of this "slurry effect" on mineralization of the herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA, (14)C-labelled), focussing on the effects of protozoan predation. Mineralization of MCPA was studied in "intact" soil and soil slurries differing in soil:water ratio, both in the presence and absence of the protozoan activity inhibitor cycloheximide. Protozoan predation inhibited mineralization in dense slurry of subsoil (soil:water ratio 1:3), but only in the most dilute slurry of topsoil (soil:water ratio 1:100). Our results demonstrate that protozoan predation in soil slurries may compromise quantification of contaminant mineralization potential, especially when the initial density of degrader bacteria is low and their growth is controlled by predation during the incubation period. PMID:22763328

Badawi, Nora; Johnsen, Anders R; Brandt, Kristian K; Sørensen, Jan; Aamand, Jens

2012-07-02

109

Effects of carbon and nitrogen amendment on soil carbon and nitrogen mineralization in volcanic immature soil in southern Kyushu, Japan  

Microsoft Academic Search

Soil N mineralization is affected by microbial biomass and respiration, which are limited by available C and N. To examine\\u000a the relationship between C and N for soil microbial dynamics and N dynamics, we conducted long-term laboratory incubation\\u000a (150 days) after C and N amendment and measured changes in C and N mineralization, microbial biomass C, and dissolved C and\\u000a N

Ayaka Yamasaki; Ryunosuke Tateno; Hideaki Shibata

110

X-ray digital imaging petrography of lunar mare soils: modal analyses of minerals and glasses.  

PubMed

It is essential that accurate modal (i.e., volume) percentages of the various mineral and glass phases in lunar soils be used for addressing and resolving the effects of space weathering upon reflectance spectra, as well as for their calibration such data are also required for evaluating the resource potential of lunar minerals for use at a lunar base. However, these data are largely lacking. Particle-counting information for lunar soils, originally obtained to study formational processes, does not provide these necessary data, including the percentages of minerals locked in multi-phase lithic fragments and fused-soil particles, such as agglutinates. We have developed a technique for modal analyses, sensu stricto, of lunar soils, using digital imaging of X-ray maps obtained with an energy-dispersive spectrometer mounted on an electron microprobe. A suite of nine soils (90 to 150 micrometers size fraction) from the Apollo 11, 12, 15, and 17 mare sites was used for this study. This is the first collection of such modal data on soils from all Apollo mare sites. The abundances of free-mineral fragments in the mare soils are greater for immature and submature soils than for mature soils, largely because of the formation of agglutinitic glass as maturity progresses. In considerations of resource utilization at a lunar base, the best lunar soils to use for mineral beneficiation (i.e., most free-mineral fragments) have maturities near the immature/submature boundary (Is/FeO approximately or = 30), not the mature soils with their complications due to extensive agglutination. The particle data obtained from the nine mare soils confirm the generalizations for lunar soils predicted by L.A. Taylor and D.S. McKay (1992, Lunar Planet Sci. Conf. 23rd, pp. 1411-1412 [Abstract]). PMID:11539387

Taylor, L A; Patchen, A; Taylor, D H; Chambers, J G; McKay, D S

1996-12-01

111

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

2008-08-27

112

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.

Xu, Xia; Ruan, Honghua; Wang, Jiashe

2013-01-01

113

Differences of natural radioactivity and radon emanation fraction among constituent minerals of rock or soil.  

PubMed

We examined differences in the radioactive characteristics among the main minerals forming granite materials. Using a non-toxic high-density agent, minerals were separated from rock (granite-gneiss) and soil (weathered granite) samples. The natural radioactivity ((238)U and (226)Ra) and radon emanation fraction of the minerals were then studied by gamma-ray spectrometry. The radon emanation fractions (27-43%) of the minerals from the soil were much higher than those (0.6-4.6%) of the rock minerals. Additionally, the emanation fractions differed greatly among the minerals separated from both the bulk rock and soil. These results were discussed in terms of the differences of surface area and radium distribution in the mineral grains. It was noticeable that a higher emanation fraction than expected for quartz was commonly observed in the rock and soil samples. We then estimated the contribution of each constituent mineral to the total radon exhalation from the bulk samples. The result depended not only on the radon emanation fraction, but also on the (226)Ra activity and the mineral content. Furthermore, using the obtained data, we also discussed the effect of grain size on radon emanation and why this has been reported to vary markedly in previous studies. PMID:20117007

Sakoda, Akihiro; Nishiyama, Yuichi; Hanamoto, Katsumi; Ishimori, Yuu; Yamamoto, Yuki; Kataoka, Takahiro; Kawabe, Atsushi; Yamaoka, Kiyonori

2010-01-04

114

[Effects of Phyllostachys edulis expansion on soil nitrogen mineralization and its availability in evergreen broadleaf forest].  

PubMed

By the methods of space-time substitution and PVC tube closed-top in situ incubation, this paper studied the soil mineralized-N content, N mineralization rate, and N uptake rate in Phyllostachys edulis-broadleaf mixed forest (PBMF) formed by P. edulis expansion and its adjacent evergreen broadleaf forest (EBF) in Dagangshan Mountain of Jiangxi Province, China. There existed the same spatiotemporal variation trend of soil total mineralized-N (TMN) content between the two forests. The annual average N mineralization rate was slightly lower in PBMF than in EBF. In PBMF, soil N mineralization was dominated by ammonification; while in EBF, soil ammonification and nitrification were well-matched in rate, and soil nitrification was dominated in growth season (from April to October). The N uptake by the plants in PBMF and EBF in a year was mainly in the form of NH4+-N, but that in EBF in growth season was mainly in the form of NO3- -N. These findings indicated that the expansion of P. edulis into EBF could promote the ammonification of soil N, weakened soil nitrification and total N mineralization, and also, increased the NH4+-N uptake but decreased the NO3- -N and TMN uptake by the plants. PMID:23705376

Song, Qing-Ni; Yang, Qing-Pei; Liu, Jun; Yu, Ding-Kun; Fang, Kai; Xu, Pei; He, Yu-juan

2013-02-01

115

Modelling the mineralization kinetics for low concentrations of pesticides in surface and subsurface soil  

Microsoft Academic Search

A number of mathematical models were fitted to mineralization results of low concentrations (004–0.08 ?g·g?1) of mecoprop, bentazon and ethylene thiourea (ETU) in surface (ploughed layer) and subsurface soil in different soil types and at different temperatures. It was shown that surface soil kinetics generally could be described with models not including growth of microorganisms and subsurface soil kinetics could

Inge S Fomsgaard

1997-01-01

116

Effect of freeze-thaw events on mineralization of soil nitrogen  

Microsoft Academic Search

In humid regions of the United States there is considerable interest in the use of late spring (April–June) soil NO3-concentrations to estimate fertilizer N requirements. However, little information is available on the environmental factors that influence soil NO3-concentrations in late winter\\/early spring. The influence of freeze-thaw treatments on N mineralization was studied on several central Iowa soils. The soils were

T. H. DeLuca; D. R. Keeney; G. W. McCarty

1992-01-01

117

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 ...

118

Formation of carbon dioxide hydrate in soil and soil mineral suspensions with electrolytes.  

PubMed

We have identified the effects of solid surface (soil, bentonite, kaolinite, nontronite, and pyrite) and electrolyte (NaCl, KCl, CaCl2, and MgCl2) types on the formation and dissociation of CO2 hydrate in this study. The hydrate formation experiments were conducted by injecting CO2 gas into the soil suspensions with and without electrolytes in a 50 mL pressurized vessel. The formation of CO2 hydrate in deionized water was faster than that in aqueous electrolyte solutions. The addition of soil suspensions accelerated the formation of CO2 hydrate in the electrolyte solutions. The hydrate formation times in the solid suspensions without electrolytes were very similar to that in the deionized water. We did not observe any significant differences between the hydrate dissociation in the solid suspension and that in the deionized water. The pHs of clay mineral suspensions decreased significantly after CO2 hydrate formation and dissociation experiments, while the pH of the soil suspension slightly decreased by less than pH 1 and that of pyrite slightly increased due to the dissolution of CO2 forming carbonic acid. The results obtained from this research could be indirectly applied to the fate of CO2 sequestered into geological formations as well as its storage as a form of CO2 hydrate. PMID:18497119

Lamorena, Rheo B; Lee, Woojin

2008-04-15

119

Analysis of Mineral Soil Analog Samples with a Pulsed UV-Laser Source  

NASA Astrophysics Data System (ADS)

In this study we were focusing on setting up a new pulsed UV laser source combined with a laboratory Raman spectrometer and apply this setup to the analysis of powdered planetary mineral soil analog samples.

Hilchenbach, M.; Lang, T.; Neumann, J.; Tarcea, N.

2010-03-01

120

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 ...

121

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

122

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

123

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

124

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

125

Relationships between mineral surfaces and organic carbon concentrations in soils and sediments  

Microsoft Academic Search

Relationships between mineral specific surface area and organic carbon (OC) concentration are examined for sediments and soil A-horizons from throughout the world. I found (published elsewhere) that continental shelf sediments from many different regions exhibit downcore loss of OC to a refractory background level which shows a consistent relationship with mineral surface area (slope = 0.8 6 mg m- 20C

Lawrence M. Mayer

1994-01-01

126

Soil organic sulfur mineralization in the presence of growing plants under aerobic or waterlogged conditions  

Microsoft Academic Search

Pot culture experiments are described which attempt to identify soil organic S mineralization and availability to plants under aerobic or waterlogged conditions. Several organic S fractions were determined using existing fractionation techniques before and after the growth of corn (Zea mays L.) or rice (Oryza sativa L.) seedlings for four successive harvests. Net mineralization occurred in organic S fractions including

Shutian Li; Bao Lin; Wei Zhou

2001-01-01

127

Earthworm species composition affects the soil bacterial community and net nitrogen mineralization  

Microsoft Academic Search

Knowledge of the effects of species diversity within taxonomic groups on nutrient cycling is important for understanding the role of soil biota in sustainable agriculture. We hypothesized that earthworm species specifically affect nitrogen mineralization, characteristically for their ecological group classifications, and that earthworm species interactions would affect mineralization through competition and facilitation effects. A mesocosm experiment was conducted to investigate

Maria B. Postma-Blaauw; Jaap Bloem; Jack H. Faber; Jan Willem van Groenigen; Ron G. M. de Goede; Lijbert Brussaard

2006-01-01

128

MINERALIZATION OF A SORBED POLYCYCLIC AROMATIC HYDROCARBON IN TWO SOILS USING CATALYZED HYDROGEN PEROXIDE. (R826163)  

EPA Science Inventory

Hydrogen peroxide (H2O2) catalyzed by soluble iron or naturally occurring soil minerals, (i.e., modified Fenton's reagent) was investigated as a basis for mineralizing sorbed and NAPL-phase benzo[ a ]pyrene (BaP), a hydrophobic and toxic polycyclic a...

129

Assessing mineralization rates of petroleum hydrocarbons in soils in relation to environmental factors and experimental scale  

Microsoft Academic Search

Mineralization rates of non-volatile petroleum hydrocarbons (HCs) in five different oil-contaminated soils with initial HC contents ranging from 0.1 to 13 g kg-1 are estimated as a function of environmental factors. The aim of the study is threefold, (i) to study the relevance of environmental factors that may influence the mineralization rate, (ii) to compare mineralization rates estimated in two

J. I. Freijer; Jonge de H; W. Bouten; J. M. Verstraten

1996-01-01

130

Effects on soil organic matter mineralization and microbiological properties of applying compost to burned and unburned soils.  

PubMed

This study was undertaken in the context of a project of reclamation of a burned forest area applying municipal waste compost (MWC) and it consisted of an incubation experience carried out under laboratory conditions. The objectives of this research were to asses the effect of three doses of MWC added to burned and unburned calcareous soils on a) SOM mineralization and b) soil microbiological parameters. The laboratory incubation experience was carried out with three compost doses (1, 2 and 4% w/w) on a burned soil and another unburned one from an adjacent plot, besides the corresponding control samples. The mineralization kinetics of the organic matter was studied for 92 days. The kinetics data were adjusted to a double exponential model, showing two C pools of different degrees of resistance to mineralization and concentration, with half-life times of 1.9-4.9 and 34-76 days, respectively. In the unburned soil, the initial potential mineralization rate of the labile and stable C pools showed an opposed behavior, increased and decreased with the MWC dose, respectively. However in the burned soil no significant tendencies were observed. Although applying compost tended to increase the size of more labile pool with respect to total mineralizable C, however most of the soil or compost OM did not result mineralizable in the short and medium term. The compost amendment did not increase soil microbial activity. PMID:21055869

Turrión, M B; Lafuente, F; Mulas, R; López, O; Ruipérez, C; Pando, V

2010-11-04

131

Interactions of Aqueous U(VI) with Soil Minerals in Slightly Alkaline Natural Systems  

SciTech Connect

Uranium (U) is a common contaminant at numerous surface and subsurface sites around the world. This paper covers some important aspects of the aqueous hexavalent uranium [U(VI)] interactions with soil minerals that are present in contaminated soils and sediments. The retention of U via interactions with soil minerals has significant consequences for the prediction of its short – and long – term behavior in soils and geological systems. Studies of the nature and type of these interactions have provided the necessary evidence for assessing the geochemical behavior of U in natural systems under different physical, biogeochemical, hydrological, and reducing or oxidizing conditions. Over the last 20 years, aqueous U(VI):solid phase interactions have been studied by geochemists, soil chemists, soil mineralogists and soil microbiologists, and the progress in some areas is remarkable. Although a mechanistic description and understanding of the complex interactions involving U and soil minerals of natural systems is currently impossible, results from carefully designed and executed experiments with these materials have improved our understanding of the heterogeneous system’s behavior and U contaminant mobility and transport. There are, however, areas that need further exploration and study. Numerous research publications were reviewed in this paper to present important findings coming out of the research, to reveal the current level of the understanding of the U(VI) interactions with soil minerals, and to provide ideas for future needs and research directions.

Qafoku, Nik; Icenhower, Jonathan P.

2008-12-01

132

How relevant is chemical recalcitrance for predicting climatic effects on mineral soil carbon stocks?  

NASA Astrophysics Data System (ADS)

The role of chemical recalcitrance in mediating the effect of warming on soil carbon stocks has been a focus of research efforts aimed toward the larger goal of prediction of carbon loss from soils in the 21st century. Arrhenius kinetics provides a theoretical basis for the prediction that reaction of chemically recalcitrant carbon compounds (those with higher activation energy) should be more temperature sensitive than compounds with faster turnover rates (lower activation energy). This relationship has even been integrated into models of soil carbon dynamics. However, since chemically recalcitrant compounds have, by definition, slower turnover rates, their response to warming should ultimately be far smaller than those of faster turnover compounds in terms of overall respiratory loss (Sierra 2011). Regardless of the relative temperature sensitivity of recalcitrant soil carbon, it remains an open question how important enhanced decomposition of chemically recalcitrant carbon in mineral soils is for potential feedbacks between warming and soil carbon stocks. To lend insight to this question, we present a series of incubation warming experiments with soils from two forest Free Air CO2 Enrichment (FACE) sites. Because of the distinct carbon isotope (radiocarbon free) signature of the CO2 fumigation gas, soil carbon in elevated CO2 plots has incorporated a decade of labeled carbon. By measuring the radiocarbon signature of flux, which reflects FACE label carbon in CO2 elevated plots, and the atmospheric history of radiocarbon in CO2 control plots, we attributed warming-induced increases in flux rates to soil carbon pools of different ages. Much of our knowledge about decomposition of recalcitrant compounds comes from litter decomposition, where chemical recalcitrance is the presumed control on decomposition rates. By comparing the response of litter and mineral soils to warming, we infer the role of chemical recalcitrance in mineral soils. Flux rates from both organic and mineral soils were initially stimulated by warming, but diminished in time for the organic soils, and not for mineral soils. These data suggest different long term decomposition controls on mineral soil carbon, which may be more temperature sensitive than those acting on litter carbon over the long term. In addition, the 14C signature of respiration suggests an increase in loss of older carbon with warming in mineral soils, but not in organic soils. The absence of change in ?14C respired by organic soils suggests that the change in mineral soils is likely due to a factor other than recalcitrance. While the effects of warming on chemically recalcitrant carbon may play a role in the short term response, it is not likely contributing to the long term stimulation of fluxes from mineral soils. Ultimately, to predict the response of carbon stocks to warming, we need a more detailed understanding of the processes controlling soil carbon stabilization in mineral soils. While chemical recalcitrance may play a limited role, we need to acknowledge and account for other stabilization pathways.

Hopkins, F. M.; Torn, M. S.; Trumbore, S.

2011-12-01

133

Factors Affecting Mineral Nitrogen Transformations by Soil Heating: A Laboratory Simulated Fire Study.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Two forest soils from the Sierra Nevada Mountains of California were brought into the laboratory and subjected to simulated burning in a muffle furnace at several durations, oven temperatures, and water contents. Soils were analyzed for NO3-, NH4+, mineral N, total N, total C, and C:N responses to t...

134

Soil Fertility and Mineral Nutrition of a Biodynamic Avocado Plantation in Tenerife  

Microsoft Academic Search

The soil fertility of a biodynamic avocado plantation in Tenerife and its relation to mineral nutrition was studied and compared with similar variables investigated previously in conventional plantations. The surface soils of the biodynamic plantation showed pH, organic matter and available P, Ca, Mg and K averages significantly higher than those of the conventional plantations. As regards the foliar nutrient

C. García; C. E. Alvarez; A. Carracedo; E. Iglesias

1989-01-01

135

CARBON AND NITROGEN MINERALIZATION OF NON-COMPOSTED AND COMPOSTED MUNICIPAL SOLID WASTE IN SANDY SOILS  

Technology Transfer Automated Retrieval System (TEKTRAN)

A sterilized, but undecomposed, organic byproduct of municipal waste processing was incubated in sandy soils to compare C and N mineralization with mature municipal waste compost. Waste products were added to two soils at rates of 17.9, 35.8, 71.6, and 143 Mg/ha dry weight and incubated at 25°C for ...

136

Soil carbon and nitrogen mineralization kinetics in organic and conventional three-year cropping systems  

Microsoft Academic Search

The scientific literature regarding the use of C and N mineralization kinetics as a tool to highlight the effects of different cropping systems on soil C and N release is scarce. In this study we aimed to assess the effectiveness of these parameters in evaluating soil C and N potential release in organic (ORG) and conventional (CONV) three-year cropping systems.

S. Marinari; A. Lagomarsino; M. C. Moscatelli; A. Di Tizio; E. Campiglia

2010-01-01

137

Anaerobic mineralization of indigenous organic matters and methanogenesis in tropical wetland soils  

Microsoft Academic Search

Tropical wetlands are one of the largest natural sources in the global methane budget due to high biological activities and the anaerobiosis in soil. We studied mineralization and gas production during the early stage of anaerobic decomposition of indigenous organic matters in soils of Narathiwat, southern Thailand, to clarify the significance of the substrate quality in controlling decomposition and methanogenesis

Toshihiro Miyajima; Eitaro Wada; Yuko T. Hanba; Pisoot Vijarnsorn

1997-01-01

138

Dynamic Response of Forest Litter and Mineral Soil to Pulsed Water Additions  

Microsoft Academic Search

Quantifying microbial responses to drought and moisture pulses are essential to understanding terrestrial C cycling in a changing climate. Using laboratory incubations we sought to determine if water added in multiple consecutive pulses to pine forest litter and mineral soil resulted in different C dynamics than water added in a single event. Soils were collected from two sites on Santa

C. M. Boot; S. M. Schaeffer; M. S. Carbone; C. J. Still; J. Schimel

2010-01-01

139

NITROGEN MINERALIZATION AND PRODUCTIVITY IN 50 HARDWOOD AND CONIFER STANDS ON DIVERSE SOILS  

Microsoft Academic Search

The generality of relationships between soil net nitrogen (N) mineralization, aboveground N cycling, and aboveground net primary production (ANPP) for temperate forest ecosystems is unclear. It is also not known whether these variables and their rela- tionships differ between evergreen and deciduous forests, or across soil types. To address these questions we compiled data on annual rates of in situ

PETER B. REICH; DAVID F. G RIGAL; JOHN D. ABER; STITH T. G OWER

1997-01-01

140

A Simulation of the Interaction of Acid Rain with Soil Minerals  

ERIC Educational Resources Information Center

|The atmospheric issue of acid rains is subjected to a five-part laboratory experiment by concentrating on the chemistry of the infiltration process of acid rainwater through soils. This procedure of quantitative scrutiny helps students realize the efficacy of soil minerals in the consumption of surplus acidity in rainwater.|

Schilling, Amber L.; Hess, Kenneth R.; Leber, Phyllis A.; Yoder, Claude H.

2004-01-01

141

NATIONALLY COORDINATED EVALUATION OF SOIL NITROGEN MINERALIZATION RATE USING A STANDARDIZED AEROBIC INCUBATION PROTOCOL  

Technology Transfer Automated Retrieval System (TEKTRAN)

Aerobic incubation methods have been widely used to assess soil nitrogen (N) mineralization, but standardized protocols are lacking. A silt loam soil (Catlin silt loam; fine-silty, mixed, superactive, mesic, Oxyaquic Arguidoll) was subjected to aerobic incubation at six USDA-ARS locations using a ...

142

Influence of Selected Inorganic Electron Acceptors on Organic Nitrogen Mineralization in Everglades Soils  

Microsoft Academic Search

regulates the size and activity of the microbial pool will also affect the biogeochemical cycling of N. Organic N mineralization can regulate the bioavailability of N in The redox status of a wetland soil system can exert wetland soils and be controlled by the availability of inorganic electron substantial control over the cycling of N (Reddy and acceptors. During the

J. R. White; K. R. Reddy

2001-01-01

143

Mineralization of soil organic matter in two elevated CO2 by warming experiments in grassland  

Technology Transfer Automated Retrieval System (TEKTRAN)

Experimentally elevated atmospheric CO2 has enhanced carbon (C) allocation belowground, while ecosystem warming has led to losses of soil C due to enhanced mineralization of soil organic matter (SOM). Few investigations of possible interactions between elevated CO2 and temperature have been reported...

144

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...

145

Experimental evidence that soil fauna enhance nutrient mineralization and plant nutrient uptake in montane grassland ecosystems  

Microsoft Academic Search

This microcosm study is concerned with understanding those factors which regulate ecosystem processes of nutrient cycling and plant productivity in a montane grassland ecosystem. We examined the effects of different groups of soil fauna, namely bacterial-feeding nematodes and Collembola, on nutrient mineralization (N and P) in an acid, organic soil taken from a montane grassland in the Peak District National

Richard D Bardgett; Kin F Chan

1999-01-01

146

Mercury contamination in agricultural soils from abandoned metal mines classified by geology and mineralization.  

PubMed

This survey aimed to compare mercury concentrations in soils related to geology and mineralization types of mines. A total of 16,386 surface soils (0~15 cm in depth) were taken from agricultural lands near 343 abandoned mines (within 2 km from each mine) and analyzed for Hg by AAS with a hydride-generation device. To meaningfully compare mercury levels in soils with geology and mineralization types, three subclassification criteria were adapted: (1) five mineralization types, (2) four valuable ore mineral types, and (3) four parent rock types. The average concentration of Hg in all soils was 0.204 mg kg(-1) with a range of 0.002-24.07 mg kg(-1). Based on the mineralization types, average Hg concentrations (mg kg(-1)) in the soils decreased in the order of pegmatite (0.250) > hydrothermal vein (0.208) > hydrothermal replacement (0.166) > skarn (0.121) > sedimentary deposits (0.045). In terms of the valuable ore mineral types, the concentrations decreased in the order of Au-Ag-base metal mines ? base metal mines > Au-Ag mines > Sn-W-Mo-Fe-Mn mines. For parent rock types, similar concentrations were found in the soils derived from sedimentary rocks and metamorphic rocks followed by heterogeneous rocks with igneous and metamorphic processes. Furthermore, farmland soils contained relatively higher Hg levels than paddy soils. Therefore, it can be concluded that soils in Au, Ag, and base metal mines derived from a hydrothermal vein type of metamorphic rocks and pegmatite deposits contained relatively higher concentrations of mercury in the surface environment. PMID:21814815

Kim, Han Sik; Jung, Myung Chae

2011-08-04

147

Differential Adsorption of Occluded and Nonoccluded Insect-Pathogenic Viruses to Soil-Forming Minerals  

PubMed Central

Soil represents the principal environmental reservoir of many insect-pathogenic viruses. We compared the adsorption and infectivity of one occluded and two nonoccluded viruses, Helicoverpa armigera single nucleopolyhedrovirus (HaSNPV) (Baculoviridae), Cricket paralysis virus (CrPV) (Dicistroviridae), and Invertebrate iridescent virus 6 (IIV-6) (Iridoviridae), respectively, in mixtures with a selection of soil-forming minerals. The relative infective titers of HaSNPV and CrPV were unchanged or slightly reduced in the presence of different minerals compared to their titers in the absence of the mineral. In contrast, the infective titer of IIV-6 varied according to the mineral being tested. In adsorption studies, over 98% of HaSNPV occlusion bodies were adsorbed by all the minerals, and a particularly high affinity was observed with ferric oxide, attapulgite, and kaolinite. In contrast, the adsorption of CrPV and IIV-6 differed markedly with mineral type, with low affinity to bentonites and high affinity to ferric oxide and kaolinite. We conclude that interactions between soil-forming minerals and insect viruses appear to be most important in nucleopolyhedroviruses, followed by invertebrate iridescent viruses, and least important in CrPV, which may reflect the ecology of these pathogens. Moreover, soils with a high content of iron oxides or kaolinite would likely represent highly effective reservoirs for insect-pathogenic viruses.

Christian, Peter D.; Richards, Andrew R.; Williams, Trevor

2006-01-01

148

Cometabolic mineralization of benzo[a]pyrene caused by hydrocarbon additions to soil  

SciTech Connect

The mineralization of [7-{sup 14}C]benzo[a]pyrene (BaP) in soil was investigated in response to additions of individual hydrocarbons, defined hydrocarbon mixtures, crude oil, and crude oil fractions. Neither substantial BaP mineralization nor enrichment of BaP degraders occurred in BaP-spiked soil in the absence of a suitable hydrocarbon supplement. Crude oil, the saturated and aromatic class components of crude oil, the distillates heating oil, jet fuel, and diesel fuel supported up to 60% mineralization of 80 {micro}g [7-{sup 14}C]BaP per gram of soil in 40 d. Neither single hydrocarbons nor defined hydrocarbon mixtures containing normal and branched alkanes, alicyclics, and aromatics supported comparable BaP mineralization. Evolution of {sup 14}CO{sub 2} occurred after lag periods characteristic to specific petroleum products and their concentrations. Time required for microbial proliferation, hydrocarbon toxicity, and competitive inhibition might have contributed to these lag periods, but the complete inhibition of BaP mineralization by diesel-fuel vapors pointed to a dominant role of competitive inhibition. A lack of radiocarbon incorporation into soil biomass from [7-{sup 14}C]BaP indicated that at least the initial steps of BaP biodegradation in soil were cometabolic in nature. Suitable hydrocarbon mixtures not only supported BaP mineralization by serving as primary substrates, but also enhanced BaP bioavailability by dissolving this hydrophobic solid.

Kanaly, R.A.; Bartha, R.

1999-10-01

149

Carbon Mineralization Potential in Soils of Different Habitats in the Semiarid Horqin Sandy Land: A Laboratory Experiment  

Microsoft Academic Search

Soil organic carbon mineralization potential in four different sandy habitats (shifting, semi-fixed, fixed sand dune, and interdunal lowland) and the effects of litter addition from shrubs and annual plants on soil microbial respiration were measured using a laboratory soil incubation experiment. Soil samples were collected from beneath and outside the canopies of shrubs in all habitats. Soils were incubated for

Yongzhong Su; Halin Zhao; Yulin Li; Jianyuan Cui

2004-01-01

150

Transfer of atrazine degradation capability to mineralize aged 14C-labeled atrazine residues in soils.  

PubMed

The degradation of environmentally long-term aged (22 years) (14)C-labeled atrazine residues in soil stimulated by inoculation with atrazine-adapted soil from Belgium, the United States (U.S.), and Brazil at two different moisture regimes (50% WHCmax/slurried conditions) was evaluated. Inoculation of the soil containing the aged (14)C-labeled atrazine residues with 5, 50, and 100% (w/w) Belgian, U.S., or Brazilian atrazine-adapted soil increased (14)C-atrazine residue mineralization by a factor of 3.1-13.9, depending upon the amount of atrazine-adapted soil inocula and the moisture conditions. Aged (14)C-atrazine residue mineralization varied between 2 and 8% for Belgian and between 1 and 2% for U.S. and Brazilian soil inoculum at 50% WHCmax but was increased under slurried conditions, accounting for 8-10% (Belgian soil), 2-7% (Brazilian soil), and 3% (American soil). The results show that an increased degradation of long-term aged (14)C-labeled atrazine residues is possible by the transfer of atrazine-adapted soil microflora from different soils and regions to non-adapted soil. PMID:23789631

Jablonowski, Nicolai David; Krutz, Jason L; Martinazzo, Rosane; Zajkoska, Petra; Hamacher, Georg; Borchard, Nils; Burauel, Peter

2013-06-21

151

Mineralization of soil nitrogen in the presence of different metallic and organic solids  

SciTech Connect

Mineralization of soil N was determined under aerobic and anaerobic conditions with four soils, three alfisols and one mollisol, for up to 24 weeks in the presence of various solids. These include: 1) metals--aluminum, brass, copper, iron, nickel, lead, stainless steel, tin, and zinc; 2) woods--cedar, pine, and redwood; and 3) other--latex paint and polyvinyl chloride. Presence of the metals, in general, had little or no effect, or depressed soil N mineralization, sometimes more than 50 percent. With a few exceptions, depression occurred mainly in the presence of brass, copper, iron, and zinc.

Smith, S.J.; Young, L.B.

1984-01-01

152

Mineral contamination from cemetery soils: case study of Zandfontein Cemetery, South Africa.  

PubMed

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

2012-02-07

153

Mineralization of polycyclic and n-heterocyclic aromatic compounds in hydrocarbon-contaminated soils  

Microsoft Academic Search

The comparative mineralization of eight polycyclic aromatic compounds in five soils collected from an abandoned coal tar refinery in eastern Ohio was determined. The soils showed differences only in total extractable hydrocarbon content of the soil chemical characteristics measured. The compounds studied included five polycyclic aromatic hydrocarbons (phenanthrene, anthracene, pyrene, and carcinogenic benz[a]anthracene and benzo[a]pyrene) and three N-heterocyclic aromatics (9H-carbazole,

Robert J. Grosser; David Warshawsky; J. Robie Vestal

1995-01-01

154

Fissure and mineral weathering impacts on heavy metal distribution in sludge-amended soil  

Microsoft Academic Search

The purpose of this study was to follow the distribution and migration of the metallic trace elements (MTE) zinc (Zn), lead\\u000a (Pb) and cadmium (Cd) in a sludge-amended soil, both at the metric scale of the bulk soil horizons and at the micrometric\\u000a scale of mineral weathering microsites. In the soil scale approach, the MTE contents determined by ICP-AES and

Dominique Proust; Jacinthe Caillaud; Claude Fontaine; Michel Fialin; Christian Courbe; Nathalie Dauger

155

Microbial biomass and mineralization-immobilization of nitrogen in some agricultural soils  

Microsoft Academic Search

The chloroform fumigation-incubation method (CFIM) was used to measure the microbial biomass of 17 agricultural soils from Punjab Pakistan which represented different agricultural soil series. The biomass C was used to calculate biomass N and the changes occurring in NH4+-N and NO3--N content of soils were studied during the turnover of microbial biomass or added C source. Mineral N released

F. Azam; K. A. Malik; F. Hussain

1986-01-01

156

Salinity effects on carbon mineralization in soils of varying texture  

Microsoft Academic Search

In salt-affected soils, soil organic carbon (SOC) levels are usually low as a result of poor plant growth; additionally, decomposition of soil organic matter (SOM) may be negatively affected. Soil organic carbon models, such as the Rothamsted Carbon Model (RothC), that are used to estimate carbon dioxide (CO2) emission and SOC stocks at various spatial scales, do not consider the

Raj Setia; Petra Marschner; Jeff Baldock; David Chittleborough; Pete Smith; Jo Smith

2011-01-01

157

Carbon and nitrogen stocks and nitrogen mineralization in organically managed soils amended with composted manures.  

PubMed

The use of composted manures and of legumes in crop rotations may control the quality and quantity of soil organic matter and may affect nutrient retention and recycling. We studied soil organic C and N stocks and N mineralization in organically and conventionally managed dryland arable soils. We selected 13 extensive organic fields managed organically for 10 yr or more as well as adjacent fields managed conventionally. Organic farmers applied composted manures ranging from 0 to 1380 kg C ha yr and incorporated legumes in crop rotations. In contrast, conventional farmers applied fresh manures combined with slurries and/or mineral fertilizers ranging from 200 to 1900 kg C ha yr and practiced a cereal monoculture. Despite the fact that the application of organic C was similar in both farming systems, organically managed soils showed higher C and similar N content and lower bulk density than conventionally managed soils. Moreover, organic C stocks responded to the inputs of organic C in manures and to the presence of legumes only in organically managed soils. In contrast, stocks of organic N increased with the inputs of N or C in both farming systems. In organically managed soils, organic N stocks were less mineralizable than in conventional soils. However, N mineralization in organic soils was sensitive to the N fixation rates of legumes and to application rate and C/N ratio of the organic fertilizers. PMID:22751078

Romanyà, Joan; Arco, Noèlia; Solà-Morales, Ignasi; Armengot, Laura; Sans, Francesc Xavier

158

Effects of simulated acid rain on glucose mineralization and some physicochemical properties of forest soils  

SciTech Connect

To study the effects of acid rain, samples of forest soils were exposed to a continuous application of 100 cm of simulated acid rain (pH 3.2-4.1) at 5 cm/hour, or to intermittent 1-hour applications of 5 cm of simulated acid rain three times per week for 7 weeks. The major effects of the simulated acid rain were localized at the top of the soil and included lower pH values and glucose mineralization rates, and higher exchangeable Al and total and exchange acidity. The acidity penetrated further in the more acid soils. The mineralization of /sup 14/C-glucose was measured at concentrations of 1.5-54 ..mu..g glucose/g of soil. Glucose mineralization in the test soils (pH values of 4.4-7.1) was inhibited by the continuous exposure to simulated acid rain at pH 3.2 but not a pH 4.1. The extent of inhibition depended on the soil and the initial glucose concentration. Exposure of one soil to 7 weeks of intermittent applications of simulated acid rain at pH 3.2 reduced the mineralization rate at the three glucose concentrations tested. These data suggest that acid rain may have a significant impact on microbial activity.

Strayer, R.F. (Oak Ridge National Lab., TN); Alexander, M.

1981-10-01

159

Soil microbial activity and structure in mineralized terranes of the Western US  

NASA Astrophysics Data System (ADS)

Mineralized terranes (areas enriched in metal-bearing minerals) occur throughout the Western US, and are characterized by highly variable soil trace metal concentrations across small spatial scales. Assuming that non-lithologic (extrinsic) soil forming factors are relatively constant between mineralized and unmineralized zones, these mineralized areas allowed us to evaluate the effect of lithology on soil microbial activity. We established the following study sites: 1) sage-grassland on a Mo/Cu deposit (Battle Mountain, NV); 2) pine-chaparral on Ni/Cr bearing rocks (Chinese Camp, CA); and 3) two pine woodland sites on acid-sulfate altered rocks (Reno, NV; Bridgeport, CA). Microbial, physical and chemical measurements were performed on soils from undisturbed mineralized areas and adjacent unmineralized areas to determine baseline conditions for comparison to sites disturbed by mining. A host of abiotic soil parameters, along with bioavailable (diethylenetriaminepentaacetic acid (DTPA)-extractable) and total metals, were measured to examine their correlation with the following measures of microbial activity: enzyme assays (arylsulfatase, phosphatase, fluorescein diacetate hydrolysis), C/N mineralization potential, C substrate utilization (Biolog Ecoplate), and microbial biomass and community structure (phospholipid fatty acid analysis). Within the Battle Mountain study area, both microbial activity and structure were statistically similar between mineralized and unmineralized soils. Nutrient and metal concentrations were also similar; the only differences being higher Cu and lower P in the mineralized soils. Within the Chinese Camp study area, soil organic carbon and total nitrogen concentrations were similar between the serpentine (Ni/Cr bearing) and adjacent andesite soils, while differences were noted for other nutrients (S, P, Ca, Mg). For the serpentine soils, Co, Fe, Mn, and Ni showed the strongest correlations with microbial activity, where Cr, Mn showed the strongest correlations in the andesite soils. Measures of microbial activity were statistically similar, except for arylsulfatase and Biolog C substrate utilization, which were greater in the andesite soils. Biolog substrate utilization richness was greater for the andesite soils, which also showed greater fungal biomass compared to the serpentine soils. In the acid sulfate systems, most measures of microbial activity were reduced in the acid sulfate soils compared to the adjacent andesite soils. Lower pH and P, and greater Al concentrations in the acid sulfate soils are potential inhibitors of microbial activity, while greater concentrations of inorganic N suggest that N is not limiting in the acid sulfate soils. Biolog substrate utilization richness was much lower in the acid sulfate soils, which also exhibited a greater proportion of polymer and carbohydrate use compared to the andesite soils. Impacts on microbial activity and microbial community structure are depend on a combination of trace metal and nutrient concentrations within a given mineralization type. Improving our understanding of biotic/abiotic relationships in undisturbed systems should increase our understanding of these relationships in areas disturbed by mining.

Blecker, S. W.; Stillings, L. L.; Decrappeo, N.; Ippolito, J.

2009-12-01

160

Clay minerals and its influence on soil respiration in southern Brazil  

NASA Astrophysics Data System (ADS)

Carbon dioxide is the greenhouse gas with the highest concentration increases in the last century caused by human activities. Despite all the efforts, new investigations should be conducted in order to understand how agricultural management and its variations would impact on soil respiration and consequently in soils potential for carbon sequestration. Soil iron content is an important aspect of tropical soils, especially in sugarcane fields, that are located in regions where iron content in soil is among the highest concentrations in world. In this work we show that as iron content increases and changes its constitution FCO2 decreases monotonically. A transect was established on an acid oxisol in a direction where soil color changed from a yellow (10 YR), passing to a red (5 YR) and finishing with a dark red latosol (2.5 YR), in just 420 meters. Soil respiration was taken each 10 meters (42 points) while soil samples were extracted (0-20 cm) in each point for further soil property analysis. X-ray analysis shows that the goethite per hematite ratio and kaolinite per gibbsite ratio are directly related to soil respiration rates, and this is confirmed by spectroreflectance analysis performed in the same samples. Also, soils with iron clay minerals having lower degree of cristalinity were the ones having the higher soil respirations. Our study suggests a more complex relationship between clay minerals and biological activity, including soil iron level as an important factor in order to infer the ecological impact of tropical soil management in the biosphere. Due to the distinguishable characteristics of the Brazilian soils in terms of iron level, new experiments are needed to elucidate the relationship of iron content and CO2 loss in different classes of soils.

Marques, José, Jr.; Tadeu Pereira, Gener; La Scala, Newton, Jr.

2010-05-01

161

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

162

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.

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

2012-01-01

163

Assessing changes in soil microbial communities and carbon mineralization in Bt and non-Bt corn residue-amended soils  

Microsoft Academic Search

The effects of Bt corn (Zea mays L.) residue on soil microbial communities and rates of C mineralization were investigated. The Bt corn residue had a higher lignin content (12%) and lignin\\/N (9.9) ratio compared with its non-Bt near-isoline (10% lignin; lignin\\/N=8.6). We examined the relationships among the Bt\\/non-Bt residue properties, residue component, soil texture, sampling time, and tillage management

Min Fang; Peter P. Motavalli; Robert J. Kremer; Kelly A. Nelson

2007-01-01

164

Interactions of DNA with clay minerals and soil colloidal particles and protection against degradation by DNase.  

PubMed

Adsorption, desorption, and degradation by nucleases of DNA on four different colloidal fractions from a Brown soil and clay minerals were studied. The adsorption of DNase I and the structures of native DNA, adsorbed and desorbed, were also investigated by Fourier Transform Infrared (FTIR), circular dichroism (CD), and fluorescence spectroscopy, to determine the protection mechanism of DNA molecules by soil colloids and minerals against enzymatic degradation. Kaolinite exhibited the highest adsorption affinity for DNA among the examined soil colloids and clay minerals. In comparison with organomineral complexes (organic clays), DNA was tightly adsorbed by H2O2-treated clays (inorganic clays). FTIR spectra showed that the binding of DNA on kaolinite and inorganic clays changed its conformation from the B-form to the Z-form, whereas montmorillonite and organic clays retained the original B-form of DNA. A structural change from the B- to the C-form in DNA molecules desorbed from kaolinite was observed by CD spectroscopy and confirmed by fluorescence spectroscopy. The presence of soil colloids and minerals provided protection to DNA against degradation by DNase I. The higher level of protection was found with montmorillonite and organic clays compared to kaolinite and inorganic clays. The protection of DNA against nuclease degradation by soil colloids and minerals is apparently not controlled by the adsorption affinity of DNA molecules for the colloids and the conformational change of bound DNA. The higher stability of DNA seemed to be attributed mainly to the presence of organic matter in the system and the adsorption of nucleases on soil colloids and minerals. The information obtained in this study is of fundamental significance for the understanding of the behavior of extracellular DNA in soil environment. PMID:16719099

Cai, Peng; Huang, Qiao-Yun; Zhang, Xue-Wen

2006-05-01

165

Development of vegetation based soil quality indices for mineralized ...  

Treesearch

... impacted by different types of geologic mineralization using the relationship between ... cover and shrub density were measured for the vegetative communities. ... three to six abiotic parameters, the latter consisting of nutrients and metals.

166

Mineral Cycling in Soil and Litter Arthropod Food Chains. Progress Report, November 1, 1980-October 31, 1981.  

National Technical Information Service (NTIS)

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 a...

D. A. Crossley

1980-01-01

167

Minerals  

MedlinePLUS

... commercials for breakfast cereal always mention vitamins and minerals ? But when you think of minerals, food isn't the first thing that comes to mind. Aren't minerals something you find in the earth, like iron ...

168

ASSESSING CHANGES IN SOIL MICROBIAL COMMUNITIES AND CARBON MINERALIZATION IN BT AND NON-BT CORN RESIDUE-AMENDED SOILS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The effects of Bt corn (Zea mays L.) residue on soil microbial communities and rates of C mineralization were investigated. The Bt corn residue had a higher lignin content (12%) and lignin/N (9.9) ratio compared with its non-Bt near-isoline (10% lignin; lignin/N = 8.6). We examined the relationships...

169

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

170

Origin and Reactivity of the Martian Soil: A 2003 Micromission  

NASA Astrophysics Data System (ADS)

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.

1999-09-01

171

Heavy metal linkages with mineral, organic and living soil compartments  

Microsoft Academic Search

For soil ecotoxicological assessment, we can observe lethal effects (on organism as presence or absence) or sublethal effects due to bioconcentrations of contaminants in organisms. This paper deals with the analysis of seven heavy metals (Cd, Cu, Fe, Mn, Ni, Pb and Zn) and Ca: (i) in soils, by three chemical extraction techniques; (ii) in earthworm tissues; (iii) the relationships

Abdul Motalib M. Abdul Rida; Marcel B. Bouché

1997-01-01

172

Soil nitrogen mineralization not affected by grass species traits  

Microsoft Academic Search

Species N use traits was evaluated as a mechanism whereby Bromus inermis (Bromus), an established invasive, might alter soil N supply in a Northern mixed-grass prairie. We compared soils under stands of Bromus with those from three representative native grasses of different litter C\\/N: Andropogon gerardii (Andropogon), Nassella viridula (Nassella) and Pascopyrum smithii (Pascopyrum); in ascending order of litter quality.

Maged Ikram Nosshi; Jack Butler; M. J. Trlica

2007-01-01

173

Regional Sr–Nd isotopic ratios of soil minerals in northern China as Asian dust fingerprints  

Microsoft Academic Search

We report that arid soils in various areas of northern China can be distinguished by using Sr–Nd isotopic ratios of acid-resistant minerals and Sr isotopic ratios of water- and weak-acid-soluble minerals. Our results show that contemporary dust falling on Beijing is transported mainly from the adjacent northwestern to western areas and is more likely to be related to desertification than

Takanori Nakano; Yoriko Yokoo; Masataka Nishikawa; Hideaki Koyanagi

2004-01-01

174

Effect of Mineral Reactions on the Hydraulic Properties of Unsaturated Soils: Model Development and Application  

Microsoft Academic Search

Precipitation\\/dissolution induces changes in the pore radii of water-filled pores, and, consequently, affects flow in porous media. The selective radius shift model was developed to relate changes in mineral volume due to precipitation\\/dissolution reactions to changes in hydraulic properties of unsaturated soils. The model considers the dependency of the amount of mineral precipitation\\/dissolution within a pore on the local pore

L. C. Wissmeier; D. A. Barry

2008-01-01

175

In situ observations of soil minerals and organic matter in the early phases of prescribed fires  

NASA Astrophysics Data System (ADS)

We examined the chemical composition of aerosol samples collected during a prescribed fire at a Great Basin Desert site in the context of samples collected from controlled combustion of vegetation clippings from the same site and resuspension of soil samples obtained prior to and after the burn event. We observed a distinct difference in the composition of organic carbon resuspended soil dust after the burn, reflecting changes caused by the heating of the soil. The relative abundances of minerals and organic carbon fractions in aerosols collected during the first period of the burn were identical to those measured in soil dust. For aerosol samples collected for the remaining two periods of the burn event, the profiles of both minerals and organic carbon matched quite well those observed for vegetation combustion. Reconstruction of aerosol samples collected during the burn event showed that vegetation combustion dominated emissions but mineral soil dust may account for about 10% of PM10emissions (reconstructed) during the early stages of the fire. A large fraction of emissions during the first two hours was also unaccounted mainly because of the insufficient conversion of organic carbon to organic mass. The abundance of heavier non-volatile organics in soil dust suggested the presence of humic/fulvic acids that exhibit higher OM-to-OC ratios and thus, account for a proportion of the unaccounted emissions. These findings indicated that soil dust may be released into the air during a fire event, probably due to the enhanced turbulent mixing near the burn front.

Kavouras, Ilias G.; Nikolich, George; Etyemezian, Vic; Dubois, David W.; King, James; Shafer, David

2012-06-01

176

Mineral weathering in ectomycorrhizosphere of subalpine fir ( Abies lasiocarpa (Hook.) Nutt.) as revealed by soil solution composition  

Microsoft Academic Search

The soil solution is considered an important index of nutrient availability, because it mimics the field conditions when plant roots obtained their nutrition, and reflects the weatherability of a particular soil mineral. The composition of soil solution is sensitive to physical, biological and chemical changes to soil systems, including the presence of fungal hyphae and rhizomorphs from ectomycorrhizal colonization. The

J. M Arocena; K. R Glowa

2000-01-01

177

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

178

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

179

Sorption equilibria of vapor-phase organic pollutants on unsaturated soils and soil minerals. Final report, Mar 85-Mar 89  

SciTech Connect

Most groundwater pollutants are volatile organic compounds; however, there is relatively little understanding of the sorption reactions that control the transport and fate of organic vapors in the vadose zone. This investigation identified the physical/chemical properties of the soil matrix and organic vapors which control vapor-solid phase distribution. The dominant property which regulates vapor sorption in the unsaturated zone is the moisture content of the soil. Under very dry conditions, soil mineral/vapor interactions are regulated by specific surface area, indicating the dominance of a relatively non-specific physical adsorption process. However, at moisture contents exceeding an average surface coverage of four to eight layers of water, vapor uptake is controlled by partitioning reactions into soil moisture and soil organic matter.

Lion, L.W.; Ong, S.K.; Linder, S.R.; Swager, J.L.; Schwager, S.J.

1990-04-01

180

Soil organic nitrogen mineralization across a global latitudinal gradient  

Treesearch

... nitrogen in the terrestrial biosphere remains a central goal in ecosystem science. ... and their availability to plants and microorganisms has been implicated as a ... it has been thought that soils from different latitudes and plant communities ...

181

Differential Adsorption of Occluded and Nonoccluded Insect-Pathogenic Viruses to Soil-Forming Minerals  

Microsoft Academic Search

Soil represents the principal environmental reservoir of many insect-pathogenic viruses. We compared the adsorption and infectivity of one occluded and two nonoccluded viruses, Helicoverpa armigera single nucleopolyhe- drovirus (HaSNPV) (Baculoviridae), Cricket paralysis virus (CrPV) (Dicistroviridae), and Invertebrate iridescent virus 6 (IIV-6) (Iridoviridae), respectively, in mixtures with a selection of soil-forming minerals. The relative infective titers of HaSNPV and CrPV were

Peter D. Christian; Andrew R. Richards; Trevor Williams

2006-01-01

182

Anaerobic mineralization of indigenous organic matters and methanogenesis in tropical wetland soils  

SciTech Connect

Tropical wetlands are one of the largest natural sources in the global methane budget due to high biological activities and the anaerobiosis in soil. We studied mineralization and gas production during the early stage of anaerobic decomposition of indigenous organic matters in soils of Narathiwat, southern Thailand, to clarify the significance of the substrate quality in controlling decomposition and methanogenesis in some different tropical wetland soils. The optimal temperature of decomposition was around 35{degrees}C, while methanogenesis did not proceed at 45{degrees}C. During the first 50 days of anaerobic incubation, 5 {approximately} 63% (carbon basis) of indigeneous plant leaves were mineralized. The mineralization rate was strongly and negatively correlated with the lignin and/or fiber contents, but not the C/N ratio, of the substrate plant materials. Difference in {delta}{sup 13}C between the substrate, indicating that H{sub 2} as opposed to acetate becomes a more important metabolic intermediate in the anaerobic food web when the decomposition rate is limited by substrate recalcitrance. Thus, the CH{sub 4} isotope signature may be used to evaluate the importance of new vs. old organic matter as CH{sub 4} isotope signature may be used to evaluate the importance of new vs. old organic matter as CH{sub 4} source in natural soils. The mineralization rate was higher, and the isotopic difference between the substrate and CH{sub 4} was smaller when plant materials were incubated with sulfate-contaminated soils than with native peat soils. The isotopic difference between the substrate and CH{sub 4} was significantly different between native peat soils. Results of a tracer experiment using {sup 13}C-labeled substrates indicated that these differences could be ascribed to difference in the mode of acetate metabolism between soils. 49 refs., 8 figs., 7 tabs.

Miyajima, Toshihiro [Univ. of Tokyo, Nakano (Japan); Wada, Eitaro; Hanba, Yuko T. [Kyoto Univ., Otsu (Japan); Vijarnsorn, P. [Dept. of Land Development, Bangkok (Thailand)

1997-09-01

183

Phosphate fixation by ando soils different in their clay mineral composition  

Microsoft Academic Search

The phosphate fixation capacity at pH 4.5 and an equilibrium concentration of 250 mM phosphate was measured. The soil samples were divided into five groups according to their clay mineralogical composition. The first group soils contain opaline silica and allophanelike constituents, and some unidentified minerals, the second opaline silica and crystalline layer .i1icates, the third opaline silica and crystalline layer

Chitoshi Mizota

1977-01-01

184

Transformations of mineral nitrogen applied to peat soil during sequential oxic\\/anoxic cycling  

Microsoft Academic Search

Shifts in oxic and anoxic conditions in soil are most frequently caused by water table fluctuations, heavy rain, snowmelt or flooding, with potentially significant impacts on microbial processes and the ability of soils to convert mineral nitrogen to nitrogen gases efficiently. The impact of oxic\\/anoxic cycles on nitrogen transformation rates was therefore explored in the upper layer (0–30 cm) of partially

Levin Pal; Blaž Stres; Tjaša Danev?i?; Simona Leskovec; Ines Mandic-Mulec

2010-01-01

185

Anaerobic mineralization of indigenous organic matters and methanogenesis in tropical wetland soils  

NASA Astrophysics Data System (ADS)

Tropical wetlands are one of the largest natural sources in the global methane budget due to high biological activities and the anaerobiosis in soil. We studied mineralization and gas production during the early stage of anaerobic decomposition of indigenous organic matters in soils of Narathiwat, southern Thailand, to clarify the significance of the substrate quality in controlling decomposition and methanogenesis in some different tropical wetland soils. The optimal temperature of decomposition was around 35°C, while methanogenesis did not proceed at 45°C. During the first 50 days of anaerobic incubation, 5 ˜ 63% (carbon basis) of indigenous plant leaves were mineralized. The mineralization rate was strongly and negatively correlated with the lignin and/or fiber contents, but not theC/N ratio, of the substrate plant materials. Difference in ? 13C between the substrate and the produced CH 4 was generally greater (more negative in CH 4) for more recalcitrant substrates, indicating that H 2 as opposed to acetate becomes a more important metabolic intermediate in the anaerobic food web when the decomposition rate is limited by substrate recalcitrance. Thus, the CH 4 isotope signature may be used to evaluate the importance of new vs. old organic matter as CH 4 source in natural soils. The mineralization rate was higher, and the isotopic difference between the substrate and CH 4 was smaller when plant materials were incubated with sulfate-contaminated soils than with native peat soils. The isotopic difference between the substrate and CH 4 was significantly different between native peat soils. Results of a tracer experiment using 13C-labeled substrates indicated that these differences could be ascribed to difference in the mode of acetate metabolism between soils.

Miyajima, Toshihiro; Wada, Eitaro; Hanba, Yuko T.; Vijarnsorn, Pisoot

1997-09-01

186

Microbial, physical, and chemical factors causing higher gross rate and lower net rate of nitrogen mineralization in volcanic ash soils than in alluvial soils in the Tokachi District  

Microsoft Academic Search

To test the hypothesis that a lower net rate of nitrogen (N) mineralization is due to a smaller ratio of N mineralization rate to immobilization rate in Brown Andosols (BA, Typic Low-humic Andosls, U.S. Soil Taxonomy: Typic Hapludands, FAO \\/ Unesco: Haplic Andosols) which have a higher gross N mineralization rate caused by a larger microbial biomass compared with Brown

Rikiya Nira

2003-01-01

187

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.

188

The role of organic matter in controlling aluminum solubility in acidic mineral soil horizons  

NASA Astrophysics Data System (ADS)

Despite the ecological importance of potentially phytotoxic Al, its solubility control in acidic mineral soils remains unresolved. We examined the solubility of Al in mineral horizons of two acidic forest soils (Inceptisol and Spodosol) in southern Sweden using a series of batch experiments. Dissolution of Al was found to consist of a rapid solubilization of reactive solid phase Al, which quickly reached an equilibrium state, superimposed on a slow dissolution of less reactive Al-containing phases (e.g., primary Al-silicates). Titration experiments in the pH range 3.2-4.7 using an equilibration time of 5 days showed that at pH < 4.1, all suspensions were undersaturated with respect to gibbsite (Al(OH) 3; log ?K SO = 8.85 at 8° C) . Under such conditions, the Al solubility could be explained qualitatively by equilibrium complexation reactions with soil organic matter. Quantitatively, our results could be reproduced reasonably well using the mechanistic model WHAM, which describes the binding of Al by humic substances in organic soils. This suggests that the pool of organically bound soil Al controls the Al solubility in suspensions of strongly acidic soils. Due to the kinetically constrained release of Al from primary and secondary minerals, the amount of organically bound Al, and therefore the Al solubility in the suspensions, gradually increases with time. Consequently, a quantitative evaluation of Al solubility data from long-term batch experiments should consider both equilibrium and kinetic processes.

Berggren, Dan; Mulder, Jan

1995-10-01

189

The influence of biological soil crusts on mineral uptake by associated vascular plants  

USGS Publications Warehouse

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 soil crusts on mineral uptake of associated vascular plants is known. These new case studies, and others previously published, demonstrate that cyanobacterial or cyanobacteria- Collema crusts significantly alter uptake by plants of many bioessential elements. In studies now available, these crusts always increase the N content of associated seed plants. Uptake of Cu, K, Mg, and Zn is usually (>70% of reported cases) increased in the presence of the biological soil crusts. Soil crusts are generally negatively associated with Fe and P levels in associated seed plant tissue, while plant tissue levels of Ca, Mn, and Na are positively as often as negatively associated with the presence of soil crusts. Increases in bioessential elements in vascular plant tissue from biologically-crusted areas are greatest for short-lived herbs that are rooted primarily within the surface soil, the horizon most influenced by crustal organisms. The mineral content of a deeply rooted shrub (Coleogyne ramosissima) was less influenced by co-occurrence of biological soil crusts.

Harper, K. T.; Belnap, Jayne

2001-01-01

190

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

NASA Astrophysics Data System (ADS)

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 the dissolution of these particles in samples of the same soil, in a sand matrix and in acid solution under constant temperature and moisture conditions in the laboratory. Under field conditions the PbO particles dissolved quite rapidly (2.4 ± 0.7 × 10 -10 mol Pb m -2 s -1), whereas the copper concentrate (<1 × 10 -11 mol Cu m -2 s -1) and the copper slag particles (4.3 ± 0.8 × 10 -11 mol Cu m -2 s -1) proved to be more resistant to weathering. In addition to qualitative information on dissolution features (SEM), the method yielded quantitative data on in situ dissolution rates. The dissolution rates followed the order: sand with acid percolation (pH 3.5; lab) < soil (lab) < soil (field) < acid solution (pH 3.5; lab). Dissolution rates in soil were found to be lower under laboratory than under field conditions. The faster field rates may in part be attributed to the higher biological activity in the field soil compared to the same soil in the laboratory.

Birkefeld, Andreas; Schulin, Rainer; Nowack, Bernd

2006-06-01

191

Canadian Field Soils I. Mineral Composition by XRD/XRF Measurements  

NASA Astrophysics Data System (ADS)

Forty Canadian soils were laboratory tested for the presence of quartz and other minerals using X-ray diffraction/X-ray fluorescence techniques. On average, the highest quartz content was observed in soil samples from sites in Nova Scotia followed by Prince Edward Island sites, whereas soil sample from British Columbia sites had the lowest quartz content. The second most abundant mineral was albite that mainly occurred in soil samples from Ontario and Quebec sites. Illite was the third most abundant and prevailed in soils mainly from British Columbia and New Brunswick sites. Soil samples from British Columbia sites had the highest combined clay and silt content and were composed of illite, albite, kaolinite, and chlorite. The lowest clay content was found in the samples from the Quebec sites. The highest microcline (a potassium feldspar) content was observed in Quebec, Ontario, and Prince Edward Island sites. In contrast to other provinces, samples from Quebec and Ontario sites also included amphibole. Soil samples from Saskatchewan and Manitoba sites also comprised carbonates, i.e., calcite and dolomite. Iron oxides (e.g., goethite) were present in all soils, except the Quebec sites, but their occurrence was rather insignificant.

Schönenberger, J.; Momose, T.; Wagner, B.; Leong, W. H.; Tarnawski, V. R.

2012-02-01

192

Effect of pH on the adsorption of carbendazim in Polish mineral soils.  

PubMed

The study aimed to determine the influence of pH on the adsorption of carbendazim in soil profiles of three mineral agricultural soils: Hyperdystric Arenosol, Haplic Luvisol and Hypereutric Cambisol. In the examined pH range between 3 and 7 the adsorption of carbendazim was inversely correlated to the pH of the soil. The adsorption coefficients were in the range between 0.3 and 151.8 m Lg(-1). Decreasing the pH in the soil suspensions from 7 to 3 increased the value of this coefficient by 3 to 70 times. A decrease in the amounts of organic matter down the soil profiles was not associated with weaker carbendazim adsorption. In the samples from all soil horizons, at pH values between 3 and 6, the predominant sorption process was carbendazim adsorption on clay minerals. The adsorption of carbendazim on organic matter prevailed over that on clays only at pH>6 and only in the Ap horizon of the examined soils. The developed mathematical models yielded very good results when the adsorption of the protonated form of carbendazim was assumed to be the predominant adsorption process on clays together with the adsorption of neutral molecules on organic matter and clays. The results from both the model fitting and the experiments revealed the negative effect of Al oxides and hydroxides and Al cations on the adsorption of the protonated form of carbendazim on clay minerals. The developed models successfully described the pH-dependent adsorption processes of carbendazim for both data from particular soil horizons and those from all three examined soil profiles. PMID:22854093

Paszko, Tadeusz

2012-07-31

193

Clay mineral formation and transformation in rocks and soils  

USGS Publications Warehouse

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 dilute solutions favoring formation of the least soluble clays. After erosion and transportation, these clays may be deposited on the ocean floor in a lateral sequence that depends on floccule size. Clays undergo little reaction in the ocean, except for ion exchange and the neoformation of smectite; therefore, most clays found on the ocean floor are inherited from adjacent continents. Upon burial and heating, however, dioctahedral smectite reacts in the diagenetic environment to yield mixed-layer illite-smectite, and finally illite. With uplift and weathering, the cycle begins again. Refs.

Eberl, D. D.

1983-01-01

194

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

195

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

196

Nanoparticulate Iron Oxide Minerals in Soils and Sediments: Unique Properties and Contaminant Scavenging Mechanisms  

Microsoft Academic Search

Nanoparticulate goethite, akaganeite, hematite, ferrihydrite and schwertmannite are important constituents of soils, sediments and mine drainage outflows. These minerals have high sorption capacities for metal and anionic contaminants such as arsenic, chromium, lead, mercury and selenium. Contaminant sequestration is accomplished mainly by surface complexation, but aggregation of particles may encapsulate sorbed surface species into the multigrain interior interfaces, with significant

Glenn A. Waychunas; Christopher S. Kim; Jillian F. Banfield

2005-01-01

197

Carbon flux to surface mineral soil after Nitrogen and Phosphorus fertilization  

SciTech Connect

The movement of organic carbon into the mineral soil profile was increased by a factor of 2 to 3 following urea application to the forest floor. Approximately 74% of the organic carbon movement occurred during the first 3 months following treatment. Phosphorus treatment and the interaction of nitrogen and phosphorus did not produce a statistically significant response.

Kelly, J.M.

1981-05-01

198

Contributions of soil fauna to decomposition and mineralization processes in semiarid and arid ecosystems  

Microsoft Academic Search

This review examines the following questions: (1) do soil fauna play an important regulatory role in decomposition and mineralization processes in arid and semiarid ecosystems? (2) if important, what are the mechanisms of the rate regulation, and (3) what are the management implications of these relationships? Because termites process more than half of the surface litter in hot deserts, this

Walter G. Whitford; Lawrence W. Parker

1989-01-01

199

Influence of sewage sludge compost stability and maturity on carbon and nitrogen mineralization in soil  

Microsoft Academic Search

Incubation experiments with soil were made to study C and N mineralization in a sewage sludge–cotton waste mixture at different stages of the composting process performed by the Rutgers static pile system. Three composting samples were selected: initial mixture (I); the end of the active phase (E); and the mature compost (M). The CO2-C evolved (as % of added C)

M. P. Bernal; A. F. Navarro; M. A. Sánchez-Monedero; A. Roig; J. Cegarra

1998-01-01

200

Long-Term Base Cation Balances of Forest Mineral Soils in Finland  

Microsoft Academic Search

Long-term base cation balances (Ca, Mg and K) for forest mineral soils in Finland were calculated with mass balance methods. The aim of the study was to identify the areas in which weathering and base cation deposition do not support leaching and uptake of base cations by vegetation. The effect of stem harvesting and whole-tree harvesting on the base cation

Päivi Joki-Heiskala; Matti Johansson; Maria Holmberg; Tuija Mattsson; Martin Forsius; Pirkko Kortelainen; Lena Hallin

2003-01-01

201

On the origin of superparamagnetic minerals of tropical soils and their impact on landmine detection  

Microsoft Academic Search

Magnetic susceptibility of soils is mainly determined by their content of ferrimagnetic minerals whereas titanomagnetite, magnetite and maghemite being the most important ones. Titanomagnetite and magnetite are of magmatic origin, i.e. they crystallise during cooling of iron-rich magma and are part of many igneous rocks. Maghemite and sometimes magnetite are of pedogenic origin. They develop by crystallisation of dissolved iron

Jan Igel; Holger Preetz; Sven Altfelder

2010-01-01

202

Characterization of Malaysian sewage sludge and nitrogen mineralization in three soils treated with sewage sludge  

Microsoft Academic Search

Studies to determine the chemical composition of sewage sludges produced in Malaysia and the potentially mineralizable nitogen (No) and mineralization rate constant (k) of sewage sludge in three Malaysian soils are reported. Analyses of the sludges collected from 10 wastewater treatment plants in Malaysia are acidic in nature and the N. P, Ca, K and Mg contents is variable. The

A. B. Rosenani; D. R. Kala; C. I. Fauziah

203

Optimized N-mineralization parameters of loess soils from incubation experiments  

Microsoft Academic Search

Summary Nitrogen mineralization from long term incubation experiments with dried loess soils from southern Lower Saxony has been split by an optimization procedure into three contributing fractions: one from the resistant organic material (index rpm), another from decomposable plant residues (index dpm), and a third one from autolyzing microbial biomass (index bom). The nitrogen contents at the end of February

J. Richter; A. Nuske; W. Habenicht; J. Bauer

1982-01-01

204

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

205

Mineral composition of native woody plants growing on a serpentine soil in California  

SciTech Connect

Using optical emission spectrography, we analyzed leaves of five native plant species (Adenostoma fasciculatum, Arctostaphylos viscida, Cupressus macnabiana, Cupressus sargentii, and Quercus durata) for mineral elements. There were 112 plants in all. In these plants, which are reasonably adapted to serpentine soil conditions, the calcium:magnesium ratios were normal in contrast to plants not adapted to such soil conditions. The nickel concentrations in the leaves were low for serpentine soil conditions, and there was no tendency for accumulation of chromium or cobalt. Strontium varied, as did calcium.

Wallace, A.; Jones, M.B.; Alexander, G.V.

1982-07-01

206

Litter carbon inputs to the mineral soil of Japanese Brown forest soils: comparing estimates from the RothC model with estimates from MODIS  

Microsoft Academic Search

The level of organic carbon found in soil is the result of the balance between litter input to the soil and decomposition.\\u000a Litter input to the soil is closely related to net primary production (NPP); at equilibrium, the NPP is equal to the litter\\u000a input to soil. Plant litter input to a depth of 30 cm in the mineral soil was

Shoji Hashimoto; Martin Wattenbach; Pete Smith

2011-01-01

207

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

2013-01-24

208

Bacterial Diversity in Three Different Antarctic Cold Desert Mineral Soils  

Microsoft Academic Search

A bacterial phylogenetic survey of three environmentally distinct Antarctic Dry Valley soil biotopes showed a high proportion of so-called “uncultured” phylotypes, with a relatively low diversity of identifiable phylotypes. Cyanobacterial phylotypic signals were restricted to the high-altitude sample, whereas many of the identifiable phylotypes, such as the members of the Actinobacteria, were found at all sample sites. Although the presence

Jacques J. Smith; Lemese Ah Tow; William Stafford; Craig Cary; Donald A. Cowan

2006-01-01

209

Degradation and Mineralization of Atrazine by a Soil Bacterial Isolate  

Microsoft Academic Search

An atrazine-degrading bacterial culture was isolated from an agricultural soil previously impacted by herbicide spills. The organism was capable of using atrazine under aerobic conditions as the sole source of C and N. Cyanuric acid could replace atrazine as the sole source of N, indicating that the organism was capable of ring cleavage. Ring cleavage was confirmed in 14CO2 evolution

MARK RADOSEVICH; SAMUEL J. TRAINA; YUE-LI HAO; ANDOLLI H. TUOVINEN

1995-01-01

210

Soil organic carbon quality in forested mineral wetlands at different ...  

Treesearch

... systems because long anaerobic periods favor the accumulation of labile substrates. Second, in FMSW, SOC quality decreases from cold to warm bioregions ... and upland forest soils at two constant temperatures (10 and 30°) for 525-d under ... Government employees on official time, and is therefore in the public domain.

211

Impact of soils minerals and properties with application of MSMA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Straighthead is a physiological disorder of rice and threatens rice production in southern states. It is know that arsenic (As) is closely associated with occurrence of straighthead, so soil application of MSMA (monosodium methanearsonate) is commonly used to study this disease. Analysis was conduct...

212

ROLE OF SOIL ORGANIC ACIDS IN MINERAL WEATHERING PROCESSES  

EPA Science Inventory

The soluble organic acids in soils consist largely of complex mixtures of polymeric compounds referred to collectively as fluvic and humic acids. These compounds are relatively refactory, and are broken down only slowly by bacteria. ow-molecular-mass acids (e.g., acetic, oxalic, ...

213

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

PubMed

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 are ecosystem engineers known to affect the dynamics of SOM. Endogeic earthworms ingest large amounts of soil and assimilate a part of organic matter it contains. During gut transit, microorganisms are transported to new substrates and their activity is stimulated by (i) the production of readily assimilable organic matter (mucus) and (ii) the possible presence of fresh organic residues in the ingested soil. The objective of our study was to see (i) whether earthworms impact the PE intensity when a fresh residue is added to a tropical soil and (ii) whether this impact is linked to a stimulation/inhibition of bacterial taxa, and which taxa are affected. A tropical soil from Madagascar was incubated in the laboratory, with a (13)C wheat straw residue, in the presence or absence of a peregrine endogeic tropical earthworm, Pontoscolex corethrurus. Emissions of (12)CO(2) and (13)CO(2) were followed during 16 days. The coupling between DNA-SIP (stable isotope probing) and pyrosequencing showed that stimulation of both the mineralization of wheat residues and the PE can be linked to the stimulation of several groups especially belonging to the Bacteroidetes phylum. PMID:21753801

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

2011-07-14

214

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

PubMed Central

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 are ecosystem engineers known to affect the dynamics of SOM. Endogeic earthworms ingest large amounts of soil and assimilate a part of organic matter it contains. During gut transit, microorganisms are transported to new substrates and their activity is stimulated by (i) the production of readily assimilable organic matter (mucus) and (ii) the possible presence of fresh organic residues in the ingested soil. The objective of our study was to see (i) whether earthworms impact the PE intensity when a fresh residue is added to a tropical soil and (ii) whether this impact is linked to a stimulation/inhibition of bacterial taxa, and which taxa are affected. A tropical soil from Madagascar was incubated in the laboratory, with a 13C wheat straw residue, in the presence or absence of a peregrine endogeic tropical earthworm, Pontoscolex corethrurus. Emissions of 12CO2 and 13CO2 were followed during 16 days. The coupling between DNA-SIP (stable isotope probing) and pyrosequencing showed that stimulation of both the mineralization of wheat residues and the PE can be linked to the stimulation of several groups especially belonging to the Bacteroidetes phylum.

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

2012-01-01

215

Effect of redox potential and pH on arsenic speciation and solubility in a contaminated soil  

SciTech Connect

The influence of redox potential and pH on arsenic speciation and solubility was studied in a contaminated soil. Alterations in the oxidation state of arsenic, and influenced by redox potential and pH, greatly affected its solubility in soil. At higher soil redox levels (500-200 mV), arsenic solubility was low and the major part (65-98%) of the arsenic in solution was present as As(V). An alkaline pH, or the reduction of As(V) to As(III), released substantial proportions of arsenic into solution. Under moderately reduced soil conditions (0-100 mV), arsenic solubility was controlled by the dissolution of iron oxyhydroxides. Arsenic was coprecipitated (as As(V)) with iron oxyhydroxides and released upon their solubilization. Upon reduction to {minus}200 mV, the soluble arsenic content increased 13-fold as compared to 500 mV. The observed slow kinetics of the As(V)-As(III) transformation and the high concentrations of Mn present indicate that, under reduced soil conditions, arsenic solubility could be controlled by a Mn{sub 3}(AsO{sub 4}){sub 2} phase.

Masscheleyn, P.H.; Delaune, R.D.; Patrick, W.H. Jr. (Louisiana State Univ., Baton Rouge (United States))

1991-08-01

216

[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

217

Transformation and mineralization of 14C-labeled cellulose, peptidoglycan, and protein by the soil-feeding termite Cubitermes orthognathus  

Microsoft Academic Search

We performed feeding trials with the soil-feeding termite Cubitermes orthognathus using soil spiked by uniformly 14C-labeled preparations of cellulose, peptidoglycan, protein, and bacterial cells (Bacillus megaterium and Escherichia coli). When incubated in soil for 8 days in the absence of termites, cellulose and peptidoglycan showed low mineralization rates\\u000a (0.5% and 0.2%, respectively). However, when termites were present, their mineralization rates

R. Ji; A. Brune

2001-01-01

218

Effects of in situ biostimulation on iron mineral speciation in a sub-surface soil  

NASA Astrophysics Data System (ADS)

The in situ alteration of Fe redox states in subsurface soils by bacteria, otherwise known as bioreduction, may play a key role in the immobilization of hazardous redox active metals such as U, Tc, and Cr. The objective of this study was to characterize changes in Fe mineralogy occurring in a subsurface soil as a result of biostimulation in order to evaluate the bioremediation potential of this approach. Biostimulation was achieved by injecting glucose into the soil through a small well next to a sampling well. Cores taken from the sampling well were analyzed by variable-temperature 57Fe Mössbauer spectroscopy. Results revealed that biostimulation resulted in an overall loss of Fe from the system and major changes in the distribution of its oxide and oxyhydroxide mineral forms. Compared to the non-biostimulated soil, the spectral components assigned to goethite were greatly diminished in intensity in the samples that had been biostimulated, whereas the hematite component was appreciably increased. The Fe(II):Fe(III) ratio in the non-oxide phase (aluminosilicate clay minerals) also increased, indicating that the bioreduction processes in the soil also affected the redox state of Fe in the constituent clay minerals.

Stucki, Joseph W.; Lee, Kangwon; Goodman, Bernard A.; Kostka, Joel E.

2007-02-01

219

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

220

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

221

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

222

Measuring Forest Floor, Mineral Soil, and Root Carbon Stocks  

Microsoft Academic Search

In forest and wildland ecosystems, forest floor and soil carbon (C) comprise a large C pool that is often of similar magnitude\\u000a to or greater than aboveground C storage. These C pools often change slowly over time, but they are susceptible to rapid release\\u000a to the atmosphere following natural or human-caused disturbances. Accurate estimates of these pools are needed both

Andrew J. Burton; Kurt S. Pregitzer

223

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

224

Ectomycorrhizal influence on particle size, surface structure, mineral crystallinity, functional groups, and elemental composition of soil colloids from different soil origins.  

PubMed

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

2013-05-23

225

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

226

Influence of edaphic factors on the mineralization of neem oil coated urea in four Indian soils.  

PubMed

The utility of neem (Azadirachta indica A Juss) oil coated urea as a value-added nitrogenous fertilizer has been now widely accepted by Indian farmers and the fertilizer industry. In the present study, the expeller grade (EG) and hexane-extracted (HE) neem oils, the two most common commercial grades, were used to prepare neem oil coated urea (NOCU) of various oil doses, for which mineralization rates were assessed in four soils at three incubation temperatures (20, 27, and 35 degrees C). Neem oil dose-dependent conservation of ammonium N was observed in NOCU treatments in all of the soils. However, a longer incubation period and a higher soil temperature caused depletion of ammonium N. Overall, the nitrification in NOCU treatment averaged 56.6% against 77.3% for prilled urea in four soils. NOCU prepared from EG neem oil was consistently superior to that derived from hexane-extracted oil. The performance of NOCUs was best in coarse-textured soil and poorest in sodic soil. The nitrification rate (NR) of the NOCUs in the soils followed the order sodic > fine-textured > medium-textured > coarse-textured. The influence of edaphic factors on NR of NOCUs has been highlighted. The utility of the present study in predicting the performance of NOCU in diverse Indian soils was highlighted through the use of algorithms for computation of the optimum neem oil dose that would cause maximum inhibition of nitrification in any soil. PMID:18841982

Kumar, Rajesh; Devakumar, C; Kumar, Dinesh; Panneerselvam, P; Kakkar, Garima; Arivalagan, T

2008-10-09

227

Cadmium, copper, lead, and zinc in secondary sulfate minerals in soils of mined areas in Southeast Spain  

Microsoft Academic Search

Soils in mined areas in southeastern Spain are commonly characterized by extreme acidity, high salinity, and metals. These present challenges to establish vegetation as a management option for these environmentally-problematic landscapes. We collected salt efflorescence and the corresponding soil materials to better understand the geochemical cycling of Cd, Cu, Pb, and Zn in soils of mined areas. Mineral composition was

D. M. Carmona; Á. Faz Cano; J. M. Arocena

2009-01-01

228

A proposed use of ion exchange resins to measure nitrogen mineralization and nitrification in intact soil cores  

Microsoft Academic Search

A procedure is proposed for measuring nitrogen mineralization and nitrification in intact soil cores. The method relies on ion exchange resins to trap ammonium and nitrate entering and leaving cores of soil otherwise open at the top and bottom. Changes in soil concentrations plus an accounting of ions trapped by the lower resin after field incubations, indicate rates of nitrogen

J. Fco. DiStefano; H. L. Gholz

1986-01-01

229

Effect of Liming on the Mineral Nutrition and Yield of Growing Guava Trees in a Typic Hapludox Soil  

Microsoft Academic Search

Abstract: High soil acidity influences the availability of mineral nutrients and increases that of toxic aluminium (Al), which has a jeopardizing effect on plant growth. The objective of this research was to evaluate the effects of soil liming on the development of guava (Psidium guajava L.) plants, on soil chemical characteristics, and on fruit yield. The experiment was carried out

Renato de Mello Prado; William Natale

2008-01-01

230

Mineral Composition and Dry Mass Production of Corn Plants Affected by Different Phosphate Sources and Different Soil Aluminum Saturation Levels  

Microsoft Academic Search

The effects of different commercial phosphate fertilizers [Triple superphosphate (TSP), Tricalcium phosphate (TCP), and ARAD rock phosphate) and soil aluminum (Al) saturation (86, 29, and 0%) on the mineral composition and dry mass production of corn (Zea mays) plants were studied. As soil Al saturation values decreased, pH, calcium (Ca), and magnesium (Mg) levels in the soil increased. High Ca

J. C. Pintro; T. T. Inoue; C. A. Tormena; A. C. S. Costa; M. A. G. Silva

2005-01-01

231

Organo-mineral interactions mask the true sorption potential of biochars in soils.  

PubMed

The sorption of carbaryl (1-naphthyl methyl carbamate) and ethion [O,O,O',O'-tetraethyl S,S'-methylene bis(phosphorodithioate)] was studied in whole soils as well as after treatment of soil with 2% hydrofluoric acid (HF) to remove paramagnetic materials and to oxidize most forms of labile carbon by photo-oxidation with high energy (UV) on < 53 microm fractions. The sorption coefficient (K(d)) values for carbaryl and ethion in soils did not follow the order of their organic carbon (OC) content, and specially their char content However, the K(oc) values in < 53 microm fractions after hydrofluoric acid/photo-oxidation with high energy (hydrofluoric acid/ultraviolet; HF/UV) treatment were found to be much higher than those in bulk untreated soils. The effect of organic matter chemistry was determined by correlating K(oc) values of contaminants in bulk soils or 53 microm fractions against sample aromaticity. A poor correlation of K(oc) in bulk soil and aromatic C values of both carbaryl and ethion was observed. However, the correlation between the K(oc) and the aromatic fraction of C after the HF/UV treatment improved significantly, reflecting the contribution of char fraction of carbon in soils towards sorption of pesticides. The increase in sorption after HF/UV treatment suggested that the sorption potential of biochars, which are expected to contribute significantly to contaminant sorption due to their high surface area, can remain masked by the organo-mineral interactions of char in whole soils. This has implications for the modification of surfaces of the freshly applied biochars in soils due to organo-mineral interactions. PMID:19280473

Singh, Neera; Kookana, Rai S

2009-03-01

232

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

233

Topsoil organic carbon mineralization and CO2 evolution of three paddy soils from South China and the temperature dependence.  

PubMed

Carbon mineralization and its response to climatic warming have been receiving global attention for the last decade. Although the virtual influence of temperature effect is still in great debate, little is known on the mineralization of organic carbon (SOC) of paddy soils of China under warming. SOC mineralization of three major types of China's paddy soils is studied through laboratory incubation for 114 d under soil moisture regime of 70% water holding capacity at 20 degrees C and 25 degrees C respectively. The carbon that mineralized as CO2 evolved was measured every day in the first 32 d and every two days in the following days. Carbon mineralized during the 114 d incubation ranged from 3.51 to 9.22 mg CO2-C/gC at 20 degrees C and from 4.24 to 11.35 mg CO2-C/gC at 25 degrees C respectively; and a mineralizable C pool in the range of 0.24 to 0.59 gC/kg, varying with different soils. The whole course of C mineralization in the 114 d incubation could be divided into three stages of varying rates, representing the three subpools of the total mineralizable C: very actively mineralized C at 1-23 d, actively mineralized C at 24-74 d and a slowly mineralized pool with low and more or less stabilized C mineralization rate at 75-114 d. The calculated Q10 values ranged from 1.0 to 2.4, varying with the soil types and N status. Neither the total SOC pool nor the labile C pool could account for the total mineralization potential of the soils studied, despite a well correlation of labile C with the shortly and actively mineralized C, which were shown in sensitive response to soil warming. However, the portion of microbial C pool and the soil C/N ratio controlled the C mineralization and the temperature dependence. Therefore, C sequestration may not result in an increase of C mineralization proportionally. The relative control of C bioavailability and microbial metabolic activity on C mineralization with respect to stabilization of sequestered C in the paddy soils of China is to be further studied. PMID:17918594

Zhang, Xu-Hui; Li, Lian-Qing; Pan, Gen-Xing

2007-01-01

234

A disconnect between O horizon and mineral soil carbon - implications for soil C sequestration  

Microsoft Academic Search

Changing inputs of carbon to soil is one means of potentially increasing carbon sequestration in soils for the purpose of mitigating projected increases in atmospheric CO2 concentrations. The effect of manipulations of aboveground carbon input on soil carbon storage was tested in a temperate, deciduous forest in east Tennessee, USA. A 4.5-year experiment included exclusion of aboveground litterfall and supplemental

Charles T. Garten Jr.

2009-01-01

235

Net N and C mineralization and soil microbial biomass with elevated CO2 in a Mojave Desert ecosystem  

NASA Astrophysics Data System (ADS)

We quantified changes in soil microbial activity and N availability with elevated CO2 in a Mojave Desert ecosystem by measuring microbial biomass N and net N and C mineralization in long-term (280 d) incubations of soil from four different cover types: Lycium spp., Larrea tridentata, Pleuraphis rigida, and plant interspaces. We also measured soil respiration in the field under the same cover types. There was no effect of elevated CO2 on microbial biomass N. Soils from under Larrea and Lycium had higher microbial biomass N (52.94 mg kg-1) than soils from plant interspaces (31.55 mg kg-1). Soil ?15N increased during the incubation (7.3 vs. 6.3‰ ), reflecting microbial activity; but there was no difference in soil ?15N with CO2 treatment. Carbon mineralization for soils under Lycium was 40% greater with elevated CO2 for the last four of the seven extraction dates. Soils from interspaces had significantly lower amounts of C mineralized (1.89 +/- 0.11 g kg-1) than soils from under shrubs (2.99 +/- 0.38 g kg-1). On the last extraction date, soils from under Lycium experienced 40% greater net N mineralization with elevated CO2. Soils from under shrubs experienced greater cumulative net N mineralization (102.64 +/- 24.15 ng kg-1) than soils from under grasses and plant interspaces (39.96 +/- 9.69 ng kg-1). Mean soil respiration across all cover types was higher with elevated CO2 (2.72 +/- 0.50 vs. 1.59 +/- 0.29 µ g C m-2 s-1). These results indicate four findings: 1) microbial activity can result in shifts in bulk soil ?15N; 2) shifts in soil microbial activity and/or structure may occur with elevated CO2; 3) these shifts may increase gross N mineralization, but increases in microbial immobilization can limit changes in net mineralization; and 4) increased rhizosphere activity can occur with elevated CO2. We suggest that elevated CO2 may induce increases in rhizodeposition and/or soil microbial activity that promote both gross N mineralization and immobilization.

Billings, S. A.; Schaeffer, S. M.; Evans, R. D.

2002-12-01

236

Seedling growth and mineral nutrition of Scots pine under acidic to calcareous soil conditions  

SciTech Connect

The growth and mineral nutrition of Scots pine (Pinus sylvestris L.) seedlings under a shift from an acidic to a calcareous soil chemical environment using a Chernozemic soil were investigated. The study consisted of a greenhouse experiment to evaluate the response of Scots pine to changes in soil chemistry, specifically, increasing soil pH, soluble ions, and CaCO/sub 3/. As the soil pH increased from 5.5-6.2, seedling weight and height decreased 15 and 37%, respectively. Further growth decreases were related to soil EC and soluble Ca levels in excess of 2 dS x m/sup -1/ and 11-19 meq x meq x L/sup -1/, respectively. In addition, active CaCO/sub 3/ and NO/sub 3-/N were also factors in conifer growth. Plant analysis indicated that increasing cation uptake, especially Ca, was associated with organic anion accumulation and a decrease in P uptake. The decrease in seedling weight was also related to organic anion accumulation. The Ca to P ratio in the seedlings increased from 2.6 to 9.9 as the soil pH increased from 5.5 to 7.9, respectively. Expressing nutrient content in proportions relative to N indicated an imbalance of Ca and K to P as soil acidity decreased. Mean proportions of nutrient content (N:P:K:Ca:Mg) were 100:5:48:14:7 and 100:3:61:33:7 at a soil pH of 5.5 and 7.9, respectively. Scots pine on high base-saturated Chenozemic soils, with neutral pH and acceptable EC and soluble Ca levels, will show a slight but significant reduction in growth rate compared with acidic soil conditions.

Carter, M.R.

1987-09-01

237

A field method for the determination of nitrogen mineralization in forest soils  

NASA Astrophysics Data System (ADS)

The mineralization of nitrogen in forest soils, one of the processes that provides forest ecosystems with nitrogen, has practically not been studied in Russia. A variant of the method used for the measurement of the nitrogen mineralization in forest soils is proposed, and a description of its field and laboratory stages is given. At the field stage, as the ammonium concentrations are determined in the soil horizons, eight soil samples free of plants and plant roots are recommended to be exposed in a uniform forest area in order to provide a 10% error of the average. The results obtained in a laboratory by the traditional method of measuring the ammonium content in litter extracts may be overstated by 5 times (on the average, by 1.7 times) as compared to the results obtained by the diffusion-isothermic method proposed. The source of errors in the former method is the specific features of Nessler’s reagent, which forms colored complexes with metals and organic compounds. In addition, extracts from loamy soils often grow turbid and opalescent at the addition of Nessler’s reagent, which makes the measurement of the optical density impossible. A highly sensitive and well-reproducible method is recommended for the reduction of nitrates to nitrites in a column with coppered cadmium. The methods proposed are simple and reliable and do not require the expensive autoanalyzers that are used abroad.

Razgulin, S. M.

2009-11-01

238

Mineral control of soil carbon storage with reforestation of abandoned pastures  

NASA Astrophysics Data System (ADS)

We applied CP MAS 13C-NMR spectroscopy and radiocarbon modeling to soil C density fractions to track changes in the quality and turnover of C with forest regrowth on former pasturelands. Our results showed that inter-aggregate, unattached particulate organic C (free light fraction) and C located inside soil aggregates (occluded light fraction) represent distinct soil C pools. The signal intensity of the O-alkyl region, representing cellulose, decreased with mineral-association, while alkyl C, attributed to waxy compounds and microbially resynthesized lipids, increased from the free to the occluded light fractions. The alkyl/O-alkyl ratio changed consistently with changes in C-to-N and ?15N across different land cover types, and thus appears to be a reliable index of humification. In contrast to cellulose, proteins, lipids and lignin did not show any consistent trends, suggesting different controls on their decomposition. Greater variability in the chemical makeup of the occluded light fraction suggests that it represents material in different stages of decay. Mean residence times (MRT) of the free light C were significantly shorter (4.3 ± 0.5 yrs) than for the occluded fraction (7.3 ± 0.8 yrs). The occluded fraction in active pastures and secondary forests in the earliest stage of succession had shorter MRT than in primary forests and older secondary forests, which would be explained by lower aggregate stability and faster cycling rates in disturbed versus undisturbed soils. The mineral associated C in the disturbed soils had slower cycling C (MRT = 98.9 ± 10.6 yrs) than the undisturbed sites (65.8 ± 2.1 yrs), most likely due to a preferential loss of labile C in the first. Incorporation of C into soil aggregates afforded some protection from decomposition, but the main mechanism of stabilization was direct mineral association. As the sorptive capacity of a soil is dependent on its mineral composition, it appears that the Oxisols at our sites have reached their maximum C storage capacity. This may explain their resiliency to land-use change and why we have observed no significant accumulation of soil C despite large increases in aboveground biomass with reforestation.

Marín-Spiotta, E.; Silver, W. L.; Swanston, C. W.; Torn, M. S.; Burton, S. D.

2006-12-01

239

Rebuilding Peatlands on Mineral Soils Utilizing Lessons Learned from Past Peatland Initiation  

NASA Astrophysics Data System (ADS)

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 the importance of paludification as a significant natural process in the initiation of peatland ecosystems has long been known by peatland ecologists, this knowledge has not been transferred to peatland and wetland restoration methodologies. We initiated this study to determine if wetland structure and function could be re-established on mineral gas/oil pads that were originally placed on organic soils. We have attempted to emulate the paludification process by removing mineral material to near the surrounding peatland natural water level and introducing a suite of wetland plants to the rewetted mineral soils. The experimental design comprised two well sites at the Shell Carmon Creek in situ plant near Peace River, Alberta. We placed 292 2 x 2 m plots over a series of fertilizer, water level, cultivation, and amendment treatments. In this presentation, we address four questions: 1) Will locally available peatland vascular plant species establish on these wet, compacted, mineral soils? If so; 2) Are species responses affected by water level, amendment, cultivation, and fertilization treatments, 3) Are invasive weeds a concern in these re-establishment trials, and 4) Will the surrounding bog water chemistry have an effect on water in contact with the mineral soils? Results after three growing season are: 1) All three species originally planted (a sedge, a willow, and tamarack) have successfully established at both well sites; 2) Carex aquatilis has performed well and responses to differing water levels and cultivation are not significant; 3) The plant responses to amendments are, in general, not different from the control plots; 4) The abundance of weeds is significantly different among some of the amendment types; and 5) Water chemistry (pH and electrical conductivity) of the ditches is affected by the surrounding bog waters. In addition, a fifth question was asked: Can Carex aquatilis establish by seed and if so, do C. aquatilis seeds require a peat amendment? In May 2009, three blank 4 m2 plots were selected on each of the experimental well site reclamations. Half of each plot was covered with approximately 4 cm of peat and the other half remained a mineral soil substrate. Each plot half was divided into 2 halves (1 m2); one that had approximately 600 Carex aquatilis seeds scattered across it and one that had no seeds added. Results from reassessment in July 2010 showed that subplots with added seeds had more seedlings than the subplots without added seeds. There was no difference between the number of seedlings between the peat and mineral soil subplots on either site, but on one of the sites, the subplots with peat had much higher percent cover of weeds than the mineral soil subplots.

Vitt, D. H.; Koropchak, S. C.; Xu, B.; Bloise, R.; Wieder, R.; Mowbray, S.

2010-12-01

240

Effects of acid soil infertility factors on mineral composition of soybean and cowpea tops  

Microsoft Academic Search

Investigations on the effects of acid soil infertility factors on legumes are often focussed on growth, nodulation, and N2?fixation, while very little emphasis has been given to the mineral composition of plants. In the present investigation, effects of varying solution pH [4.5, 5.0 and 5.5], concentrations of Ca [0.05, 0.5 and 2.5 mM] and activities of Al [0 ? 33

A. K. Alva; D. G. Edwards; C. J. Asher

1991-01-01

241

Automated SEM-EDS (QEMSCAN®) Mineral Analysis in Forensic Soil Investigations: Testing Instrumental Reproducibility  

Microsoft Academic Search

The complex mix of organic and inorganic components present in urban and rural soils and sediments potentially enable them\\u000a to provide highly distinctive trace evidence in both criminal and environmental forensic investigations. Organic components\\u000a might include macroscopic or microscopic plants and animals, pollen, spores, marker molecules, etc. Inorganic components comprise\\u000a naturally derived minerals, mineralloids and man-made materials which may also

Duncan Pirrie; Matthew R. Power; Gavyn K. Rollinson; Patricia E. J. Wiltshire; Julia Newberry; Holly E. Campbell

242

[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

243

Phosphorus fractions in an acid soil continuously fertilized with mineral and organic fertilizers  

Microsoft Academic Search

The effect of different treatments on the fate of applied P was investigated in a long-term field experiment started in 1972–1973 following a maize–wheat sequence. The soil samples were collected after 29 years of continuous addition of mineral fertilizers and amendments such as farmyard manure (FYM) and lime. The total P content of all the treatments increased compared to the

S. Verma; S. K. Subehia; S. P. Sharma

2005-01-01

244

Light-Catalyzed Chromium(VI) Reduction by Organic Compounds and Soil Minerals  

Microsoft Academic Search

light in the presence of organic materials with or without specific soil cant roles in reactions of contaminants, either organic minerals. Experimental results showed that dissolved organic com- or inorganic species. These reactions include adsorp- pounds reduced Cr(VI) slowly under laboratory light; however, Cr(VI) reduction was greatly enhanced when growth chamber light tion-desorption, hydrolysis, oxidation-reduction, and was applied. Low photon

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

2003-01-01

245

[Effects of temperature on mineralization and adsorption of exogenous amino acids and peptides in soil].  

PubMed

An incubation test was conducted to study the effects of different temperature (1 degrees C, 15 degrees C, and 25 degrees C) on the mineralization and adsorption of exogenous amino acid and peptide in the soils of horticultural production systems, including organic farming system (OS), transitional farming system (TS), and conventional farming system (CS). With the increase of incubation temperature, the mineralization of exogenous amino acids and peptides in test soils quickened. The mean half-life (D50) of Glu at 1 degrees C, 15 degrees C, and 25 degrees C was 13.3, 6.8, and 5.5 h, while the D50 of Glu-Phe was 29.7, 7.5, and 4.4 h, respectively. The adsorption rate of the exogenous amino acids and peptides was dependent on their concentrations and incubation temperature. The maximum adsorption rate (V(max)) and affinity (K(m)) of amino acids and the adsorption rate (V(h)) of peptides were all increased with incubation temperature. In the range of 0-2.5 mmol x L(-1), the adsorption of amino acids conformed to classical Michaelis-Menten equation, while that of peptides conformed to linear equation. The turnover rate and the V(max), K(m), and V(h) values of exogenous amino acids and peptides generally followed the series OS > TS > CS. In summary, temperature had significant effects on the mineralization and adsorption of exogenous amino acids and peptides in test soils. PMID:20560327

Ge, Ti-Da; Song, Shi-Wei; Huang, Dan-Feng

2010-03-01

246

Effect of potassium salts and distillery effluent on carbon mineralization in soil.  

PubMed

Distillery effluent, a rich source of potassium, is used for irrigation at many places in the world. A laboratory experiment was conducted to study the influence of potassium salts present in post-methanation distillery effluent (PME) along with two other salts, KCl and K2SO4, on mineralization of carbon in soil. PME oxidized with H2O2, raw PME, KCl and K2SO4 solutions containing K equivalent to 10%, 20%, 40% and 100% of K present in PME were added to the soil separately, maintaining four replications for each treatment and control. Addition of salts up to a certain concentration stimulated C mineralization but a decline was noticed at higher concentrations. All the levels of salts caused higher CO2 evolution than the control suggesting that the presence of K salts enhanced the microbial activity resulting in increased CO2 evolution. The influence of K2SO4 was significantly higher than KCl in stimulating C mineralization in soil. Oxidized effluent had a higher stimulating effect than inorganic salts, showing the influence of other salts accompanying K in the PME. Raw PME, which contained excess organic C, increased CO2 evolution even at the highest salt level (100% PME) signifying the effect of added C on alleviating the salt stress on microbial activity. PMID:12094803

Chandra, Suresh; Joshi, H C; Pathak, H; Jain, M C; Kalra, N

2002-07-01

247

Which 2:1 clay minerals are involved in the soil potassium reservoir? Insights from potassium addition or removal experiments on three temperate grassland soil clay assemblages  

Microsoft Academic Search

Field and laboratory observations based on X-ray diffraction techniques suggest that 2:1 clay minerals behave as a K reservoir. However, 2:1 soil clay assemblages are most often composed of a mixture of different 2:1 clay mineral populations and the role of these different clay mineral populations in K absorption or K release are not fully understood. This present work addressed

Pierre Barré; Bruce Velde; Colin Fontaine; Nicole Catel; Luc Abbadie

2008-01-01

248

Measurement of Microbially Induced Transformation of Magnetic Iron Minerals in Soils Allows Localization of Hydrocarbon Contamination  

NASA Astrophysics Data System (ADS)

Soil contamination by crude oil and other hydrocarbons represents a severe environmental problem, but often the location and extent of contamination is not known. Hydrocarbons, or their degradation products, can stimulate iron-metabolizing microorganisms, leading to the formation or dissolution of (magnetic) iron minerals and an associated change of soil magnetic properties. Therefore, the screening of soil magnetic properties has the potential to serve as an efficient and inexpensive tool to localize such contaminations. In order to identify the influence of different biogeochemical factors on the microbially influenced changes of magnetic iron minerals after hydrocarbon contamination, oil spills were simulated in laboratory batch experiments. The parameters tested in these experiments included soils with different bedrocks, type and amount of added hydrocarbon, and microbiological parameters (sterile and autochthonous microorganisms). In order to follow the changes of the soil magnetic properties, the magnetic susceptibility of the samples was measured weekly. First results show that changes in the magnetic mineralogy are caused by microbial activity, as sterile samples showed no changes. In the microbially active set-ups, the magnetic susceptibility increased or decreased up to 10% in comparison to the initial magnetic susceptibility within a few weeks. In one iron-rich soil even a decrease of the magnetic susceptibility of ~40% was observed. Although the amount and type of hydrocarbons did not effect the changes in magnetic susceptibility, DGGE fingerprints revealed that they influenced microbial communities. These results show that the magnetic susceptibility changes in the presence of hydrocarbons and that this change is microbially induced. This suggests that the screening of soil magnetic properties can be applied to localize and assess hydrocarbon contamination. In order to understand the biogeochemical processes better, the change of the iron mineralogy will be followed by Moessbauer spectroscopy in future batch experiments. Furthermore, iron-metabolizing microorganisms are currently isolated and identified.

Kappler, A.; Porsch, K.; Rijal, M.; Appel, E.

2007-12-01

249

Mineralization of soil organic matter initiated by the application of an available substrate to the profiles of surface and buried podzolic soils  

NASA Astrophysics Data System (ADS)

The priming effect (PE) initiated by the application of 14C-glucose was studied for copiotrophic microbial communities of organic horizons and for oligotrophic microbial communities of mineral soil horizons, as well as for mineral horizons of buried soils depleted in the input of fresh organic matter. The intensity of the PE depended on the reserves of Corg, the initial amount of the microbial biomass, and the enzymatic activity, which decreased from the organic to the mineral soil horizons. The ratio of the PE to the applied carbon was two times higher in the mineral horizons as compared with the organic horizons. This is explained by the predominance of K-strategists capable of decomposing difficultly available organic compounds in the mineral horizons, so that the turnover of the microbial biomass in the mineral horizons was more active than that in the organic horizons. The predominance of K-strategists was confirmed by the close correlation between the PE and the activity of the cellobiohydrolase enzyme decomposing cellulose ( R = 0.96). In general, the absolute value of the PE was controlled by the soil organic matter content, whereas the specific PE was controlled by the functional features of the microorganisms. It was shown that the functional features of the soil microorganisms remained unchanged under the conditions of their preservation in the buried soil.

Zhuravleva, A. I.; Yakimov, A. S.; Demkin, V. A.; Blagodatskaya, E. V.

2012-04-01

250

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.

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

1996-01-01

251

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

PubMed

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

1996-04-01

252

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

253

Variation of MCPA, metribuzine, methyltriazine-amine and glyphosate degradation, sorption, mineralization and leaching in different soil horizons  

Microsoft Academic Search

Pesticide mineralization and sorption were determined in 75 soil samples from 15 individually drilled holes through the vadose zone along a 28km long transect of the Danish outwash plain. Mineralization of the phenoxyacetic acid herbicide MCPA was high both in topsoils and in most subsoils, while metribuzine and methyltriazine-amine was always low. Organic matter and soil pH was shown to

Carsten S. Jacobsen; Peter van der Keur; Bo V. Iversen; Per Rosenberg; Heidi C. Barlebo; Søren Torp; Henrik Vosgerau; René K. Juhler; Vibeke Ernstsen; Jim Rasmussen; Ulla Catrine Brinch; Ole Hørbye Jacobsen

2008-01-01

254

INFLUENCE OF STABLE Cs AND K ON THE REACTIONS OF Cs137 AND K42 IN SOILS AND CLAY MINERALS  

Microsoft Academic Search

Experiments were conducted to study the influence of stable Cs and K on ; the reactions of tracer quantities of Cs¹³⁷ and K⁴² in soils and clay ; minerals, using an equilibrium batch method. Tracer quantities of both Cs\\/sup ; 137\\/ and K⁴² were strongly sorbed in soils and clay minerals. Cesium was ; more strongly sorbed than K. Since

H. Nishita; P. Taylor; G. V. Alexander; K. H. Larson

1962-01-01

255

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

Microsoft Academic Search

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

Kate Maher; Carl I. Steefel; Art F. White; Dave A. Stonestrom

2009-01-01

256

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

257

Effect of addition of rhamnolipid biosurfactants or rhamnolipid-producing Pseudomonas aeruginosa on phenanthrene mineralization in soil slurries  

Microsoft Academic Search

The effect of Pseudomonas aeruginosa UG2 biosurfactants or UG2 inocula on phenanthrene mineralization in uninoculated nonsterile soil slurries and slurries inoculated with the phenanthrene-mineralizing Pseudomonas sp. UG14r was investigated. In sandy loam and silt loam slurries amended with phenanthrene, inoculation with UG14r alone or in co-culture with UG2Lr reduced the lag period before onset of phenanthrene mineralization by 1 week.

Miguel A. Providenti; Cecily A. Flemming; Hung Lee; Jack T. Trevors

1995-01-01

258

Mineralization of carbon during moist incubation of soil JF79 treated with organic heat-transfer and storage fluids  

Microsoft Academic Search

Biodegradability of four heat transfer\\/storage fluids (ethylene glycol, Therminol 66, Caloria HT43, and Dow Corning Fluid No. 200) were examined. The degradation was monitored by periodically measuring the mineralization of carbon in moist fluid-contaminated soils incubated at 28° and 37°C for 8 weeks. Ethylene glycol mineralized relatively readily. The other three fluids did not show measurable amount of carbon mineralization

H. Nishita; R. M. Haug

1981-01-01

259

Soil Fauna Alter the Effects of Litter Composition on Nitrogen Cycling in a Mineral Soil  

EPA Science Inventory

Plant chemical composition and the soil community are known to influence litter and soil organic matter decomposition. Although these two factors are likely to interact, their mechanisms and outcomes of interaction are not well understood. Studies of their interactive effects are...

260

Modeling mineral dust emissions from the Sahara desert using new surface properties and soil database  

NASA Astrophysics Data System (ADS)

The present study investigates the mineral dust emissions and the occurrence of dust emission events over the Sahara desert from 1996 to 2001. Mineral dust emissions are simulated over a region extending from 16°N to 38°N and from 19°W to 40°E with a ?° × ?° spatial resolution. The input parameters required by the dust emission model are surface features data (aerodynamic roughness length, dry soil size distribution and texture for erodible soils), and meteorological surface data (mainly surface wind velocity and soil moisture). A map of the aerodynamic roughness lengths is established based on a composition of protrusion coefficients derived from the POLDER-1 surface products. Soil dry size distribution and texture are derived from measurements performed on soil samples from desert areas, and from a soil map derived from a geomorphologic analysis of desert landscapes. Surface re-analyzed meteorological databases (ERA-40) of the European Centre for Medium range Weather Forecasts (ECMWF) are used. The influence of soil moisture on simulated dust emissions is quantified. The main Saharan dust sources identified during the 6-year simulated period are in agreement with the previous studies based on in situ or satellite observations. The relevance of the simulated large dust sources and point sources ("hot spots") is tested using aerosol indexes derived from satellite observations (TOMS Absorbing Aerosol Index and Infrared Dust Difference Index Meteosat). The Saharan dust emissions simulated from 1996 to 2001 range from 585 to 759 Tg a-1. The simulations show marked seasonal cycles with a maximum in summer for the western Sahara and in spring for the eastern Sahara. The interannual variability of dust emissions is pronounced in the eastern part of the Sahara while the emissions from the western Sahara are more regular over the studied period. The soil moisture does not noticeably affect the Saharan dust emissions, their seasonal cycle or their interannual variability, but it can partly control and limit the dust emissions in some parts of the northern desert margin, where the precipitation rates are higher. Our simulations also tend to confirm that the Sahara is the major terrestrial source of mineral dust.

Laurent, B.; Marticorena, B.; Bergametti, G.; LéOn, J. F.; Mahowald, N. M.

2008-07-01

261

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

262

Effects of Temperature, pH and Salt Concentrations on the Adsorption of Bacillus subtilis on Soil Clay Minerals Investigated by Microcalorimetry  

Microsoft Academic Search

Adsorption of microorganisms on minerals is a ubiquitous interfacial phenomenon in soil. Knowledge of the extent and mechanisms of bacterial adsorption on minerals is of great agronomic and environmental importance. This study examined adsorption of Bacillus subtilis on three common minerals in soils such as kaolinite, montmorillonite and goethite under various environmental conditions. Isothermal titration calorimetry (ITC) was used to

Zhineng Hong; Xingmin Rong; Peng Cai; Wei Liang; Qiaoyun Huang

2011-01-01

263

Carbonation of Artificial Silicate Minerals in Soils: Passive Removal of Atmospheric CO2  

NASA Astrophysics Data System (ADS)

Sequestration of CO2 in global soils is a widely recognised phenomenon, which is amenable to an environmental engineering approach. It is proposed that the use of direct soil engineering, promoting CO2 sequestration by accelerating the activity of reactive mineral substrates, has the potential to harness the significant carbon turnover of the global pedologic system (75 x 10^15 gC/yr [1]) [2][3][4]. Estimates of C capture potential through this process are 100-1000 MTa-1. This study focuses on the ambient carbonation of high-Ca residues as agents of mineral CCS. A synergy of contemporary field observations is presented, alongside data acquired from laboratory testing (acid digestion, optical petrography, SEM, IRMS) of carbonated material recovered from urban brown-field and former industrial sites in north east England. It is demonstrated that urban soils may accumulate ~30 kg/m2 (300 T/ha) of carbon over 10 years as inorganic calcium carbonate, approximately twice the typical organic C content of rural soils, ~17.5 kg/m2 in the UK. Stable isotope data (?13C and ?18O) confirm that over 90% of the carbon is derived from the atmosphere. Economic and mechanical constraints on experimental performance in industrial batch reactor settings have strongly influenced the contemporary view on the efficacy of mineral CCS for large-scale environmental application [5][6][7]. Effective, low-energy field-scale implementation of mineral CCS through soil engineering would counter many of these concerns. Proof of principle for carbon capture efficacy of artificial silicates in soil engineering has been demonstrated [4]; proof of field scale feasibility will be demonstrated though continuing empirical field observation, engineered field cell construction and laboratory investigation. [1] Schlesinger, W. H., et al. (2000), Biogeochemistry, Vol. 48: 7-20. [2] Lal, R. (2003), Critical Reviews in Plant Sciences, 22, pp. 151-184. [3] Manning, D. A. C., (2008), Mineralogical Magazine, Mineralogical Society, Vol. 72: 639-649. [4] Renforth, P., et al., (2009), Applied Geochemistry, Vol. 24(9): 1757-1764 [5] Butt, D. P., Lackner, K.S., Wendt, C.H., et al. (1997), Global Warming International Conference, Columbia University, NY. [6] Huijgen, W. J. J., et al. (2005), Environmental Science and Technology Vol. 39: 9676-9682. [7] Lackner, K. S., et al. (1997), Energy Conversion and Management Vol. 38: S259-S264.

Washbourne, C.; Renforth, P.; Manning, D. A.

2010-12-01

264

Effects of organic matter removal and soil compaction on fifth-year mineral soil carbon and nitrogen contents for sites across the United States and Canada  

Microsoft Academic Search

This study describes the main treatment effects of organic matter removal and compaction and a split-plot effect of competition control on mineral soil carbon (C) and nitrogen (N) pools. Treatment effects on soil C and N pools are discussed for 19 sites across five locations (British Columbia, Northern Rocky Mountains, Pacific Southwest, and Atlantic and Gulf coasts) that are part

Felipe G. Sanchez; Allan E. Tiarks; J. Marty Kranabetter; Deborah S. Page-Dumroese; Robert F. Powers; Paul T. Sanborn; William K. Chapman

2006-01-01

265

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

266

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

2010-02-19

267

Clay Mineralogy of Central Victorian (Creswick) Soils: Clay Mineral Contents as a Possible Tool of Environmental Indicator  

Microsoft Academic Search

The clay mineralogy and heavy metal\\/metalloid (As, Pb and Cu) contents of soils developed on the various rock units in a central highlands environment in Victoria (Creswick, Australia) have been investigated. The clay minerals identified showed an order of abundance as: kaolinite ? illite > smectite > mixed-layer (ML) ? vermiculite. The soil clay mineralogy did not change systematically with

Khawar Sultan

2006-01-01

268

Particle size and concentration of poly(?-caprolactone) and adipate modified starch blend on mineralization in soils with differing textures  

Microsoft Academic Search

The objective of this study was to evaluate the effect of particle size and concentration of poly(?-caprolactone) and adipate modified starch blend on mineralization in soils with differing textures, comparing it with polyethylene under the same experimental conditions. Two soil types were used: a Kandiudalfic Eutrudox with a clayey texture and an Arenic Hapludult with a sandy texture. The two

M. E. F. César; P. D. S. C. Mariani; L. H. Innocentini-Mei; E. J. B. N. Cardoso

2009-01-01

269

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

270

Soil nitrogen mineralization rates of rainforests in a matrix of elevations and geological substrates on Mount Kinabalu, Borneo  

Microsoft Academic Search

Mt Kinabalu, Borneo, is characterized by a deep elevational gradient and mosaics of geological substrates. We chose a pair of two geological substrates (sedimentary vs ultrabasic) at five altitudes (800, 1400, 2100, 2700 and 3100 m a.s.l.). We investigated soil nitrogen (N) mineralization and nitrification rates using an incubation technique to assay the pattern and control of soil N status

Kanehiro Kitayama; Shin-Ichiro Aiba; Noreen Majalap-Lee; Masahiko Ohsawa

1998-01-01

271

Spectral unmixing for mineral identification in pancam images of soils in Gusev crater, Mars  

NASA Astrophysics Data System (ADS)

The objective of this work is to propose an automated unmixing technique for the analysis of 11-channel Mars Exploration Rover Panoramic Camera (MER/Pancam) spectra. Our approach is to provide a screening tool for identifying unique/distinct reflectance spectra. We demonstrate the utility of this unmixing technique in a study of the mineralogy of the bright salty soils exposed by the rover wheels in images of Gusev crater regions known as Paso Robles (Sols 400,426), Arad (Sol 721), and Tyrone (Sol 790). The unmixing algorithm is based on a novel derivation of the Nonnegative Matrix Factorization technique and includes added features that preclude the adverse effects of low abundance materials that would otherwise skew the unmixing. In order to create a full 11-channel spectrum out of the left and right eye stereo pairs, we also developed a new registration procedure that includes rectification and disparity calculation of the images. We identified two classes of endmember spectra for the bright soils imaged on Sols 426 and 790. One of these endmember classes is also observed for soils imaged on Sols 400 and 721 and has a unique spectral shape that is distinct from most iron oxide, sulfate and silicate spectra and differs from typical martian surface spectra. Instead, its unique spectral character resembles the spectral shape of the ferric sulfate minerals fibroferrite (Fe3+(SO4)(OH) · 5H2O) and ferricopiapite ((Fe3,Al,Mg)Fe53+(SO)6(OH)2·20HO) and the phosphate mineral ferristrunzite ((Mn2,Fe23+)2(PO)2(OH)2·6HO). The other endmember class is less consistent with specific minerals and is likely a mixture of altered volcanic material and some bright salts. Further analyses of data from Sols 400 and 790 using an anomaly detection algorithm as a tool for detecting low abundance materials additionally suggests the identification of the sulfate mineral paracoquimbite (Fe2(SO4)3 · 9H2O). This spectral study of Pancam images of the bright S- and P-enriched soils of Gusev crater identifies specific ferric sulfate and ferric phosphate minerals that are consistent with the unique spectral properties observed here in the 0.4-1 ?m range.

Parente, M.; Bishop, J. L.; Bell, J. F.

2009-10-01

272

Soil organic matter and nitrogen cycling in response to harvesting, mechanical site preparation, and fertilization in a wetland with a mineral substrate  

Microsoft Academic Search

Forested wetlands are becoming an important timber resource in the Upper Great Lakes Region of the US. However, there is limited information on soil nutrient cycling responses to harvesting and post-harvest manipulations (site preparation and fertilization). The objective of this study was to examine cellulose decomposition, nitrogen mineralization, and soil solution chemistry four years after a forested, mineral soil wetland

James W. McLaughlin; Margaret R. Gale; Martin F. Jurgensen; Carl C. Trettin

2000-01-01

273

A simple model for estimating the contribution of nitrogen mineralization to the nitrogen supply of crops from a stabilized pool of soil organic matter and recent organic input  

Microsoft Academic Search

A simple model was developed to estimate the contribution of nitrogen (N) mineralization to the N supply of crops. In this model the soil organic matter is divided into active and passive pools. Annual soil mineralization of N is derived from the active pool. The active pool comprises stabilized and labile soil organic N. The stabilized N is built up

F. J. Matus; J. Rodríguez

1994-01-01

274

Plant Litter to Mineral Soil Sinks: Tracking Carbon Flux into Soil Sinks in Temperate Broadleaf Forests in the Eastern US with Radiocarbon  

NASA Astrophysics Data System (ADS)

In 2007, a multiyear study was initiated to characterize the rate of C flux from litter sources to mineral soil sinks in four Eastern deciduous forests spanning a range of climatic and soil conditions. The Enriched Background Isotope Study focusing on AmeriFlux Sites (EBIS-AmeriFlux) provides quantitative data on the rate of C flux from litter to soil sinks using unique radiocarbon-enriched materials. Radiocarbon-enriched leaf and root litter and humus have been deployed under at the University of Michigan Biological Station (MI-UMBS), Bartlett Forest (NH-BF), Harvard Forest (MA-HF), and Baskett Research and Education Area in the Missouri Ozarks (MO-OZ). In addition to investigating rates of C transfer from litter to bulk O horizon sand mineral soil, we used density fractionation to separate bulk mineral soil into three pools of varying stability. These fractions are being used to identify which soil organic matter pools incorporate C from the experimental sources and determine pool-specific transfer rates. We will present results from the first two years of enriched-leaf and -humus applications and first year of enriched-root decomposition experiments. Preliminary results show that little humus-C was incorporated into soil over 2 years, but that by the second year after enriched-litter applications began new litter C had been transferred to mineral soil at MO-OZ and MI-UMBS. After 1 year, root-derived 14C label was detected in all three soil-density fractions isolated from the MO-OZ, but not in fractions from NH-BF. These data allow for the calculation of annual transfer rates for carbon from plant litter sources to mineral soil sinks.

McFarlane, K. J.; Hanson, P. J.; Matamala, R.; Porras, R. C.; Torn, M. S.

2011-12-01

275

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

276

Temporal patterns of net soil N mineralization and nitrification through secondary succession in the subtropical forests of eastern China  

Microsoft Academic Search

Linking temporal trends of soil nitrogen (N) transformation with shifting patterns of plants and consequently changes of litter\\u000a quality during succession is important for understanding developmental patterns of ecosystem function. However, the successional\\u000a direction of soil N mineralization and nitrification in relation to species shifts in the subtropical regions remains little\\u000a studied. In this study, successional patterns of net soil

En-Rong Yan; Xi-Hua Wang; Ming Guo; Qiang Zhong; Wu Zhou; Yong-Fu Li

2009-01-01

277

Effect of Calcareous Soil on Photosynthesis Rate, Mineral Nutrition, and Source?Sink Ratio of Table Grape  

Microsoft Academic Search

Vitis vinifera L. cv Aurora grafted on S.O.4 (medium lime?tolerance) rootstock was grown in pot with a high?carbonate?soil and a low?carbonate?soil. The aim of the trial was to check soil effect on some physiological features such as leaf chlorophyll (Chl) concentration and gas exchange, whole?canopy gas exchange, mineral nutrition, dry matter partitioning, and technological grape parameters. Measurements for whole?canopy gas

L. Bavaresco; S. Poni

2003-01-01

278

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

279

Centimeter-scale spatial variability in 2-methyl-4-chlorophenoxyacetic Acid mineralization increases with depth in agricultural soil.  

PubMed

Mineralization of organic chemicals in soil is typically studied using large homogenized samples, but little is known about the small-scale spatial distribution of mineralization potential. We studied centimeter-scale spatial distribution of 2-methyl-4-chlorophenoxyacetic acid (MCPA) mineralization activity at different depths (8-115 cm) in a Danish agricultural soil profile using a 96-well microplate C-radiorespirometric method for small-volume samples. The heterotrophic microbial population and specific MCPA degraders decreased 10- to 100-fold from the plow layer to a depth of 115 cm. MCPA was mineralized in all samples in the plow layer, but only about 60% in the transition zone immediately below the plow layer showed mineralization; at greater depth even fewer samples showed mineralization. A patchy spatial distribution of mineralization activity was observed from right below the plow layer and in the subsoil, with a few clearly defined active zones surrounded by areas devoid of mineralization activity. Due to the patchy distribution of mineralization activity at the centimeter scale just beneath the plow layer, MCPA and presumably other weakly sorbing pesticides might be at risk of leaching to the groundwater if transported from the plow layer into the subsoil. PMID:23673934

Badawi, Nora; Johnsen, Anders R; Sørensen, Jan; Aamand, Jens

280

Ice nucleation by soil dusts: relative importance of mineral dust and biogenic components  

NASA Astrophysics Data System (ADS)

Agricultural dust emissions have been estimated to contribute around 20% to the global dust burden. In contrast to dusts from arid source regions, the ice-nucleating abilities of which have been relatively well studied, soil dusts from fertile sources often contain a substantial fraction of organic matter. Using an experimental methodology which is sensitive to a wide range of ice nucleation efficiencies, we have characterised the immersion mode ice-nucleating activities of dusts extracted from fertile soils collected at four locations around England. By controlling droplet sizes, which ranged in volume from 10-12 to 10-6 L, we have been able to determine the ice nucleation behaviour of soil dust particles at temperatures ranging from 267 K (-6 °C) down to the homogeneous limit of freezing at about 237 K (-36 °C). At temperatures above 258 K (-15 °C) we find that the ice-nucleating activity of soil dusts is diminished by heat treatment or digestion with hydrogen peroxide, suggesting that the ice nuclei stem from biogenic components in the soil. However, below 258 K, we find that the ice active site densities tend towards those expected from the mineral components in the soils, suggesting that the inorganic fraction of soil dusts, in particular the K-feldspar fraction, becomes increasingly important in the initiation of the ice phase at lower temperatures. We conclude that although only a relatively minor contributor to the global atmospheric dust burden, the enhanced IN activities of dusts generated from agricultural activities may play an important role in cloud glaciation, particularly at temperatures above 258 K.

O'Sullivan, D.; Murray, B. J.; Malkin, T. L.; Whale, T.; Umo, N. S.; Atkinson, J. D.; Price, H. C.; Baustian, K. J.; Browse, J.; Webb, M. E.

2013-08-01

281

Interactive influences of silvicultural management and soil chemistry upon soil microbial abundance and nitrogen mineralization  

Microsoft Academic Search

The purpose of this study was to determine whether soil acidification, a widespread, chronic mode of disturbance and forest thinning, a site specific acute disturbance, produced interactive effects capable of producing changes in more general ecosystem properties and processes. Two forested sites in the Daniel Boone National Forest, KY which were similar in history, management, and parent material but which

Sherri Jeakins Morris; R. E. J. Boerner

1998-01-01

282

Soil solid materials affect the kinetics of extracellular enzymatic reactions  

NASA Astrophysics Data System (ADS)

INTRODUCTION Soil solid materials affect the degradation processes of many organic compounds by decreasing the bioavailability of substrates and by interacting with degraders. The magnitude of this effect in the environment is shown by the fact that xenobiotics which are readily metabolized in aquatic environments can have long residence times in soil. Extracellular enzymatic hydrolysis of cellobiose (enzyme: beta-glucosidase from Aspergillus niger) was chosen as model degradation process since it is easier to control and more reproducible than a whole cell processes. Furthermore extracellular enzymes play an important role in the environment since they are responsible for the first steps in the degradation of organic macromolecules; beta-glucosidase is key enzyme in the degradation of cellulose and therefore it is fundamental in the carbon cycle and for soil in general. The aims of the project are: 1) quantification of solid material effect on degradation, 2) separation of the effects of minerals on enzyme (adsorption ?change in activity) and substrate (adsorption ?change in bioavailability). Our hypothesis is that a rate reduction in the enzymatic reaction in the presence of a solid phase results from the sum of decreased bioavailability of the substrate and decreased activity of enzyme molecules. The relative contribution of the two terms to the overall effect can vary widely depending on the chemical nature of the substrate, the properties of the enzyme and on the surface properties of the solid materials. Furthermore we hypothesize that by immobilizing the enzyme in an appropriate carrier the adsorption of enzymes to soil materials can be eliminated and that therefore immobilization can increase the overall reaction rate (activity loss caused by immobilization < activity loss caused by adsorption to soil minerals). MATERIALS AND METHODS Enzymatic kinetic experiments are carried out in homogeneous liquid systems and in heterogeneous systems where solid materials (bentonite, kaolinite, goethite, activated charcoal) are suspended in a mixed liquid (standard experimental conditions: 66 mM phosphate buffer, pH 5, 25°C, 20 mg solid/ml buffer). The enzyme in an immobilized form (covalent bonding to oxirane groups on the surfaces of macroporous Eupergit® C particles) is used to exclude a direct effect of soil solid materials on the enzyme without excluding their effect on the availability of the substrate.The progress of the reactions is determined by measuring the accumulation of the product (i.e. glucose) in the systems at different times (after destroying enzymatic activity by boiling the samples) with a coupled enzymatic assay and an automatic microplate spectrophotometer. A regression analysis on the data points is performed to calculate the initial reaction rates, which is the parameter that allows to compare the different systems. RESULTS AND DISCUSSION The results show that, under the standard experimental conditions, cellobiose is not adsorbed by the clay minerals bentonite and kaolinite and by the iron oxyhydroxide goethite. In the case of activated charcoal a rapid adsorption phase in the first 20' is followed by a much slower process; after 4h 30' approximately 98% of cellobiose was adsorbed. The results from the adsorption experiments of beta-glucosidase to bentonite, kaolinite, goethite and activated charcoal show that, under the standard experimental conditions, the adsorption process is rapid in all cases (more than 80% of the adsorption takes place in the first 20 minutes). After 1h 20min the following fractions of enzyme were adsorbed: 30 % to bentonite, 60% to kaolinite, 67% to goethite, 100% to activated charcoal. The effect of kaolinite on the reaction rate was quantified: under the standard experimental conditions the initial reaction rate in presence of the mineral was 22% less then in the control. The fraction of enzyme molecules which are adsorbed to kaolinite (60%) loses 37% of its activity. CONCLUSIONS The results from the adsorption experiments lead to the conclusion that, among the sol

Lammirato, C.; Miltner, A.; Kästner, M.

2009-04-01

283

Biodegradability of nonaqueous-phase liquids affects the mineralization of phenanthrene in soil because of microbial competition  

SciTech Connect

A study was conducted to determine the effects of biodegradability of nonaqueous-phase liquids (NAPLs) and microbial competition on the biodegradation in soil of a constituent of the NAPLs. The rates of mineralization of phenanthrene dissolved in 8 mg of 2,2,4,4,6,8,8-heptamethylnonane (HMN), di(2-ethylhexyl) phthalate (DEHP), or pristane per g of soil were faster than the rates when the compound was dissolved in hexadecane or dodecane. Addition of inorganic N and P to the soil increased the mineralization rate in the first two but not the last two NAPLs. N and P addition did not enhance mineralization of phenanthrene when added in 500 {micro}g of hexadecane, pristane, or HMN per g of soil. Hexadecane was rapidly degraded, pristane was slowly metabolized, DEHP was still slower, and HMN was not mineralized in the test period. Mixing the soil stimulated mineralization of phenanthrene dissolved in HMN but not in hexadecane. Mineralization of phenanthrene dissolved in HMN was the same if the gas phase contained 21%, 2.1%, or traces of O{sub 2}. In contrast, the biodegradation of phenanthrene dissolved in hexadecane, although the same at 21 and 2.1% O{sub 2}, was not observed if traces of O{sub 2} were present. The mineralization was slower in unshaken soil-water mixtures if phenanthrene was added in hexadecane than in HMN or pristane, but the rates with the 3 NAPLs were increased by shaking the suspensions. The authors suggest that the biodegradability of major components of NAPLs and microbial competition for N, P, or O{sub 2} will have a major impact on the rate of transformation of minor constituents of NAPLs.

Morrison, D.E.; Alexander, M. [Cornell Univ., Ithaca, NY (United States)

1997-08-01

284

Response of forest seedling/soil microcosms to elevated CO{sub 2} and soil temperature, water, and light: Carbon and nitrogen mineralization and allocation  

SciTech Connect

Soils from 500-year-old old-growth Douglas-fir forests in the western Oregon Cascade Mtns. (945m and 1325m sites) were {open_quotes}incubated{close_quotes} for 32 weeks in controlled-environment chambers. Objectives were (1) to determine the interacting effects of soil temperature and atmospheric CO{sub 2} on N availability in soils, growth of Douglas-fir seedlings, and resulting C & N fluxes among trees, soils, and the atmosphere, and (2) to model these interactions with a version of Fregro linked with the GEM soil-decomposition model. The experiment was a split-plot with a factorial treatment combination containing two leves each of atmospheric CO{sub 2} (350/700 ppm), soil temperature (13.8/17.7{degrees}C), soil C & N (1325m soils had 2.3x more C and 1.25x more N than 945m soils), and vegetation (+/-seedlings). Each wholeplot (chamber) treatment (CO{sub 2} x temperature) was replicated three times. Photosynthetic photon flux density, soil temperature, and volume of added water were determined for each pot and analyzed as covariates. Responses measured include differences in soil C & N mineralization and total soil C & N in the presence/absence of seedlings, the extent to which subsequent seedling growth offsets potential {open_quote}system{close_quote} losses of C & N, and allocation of C & N to foliage and fine roots. Previously reported early results (ESA, 1994) suggest that (1) as hypothesized, soil temperatures is the main driver of changes in both N mineralization and biomass production in seedling microcosms, (2) allocation is primarily influenced by atmospheric CO{sub 2} concentration, and (3) a soil type x soil temperature x CO{sub 2} interaction influences seedling growth.

Gillham, M.L.; Perry, D.A. [Oregon State Univ., Corvallis, OR (United States)

1995-09-01

285

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

286

Soils in the zone affected by mineral water springs at the foothills of the Eastern Sayan Ridge  

NASA Astrophysics Data System (ADS)

Data on soils in the zone affected by mineral water springs at the foothills of the Eastern Sayan Ridge are analyzed. Changes in the soil properties take place with the increase in the distance from the sites of the water discharge: primitive petrozems (Lithosols) are replaced by calcareous petrozems and, then, by burozems (brown taiga soils, Cambisols). In dependence on the degree of the water mineralization, the salt content in the soils varies from 0.05 to 0.26%. The readily soluble salts include calcium, magnesium, and sodium chlorides; sulfates; and bicarbonates. The soil reaction varies from acid to alkaline, and the organic matter content varies from 0.5 to 15.0%.

Lopatovskaya, O. G.

2009-08-01

287

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

288

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

2008-02-20

289

Mineral characteristics of leaves of plants from different phylogeny grown in various soil types in the temperate region.  

PubMed

The objective of this research was to analyze selected minerals in leaves of plants, belonging to 166 species growing in alluvial, low pH, brown forest and serpentine soils. Mineral characteristics of the soils involved were also determined. For the macronutrients, in trees grown in alluvial soil, N, P, Ca, and Mg concentrations of leaves were higher in recently evolved plants than in plants with a longer period of evolution; K concentration remained constant regardless of evolution. In grasses grown in alluvial soil, it was difficult to detect the general tendency of mineral concentration. N, P, and K concentrations in alluvial soil were closely related to those in low pH and serpentine soils. Ca concentration in alluvial soil was lower than that in low pH and serpentine soils. Mg concentration in alluvial soils was higher than that in low pH soils, while lower than that in serpentine soil. Therefore, N, P, and K accumulated according to the plant characteristics for these elements, while Ca and Mg accumulation was strongly affected by the soil properties. For the micronutrients, in trees, Fe and Mn remained constant regardless of evolution; Zn concentration was lower in recently-evolved plants than in plants with a longer period of evolution. In grasses, Fe, Mn, and Zn concentrations in Caryophyllids were high. Except for Caryophyllids, Fe and Cu concentrations remained constant. Mn concentration decreased with evolution, Zn concentration was higher in recently-evolved plants than in plants with a longer period of evolution. PMID:12906351

Osaki, M; Yamada, S; Ishizawa, T; Watanabe, T; Shinano, T; Tuah, S J; Urayama, M

2003-01-01

290

Influence of soil minerals on chromium(VI) reduction by sulfide under anoxic conditions  

PubMed Central

The effects of soil minerals on chromate (CrVIO42-, noted as Cr(VI)) reduction by sulfide were investigated in the pH range of 7.67 to 9.07 under the anoxic condition. The examined minerals included montmorillonite (Swy-2), illite (IMt-2), kaolinite (KGa-2), aluminum oxide (?-Al2O3), titanium oxide (TiO2, P-25, primarily anatase), and silica (SiO2). Based on their effects on Cr(VI) reduction, these minerals were categorized into three groups: (i) minerals catalyzing Cr(VI) reduction – illite; (ii) minerals with no effect – Al2O3; and (iii) minerals inhibiting Cr(VI) reduction- kaolinite, montmorillonite, SiO2 and TiO2 . The catalysis of illite was attributed primarily to the low concentration of iron solubilized from the mineral, which could accelerate Cr(VI) reduction by shuttling electrons from sulfide to Cr(VI). Additionally, elemental sulfur produced as the primary product of sulfide oxidation could further catalyze Cr(VI) reduction in the heterogeneous system. Previous studies have shown that adsorption of sulfide onto elemental sulfur nanoparticles could greatly increase sulfide reactivity towards Cr(VI) reduction. Consequently, the observed rate constant, kobs, increased with increasing amounts of both iron solubilized from illite and elemental sulfur produced during the reaction. The catalysis of iron, however, was found to be blocked by phenanthroline, a strong complexing agent for ferrous iron. In this case, the overall reaction rate at the initial stage of reaction was pseudo first order with respect to Cr(VI), i.e., the reaction kinetics was similar to that in the homogeneous system, because elemental sulfur exerted no effect at the initial stage prior to accumulation of elemental sulfur nanoparticles. In the suspension of kaolinite, which belonged to group (iii), an inhibitive effect to Cr(VI) reduction was observed and subsequently examined in more details. The inhibition was due to the sorption of elemental sulfur onto kaolinite, which reduced or completely eliminated the catalytic effect of elemental sulfur, depending on kaolinite concentration. This was consistent with the observation that the catalysis of externally added elemental sulfur (50 ?M) on Cr(VI) reduction would disappear with a kaolinite concentration of more than 5.0 g/L. In kaolinite suspension, the overall reaction rate law was: -d[Cr(VI)]/dt = kobs[H+]2[Cr(VI)][HS-]0.70

Lan, Yeqing; Deng, Baolin; Kim, Chulsung; Thornton, Edward C

2007-01-01

291

Stabilisation of soil organic matter by interactions with minerals as revealed by mineral dissolution and oxidative degradation  

Microsoft Academic Search

Soil organic matter is known to contain a stable fraction with an old radiocarbon age. Size and stabilisation processes leading to the formation of this old soil carbon pool are still unclear. Our study aims to differentiate old organic matter from young and labile carbon compounds in two acid forest soils (dystric cambisol, haplic podzol). To identify such fractions soil

Karin Eusterhues; Cornelia Rumpel; Markus Kleber; Ingrid Kögel-Knabner

2003-01-01

292

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

293

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

294

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

295

Stable isotopes of carbon dioxide in soil gas over massive sulfide mineralization at Crandon, Wisconsin  

USGS Publications Warehouse

Stable isotope ratios of oxygen and carbon were determined for CO2 in soil gas in the vicinity of the massive sulfide deposit at Crandon, Wisconsin with the objective of determining the source of anomalously high CO2 concentrations detected previously by McCarthy et al. (1986). Values of ??13C in soil gas CO2 from depths between 0.5 and 1.0 m were found to range from -12.68??? to -20.03??? (PDB). Organic carbon from the uppermost meter of soil has ??13C between -24.1 and -25.8??? (PDB), indicating derivation from plant species with the C3 (Calvin) type of photosynthetic pathway. Microbial decomposition of the organic carbon and root respiration from C3 and C4 (Hatch-Slack) plants, together with atmospheric CO2 are the likely sources of carbon in soil gas CO2. Values of ??18O in soil-gas CO2 range from 32 to 38??? (SMOW). These ??18O values are intermediate between that calculated for CO2 gas in isotopic equilibrium with local groundwaters and that for atmospheric CO2. The ??18O data indicate that atmospheric CO2 has been incorporated by mixing or diffusion. Any CO2 generated by microbial oxidation of organic matter has equilibrated its oxygen isotopes with the local groundwaters. The isotopic composition of soil-gas CO2 taken from directly above the massive sulfide deposit was not distinguishable from that of background samples taken 1 to 2 km away. No enrichment of the ??13C value of soil-gas CO2 was observed, contrary to what would be expected if the anomalous CO2 were derived from the dissolution of Proterozoic marine limestone country rock or of Paleozoic limestone clasts in glacial till. Therefore, it is inferred that root respiration and decay of C3 plant material were responsible for most CO2 generation both in the vicinity of the massive sulfide and in the "background" area, on the occasion of our sampling. Interpretation of our data is complicated by the effects of rainfall, which significantly reduced the magnitude of the CO2 anomaly. Therefore, we cannot rule out the possible mechanism of carbonate dissolution driven by pyrite oxidation, as proposed by Lovell et al. (1983) and McCarthy et al. (1986). Further work is needed on seasonal and daily variations of CO2 concentrations and stable isotope ratios in various hydrogeologic and ecologic settings so that more effective sampling strategies can be developed for mineral exploration using soil gases. ?? 1990.

Alpers, C. N.; Dettman, D. L.; Lohmann, K. C.; Brabec, D.

1990-01-01

296

Does temperature of charcoal creation affect subsequent mineralization of soil carbon and nitrogen?  

NASA Astrophysics Data System (ADS)

Forest fire is the most common form of natural disturbance of boreal forest ecosystems and has primordial influence on successional processes. This may be due in part to the pre-disturbance vegetation development stage and species composition, but these successional pathways could also vary with differences in fire behavior and consequently in fire intensity, defined as the energy released during various phases of a fire. Fire intensity may also affect soil C and N cycling by affecting the quality of the charcoal that is produced. For example, the porosity of coal tends to increase with increasing temperature at which it is produced Higher porosity would logically increase the surface area to which dissolved soil molecules, such as tannins and other phenolics, may be adsorbed. We report on a microcosm study in which mineral and organic soils were jointly incubated for eight weeks with a full factorial array of treatments that included the addition of Kalmia tannins, protein, and wood charcoal produced at five different temperatures. A fourth experimental factor comprised the physical arrangement of the material (stratified vs. mixed), designed to simulate the effect of soil scarification after fire and salvage harvest. We examined the effects of these treatments on soil C and N mineralisation and soil microbial biomass. The furnace temperature at which the charcoal was produced had a significant effect on its physico-chemical properties; increasing furnace temperatures corresponded to a significant increase in % C (P<0.001), and a significant decrease in %O (P<0.001) and %H (P<0.001). Temperature also had significant impacts on microporosity (surface area and volume). Temperature of production had no effect (P=0.1355) on soil microbial biomass. We observed a linear decreasing trend (P<0.001) in qCO2 with increasing temperature of production, which was mainly reflected in a decline in basal respiration. Finally, we found a significant interaction (P=0.010) between temperature of charcoal production x soil mixing in controlling post incubation NH4+ concentrations. We discuss the results in relation to potential implications for changing fire regime and C and N cycles.

Pelletier-Bergeron, S.; Bradley, R.; Munson, A. D.

2012-04-01

297

Vertical gradients of mineral elements in Pinus sylvestris crown in alkalised soil.  

PubMed

Alkalisation of soil has been assumed to be the principal cause of changes in vertical gradients of nutrients in Pinus sylvestris crown. The long-term influence of alkaline dust pollution (pHH2O 12.3-12.6) emitted from a cement plant on the element composition of soil and needles of Scots pine in different canopy layers was studied. In the polluted area, the pH of soils was >7, and high amounts of Ca, K and Mg were measured in the upper layers of soil (0-30 cm), while the mobility and solubility of some contaminants have decreased, nutrition processes have become complicated, and imbalance of mineral composition of trees was revealed. Reduced N and increased K, Ca and Mg concentrations in needles were observed in the heavily polluted area. Vertical gradients of elements and their ratios in canopies varied depending on the alkalisation level of soil. Needles on the upper-crown shoots had higher concentrations of N, C, Ca and Mg and lower concentrations of P and K compared to the lower layer of the crown. In the unpolluted area, higher concentrations of N, P, K and Ca were found in lower-crown needles and of C and Mg in needles at the top of the canopy. The P/N ratio below 0.125 indicated P deficiency in pines. The ratios N/Ca, N/Mg and N/K had significantly decreased, while the ratios Ca/Mg, K/Mg and K/Ca had a tendency to increase in heavily polluted sample plots. Magnitude of changes of element ratios indicates on the disbalances of availability and translocation of nutrients in the crown of trees. PMID:19015943

Mandre, Malle

2008-11-08

298

Enhanced Mineralization of [U-14C]2,4-Dichlorophenoxyacetic Acid in Soil from the Rhizosphere of Trifolium pratense  

PubMed Central

Enhanced biodegradation in the rhizosphere has been reported for many organic xenobiotic compounds, although the mechanisms are not fully understood. The purpose of this study was to discover whether rhizosphere-enhanced biodegradation is due to selective enrichment of degraders through growth on compounds produced by rhizodeposition. We monitored the mineralization of [U-14C]2,4-dichlorophenoxyacetic acid (2,4-D) in rhizosphere soil with no history of herbicide application collected over a period of 0 to 116 days after sowing of Lolium perenne and Trifolium pratense. The relationships between the mineralization kinetics, the number of 2,4-D degraders, and the diversity of genes encoding 2,4-D/?-ketoglutarate dioxygenase (tfdA) were investigated. The rhizosphere effect on [14C]2,4-D mineralization (50 ?g g?1) was shown to be plant species and plant age specific. In comparison with nonplanted soil, there were significant (P < 0.05) reductions in the lag phase and enhancements of the maximum mineralization rate for 25- and 60-day T. pratense soil but not for 116-day T. pratense rhizosphere soil or for L. perenne rhizosphere soil of any age. Numbers of 2,4-D degraders in planted and nonplanted soil were low (most probable number, <100 g?1) and were not related to plant species or age. Single-strand conformational polymorphism analysis showed that plant species had no impact on the diversity of ?-Proteobacteria tfdA-like genes, although an impact of 2,4-D application was recorded. Our results indicate that enhanced mineralization in T. pratense rhizosphere soil is not due to enrichment of 2,4-D-degrading microorganisms by rhizodeposits. We suggest an alternative mechanism in which one or more components of the rhizodeposits induce the 2,4-D pathway.

Shaw, Liz J.; Burns, Richard G.

2004-01-01

299

Seasonal dynamics of mineral N pools and N-mineralization in soils under homegarden trees in South Andaman, India  

Microsoft Academic Search

Agroforestry trees are now well known to play a central role in the build up of nutrients pools and their transformations\\u000a similar to that of forest ecosystem, however, information on the potential of homegarden trees accumulating and releasing\\u000a nitrogen (mineralization) is lacking. The present study reports seasonal variations in pool sizes of mineral N (NH4+-N and NO3?-N), and net N-mineralization

Chandra Bhushan Pandey; Ram Bahal Rai; Lalita Singh

2007-01-01

300

Net mineralization and nitrification rates in a clay soil measured and predicted in permanent grassland from soil temperature and moisture content  

Microsoft Academic Search

Summary Net mineralization of N and net nitrification in field-moist clay soils (Evesham-Kingston series) from arable and grassland sites were measured in laboratory incubation experiments at 4, 10 and 20°C. Three depth fractions to 30 cm were used. Nitrate accumulated at all temperatures except when the soil was very dry (?=0.13 cm3 cm?3). Exchangeable NH4-ions declined during the first 24

J. H. Macduff; R. E. White

1985-01-01

301

Accumulation of organic matter in the mineral layers of permafrost-affected soils of coastal lowlands in East Siberia  

NASA Astrophysics Data System (ADS)

On the basis of a large volume of literature and original data, the high content (1-7%) of organic matter in the mineral layer of loamy permafrost-affected soils of coastal lowlands in East Siberia (from the lower reaches of the Lena River to the lower reaches of the Kolyma River) has been statistically proved. In most cases, the reserves of Corg in the mineral layer of these soils exceed those in the surface organic horizons and constitute 60-90% of the total soil pool of Corg. The enrichment of the mineral layer with Corg is due to the cryogenic retention (retenization) of humus (the illuviation and accumulation of colorless humic substances above permafrost) and the cryogenic mass exchange (mechanical admixture of organic matter from the upper organic horizons into the mineral layers). The analysis of 60 soil profiles showed that the accumulation of organic matter above the permafrost table is observed in 43% of cases; in general, the organic matter distribution in the soil profiles is highly variable. A specific type of colorless humus is accumulated above the permafrost table. The mechanisms of its precipitation and transformation in the profile require further studies.

Mergelov, N. S.; Targulian, V. O.

2011-03-01

302

Mineralization of carbon during moist incubation of soil JF79 treated with organic heat-transfer and storage fluids  

SciTech Connect

Biodegradability of four heat transfer/storage fluids (ethylene glycol, Therminol 66, Caloria HT43, and Dow Corning Fluid No. 200) were examined. The degradation was monitored by periodically measuring the mineralization of carbon in moist fluid-contaminated soils incubated at 28/sup 0/ and 37/sup 0/C for 8 weeks. Ethylene glycol mineralized relatively readily. The other three fluids did not show measurable amount of carbon mineralization during the experimental period. This implies potential long term environmental effects of mismanaged or accidental releases of these fluids into natural environment.

Nishita, H.; Haug, R.M.

1981-01-01

303

Carbon mineralization of flooded boreal soil and vegetation under different temperature and oxygen conditions  

NASA Astrophysics Data System (ADS)

Flooding of terrestrial ecosystems significantly alters carbon (C) mineralization rates, which results in increasing emissions of carbon dioxide (CO2) and methane (CH4). To better understand the changes after water impoundment, C mineralization under flooded conditions needs to be investigated. This study investigates CO2 and CH4 fluxes from flooded boreal soil and vegetation, compares them to the fluxes of non- flooded treatment, and examines how environmental factors affect the fluxes. We conducted short-term in vitro experiments using boreal forest soil (FH layer), peat soil (0 to 5 and 5 to 15 cm) layer, and black spruce needles and small twigs, and shrub, sedge, lichen, and moss tissues. Flooded samples were incubated in 1- L Mason jars without light, under three temperatures (5, 12, and 24degC) and 0 and 50 percent of ambient oxygen (O2) concentration, and non-flooded ones were incubated in 1-L plastic containers under same light and temperature conditions to those of flooded samples and ambient oxygen concentration. We collected gas samples after flushing with nitrogen gas and air, and the fluxes of CO2 and CH4 were determined by gas chromatography. The average CO2 and CH4 fluxes in all materials were 200 and 0.8 microgram C/g organic matter/day, with smaller CO2 fluxes and larger CH4 fluxes than the fluxes of non-flooding (CO2 and CH4: 370 and 0.2 microgram C/g organic matter/day). Among the flooded samples, forest and peatland ground vegetation showed much high CO2 fluxes, and peat soils released more CH4 than other materials. Higher temperatures increased emissions of both CO2 and CH4, and the lower O2 concentration increased CH4 emissions. These results suggest the flooded vegetation and peat soil largely contribute to the total C emission in the flooded ecosystem and that spatial and temporal variability in CO2 and CH4 emissions can be related to substrate type, temperature and O2 concentration.

Kim, Y.; Ullah, S.; Roulet, N.; Moore, T.

2009-05-01

304

Phylogenetic analysis of actinobacterial populations associated with Antarctic Dry Valley mineral soils.  

PubMed

Despite the apparent severity of the environmental conditions in the McMurdo Dry Valleys, Eastern Antarctica, recent phylogenetic studies conducted on mineral soil samples have revealed the presence of a wide diversity of microorganisms, with actinobacteria representing one of the largest phylotypic groups. Previous metagenomic studies have shown that the majority of Antarctic actinobacterial populations are classified as 'uncultured'. In this study, we assessed the diversity of actinobacteria in Antarctic cold desert soils by complementing traditional culture-based techniques with a metagenomic study. Phylogenetic analysis of clones generated with actinobacterium- and streptomycete-specific PCR primers revealed that the majority of the phylotypes were most closely related to uncultured Pseudonocardia and Nocardioides species. Phylotypes most closely related to a number of rarer actinobacteria genera, including Geodermatophilus, Modestobacter and Sporichthya, were also identified. While complementary culture-dependent studies isolated a number of Nocardia and Pseudonocardia species, the majority of the cultured isolates (> 80%) were Streptomyces species--although phylotypes affiliated to the genus Streptomyces were detected at a low frequency in the metagenomic study. This study confirms that Antarctic Dry Valley desert soil harbours highly diverse actinobacterial communities and suggests that many of the phylotypes identified may represent novel, uncultured species. PMID:19278445

Babalola, Olubukola O; Kirby, Bronwyn M; Le Roes-Hill, Marilize; Cook, Andrew E; Cary, S Craig; Burton, Stephanie G; Cowan, Don A

2009-03-01

305

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

306

Respiratory interactions of soil bacteria with (semi)conductive iron-oxide minerals.  

PubMed

Pure-culture studies have shown that dissimilatory metal-reducing bacteria are able to utilize iron-oxide nanoparticles as electron conduits for reducing distant terminal acceptors; however, the ecological relevance of such energy metabolism is poorly understood. Here, soil microbial communities were grown in electrochemical cells with acetate as the electron donor and electrodes (poised at 0.2 V versus Ag/AgCl) as the electron acceptors in the presence and absence of iron-oxide nanoparticles, and respiratory current generation and community structures were analysed. Irrespective of the iron-oxide species (hematite, magnetite or ferrihydrite), the supplementation with iron-oxide minerals resulted in large increases (over 30-fold) in current, while only a moderate increase (?10-fold) was observed in the presence of soluble ferric/ferrous irons. During the current generation, insulative ferrihydrite was transformed into semiconductive goethite. Clone-library analyses of 16S rRNA gene fragments PCR-amplified from the soil microbial communities revealed that iron-oxide supplementation facilitated the occurrence of Geobacter species affiliated with subsurface clades 1 and 2. We suggest that subsurface-clade Geobacter species preferentially thrive in soil by utilizing (semi)conductive iron oxides for their respiration. PMID:20561016

Kato, Souichiro; Nakamura, Ryuhei; Kai, Fumiyoshi; Watanabe, Kazuya; Hashimoto, Kazuhito

2010-12-01

307

Influence of litter removal and mineral soil disturbance on the spread of an invasive grass in a Central Hardwood forest  

Microsoft Academic Search

Soil and litter disturbances within Central Hardwood forests may facilitate exotic plant species invasion of interior forest\\u000a areas. Microstegium vimineum is an annual exotic grass that has become common throughout the Southeastern United States. Three replicates of three different\\u000a mineral soil and litter disturbance treatments, plus a control with no disturbance, were established on the leading edge of\\u000a M. vimineum

Jordan M. Marshall; David S. Buckley

2008-01-01

308

Soil restoration under pasture after topsoil removal: Some factors influencing C and N mineralization and measurements of microbial biomass  

Microsoft Academic Search

Factors influencing rates of C and N mineralization of soil and plant materials, and the reliability of different procedures\\u000a for estimating microbial biomass, were measured in a soil (Typic Dystrochrept) that had been restored under grazed pasture\\u000a in a temperate environment for 10–11 years after 20 cm of the original topsoil had been removed by stripping.\\u000a \\u000a Rates of net N

D. J. Ross; P. B. S. Hart; G. P. Sparling; J. A. August

1990-01-01

309

The rate of iron oxide enrichment in arid zone alluvial fan soils, Tunisian southern atlas, measured by mineral magnetic techniques  

Microsoft Academic Search

Rates of iron oxide enrichment of soils on a segmented alluvial fan in southern Tunisia are examined. Mineral magnetic and chemical characteristics of soils developed on two dated relict segments and on contemporary alluvium suggest that the rate of Fe-oxide enrichment was more rapid in the Holocene (2.6 × 10?8 g g?1 yr?1 over the last 5000 years) than in

Kevin White; John Walden

1997-01-01

310

Fate of phosphorus applied in slurry and mineral fertilizer: accumulation in soil and release into surface runoff water  

Microsoft Academic Search

Phosphorus (P) accumulation on the soil surface and its effect on the concentration of dissolved orthophosphate P (PO4-P) in surface runoff water were studied after three years of surface application of slurry and mineral fertilizer to grass ley on a sandy soil, poor in P. The total amount of P applied was 107–143 kg ha-1>, of which 72–119 kg ha-1>

E. Turtola; M. Yli-Halla

1999-01-01

311

Crop nitrogen use and soil mineral nitrogen accumulation under different crop combinations and patterns of strip intercropping in northwest China  

Microsoft Academic Search

Increasing crop nitrogen use efficiency while also simultaneously decreasing nitrogen accumulation in the soil would be key\\u000a steps in controlling nitrogen pollution from agricultural systems. Long-term field experiments were started in 2003 to study\\u000a the effects of intercropping on crop N use and soil mineral N accumulation in wheat (Triticum aestivum L. cv 2014)\\/maize (Zea mays L. cv Shendan16), wheat\\/faba

Chun-Jie Li; Yu-Ying Li; Chang-Bing Yu; Jian-Hao Sun; Peter Christie; Min An; Fu-Suo Zhang; Long Li

2011-01-01

312

Decreasing soil water Ca2+ reduces DOC adsorption in mineral soils: implications for long-term DOC trends in an upland forested catchment in southern Ontario, Canada.  

PubMed

Positive trends in dissolved organic carbon (DOC) concentration have been observed in surface waters throughout North America and northern Europe. Although adsorption in mineral soils is an important driver of DOC in upland streams, little is known about the potential for changes in DOC adsorption to contribute to these trends. We hypothesized that long-term declines in soil water Ca(2+) levels, in response to declining acid deposition, might influence DOC adsorption and that this could contribute to long-term DOC trends in an upland forested catchment in south-central Ontario, Canada. Between 1987 and 2009, DOC concentrations increased significantly (p<0.05) in stream water and B horizon soil water (2 out of 3 sites). The null point DOC concentration (DOC(np)), which is a measure of the soil water DOC concentration at equilibrium with the soil, ranged from 1.27 to 3.75 mg L(-1) in B horizon soils. This was similar to the mean DOC concentrations of B horizon soil water (2.04-6.30 mg L(-1)) and stream water (2.20 mg L(-1)), indicating that soil and stream water DOC concentrations are controlled by equilibrium processes at the soil-water interface. Adsorption experiments using variable Ca(2+) concentrations demonstrated that as Ca(2+) decreased the DOC(np) increased (1.96 to 4.74 mg L(-1)), which was consistent with the observed negative correlation between DOC and Ca(2+) in B horizon soil water (p<0.05; r(2)=0.21). Additional adsorption experiments showed that Na(+) had no effect on DOC adsorption (p>0.05), indicating that changes in DOC adsorption might be related to cation bridging. We conclude that declines in soil water Ca(2+) concentration can contribute to increasing DOC trends in upland streams by reducing DOC adsorption in mineral soils. PMID:22554533

Kerr, Jason Grainger; Eimers, M Catherine

2012-05-01

313

Local coordination of Zn in hydroxy-interlayered minerals and implications for Zn retention in soils  

NASA Astrophysics Data System (ADS)

The objective of this study was to determine the local coordination of Zn in hydroxy-interlayered smectite (HIS) as a function of Zn loading and synthesis conditions and to assess the importance of hydroxy-interlayered minerals (HIM) for Zn retention in contaminated soils. Published and newly collected extended X-ray absorption fine structure (EXAFS) spectra of HIS reacted with Zn at molar Zn/hydroxy-Al ratios from 0.013 to 0.087 (corresponding to final Zn contents of 1615-8600 mg/kg Zn) were evaluated by shell fitting. In Zn-HIS, Zn was octahedrally coordinated to oxygen at 2.06-2.08 Å and surrounded by Al atoms at 3.03-3.06 Å in the second-shell. With increasing molar Zn/hydroxy-Al ratio, the coordination number of second-shell Al decreased from 6.6 to 2.1. These results were interpreted as a progressive shift from Zn incorporation in the vacancies of gibbsitic Al-polymers to Zn adsorption to incomplete Al-polymers and finally uptake by cation exchange in the polymer-free interlayer space of HIS with increasing Zn loadings. In a second part, we determined the speciation of Zn in eight contaminated soils (251-1039 mg/kg Zn) with acidic to neutral pH (pH 4.1-6.9) using EXAFS spectroscopy. All soils contained hydroxy-Al interlayered vermiculite (HIV). The analysis of EXAFS spectra by linear combination fitting (LCF) showed that a substantial fraction of total Zn (29-84%) was contained in HIM with high Zn loading. The remaining Zn was adsorbed to organic and inorganic soil components and incorporated into phyllosilicates. In sequential extractions of Zn-HIS spiked into quartz powder and the Zn contaminated soils, Zn was mainly released in the two most resistant fractions, in qualitative agreement with the findings from LCF. Our results suggest that formation of Zn-HIM may strongly retain Zn in pristine and moderately contaminated acidic to neutral soils. Due to their limited sorption capacity, however, HIM do not allow for the accumulation of high levels of Zn in response to continued Zn input into soils.

Jacquat, Olivier; Voegelin, Andreas; Kretzschmar, Ruben

2009-01-01

314

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 R²=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 (R² = 0.89, RMSE = 352.57 mg C / kg and ME = -50.16mg C / kg) and organic nitrogen (R² = 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

315

Field-Scale Variation in Microbial Activity and Soil Properties in Relation to Mineralization and Sorption of Pesticides in a Sandy Soil  

Microsoft Academic Search

Pesticides applied to agricultural soils are subject to environmental concerns because leaching to groundwater reservoirs and aquatic habitats may occur. Knowledge of fi eld variation of pesticide-related parameters is required to evaluate the vulnerability of pesticide leaching. Th e mineralization and sorption of the pesticides glyphosate and metribuzin and the pesticide degradation product triazinamin in a fi eld were measured

F. P. Vinther; U. C. Brinch; L. Elsgaard; L. Fredslund; B. V. Iversen; S. Torp; C. S. Jacobsen

2008-01-01

316

Temperature, Water Content and Wet-Dry Cycle Effects on DOC Production and Carbon Mineralization in Agricultural Peat Soils.  

Technology Transfer Automated Retrieval System (TEKTRAN)

A series of controlled laboratory experiments were utilized to examine factors affecting dissolved organic carbon (DOC) production and C mineralization rates over a range of conditions experienced resulting from agricultural practices in peat soils from the Sacramento-San Joaquin Delta. We conclude...

317

Microbiological quality of organic vegetables produced in soil treated with different types of manure and mineral fertilizer  

Microsoft Academic Search

An attempt was made to evaluate microbiological quality of horticultural crops grown organically. Three species of vegetables were used, lettuce (Lactuva sativa), radish (Raphanus sativus) and spinach (Tetragonia expansa), grown organically, in fertile soil. Six different treatments were applied: mineral fertilizer, chicken, cow, and pig manure, chicken litter and cow manure, in association with a liquid foliar biofertilizer. These crops

Débora Cabral Machado; Carla Marques Maia; Isabel Dias Carvalho; Natan Fontoura da Silva; Maria Cláudia Dantas Porfírio Borge André; Álvaro Bisol Serafini

2006-01-01

318

Nitrogen mineralization in volcanic soil under grassland, shrub and forest vegetation in the Aegean region of Turkey  

Microsoft Academic Search

Net nitrogen mineralization of a grassland-, Quercus coccifera shrub- and Pinus brutia forest-site within the Aegean region was investigated continuously through a year by field and standard incubation methods. Seasonal fluctuations resulting from field incubation are marked in grassland and shrub, but less pronounced in the forest. They are mainly associated with the changes in soil moisture being at minimum

M. Gökçeo?lu

1988-01-01

319

Mineralization and microbial assimilation of 14C-labeled straw in soils of organic and conventional agricultural systems  

Microsoft Academic Search

An incubation experiment on straw decomposition was carried out with soils from a long-term field trial at Therwil, Switzerland. Two conventional agricultural systems, one with (CONFYM) and one without manure, an organic system managed according to bio-dynamic farming practice (BIODYN) and an unfertilized control were compared. CONFYM received stacked manure and an additional mineral fertilizer. BIODYN received composted farmyard manure

Andreas Fließbach; Paul Mäder; Urs Niggli

2000-01-01

320

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.

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

2012-01-01

321

Post-fire spatial patterns of soil nitrogen mineralization and microbial abundance.  

PubMed

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 21(st) Century. PMID:23226324

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

2012-11-30

322

Electron microbeam investigation of uranium-contaminated soils from Oak Ridge, TN, USA.  

PubMed

Two samples of uranium-contaminated soil from the Department of Energy's Oak Ridge Reservation in Oak Ridge, Tennessee were investigated using electron microprobe analysis and transmission electron microscopy. The objectives of this research were to identify and characterize soil particles and rock chips with high uranium concentrations, to investigate the extent of uranium penetration into chips of parent material, and to identify solid-phase hosts for uranium in the samples. Three distinct solid-phase hosts for uranium have been identified: (1) iron oxyhydroxides, including goethite and ferrihydrite; (2) mixed Mn-Fe oxides; and (3) discrete uranium phosphates. In all three, uranium is associated with phosphorus. The ubiquitous U-P association highlights the influence of phosphate on the environmental fate of uranium. Uranium-bearing phases are found well within chips of weathered shale, as far as 900 microm from fractures and chip edges, indicating that uranium has diffused into the shale matrix. PMID:16646440

Stubbs, Joanne E; Elbert, David C; Veblen, David R; Zhu, Chen

2006-04-01

323

[Effects of litter and mineral nitrogen input on soil organic carbon decomposition in subtropical mixed forest in Dinghu Mountain, South China].  

PubMed

In July-December 2010, a complete factor-controlled experiment was conducted to study the effects of litter and mineral nitrogen addition on soil organic matter decomposition (soil respiration) at the depths of 0-10 cm and 20-30 cm in Dinghu Mountain National Reserve. Coniferous needle litter and broadleaved litter were added, respectively, and 70 g N x m(-2) x yr(-1) of NH4 NO3 was applied to simulate soil nitrogen saturation whereas soil mineral nitrogen was removed by ion-exchange membrane to simulate the decreased nitrogen absorption by root. The addition of both needle litter and broadleaved litter increased the respiration rate of soil-litter system significantly from July to November, but this effect disappeared in December. Both mineral nitrogen application and soil mineral nitrogen removal increased the soil-litter respiration significantly. These results suggest that litter decomposed completely in a short period therefor had limited effects on soil organic matter decomposition and accumulation, and thus, foliar litters could be not the major source of soil organic matter, whereas soil mineral nitrogen removal could obviously promote the soil organic matter decomposition in the system. PMID:22384572

Sun, Li-Juan; Zeng, Hui; Guo, Da-Li

2011-12-01

324

Interplay between physical movements of soils and mineral grains and chemical weathering  

Microsoft Academic Search

Most soil biogeochemistry studies treat the soils and their inorganic and organic constituents as physically immobile. Those soil materials, however, are in perpetual motion due to the conversion of bedrock to soils, colluvial transport, and vertical mixing by various biophysical perturbations of the soils. Subsequently, a soil is continuously replaced by the materials from the neighboring soils and the underlying

K. Yoo

2007-01-01

325

Mineralization of organic matter with warming in boreal forest soils is influenced by nitrogen dynamics  

NASA Astrophysics Data System (ADS)

Temperature is an important factor in regulating soil organic matter (SOM) decomposition, but the drivers of microbial substrate choice with changing temperature regimes remain poorly elucidated. For example, nitrogen (N) dynamics play a key role in dictating activity levels of different microbial groupings, which in turn may influence who in a microbial community is better able to take advantage of more favorable energetics in a warmer soil profile. These issues are particularly important for large SOM reservoirs, such as those in the boreal biome. To address these issues, we collected soils in organic horizons from two forested sites along the Newfoundland-Labrador Boreal Ecosystem Latitude Transect (NL-BELT) in eastern Canada. Sites differ in latitude and mean annual temperature, but are similar in forest cover and soil type. We incubated humified Oe+Oa materials and replaced Oi with low or high C:N coniferous litter possessing a distinct ?13C signature for 120 days at 15°C and 20°C. During the incubation, we assessed respiratory CO2 losses and its origin via ?13C of CO2, microbial biomass, and the activity of multiple exo-enzymes associated with the mineralization of slow-turnover and more labile substrates. As predicted by enzyme kinetics, warming positively influenced respiratory loss and the proportion of CO2 derived from more humified SOM, particularly in late stages of the incubation. We observed no interaction effect of warming and Oi C:N on respired CO2 or microbial biomass C or N in soil from either site. Oi C:N influenced respiratory loss from higher latitude soils, with lower C:N Oi input dampening respiration rates early in the incubation, and promoting it at later stages. Late in the incubation, when the positive effect of warming on CO2 release from more humified SOM was most pronounced, the warming-induced increase in phenol oxidase activity was further enhanced when Oi material had a relatively low C:N by factors of 1.87 and 17 for lower vs. higher latitude soils, respectively. Overall, these results indicate that the C:N of inputs to the O horizon such as the Oi sub-horizon can exert a quantifiable influence on CO2 efflux rates in some boreal soils. That we observed a general effect of Oi C:N on the activity of an enzyme linked to decay of relatively slow-turnover SOM suggests that Oi C:N can serve as a driver of microbial substrate choices, such that the relatively greater influence of warming on humified SOM decay is magnified by increased organic N availability. These results highlight the potentially positive feedbacks to warming that may result in boreal soil systems, as well as the important role that N plays in dictating microbial responses to climate warming.

Li, J.; Ziegler, S. E.; Lane, C. S.; Billings, S. A.

2011-12-01

326

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

327

Characterization of ^{239,240}Pu Radionuclide Adsorption to Soil Particles and Mineral Dust Aerosols  

NASA Astrophysics Data System (ADS)

The release of ^{239,240}Pu into the environment by nuclear weapons testing 50 years ago initiated the cyclic mobilization of Pu-contaminated soil particles via the resuspension of dust resulting in a widespread distribution of Pu and other radionuclides. It is unclear what enables the aeolian transport of Pu in the environment; plausible hypotheses of Pu binding to dust and soil particles include Pu adsorption to iron oxides/hydroxides, organic acids, or silicate minerals such as clays. To investigate the connections between surface soils, dust and radionuclides, samples of soil and/or dust were collected from the Project Gnome Site in Eddy County, NM, the Jemez Mountains near Los Alamos, NM, and two 50-year old attics and wind-blown dust in Big Spring, TX. This study tests the hypothesis that Pu is adsorbed onto Fe oxides and hydroxides that coat dust/soil particles. The samples are generally low in organic carbon (0.2 - 4.8%, except for the unburned Los Alamos sample at 9.4%), as measured by LOI (Loss On Ignition) at 360 °C. The citrate-bicarbonate-dithionite method (CDB) of Fe oxide removal, first proposed by Mehra and Jackson in 1960, was used to selectively extract Fe oxides from the samples while leaving silicate Fe intact. Chemical digestion of each sample creates two fractions, the extracted supernatant and a solid pellet residue. If the Pu were associated with Fe oxides, then Fe and Pu should both be selectively removed from the bulk sample during the CBD process, leaving the pellet depleted in Fe and Pu and the supernatant enriched. For Fe, this was confirmed by scanning electron microscope and petrographic analyses. Preliminary radiochemical analyses of Pu activity also verify this hypothesis. Pu activity is significantly lower in pellets than bulk samples (Pu activitypellet/Pu activitybulk average = 0.07, range 0.02-0.12); Pu activity in supernatants is significantly higher than in bulk samples (Pu activitysupernatant/Pu activitybulk average = 4.45, range 2.53-6.92). The Big Springs wind-blown dust sample is an outlier; further analyses are in progress to evaluate its composition.

Tatro, D. P.; Arimoto, R.; McMillan, N. J.; Barnes, M.

2006-12-01

328

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

329

Immediate Effects of Time and Method of Alfalfa Termination on Soil Mineral Nitrogen, Moisture, Weed Control, and Seed Yield, Quality, and Nitrogen Uptake  

Microsoft Academic Search

Three field experiments were conducted on Gray Luvisol (Typic Cryoboralf) soils in northeastern Saskatchewan to compare the effects of alfalfa (Medicago sativa Leyss) stand termination with tillage and herbicides at different times on mineral nitrogen (N) (ammonium-N and nitrate-N) and moisture content of soil in spring (experiments 1 and 2), soil moisture, volunteer alfalfa and dandelion control, plant density, seed

S. S. Malhi; A. M. Johnston; H. Loeppky; C. L. Vera; H. J. Beckie; P. M. S. Bandara

2007-01-01

330

Ecological Risk Assessment Quantification of the Effect of Fumigation on Short and Long-Term Nitrogen Mineralization and Nitrification in Different Soils  

Microsoft Academic Search

soil consumes more O2 and evolves more CO2 than the untreated soil. Moreover, fumigants usually cause an The effect of soil fumigation on N mineralization and nitrification immediate increase in the extractable NH 4 content of needs to be better quantified to optimize N fertilizer advice and predict NO 3 concentrations in crops and NO 3 leaching risks. Seven the

Stefaan De Neve; Gabor Csitari; Joost Salomez; Georges Hofman

331

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

SciTech Connect

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 et al., 2008, GCA) 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 Tisser and [2006] or the aluminum inhibition model proposed by Oelkers et al. [1994], 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. 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, SiO{sub 2}(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.

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

2009-02-25

332

[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

333

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

334

The role of mineralization of the organic matter of soddy-podzolic and peat bog soils in the accumulation of 137Cs by plants  

NASA Astrophysics Data System (ADS)

The role of mineralization of soil organic matter (SOM) in the mobilization of 137Cs was estimated on the basis of data on the biokinetic fractionation of the organic matter of soddy-podzolic sandy-loam and peat bog soils and on the coefficients of the soil-to-plant transfer of radiocesium under field conditions. The peat bog soils were richer than the soddy-podzolic soils in the total organic carbon (by 7.9-23.8 times), the potentially mineralizable carbon (by 2.4-6.5 times), and the carbon of the microbial biomass (by 2.9-4.6 times). The agricultural use of the soddy-podzolic and peat bog soils led to a decrease in the SOM mineralization capacity by 1.1-1.8 and 1.4-2.0 times, respectively. Simultaneously, the portions of the easily, moderately, and difficultly mineralizable fraction of the SOM active pool changed. The coefficients of the 137Cs transfer from the peat bog soils to plants were 3.3-17.6 times higher than those for the soddy-podzolic soils. The content of 137Cs in plants grown on the peat bog soils was 2-65 times higher than that in the mobile (salt-extractable) soil pool by the beginning of the growing season. Strong positive linear correlations were found between the coefficients of the soil-to-plant transfer of 137Cs and the total content of the SOM, the content of the microbial biomass, the content of the potentially mineralizable carbon, and the intensity of its mineralization. It was concluded that the decisive factors controlling the intensity of the 137Cs transfer from mineral and organic soils into plants are the SOM content and its mineralization potential. The mineralization of the SOM is accompanied by the release of both 137Cs and mineral nitrogen; the latter facilitates the transfer of radiocesium into plants.

Tulina, A. S.; Semenov, V. M.; Tsybul'Ka, N. N.; Shapsheeva, T. P.; Zaitsev, A. A.; Arastovich, T. V.

2010-10-01

335

Mineralization of organic-matter labile fragments in the humus-accumulative horizon of soddy-podzolic soil  

NASA Astrophysics Data System (ADS)

The mineralization rate of the 14C-labeled organic matter (OM) in the humus-accumulative AE horizon of a soddy-podzolic soil was determined in a laboratory experiment. The labeling was performed in a field experiment when microamounts of 14C-labeled glucose, glycine, and uracil were added to tree waste in sacks embedded in the upper layer of the forest litter. Samples containing 14C were taken from the AE horizon (above which the sacks with the labeled material were placed) 7 and 20 months after the beginning of the experiment. The soil samples were wetted to a water content corresponding to ˜80% of the total water capacity and placed in hermetic vessels containing vials with a periodically renewed alkali solution. The incubation was performed at room temperature for 3.5 months; the alkali solutions in the vials were replaced and titrated 12 times during this period. Mineralization curves were plotted from the amounts of carbon dioxide absorbed by a 0.3 N NaOH solution, which were calculated for each time interval; its 14C content was determined by the scintillation method. The experimental treatments also included the determination of the OM mineralization rate in material from the AE horizon pretreated with a heavy liquid or a heavy liquid and a 0.1 N NaOH solution. The differences between the mineralization rates of the labeled organic matter applied to the soil in the form of glucose, glycine, and uracil under the field conditions after the interaction for 7 and 20 months were revealed. The changes in the mineralization rate after the successive extraction of the labile organic matter with a heavy liquid and a 0.1 N NaOH solution were studied. It was shown that the transformation of the labeled low-molecular-weight organic compounds in the soil over 20 months included their strong inclusion into the humus composition, which was confirmed by the similar values of the mineralization constants of the native and 14C-labeled OM. In addition, the treatments with the heavy liquid or the heavy liquid and the NaOH solution had almost identical effects on the mineralization of the native and 14C-labeled OM. The mineralization constants of the native and 14C-labeled OM in the samples taken after 7 months of the field experiment differed significantly.

Trofimov, S. Ya.; Lazarev, A. S.; Fokin, A. D.

2012-12-01

336

Aerobic mineralization of nitroguanidine by Variovorax strain VC1 isolated from soil.  

PubMed

Nitroguanidine (NQ) is an energetic material that is used as a key ingredient of triple-base propellants and is currently being considered as a TNT replacement in explosive formulations. NQ was efficiently degraded in aerobic microcosms when a carbon source was added. NQ persisted in unamended microcosms or under anaerobic conditions. An aerobic NQ-degrading bacterium, Variovorax strain VC1, was isolated from soil microcosms containing NQ as the sole nitrogen source. NQ degradation was inhibited in the presence of a more favorable source of nitrogen. Resting cells of VC1 degraded NQ effectively (54 ?mol h(-1) g(-1) protein) giving NH(3) (50.0%), nitrous oxide (N(2)O) (48.5%) and CO(2) (100%). Disappearance of NQ was accompanied by the formation of a key intermediate product that we identified as nitrourea by comparison with a reference material. Nitrourea is unstable in water and suffered both biotic and abiotic decomposition to eventually give NH(3), N(2)O, and CO(2). However, we were unable to detect urea. Based on products distribution and reaction stoichiometry, we suggested that degradation of NQ, O(2)NN?C(NH(2))(2), might involve initial enzymatic hydroxylation of the imine, -C?N- bond, leading first to the formation of the unstable ?-hydroxynitroamine intermediate, O(2)NNHC(OH)(NH(2))(2), whose decomposition in water should lead to the formation of NH(3), N(2)O, and CO(2). NQ biodegradation was induced by nitroguanidine itself, L-arginine, and creatinine, all being iminic compounds containing a guanidine group. This first description of NQ mineralization by a bacterial isolate demonstrates the potential for efficient microbial remediation of NQ in soil. PMID:22563908

Perreault, Nancy N; Halasz, Annamaria; Manno, Dominic; Thiboutot, Sonia; Ampleman, Guy; Hawari, Jalal

2012-05-17

337

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.

Rosenzweig, William D.; Stotzky, G.

1979-01-01

338

[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

339

Clay minerals in chernozem-like soils of mesodepressions in the northern forest-steppe of European Russia  

NASA Astrophysics Data System (ADS)

In the northern forest-steppe of European Russia, under the conditions of surface waterlogging (freshwater) and a stagnant-percolative regime, gleyic podzolic chernozem-like soils with thick light-colored eluvial horizons are formed. These horizons are close or similar to the podzolic horizons of bog-podzolic soils in many properties of their solid phase. They are bleached in color and characterized by the removal of Ca, Mg, Fe, Al, and Mn and the relative accumulation of quartz SiO2. These soils differ from leached chernozems in their acid reaction and very low CEC, the presence of Fe-Mn concretions and coatings, and the significant decrease in the clay content in the A2 horizon as compared to the parent rock. The soils studied differ significantly from loamy podzolic and bog-podzolic soils by the composition of the clay minerals in the A2 horizons: (1) no essential loss of smectite minerals from this horizon was found as compared to the rest of the solum, (2) pedogenic chlorites (HIV and HIS) are absent, and (3) the distinct accumulation of illites is observed as compared to the subsoil and parent material, probably, due to the process of illitization.

Sokolova, T. A.; Zaidel'Man, F. R.; Ginzburg, T. M.

2010-01-01

340

Effect of soil type and fertilization level on mineral concentration of pasture: potential relationships to ruminant performance and health.  

PubMed

A three-year study was conducted to measure the effects of varying levels of dairy slurry application on mineral concentration of forages from three soils types. Slurry was applied to orchardgrass (Dactylis glomerata [L.] cv. Pennlate) growing in 60-cm diameter drainage lysimeters to measure the effect of four levels of slurry (urine and feces) N application (0, 168, 336, and 672 kg of N.ha-1.yr-1) on mineral (P, K, Ca, Mg) concentration of the forage on three soil types (Hagerstown, Hartleton, and Rayne). The results were then related to potential effects on performance and health of grazing ruminants. Forage P was not affected by slurry application (mean = 0.46% of DM). Forage grown on the Hartleton soil had the highest (P < 0.05) P concentration (0.6% of DM). Forage K increased (P < 0.05) with increased slurry (2.50, 2.85, 3.22, and 3.45% of DM, respectively), and was lowest (P < 0.05) for forage grown on the Rayne soil (2.69% of DM). Forage Ca decreased (P < 0.05) with increased slurry (0.59, 0.56, 0.50, and 0.49% of DM, respectively) and was not affected by soil type. Forage Mg also decreased (P < 0.05) with increased slurry (0.25, 0.24, 0.24, and 0.23% of DM, respectively), and was highest (P < 0.05) for the Hartleton soil (0.27% of DM). The variable results in mineral concentration associated with soil type may have, in part, been due to prior soil fertility. The P and Mg concentrations in all treatments were generally adequate for grazing ruminants. The K concentrations were high in relation to NRC recommendations for prepartum dairy cows, which might predispose them to milk fever. The Ca concentrations were inadequate for lactating dairy cows. Comprehensive forage testing and diet formulation based on individual farm situations is the best strategy to ensure proper mineral nutrition of grazing animals. PMID:12817509

Soder, K J; Stout, W L

2003-06-01

341

Responses of soil microbial biomass, nematode trophic groups, N-mineralization, and litter decomposition to disturbance events in the southern Appalachians  

Microsoft Academic Search

Seasonal measurements of soil microbial biomass, nematode trophic groups, net N-mineralization, net nitrification, net ammonification, litter decomposition, and soil respiration rates were examined to assess the effects of rhododendron (Rhododendron maximum L.) removal and hurricane windthrow upon these factors. Comparisons of pre- and post-disturbance quantities of soil microbial biomass carbon ranged from 503 to 1080?g C g soil?1 and microbial

C. J Wright; D. C Coleman

2002-01-01

342

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

343

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

2010-10-22

344

Surfactant-mediated extraction of iron and its spectrophotometric determination in rocks, minerals, soils, stream sediments and water samples  

Microsoft Academic Search

An extraction spectrophotometric method for iron determination in rocks, minerals, soils, stream sediments and water samples has been developed. At pH 3-4, iron (III) forms a 1:2:1 ternary complex with thiocyanate and cetyltrimethylammonium bromide (Fe\\/SCN\\/CTAB) which is extracted into ethyl acetate. The readily formed purple complex is suitable for extraction spectrophotometric determination of iron in rocks and related materials from

Pranab K. Tarafder; Raghbendra Thakur

2005-01-01

345

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

346

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

347

Mineralization and conversion of pentachlorophenol (PCP) in soil inoculated with the white-rot fungus Trametes versicolor  

Microsoft Academic Search

The fate of pentachlorophenol (PCP) in autoclaved soil supplemented with straw and inoculated with the white-rot fungus Trametes versicolor was investigated. Inoculated flasks were incubated for 0 to 42d and control flasks for 0 to 28d. Mineralization and volatilization of PCP and its transformation products were measured using 14C-labelled PCP for radiorespirometry and extraction analysis, and non-labelled PCP to monitor

Marja Tuomela; Merja Lyytikäinen; Pekka Oivanen; Annele Hatakka

1998-01-01

348

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

349

Carbon-to-nitrogen ratio is a poor predictor of low molecular weight organic nitrogen mineralization in soil  

Microsoft Academic Search

Carbon-to-nitrogen ratio (C:N) has frequently been shown to be a good predictor of the speed of organic residue decomposition and N mineralization in soil. While this relationship appears to work well for complex organic materials (e.g. plant litter), its applicability to smaller organic substrates containing N remains unknown. Here we evaluated whether the intrinsic properties of amino acids and peptides

P. Roberts; R. Stockdale; M. Khalid; Z. Iqbal; D. L. Jones

2009-01-01

350

Soil carbon sequestration and mineralization potential in an old-field revegetated with shrubs in semi-arid climate conditions  

NASA Astrophysics Data System (ADS)

Revegetation and afforestation of abandoned fields can modify mineralisation processes of soil organic matter and, as a consequence, the potential for C sequestration. Our work aimed to analyse these changes identifying C fractions with different degrees of physical protection and potential mineralization, in a old-field revegetated with shrubby species in a Mediterranean semi-arid area. A multi-specific plantation was made up in February 2006, by planting Juniperus phoenicea L. (JP), Pistacia lentiscus L. (PL) and Rosmarinus officinalis L. (RO). The area has a typical Mediterranean climate with an average temperature of 16.8 °C and a total annual precipitation of 643 mm. Soil cores were collected in three plots with a mixed specific composition, and in one plot used as control (grass cover). Soil cores (0 - 20 cm depth) were sampled in April 2010 at two distances (30 and 60 cm) from the centre of shrub crown cover in revegetated plots, and randomly in the control. The following variables were examined: soil aggregates (macro- > 250 µm and micro-aggregates between 53 and 250 µm), fine particulate organic matter (F-POM) and its C and N content, microbial respiration after 28 days at 24 °C, and mineralization rate of labile and stable C. In the short period, no variation in soil C accumulation induced by the plantation was detected. On the other hand, C input from the different soil covers had a distinct pattern: in revegetated plots it was mainly made up by POM, while fine roots represented the major C input in the control. Macro- and micro-aggregates distribution differed in the control and revegetated plots, allowing a higher physical protection of organic carbon in the control. Nevertheless, more recalcitrant organic matter inputs in the plantation can likely determine a more robust soil C accumulation in the long term.

de Dato, G.; Lagomarsino, A.; Abou Jaoudé, R.; De Angelis, P.

2012-04-01

351

Estimating Soil Erosion and Carbon Mineralization by Rainfall Erosion for Select Management Practices in Corn-based Cropping Rotations: A Case Study for Iowa  

NASA Astrophysics Data System (ADS)

This paper presents estimates of changes in rainfall-induced soil erosion and soil carbon mineralization of individual land capability class I-VIII soil types in Iowa. Land management considered in this analysis includes various quantities of corn stover removal on continuous corn and corn-soybean rotations that are subject to conventional, reduced, and no-till tillage practices. For each rotation and tillage scenario, calculations of soil erosion and carbon mineralization were made for: 1) a ``baseline'' case (e.g., the annual quantity of rainfall-induced soil erosion (tons per acre) that would have occurred with no corn stover removal), 2) a minimum residue level at harvest such that the USDA-NRCS prescribed tolerable soil loss limit (T) is not exceeded for each individual soil type, and 3) a minimum residue at harvest set at 50 bushels corn stover equivalent. Results indicate a large variation in soil erosion and soil carbon mineralization, with this variation depending on rotation, tillage, residue level at harvest, stover removal, physical characteristics of individual soil types, field topology (average % slope), and localized climate. For each county, soil erosion and carbon mineralization increased within a set tillage practice in the corn-soybean rotation versus continuous corn with a range of 11.5% to nearly 600%. Also, an expected decrease in soil erosion and carbon mineralization occurred as tillage decreased in intensity from conventional to conservation/reduced to no-till. Moving from conventional to no-till in continuous corn and corn/soybean rotations with no stover removal, for example, resulted in average decreases of soil erosion of 60% and 88% respectively, and an average decrease of 0.084 tons of carbon dioxide efflux per acre between the two rotations. Allowing a minimum stover level at harvest based either on T or 50 bushels per acre stover equivalent resulted in average increases in soil erosion and carbon mineralization between 27% to over 1,000%, depending upon rotation and tillage practice. A case study at the individual soil type level for Adair County, Iowa is presented to demonstrate differences in soil erosion and carbon mineralization within a single county subject to differing crop rotations, tillage management, and residue removal. This case study will illustrate the significance of including estimates of carbon dioxide efflux from soil erosion in regional carbon accounting and in bottom-up carbon modeling scenarios.

Nelson, R. G.; Sheehan, J. J.; West, T. O.

2005-12-01

352

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

353

Effects of soil applied humic substances to dry weight and mineral nutrients uptake of maize under calcareous soil conditions  

Microsoft Academic Search

A greenhouse research was conducted to determine the effects of soil application of humus on dry matter and some nutrient element uptake of maize grown under calcareous soil conditions. Agricultural lime was used to obtain five CaCO3 doses (0, 5, 10, 20 and 40%). Three doses of solid humus (0, 1 and 2 g kg) were applied to soil one

Hakan Çelik; A. Vahap Katkat; B. Bülent A??k; M. Ali Turan

2008-01-01

354

Development and application of a soil organic matter based soil quality index in mineralized terrane of the Western US  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soil quality indices provide a means of distilling large amounts of data into a single metric that evaluates the soil’s ability to carry out key ecosystem functions. Primarily developed in agroecosytems, then forested ecosystems, we set out to develop and apply an index using the relation between so...

355

Spatial and Temporal Variability of Arsenic Solid-State Speciation in Historically Lead Arsenate Contaminated Soils  

SciTech Connect

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 ({approx}71%) present as As(V) adsorbed onto amorphous iron oxyhydroxides with a residue ({approx}29%) of an original contaminant, schultenite (PbHAsO{sub 4}). 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 (As{sub 2}S{sub 3}). The rest of the fractions ({approx}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.

Arai,Y.; Lanzirotti, A.; Sutton, S.; Newville, M.; Dyer, J.; Sparks, D.

2006-01-01

356

13C FRACTIONATION DURING RELIC SOIL ORGANIC C MINERALIZATION ON CARBON BUDGETS AND HALF-LIVES CALCULATED USING THE STABLE ISOTOPE APPROACH  

Technology Transfer Automated Retrieval System (TEKTRAN)

The 13C natural abundance approach for determining soil organic C (SOC) stability and turnover has been used to determine SOC mineralization kinetics. These calculations often assume that 13C fractionation during relic SOC and non-harvested biomass mineralization is insignificant. The objective of t...

357

Effects of different manuring systems with and without biogas digestion on soil mineral nitrogen content and on gaseous nitrogen losses (ammonia, nitrous oxides)  

Microsoft Academic Search

Nitrogen (N) is the most susceptible nutrient to transformations affecting plant availability. These transformations include mineralization, immobilization, nitrification and denitrification, as well as leaching and ammonia volatilization. Use of stable wastes and other residues for biogas digestion may reduce N-losses. It is the purpose of this paper (i) to assess the effects of biogas digestion on soil mineral N (SMN)

Kurt Möller; Walter Stinner

2009-01-01

358

Microbial processes in relation to carbon, nitrogen and temperature regimes in litter and a sandy mineral soil from a central Siberian Pinus sylvestris L. forest  

Microsoft Academic Search

The coniferous forests of Siberia contain a significant fraction of the world's terrestrial C. We have assessed organic matter storage and potential metabolic activities in one of these forest stands by determining C and N pools, microbial properties and C and N mineralization at different temperatures in litter and a sandy mineral soil (a Pergelic Cryochrept) from a 215-y old

D. J. Ross; F. M. Kelliher; K. R. Tate

1999-01-01

359

Effect of Clay Minerals on Immobilization of Heavy Metals and Microbial Activity in a Sewage Sludge-Contaminated Soil (8 pp)  

Microsoft Academic Search

Conclusions. Our results clearly show that the addition of clay minerals, especially of Na-bentonite and Ca-bentonite, decreased the extractability of four metals during incubation. The decreased metal extractability was accompanied by an increase of soil respi- ration, Corg mineralization, microbial biomass C, and inorganic N and a decrease of metabolic quotient (qCO 2 ), showing positive effect of clay mineral

Adel Usman; Yakov Kuzyakov; Karl Stahr

2005-01-01

360

Metal oxides, clay minerals and charcoal determine the composition of microbial communities in matured artificial soils and their response to phenanthrene.  

PubMed

Microbial communities in soil reside in a highly heterogeneous habitat where diverse mineral surfaces, complex organic matter and microorganisms interact with each other. This study aimed to elucidate the long-term effect of the soil mineral composition and charcoal on the microbial community composition established in matured artificial soils and their response to phenanthrene. One year after adding sterile manure to different artificial soils and inoculating microorganisms from a Cambisol, the matured soils were spiked with phenanthrene or not and incubated for another 70 days. 16S rRNA gene and internal transcribed spacer fragments amplified from total community DNA were analyzed by denaturing gradient gel electrophoresis. Metal oxides and clay minerals and to a lesser extent charcoal influenced the microbial community composition. Changes in the bacterial community composition in response to phenanthrene differed depending on the mineral composition and presence of charcoal, while no shifts in the fungal community composition were observed. The abundance of ring-hydroxylating dioxygenase genes was increased in phenanthrene-spiked soils except for charcoal-containing soils. Here we show that the formation of biogeochemical interfaces in soil is an ongoing process and that different properties present in artificial soils influenced the bacterial response to the phenanthrene spike. PMID:23336569

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

2013-01-21

361

Interactive effects of belowground organic matter input, increased precipitation and clipping on soil carbon and nitrogen mineralization in a temperate steppe  

NASA Astrophysics Data System (ADS)

Soil organic matter (SOM) inputs, increased precipitation and clipping (reducing belowground photosynthates allocation) are predicted to affect soil C and N cycling in temperate grassland ecosystems. However, the interactive effects between SOM inputs (or increased precipitation) and clipping on soil C and N mineralization in temperate steppes are still poorly understood. A field manipulation experiment was conducted to quantify the effects of SOM inputs, increased precipitation, clipping and their interactions on soil C and N mineralization in a temperate steppe of northeastern China from 2010 to 2011. The results showed that SOM inputs significantly increased soil C mineralization rate (CMR) and net N mineralization rate (NMR). Increased precipitation-induced enhancement of soil CMR essentially ceased after the first year, stimulation of soil NMR and NNR continued into the second year. However, clipping only marginally decreased soil CMR and NMR during the two years. There were significant synergistic interactions between SOM inputs (or increased precipitation) and clipping on soil CMR and NMR, as SOM inputs (or increased precipitation) showed greater effects on soil CMR and NMR under clipped plots than under unclipped plots, which could be explained by the relative shifts in soil microbial community structure because of bacterial biomass increases, and by the relative decreases in arbuscular mycorrhizal fungi biomass due to the reduction of belowground photosynthates allocation. These results highlight the importance of plants in mediating the responses of soil C and N mineralization to potentially increased SOM and precipitation by controlling belowground photosynthates allocation in the temperate steppe. Thus, the findings have important implications for improving prediction of C and N sequestration potential and its feedbacks to climate change in temperate steppe ecosystems.

Ma, L. N.; Guo, C. Y.; Xin, X. P.; Yuan, S.; Wang, R. Z.

2013-06-01

362

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

363

Factors controlling mineralization of soil organic matter in the Eurasian steppe  

Microsoft Academic Search

To understand the dynamics of soil organic matter (SOM) in the Eurasian steppe, several soil and meteorological properties were tested in order to estimate the amounts of potentially mineralizable organic carbon (PMC) and nitrogen (PMN). Total 41 surface soil samples were collected in Ukraine and Kazakhstan from cropland, forest, grassland, and desert ecosystems. The fresh soils were incubated for 133

Atsunobu Kadono; Shinya Funakawa; Takashi Kosaki

2008-01-01

364

Organic Matter Stabilization in Surface and Subsurface Soil Horizons: C Mineralization and Early Formation of Water-Stable Macroaggregates  

NASA Astrophysics Data System (ADS)

Fine-textured Gleysolic soils in Eastern Canada are widespread and productive. Their high silt and clay content (>80%) suggests that they may have a high C storage capacity. Recent research has shown that while the absence of tillage increases the level of macroaggregation and the amount of C stored in surface soil, incorporation of crop residues by full inversion tillage commonly practiced in Eastern Canada can increase the level of organo-mineral interaction and the amount of C retained in deeper soil layers. The objective of this experiment was to evaluate the intrinsic potential of surface and subsurface horizons of fine-textured Gleysolic soils to retain additional C input. Topsoil (0-20 cm) and subsoil (30-70 cm) samples were taken from a cultivated clayey soil profile of the Kamouraska serie located near Québec and incubated with 0, 2.5, 5.0, 10.0, 20.0, and 40.0 g C kg-1 soil of 13C-15N-labelled corn residues. Large amounts of residues were added to the soils in order to saturate SOC pools. Soils and residues were mixed and incubated under optimal temperature (25°C), water potential (-38 kPa), and nutrient (C:N = 10) conditions for 52 d. More C was lost as CO2 in the topsoil than in the subsoil for all residue-C treatment, except of the highest level (40 g C kg-1 soil). At each level of C input, the ratio of C lost to C added was lower in the subsoil than in the topsoil indicating higher C protection in the subsoil than in the topsoil, especially with lower plant C input rates. The effect of C input on macroaggregate formation and stabilization was greater in subsoil than topsoil, but both soils reach a plateau of 90% macroaggregates in the 20 g C kg-1 soil treatment. The formation of new water-stable macroaggregates was greater in the subsoil than topsoil, and was related to lower C lost through respiration. These preliminary results clearly show that the subsoil is responding differently to C additions than does the topsoil. Upcoming results on isotopic signature will give us more information on the incorporation of added-C within specific soil fractions. Moreover, the use of molecular analytical techniques to trace biomarkers within specific soil fractions could help us elucidate preferential stabilization mechanisms operating under C saturated and unsaturated conditions, and during the early C stabilization period.

Poirier, V.; Angers, D. A.; Rochette, P.; Whalen, J. K.

2009-05-01

365

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

366

Effect of the Quantity and Duration of Application of Simulated Acid Precipitation on Nitrogen Mineralization and Nitrification in a Forest Soil.  

National Technical Information Service (NTIS)

A study was conducted of the influence of the rate of application of simulated acid rain on N mineralization and nitrification in a forest soil. The rates were varied by applying different quantities of simulated rain for varying periods of time. The soil...

T. M. Klein M. Alexander

1986-01-01

367

EFFECT OF THE QUANTITY AND DURATION OF APPLICATION OF SIMULATED ACID PRECIPITATION ON NITROGEN MINERALIZATION AND NITRIFICATION IN A FOREST SOIL  

EPA Science Inventory

A study was conducted of the influence of the rate of application of simulated acid rain on N mineralization and nitrification in a forest soil. The rates were varied by applying different quantities of simulated rain for varying periods of time. The soil was exposed in the labor...

368

Multi-scale Assessment of Methylarsenic Reactivity in Soil: 2. Distribution and Speciation in Soil  

PubMed Central

Methylated forms of arsenic (As), monomethylarsenate (MMA) and dimethylarsenate (DMA), have historically been used as herbicides and pesticides. Because of their large application to agriculture fields and the toxicity of MMA and DMA, the distribution, speciation, and sorption of methylated As to soils requires investigation. Monomethylarsenate and DMA were reacted with a soil up to one year under aerobic and anaerobic conditions. Micro-synchrotron based X-ray fluorescence (?-SXRF) mapping studies showed that MMA and DMA were heterogeneously distributed in the soil and were mainly associated with iron oxyhydroxides, goethite, in the soil. Micro-X-ray absorption near edge structure (XANES) spectra collected from As hotspots showed MMA and DMA were demethylated to arsenate over one year incubation under aerobic conditions. Monomethylarsenate was methylated to DMA, and DMA was maintained as DMA over three month incubation under anaerobic conditions. Arsenic-iron precipitation, such as the formation of scorodite (FeAsO4·2H2O), was not observed, indicating that MMA and DMA were mainly associated with Fe-oxyhydroxides as sorption complexes.

Shimizu, Masayuki; Arai, Yuji; Sparks, Donald L.

2011-01-01

369

Calibration of a combined dielectric probe for soil moisture and porewater salinity measurement in organic and mineral coastal wetland soils  

Microsoft Academic Search

Accurate measurement of soil moisture (?), bulk electrical conductivity (?b), and porewater electrical conductivity (?w) in the vadose zone is critical for a wide range of environmental monitoring applications. The use of combined dielectric probes allows for the automated collection of high-resolution, long-term data, however variation in probe response to different soil types can lead to unacceptably large measurement errors,

A. Mortl; R. Muñoz-Carpena; D. Kaplan; Y. Li

2011-01-01

370

Temperature effects on soil organic sulphur mineralization and elemental sulphur oxidation in subtropical soils of varying pH  

Microsoft Academic Search

The increasing sulphur (S) deficiency in soils of several parts of world has led to the use of fertilizer S, an important factor in enhancing the production and quality of crops. Very limited information is available on the use of elemental sulphur (S0) as a fertilizer, its oxidation into SO42- and transformation into organic S in semiarid subtropical soils. We

Milkha S. Aulakh; Randhir Sharma

1999-01-01

371

Volatilization, Plant Uptake and Mineralization of Nitrogen in Soils Treated with Sewage Sludge.  

National Technical Information Service (NTIS)

Field and laboratory experiments were conducted to quantify the amount of ammonia volatilization taking place after application of sewage sludge to the soil surface, evaluate the movement of nitrogen and plant uptake from soils treated with sewage sludge,...

L. E. Sommers C. F. Parker G. J. Meyers

1981-01-01

372

Warming-enhanced preferential microbial mineralization of humified boreal forest soil organic matter: Interpretation of soil profiles along a climate transect using laboratory incubations  

NASA Astrophysics Data System (ADS)

Humified soil organic matter storage in boreal forests is large, and its responses to warming over relatively long timescales is critical for predicting soil feedbacks to climate change. To derive information relevant across decades to centuries from manipulative short-term experiments, we conducted incubations of soils from two forested sites along the Newfoundland-Labrador Boreal Ecosystem Latitude Transect in eastern Canada and assessed linkages between incubation data and these sites' profile characteristics. The sites differ in mean annual temperature by 3.4°C, but vegetation and soil types are similar. Organic soils (Oe + Oa) were incubated for 120 days at 15°C and 20°C, with and without a replaced Oi subhorizon possessing a distinct ?13C signature. Laboratory warming induced significantly greater mineralization and leaching of humified SOM relative to replaced Oi, congruent with greater warming-induced increases in phenol oxidase activity relative to enzymes associated with labile C acquisition (percent increases of 101% versus 50%, respectively). These data suggest that warming can influence microbial communities and their enzymatic dynamics such that relative losses of humified SOM are disproportionately enhanced. This is consistent with stable isotopic, C:N, and radiocarbon profile differences between the two sites, which suggest a greater degree of microbial processing and greater relative losses of older SOC over the preceding decades at the warmer site, given our knowledge of organic inputs in these soils. This study is a first step toward linking the divergent timescales represented by soil profiles and laboratory manipulations, an important goal for biogeochemists assessing climate change impacts on SOM dynamics.

Li, Jianwei; Ziegler, Susan; Lane, Chad S.; Billings, Sharon A.

2012-06-01

373

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...

374

Estimating Soil Carbon, Nitrogen, and Phosphorus Mineralization from Short?Term Carbon Dioxide Respiration  

Microsoft Academic Search

The measurement of soil carbon dioxide (CO2) respiration is a means to gauge biological soil fertility. Test methods for respiration employed in the laboratory vary somewhat, and to date the equipment and labor required have limited more widespread adoption of such methodologies. A new method to measure soil respiration was tested along with the traditional alkali trap and titration method.

R. L. Haney; W. H. Brinton; Eric Evans

2008-01-01

375

Mobilities of heavy metals in surface waters: A field study of Mineral Branch, Tri-State Mining District  

SciTech Connect

A field study of the mobilities of heavy metals was done in the Tri-State Mining District near Joplin, Missouri. The processing of ores left many large tailings piles in this region which are predominantly chert, but contain minor amounts of carbonate and sulfide minerals. The residual sphalerite, galena, marcasite, and pyrite readily dissolve when exposed to surface waters, increasing the acidity and concentrations of Pb, Zn, and Cd in the streams of the region. Mineral Branch is a local stream that originates in and flows through a tailings field. Water and sediment (bed and suspended load) samples were collected and analyzed by ICP and XRD methods in order to determine trace and major element concentrations and mineral compositions, respectively. The solids are primarily chert and carbonates, with small amounts of crystalline and amorphous iron hydroxides and oxyhydroxides. Over the two mile study area, pH increases steadily downstream. As the pH rises, the dissolved heavy metal concentrations fall, some by an order of magnitude or more. It was also found that over 99% of the Pb, Zn,and Cd in the system is presents in the solids. Precipitation of carbonates or hydroxides does not adequately explain the concentration changes seen in the system. The adsorption of the metal species onto the carbonates and iron oxyhydroxides of the stream sediments as a function of pH is an additional controlling factor in the Mineral Branch.

Piechowski, M.F.; Carroll, S.A. (Univ. of Missouri, Columbia, MO (United States). Dept. of Geological Sciences)

1992-01-01

376

Changes in mineral nitrogen, soil organic matter fractions and microbial community level physiological profiles after application of digested pig slurry and compost from municipal organic wastes to burned soils  

Microsoft Academic Search

In this study, mineralization of digested pig slurry and compost from municipal organic wastes in burned soils was followed for 60 days. The effects of amendments on organic matter fractions and microbial community level physiological profiles (CLPP) were also investigated at the end of the incubation period. Soil from a forest 10 days after a fire had a greater basal

C. M. d. S. Cordovil; A. de Varennes; R. Pinto; R. C. Fernandes

2011-01-01

377

Rock magnetism investigation of highly magnetic soil developed on calcareous rock in Yun-Gui Plateau, China: Evidence for pedogenic magnetic minerals  

NASA Astrophysics Data System (ADS)

Detailed rock-magnetic and pedological analyses were conducted on the highly magnetic soils developed on calcareous rocks in the Yun-Gui Plateau of west-southern China in order to characterize its particular magnetic characteristics and pedogenesis of magnetic minerals. The magnetic concentration and mineralogy in the soils were determined by rock magnetism, powder X-ray diffraction and high resolution transmission electron microscope (HRTEM) with the energy dispersive X-ray analysis (EDX). The highly magnetic soils contained characteristics of highly weathered soils with a hue of 2.5YR, dominantly gibbsite-sesquioxide mineralogy, low organic matter content and high clay and free iron (Fed) content. Soil magnetic susceptibility (?lf) ranged from 2000 × 10- 8 to 6000 × 10- 8 m3 kg- 1; but in some layers it exceeded 6000 × 10- 8 or 6500 × 10- 8 m3 kg- 1, which was the highest magnetic soils so far found in the world. Magnetic measurements indicated that the frequency-dependent susceptibility (?lf - ?hf) ranged from 210 × 10- 8 to 720 × 10- 8 m3 kg- 1, suggesting the presence of abundant ultrafine magnetic grains. High-temperature magnetization (M-T) identified the magnetic carriers as maghemite and magnetite with a Curie point (Tc) at about 230 °C and 580 °C, respectively. XRD patterns showed that the gibbsite and hematite were main clay minerals in these highly weathered soils. HRTEM/EDX analysis showed that the pedogenic nano-scale magnetite/maghemite were responsible for the high magnetic susceptibility value of the soil. These particles varied from 20 to 100 nm in size and exhibited well crystalline nanoparticles. Magnetic enhancement in the soil profile was due to increased concentration of pedogenic superparamagnetic (SP) ferrimagnetic minerals upon pedogenesis. This study provided a strong evidence for the evolution of pedogenic magnetic minerals in the soils formed on non-magnetic parent materials. The identification in magnetic properties and mineralogy of the highly magnetic soils has significance for pedoenvironmental implications.

Lu, S. G.; Chen, D. J.; Wang, S. Y.; Liu, Y. D.

2012-02-01

378

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

2013-01-24

379

Enumeration and characterization of the soil microflora from hydrocarbon-contaminated soil sites able to mineralize polycyclic aromatic hydrocarbons (PAH)  

Microsoft Academic Search

The use of a plate screening technique allowed the direct isolation and quantification of polycylic aromatic hydrocarbon (PAH)-degrading bacteria from different soil sites. Bacteria that were able to grow on anthracene, phenanthrene, fluoranthene or pyrene as a sole carbon source were found with numbers between 103 and 105 colony-forming units (cfu)\\/g of soil dry weight, but only in samples that

M. Kästner; M. Breuer-Jammali; B. Mahro

1994-01-01

380

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

381

The impact of four ethylene oxide-propylene oxide block copolymers on the surface tension of dispersions of soils and minerals in water  

NASA Astrophysics Data System (ADS)

A comprehensive series of aqueous solutions of four ethylene oxide-propylene oxide-ethylene oxide block copolymers (EPE) of varying concentrations have been prepared. The EPE molecules are amphiphilic with the P blocks providing the hydrophobic segment of the molecules and the E blocks providing the hydrophilic parts. The surface tension of these solutions has been measured and compared with the surface tension of dispersions of soils (a clay soil and a sandy soil) and minerals (quartz-silica sand, bentonite and kaolinite) in the same aqueous solutions. It is observed that all the block copolymers reduce the surface tension of water; the extent to which it is reduced is determined by the surface activity of the EPE block copolymer, which in turn is related to the balance between the sizes of the P and E blocks. It is further observed that the in the presence of soil the surface tension increases as a result of block copolymer adsorption to the soil/water interface. The extent of adsorption appears to be related to the texture of the soil - the clay soil used in this investigation adsorbs more block copolymer than the sandy soil. In the presence of the mineral phases the surface tension reductions are variable. With bentonite the EPE block copolymers are completely adsorbed at low EPE concentrations as shown by surface tension values that are the same as those measured for pure water. Adsorption to kaolinite is limited and once the adsorption sites have been filled the surface tension of the aqueous phase is approaches the surface tension of the same solution without the presence of bentonite. On the other hand the silica sand is a poor adsorbent. Adsorption to the mineral phases is also dependent upon the relative hydrophobicity of the block copolymer. The more hydrophobic (as inferred by the critical micelle concentration) the copolymer the less readily it is adsorbed by the mineral phases. Thus relatively hydrophobic EPE block copolymers produce a relatively large decrease in surface tension and are less readily adsorbed by the soil and mineral phases. It is concluded that the presence of EPE block copolymers in soils can result in the drainage of soil water from the saturated zone as a result of surface tension reductions. However the extent of drainage is related to the surface activity/molecular composition of the EPE block copolymer; the textural class of the soil and the nature of the minerals present in the soil.

Hagenhoff, Kerstin; Dong, Jingfeng; Chowdhry, Babur; Torres, Luis; Leharne, Stephen

382

Influence of mineral characteristics and long-term arable and forest land use on stocks, composition, and stability of soil organic matter  

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 on organic carbon (OC) stocks 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. Topsoil samples of each soil type were taken from a deciduous forest and an adjacent arable site, which have been continuously used for more than 100 years. The sequentially extracted Na-pyrophosphate soluble OM fractions (OM(PY)), representing mineral associated OM, were analyzed on their OC and 14C content and characterized by infrared 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, a linear relationship was found between the stocks of OC and exchangeable Ca. Only for the near neutral arable topsoils, 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 the mineral phase and the content of exchangeable Ca. For the acidic forest topsoils, 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. The results indicate cation bridging of OM to mineral surfaces in near neutral arable soils and OM-crosslinking in acidic forest soil as important mechanisms for the stabilization of OM(PY).

Kaiser, Michael; Ellerbrock, Ruth H.; Wulf, Monika; Dultz, Stefan; Hierath, Christina; Michael, Sommer

2013-04-01

383

Carbon Mineralization and Labile Organic Carbon Pools in the Sandy Soils of a North Florida Watershed  

Microsoft Academic Search

The large pool of actively cycling carbon (C) held in soils is susceptible to release due to changes in landuse, management,\\u000a or climate. Yet, the amount and distribution of potentially mineralizable C present in soils of various types and the method\\u000a by which this soil C fraction can best be quantified, are not well established. The distribution of total organic

Mi-Youn Ahn; Andrew R. Zimmerman; Nick B. Comerford; James O. Sickman; Sabine Grunwald

2009-01-01

384

Non-Ligninolytic TNT Mineralization in Contaminated Soil by Phanerochaete chrysosporium  

Microsoft Academic Search

The explosive 2,4,6-trinitrotoluene (TNT) is widely used and results in widespread soil contamination. The white-rot fungus Phanerochaete chrysosporium has been shown to degrade TNT, using the peroxidase enzyme. In this study, we report peroxidase-independent degradation of TNT by non-ligninolytic P. chrysosporium. Significant disappearance of TNT from highly contaminated soil using P. chrysosporium has been observed. Soil highly contaminated with TNT

Sisir K. Dutta; Michelle M. Jackson; Li Hua Hou; David Powell; Henry E. Tatem

1998-01-01

385

Effect of mineral reactions on the hydraulic properties of unsaturated soils: Model development and application  

Microsoft Academic Search

The selective radius shift model was used to relate changes in mineral volume due to precipitation\\/dissolution reactions to changes in hydraulic properties affecting flow in porous media. The model accounts for (i) precipitation\\/dissolution taking place only in the water-filled part of the pore space and further that (ii) the amount of mineral precipitation\\/dissolution within a pore depends on the local

L. Wissmeier; D. A. Barry

2009-01-01

386

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

387

[A spectral unmixing method of estimating main minerals abundance of lunar soils].  

PubMed

Estimating minerals abundance from reflectance spectra is one of the fundamental goals of remote sensing lunar exploration, and the main difficulties are the complicated mixing law of minerals spectrum and spectral features being sensitive to several kinds of factors such as topography, particle size and roughness etc. A method based on spectral unmixing was put forward and tested in the present paper. Before spectra are unmixed the spectral continuum is removed for clarifying and strengthening spectral features. The absorption features and reflectance features (the upward curving parts of spectra between absorption features) are integrated for unmixing to improve the unmixing performance. The Hapke model was used to correct unmixing error due to nonlinear mixing of minerals spectra. Forty three mixed spectra of olivine, clinopyroxene, hypersthene and plagioclase were used to validate the above method. The four minerals abundance was estimated under the conditions of being unaware of endmember spectra used to mix, granularity and chemical composition of minerals. Residual error, abundance error and correlation coefficient between retrieved and true abundance were 5.0 Vol%, 14.4 Vol% and 0.92 respectively. The method and result of this paper could be referred in the lunar minerals mapping of imaging spectrometer data such as M3. PMID:23427563

Yan, Bo-Kun; Li, Jian-Zhong; Gan, Fu-Ping; Yang, Su-Ming; Wang, Run-Sheng

2012-12-01

388

Complementary Enzymes Activities in Organic Phosphorus Mineralization and Cycling by Phosphohydrolases in Soils  

Technology Transfer Automated Retrieval System (TEKTRAN)

Inorganic and organic phosphates react strongly with soil constituents, resulting in relatively low concentrations of soluble phosphates in the soil solution. Multiple competing reactions control the solution-phase concentration and the cycling of phosphorus-containing organic substrates and the re...

389

EFFECT OF SIMULATED ACID RAIN ON NITRIFICATION AND NITROGEN MINERALIZATION IN FOREST SOILS  

EPA Science Inventory

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 1.5-hour application of 1.2...

390

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

391

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

392

COMPARISON OF NITROGEN MINERALIZATION FOLLOWING US AND BRAZILIAN COVER CROPS FOR A SOUTHERN PIEDMONT SOIL  

Technology Transfer Automated Retrieval System (TEKTRAN)

Winter cover crops are essential in conservation tillage systems to protect soils from erosion and for improving soil productivity. Black oat (Avena strigosa Schreb) and oilseed radish (Raphanus sativus L.) could be useful cover crops in the Southeastern USA but successful adoption requires underst...

393

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...

394

Mineral magnetic properties of acid gleyed soils under oak and Corsican Pine  

Microsoft Academic Search

A comparison is made of the magnetic properties of acid gleyed soil